Tag Archives: Developers

New Consent and Bot Management features for Cloudflare Zaraz

Post Syndicated from Yo'av Moshe original https://blog.cloudflare.com/new-consent-and-bot-management-features-for-cloudflare-zaraz

Managing consent online can be challenging. After you’ve figured out the necessary regulations, you usually need to configure some Consent Management Platform (CMP) to load all third-party tools and scripts on your website in a way that respects these demands. Cloudflare Zaraz manages the loading of all of these third-party tools, so it was only natural that in April 2023 we announced the Cloudflare Zaraz CMP: the simplest way to manage consent in a way that seamlessly integrates with your third-party tools manager.

As more and more third-party tool vendors are required to handle consent properly, our CMP has evolved to integrate with these new technologies and standardization efforts. Today, we’re happy to announce that the Cloudflare Zaraz CMP is now compatible with the Interactive Advertising Bureau Transparency and Consent Framework (IAB TCF) requirements, and fully supports Google’s Consent Mode v2 signals. Separately, we’ve taken efforts to improve the way Cloudflare Zaraz handles traffic coming from online bots.

IAB TCF Compatibility

Earlier this year, Google announced that websites that would like to use AdSense and other advertising solutions in the European Economic Area (EEA), the UK, and Switzerland, will be required to use a CMP that is approved by IAB Europe, an association for digital marketing and advertising. Their Transparency and Consent Framework sets guidelines for how CMPs should operate. Since March 2024, the Cloudflare Zaraz CMP is compliant with these guidelines, and Zaraz users in Europe can use Google’s advertising products without any restrictions.

Since the IAB TCF requirements can make the consent modal a little complex for users, we have made this compliance mode an opt-in feature. See the official documentation for information on how to enable it.

Google Consent Mode v2

Another new requirement from Google was the need to send “Consent Signals”. These signals are part of what is also known as “Consent Mode”, and later, Consent Mode v2. Together with each event sent to Google Analytics and Google Ads, they tell the Google servers about the consent status of the current visitor – did they agree to have their data used for personalized advertising? Did they accept cookies? These and other questions are answered by Consent Mode v2, telling the Google servers how to treat the data it receives.

Consent Mode v2 usually requires setting two values for each consent category – a default value and an updated one. The default value represents the consent status (granted or denied) a certain category (e.g. using cookies) has before the user has submitted their personal preferences. Usually, and especially within the EU, the default value would be `denied`. Once the user submits their preferences, Consent Mode v2 sends an additional “updated” value that represents the choice the user made.

Implementing Consent Mode v2 is quick and easy with Cloudflare Zaraz, although the specific implementation depends on your CMP. Examples, including integration with the Cloudflare Zaraz CMP, are available in our official documentation.

We believe that better standardization around online consent benefits everyone, and we are glad to be working on tools that respect users’ privacy and improve online user experience.

Bot Management

We also recently integrated better Bot Management support within Cloudflare Zaraz. You often want crawlers to be able to access your website, but you don’t want them to trigger your analytics and conversion pixels. Using the Bot Management feature in the Cloudflare Zaraz Settings page allows you to fine tune which requests will make it to Cloudflare Zaraz and which ones will be skipped. Since Zaraz pricing is based on the total number of Zaraz Events, this can also be useful if you want more control over your Cloudflare Zaraz costs, ensuring you will not be paying for events triggered by bots. Like all other Cloudflare Zaraz features, these new features are also available to users on all plans, including the free plan. For us, it is part of making sure that everyone can benefit from a faster, safer, and more private way to manage third parties online. If you haven’t started using Cloudflare Zaraz already, now is a great time. Go to the Cloudflare dashboard and set it up in just a few clicks.

Using Fortran on Cloudflare Workers

Post Syndicated from John Graham-Cumming original https://blog.cloudflare.com/using-fortran-on-cloudflare-workers

In April 2020, we blogged about how to get COBOL running on Cloudflare Workers by compiling to WebAssembly. The ecosystem around WebAssembly has grown significantly since then, and it has become a solid foundation for all types of projects, be they client-side or server-side.

As WebAssembly support has grown, more and more languages are able to compile to WebAssembly for execution on servers and in browsers. As Cloudflare Workers uses the V8 engine and supports WebAssembly natively, we’re able to support languages that compile to WebAssembly on the platform.

Recently, work on LLVM has enabled Fortran to compile to WebAssembly. So, today, we’re writing about running Fortran code on Cloudflare Workers.

Before we dive into how to do this, here’s a little demonstration of number recognition in Fortran. Draw a number from 0 to 9 and Fortran code running somewhere on Cloudflare’s network will predict the number you drew.

Try yourself on handwritten-digit-classifier.fortran.demos.cloudflare.com.

This is taken from the wonderful Fortran on WebAssembly post but instead of running client-side, the Fortran code is running on Cloudflare Workers. Read on to find out how you can use Fortran on Cloudflare Workers and how that demonstration works.

Wait, Fortran? No one uses that!

Not so fast! Or rather, actually pretty darn fast if you’re doing a lot of numerical programming or have scientific data to work with. Fortran (originally FORmula TRANslator) is very well suited for scientific workloads because of its native functionality for things like arithmetic and handling large arrays and matrices.

If you look at the ranking of the fastest supercomputers in the world you’ll discover that the measurement of “fast” is based on these supercomputers running a piece of software called LINPACK that was originally written in Fortran. LINPACK is designed to help with problems solvable using linear algebra.

The LINPACK benchmarks use LINPACK to solve an n x n system of linear equations using matrix operations and, in doing so, determine how fast supercomputers are. The code is available in Fortran, C and Java.

A related Fortran package, BLAS, also does linear algebra and forms the basis of the number identifying code above. But other Fortran packages are still relevant. Back in 2017, NASA ran a competition to make FUN3D (used to perform calculations of airflow over simulated aircraft). FUN3D is written in Fortran.

So, although Fortran (or at the time FORTRAN) first came to life in 1957, it’s alive and well and being used widely for scientific applications (there’s even Fortran for CUDA). One particular application left Earth 20 years after Fortran was born: Voyager. The Voyager probes use a combination of assembly language and Fortran to keep chugging along.

But back in our solar system, and back on Region: Earth, you can now use Fortran on Cloudflare Workers. Here’s how.

How to get your Fortran code running on Cloudflare Workers

To make it easy to run your Fortran code on Cloudflare Workers, we created a tool called Fortiche (translates to smart in French). It uses Flang and Emscripten under the hood.

Flang is a frontend in LLVM and, if you read the Fortran on WebAssembly blog post, we currently have to patch LLVM to work around a few issues.

Emscripten is used to compile LLVM output and produce code that is compatible with Cloudflare Workers.

This is all packaged in the Fortiche Docker image. Let’s see a simple example.


SUBROUTINE add(a, b, res)
    INTEGER, INTENT(IN) :: a, b

    res = a + b

Here we defined a subroutine called add that takes a and b, sums them together and places the result in res.

Compile with Fortiche:

docker run -v $PWD:/input -v $PWD/output:/output xtuc/fortiche --export-func=add add.f90

Passing --export-func=add to Fortiche makes the Fortran add subroutine available to JavaScript.

The output folder contains the compiled WebAssembly module and JavaScript from Emscripten, and a JavaScript endpoint generated by Fortiche:

$ ls -lh ./output
total 84K
-rw-r--r-- 1 root root 392 avril 22 12:00 index.mjs
-rw-r--r-- 1 root root 27K avril 22 12:00 out.mjs
-rwxr-xr-x 1 root root 49K avril 22 12:00 out.wasm

And finally the Cloudflare Worker:

// Import what Fortiche generated
import {load} from "../output/index.mjs"

export default {
    async fetch(request: Request): Promise<Response> {
        // Load the Fortran program
        const program = await load();

        // Allocate space in memory for the arguments and result
        const aPtr = program.malloc(4);
        const bPtr = program.malloc(4);
        const outPtr = program.malloc(4);

        // Set argument values
        program.HEAP32[aPtr / 4] = 123;
        program.HEAP32[bPtr / 4] = 321;

        // Run the Fortran add subroutine
        program.add(aPtr, bPtr, outPtr);

        // Read the result
        const res = program.HEAP32[outPtr / 4];

        // Free everything

        return Response.json({ res });

Interestingly, the values we pass to Fortran are all pointers, therefore we have to allocate space for each argument and result (the Fortran integer type is four bytes wide), and pass the pointers to the `add` subroutine.

Running the Worker gives us the right answer:

$ curl https://fortran-add.cfdemos.workers.dev


You can find the full example here.

Handwritten digit classifier

This example is taken from https://gws.phd/posts/fortran_wasm/#mnist. It relies on the BLAS library, which is available in Fortiche with the flag: --with-BLAS-3-12-0.

Note that the LAPACK library is also available in Fortiche with the flag: --with-LAPACK-3-12-0.

You can try on https://handwritten-digit-classifier.fortran.demos.cloudflare.com and find the source code here.

Let us know what you write using Fortran and Cloudflare Workers!

Meta Llama 3 available on Cloudflare Workers AI

Post Syndicated from Michelle Chen original https://blog.cloudflare.com/meta-llama-3-available-on-cloudflare-workers-ai

Workers AI

Workers AI’s initial launch in beta included support for Llama 2, as it was one of the most requested open source models from the developer community. Since that initial launch, we’ve seen developers build all kinds of innovative applications including knowledge sharing chatbots, creative content generation, and automation for various workflows.  

At Cloudflare, we know developers want simplicity and flexibility, with the ability to build with multiple AI models while optimizing for accuracy, performance, and cost, among other factors. Our goal is to make it as easy as possible for developers to use their models of choice without having to worry about the complexities of hosting or deploying models.

As soon as we learned about the development of Llama 3 from our partners at Meta, we knew developers would want to start building with it as quickly as possible. Workers AI’s serverless inference platform makes it extremely easy and cost effective to start using the latest large language models (LLMs). Meta’s commitment to developing and growing an open AI-ecosystem makes it possible for customers of all sizes to use AI at scale in production. All it takes is a few lines of code to run inference to Llama 3:

export interface Env {
  // If you set another name in wrangler.toml as the value for 'binding',
  // replace "AI" with the variable name you defined.
  AI: any;

export default {
  async fetch(request: Request, env: Env) {
    const response = await env.AI.run('@cf/meta/llama-3-8b-instruct', {
        messages: [
{role: "user", content: "What is the origin of the phrase Hello, World?"}

    return new Response(JSON.stringify(response));

Built with Meta Llama 3

Llama 3 offers leading performance on a wide range of industry benchmarks. You can learn more about the architecture and improvements on Meta’s blog post. Cloudflare Workers AI supports Llama 3 8B, including the instruction fine-tuned model.

Meta’s testing shows that Llama 3 is the most advanced open LLM today on evaluation benchmarks such as MMLU, GPQA, HumanEval, GSM-8K, and MATH. Llama 3 was trained on an increased number of training tokens (15T), allowing the model to have a better grasp on language intricacies. Larger context windows doubles the capacity of Llama 2, and allows the model to better understand lengthy passages with rich contextual data. Although the model supports a context window of 8k, we currently only support 2.8k but are looking to support 8k context windows through quantized models soon. As well, the new model introduces an efficient new tiktoken-based tokenizer with a vocabulary of 128k tokens, encoding more characters per token, and achieving better performance on English and multilingual benchmarks. This means that there are 4 times as many parameters in the embedding and output layers, making the model larger than the previous Llama 2 generation of models.

Under the hood, Llama 3 uses grouped-query attention (GQA), which improves inference efficiency for longer sequences and also renders their 8B model architecturally equivalent to Mistral-7B. For tokenization, it uses byte-level byte-pair encoding (BPE), similar to OpenAI’s GPT tokenizers. This allows tokens to represent any arbitrary byte sequence — even those without a valid utf-8 encoding. This makes the end-to-end model much more flexible in its representation of language, and leads to improved performance.

Along with the base Llama 3 models, Meta has released a suite of offerings with tools such as Llama Guard 2, Code Shield, and CyberSec Eval 2, which we are hoping to release on our Workers AI platform shortly.

Try it out now

Meta Llama 3 8B is available in the Workers AI Model Catalog today! Check out the documentation here and as always if you want to share your experiences or learn more, join us in the Developer Discord.

Developer Week 2024 wrap-up

Post Syndicated from Phillip Jones original https://blog.cloudflare.com/developer-week-2024-wrap-up

Developer Week 2024 has officially come to a close. Each day last week, we shipped new products and functionality geared towards giving developers the components they need to build full-stack applications on Cloudflare.

Even though Developer Week is now over, we are continuing to innovate with the over two million developers who build on our platform. Building a platform is only as exciting as seeing what developers build on it. Before we dive into a recap of the announcements, to send off the week, we wanted to share how a couple of companies are using Cloudflare to power their applications:

We have been using Workers for image delivery using R2 and have been able to maintain stable operations for a year after implementation. The speed of deployment and the flexibility of detailed configurations have greatly reduced the time and effort required for traditional server management. In particular, we have seen a noticeable cost savings and are deeply appreciative of the support we have received from Cloudflare Workers.
FAN Communications

Milkshake helps creators, influencers, and business owners create engaging web pages directly from their phone, to simply and creatively promote their projects and passions. Cloudflare has helped us migrate data quickly and affordably with R2. We use Workers as a routing layer between our users’ websites and their images and assets, and to build a personalized analytics offering affordably. Cloudflare’s innovations have consistently allowed us to run infrastructure at a fraction of the cost of other developer platforms and we have been eagerly awaiting updates to D1 and Queues to sustainably scale Milkshake as the product continues to grow.

In case you missed anything, here’s a quick recap of the announcements and in-depth technical explorations that went out last week:

Summary of announcements


Announcement Summary
Making state easy with D1 GA, Hyperdrive, Queues and Workers Analytics Engine updates A core part of any full-stack application is storing and persisting data! We kicked off the week with announcements that help developers build stateful applications on top of Cloudflare, including making D1, Cloudflare’s SQL database and Hyperdrive, our database accelerating service, generally available.
Building D1: a Global Database D1, Cloudflare’s SQL database, is now generally available. With new support for 10GB databases, data export, and enhanced query debugging, we empower developers to build production-ready applications with D1 to meet all their relational SQL needs. To support Workers in global applications, we’re sharing a sneak peek of our design and API for D1 global read replication to demonstrate how developers scale their workloads with D1.
Why Workers environment variables contain live objects Bindings don’t just reduce boilerplate. They are a core design feature of the Workers platform which simultaneously improve developer experience and application security in several ways. Usually these two goals are in opposition to each other, but bindings elegantly solve for both at the same time.


Announcement Summary
Leveling up Workers AI: General Availability and more new capabilities We made a series of AI-related announcements, including Workers AI, Cloudflare’s inference platform becoming GA, support for fine-tuned models with LoRAs, one-click deploys from HuggingFace, Python support for Cloudflare Workers, and more.
Running fine-tuned models on Workers AI with LoRAs Workers AI now supports fine-tuned models using LoRAs. But what is a LoRA and how does it work? In this post, we dive into fine-tuning, LoRAs and even some math to share the details of how it all works under the hood.
Bringing Python to Workers using Pyodide and WebAssembly We introduced Python support for Cloudflare Workers, now in open beta. We’ve revamped our systems to support Python, from the Workers runtime itself to the way Workers are deployed to Cloudflare’s network. Learn about a Python Worker’s lifecycle, Pyodide, dynamic linking, and memory snapshots in this post.


Announcement Summary
R2 adds event notifications, support for migrations from Google Cloud Storage, and an infrequent access storage tier We announced three new features for Cloudflare R2: event notifications, support for migrations from Google Cloud Storage, and an infrequent access storage tier.
Data Anywhere with Pipelines, Event Notifications, and Workflows We’re making it easier to build scalable, reliable, data-driven applications on top of our global network, and so we announced a new Event Notifications framework; our take on durable execution, Workflows; and an upcoming streaming ingestion service, Pipelines.
Improving Cloudflare Workers and D1 developer experience with Prisma ORM Together, Cloudflare and Prisma make it easier than ever to deploy globally available apps with a focus on developer experience. To further that goal, Prisma ORM now natively supports Cloudflare Workers and D1 in Preview. With version 5.12.0 of Prisma ORM you can now interact with your data stored in D1 from your Cloudflare Workers with the convenience of the Prisma Client API. Learn more and try it out now.
How Picsart leverages Cloudflare’s Developer Platform to build globally performant services Picsart, one of the world’s largest digital creation platforms, encountered performance challenges in catering to its global audience. Adopting Cloudflare’s global-by-default Developer Platform emerged as the optimal solution, empowering Picsart to enhance performance and scalability substantially.


Announcement Summary
Announcing Pages support for monorepos, wrangler.toml, database integrations and more! We launched four improvements to Pages that bring functionality previously restricted to Workers, with the goal of unifying the development experience between the two. Support for monorepos, wrangler.toml, new additions to Next.js support and database integrations!
New tools for production safety — Gradual Deployments, Stack Traces, Rate Limiting, and API SDKs Production readiness isn’t just about scale and reliability of the services you build with. We announced five updates that put more power in your hands – Gradual Deployments, Source mapped stack traces in Tail Workers, a new Rate Limiting API, brand-new API SDKs, and updates to Durable Objects – each built with mission-critical production services in mind.
What’s new with Cloudflare Media: updates for Calls, Stream, and Images With Cloudflare Calls in open beta, you can build real-time, serverless video and audio applications. Cloudflare Stream lets your viewers instantly clip from ongoing streams. Finally, Cloudflare Images now supports automatic face cropping and has an upload widget that lets you easily integrate into your application.
Cloudflare Calls: millions of cascading trees all the way down Cloudflare Calls is a serverless SFU and TURN service running at Cloudflare’s edge. It’s now in open beta and costs $0.05/ real-time GB. It’s 100% anycast WebRTC.


Announcement Summary
Browser Rendering API GA, rolling out Cloudflare Snippets, SWR, and bringing Workers for Platforms to all users Browser Rendering API is now available to all paid Workers customers with improved session management.
Cloudflare acquires Baselime to expand serverless application observability capabilities We announced that Cloudflare has acquired Baselime, a serverless observability company.
Cloudflare acquires PartyKit to allow developers to build real-time multi-user applications We announced that PartyKit, a trailblazer in enabling developers to craft ambitious real-time, collaborative, multiplayer applications, is now a part of Cloudflare. This acquisition marks a significant milestone in our journey to redefine the boundaries of serverless computing, making it more dynamic, interactive, and, importantly, stateful.
Blazing fast development with full-stack frameworks and Cloudflare Full-stack web development with Cloudflare is now faster and easier! You can now use your framework’s development server while accessing D1 databases, R2 object stores, AI models, and more. Iterate locally in milliseconds to build sophisticated web apps that run on Cloudflare. Let’s dev together!
We’ve added JavaScript-native RPC to Cloudflare Workers Cloudflare Workers now features a built-in RPC (Remote Procedure Call) system for use in Worker-to-Worker and Worker-to-Durable Object communication, with absolutely minimal boilerplate. We’ve designed an RPC system so expressive that calling a remote service can feel like using a library.
Community Update: empowering startups building on Cloudflare and creating an inclusive community We closed out Developer Week by sharing updates on our Workers Launchpad program, our latest Developer Challenge, and the work we’re doing to ensure our community spaces – like our Discord and Community forums – are safe and inclusive for all developers.

Continue the conversation

Thank you for being a part of Developer Week! Want to continue the conversation and share what you’re building? Join us on Discord. To get started building on Workers, check out our developer documentation.

Cloudflare acquires Baselime to expand serverless application observability capabilities

Post Syndicated from Boris Tane original https://blog.cloudflare.com/cloudflare-acquires-baselime-expands-observability-capabilities

Today, we’re thrilled to announce that Cloudflare has acquired Baselime.

The cloud is changing. Just a few years ago, serverless functions were revolutionary. Today, entire applications are built on serverless architectures, from compute to databases, storage, queues, etc. — with Cloudflare leading the way in making it easier than ever for developers to build, without having to think about their architecture. And while the adoption of serverless has made it simple for developers to run fast, it has also made one of the most difficult problems in software even harder: how the heck do you unravel the behavior of distributed systems?

When I started Baselime 2 years ago, our goal was simple: enable every developer to build, ship, and learn from their serverless applications such that they can resolve issues before they become problems.

Since then, we built an observability platform that enables developers to understand the behaviour of their cloud applications. It’s designed for high cardinality and dimensionality data, from logs to distributed tracing with OpenTelemetry. With this data, we automatically surface insights from your applications, and enable you to quickly detect, troubleshoot, and resolve issues in production.

In parallel, Cloudflare has been busy the past few years building the next frontier of cloud computing: the connectivity cloud. The team is building primitives that enable developers to build applications with a completely new set of paradigms, from Workers to D1, R2, Queues, KV, Durable Objects, AI, and all the other services available on the Cloudflare Developers Platform.

This synergy makes Cloudflare the perfect home for Baselime. Our core mission has always been to simplify and innovate around observability for the future of the cloud, and Cloudflare’s ecosystem offers the ideal ground to further this cause. With Cloudflare, we’re positioned to deeply integrate into a platform that tens of thousands of developers trust and use daily, enabling them to quickly build, ship, and troubleshoot applications. We believe that every Worker, Queue, KV, Durable Object, AI call, etc. should have built-in observability by default.

That’s why we’re incredibly excited about the potential of what we can build together and the impact it will have on developers around the world.

To give you a preview into what’s ahead, I wanted to dive deeper into the 3 core concepts we followed while building Baselime.

High Cardinality and Dimensionality

Cardinality and dimensionality are best described using examples. Imagine you’re playing a board game with a deck of cards. High cardinality is like playing a game where every card is a unique character, making it hard to remember or match them. And high dimensionality is like each card has tons of details like strength, speed, magic, aura, etc., making the game’s strategy complex because there’s so much to consider.

This also applies to the data your application emits. For example, when you log an HTTP request that makes database calls.

  • High cardinality means that your logs can have a unique userId or requestId (which can take millions of distinct values). Those are high cardinality fields.
  • High dimensionality means that your logs can have thousands of possible fields. You can record each HTTP header of your request and the details of each database call. Any log can be a key-value object with thousands of individual keys.

The ability to query on high cardinality and dimensionality fields is key to modern observability. You can surface all errors or requests for a specific user, compute the duration of each of those requests, and group by location. You can answer all of those questions with a single tool.


OpenTelemetry provides a common set of tools, APIs, SDKs, and standards for instrumenting applications. It is a game-changer for debugging and understanding cloud applications. You get to see the big picture: how fast your HTTP APIs are, which routes are experiencing the most errors, or which database queries are slowest. You can also get into the details by following the path of a single request or user across your entire application.

Baselime is OpenTelemetry native, and it is built from the ground up to leverage OpenTelemetry data. To support this, we built a set of OpenTelemetry SDKs compatible with several serverless runtimes.

Cloudflare is building the cloud of tomorrow and has developed workerd, a modern JavaScript runtime for Workers. With Cloudflare, we are considering embedding OpenTelemetry directly in the Workers’ runtime. That’s one more reason we’re excited to grow further at Cloudflare, enabling more developers to understand their applications, even in the most unconventional scenarios.

Developer Experience

Observability without action is just storage. I have seen too many developers pay for tools to store logs and metrics they never use, and the key reason is how opaque these tools are.

The crux of the issue in modern observability isn’t the technology itself, but rather the developer experience. Many tools are complex, with a significant learning curve. This friction reduces the speed at which developers can identify and resolve issues, ultimately affecting the reliability of their applications. Improving developer experience is key to unlocking the full potential of observability.

We built Baselime to be an exploratory solution that surfaces insights to you rather than requiring you to dig for them. For example, we notify you in real time when errors are discovered in your application, based on your logs and traces. You can quickly search through all of your data with full-text search, or using our powerful query engine, which makes it easy to correlate logs and traces for increased visibility, or ask our AI debugging assistant for insights on the issue you’re investigating.

It is always possible to go from one insight to another, asking questions about the state of your app iteratively until you get to the root cause of the issue you are troubleshooting.

Cloudflare has always prioritised the developer experience of its developer platform, especially with Wrangler, and we are convinced it’s the right place to solve the developer experience problem of observability.

What’s next?

Over the next few months, we’ll work to bring the core of Baselime into the Cloudflare ecosystem, starting with OpenTelemetry, real-time error tracking, and all the developer experience capabilities that make a great observability solution. We will keep building and improving observability for applications deployed outside Cloudflare because we understand that observability should work across providers.

But we don’t want to stop there. We want to push the boundaries of what modern observability looks like. For instance, directly connecting to your codebase and correlating insights from your logs and traces to functions and classes in your codebase. We also want to enable more AI capabilities beyond our debugging assistant. We want to deeply integrate with your repositories such that you can go from an error in your logs and traces to a Pull Request in your codebase within minutes.

We also want to enable everyone building on top of Large Language Models to do all your LLM observability directly within Cloudflare, such that you can optimise your prompts, improve latencies and reduce error rates directly within your cloud provider. These are just a handful of capabilities we can now build with the support of the Cloudflare platform.


We are incredibly thankful to our community for its continued support, from day 0 to today. With your continuous feedback, you’ve helped us build something we’re incredibly proud of.

To all the developers currently using Baselime, you’ll be able to keep using the product and will receive ongoing support. Also, we are now making all the paid Baselime features completely free.

Baselime products remain available to sign up for while we work on integrating with the Cloudflare platform. We anticipate sunsetting the Baselime products towards the end of 2024 when you will be able to observe all of your applications within the Cloudflare dashboard. If you’re interested in staying up-to-date on our work with Cloudflare, we will release a signup link in the coming weeks!

We are looking forward to continuing to innovate with you.

Blazing fast development with full-stack frameworks and Cloudflare

Post Syndicated from Igor Minar original https://blog.cloudflare.com/blazing-fast-development-with-full-stack-frameworks-and-cloudflare

Hello web developers! Last year we released a slew of improvements that made deploying web applications on Cloudflare much easier, and in response we’ve seen a large growth of Astro, Next.js, Nuxt, Qwik, Remix, SolidStart, SvelteKit, and other web apps hosted on Cloudflare. Today we are announcing major improvements to our integration with these web frameworks that makes it easier to develop sophisticated applications that use our D1 SQL database, R2 object store, AI models, and other powerful features of Cloudflare’s developer platform.

In the past, if you wanted to develop a web framework-powered application with D1 and run it locally, you’d have to build a production build of your application, and then run it locally using `wrangler pages dev`. While this worked, each of your code iterations would take seconds, or tens of seconds for big applications. Iterating using production builds is simply too slow, pulls you out of the flow, and doesn’t allow you to take advantage of all the DX optimizations that framework authors have put a lot of hard work into. This is changing today!

Our goal is to integrate with web frameworks in the most natural way possible, without developers having to learn and adopt significant workflow changes or custom APIs when deploying their app to Cloudflare. Whether you are a Next.js developer, a Nuxt developer, or prefer another framework, you can now keep on using the blazing fast local development workflow familiar to you, and ship your application on Cloudflare.

All full-stack web frameworks come with a local development server (dev server) that is custom tailored to the framework and often provides an excellent development experience, with only one exception — they don’t natively support some important features of Cloudflare’s development platform, especially our storage solutions.

So up until recently, you had to make a tough choice. You could use the framework-specific dev server to develop your application, but forgo access to many of Cloudflare’s features. Alternatively, you could take full advantage of Cloudflare’s platform including various resources like D1 or R2, but you would have to give up using the framework specific developer tooling. In that case, your iteration cycle would slow down, and it would take seconds rather than milliseconds for you to see results of your code changes in the browser. But not anymore! Let’s take a look.

Let’s build an application

Let’s create a new application using C3 — our create-cloudflare CLI. We could use any npm client of our choice (pnpm anyone?!?), but to keep things simple in this post, we’ll stick with the default npm client. To get started, just run:

$ npm create cloudflare@latest

Provide a name for your app, or stick with the randomly generated one. Then select the “Website or web app” category, and pick a full-stack framework of your choice. We support many: Astro, Next.js, Nuxt, Qwik, Remix, SolidStart, and SvelteKit.

Since C3 delegates the application scaffolding to the latest version of the framework-specific CLI, you will scaffold the application exactly as the framework authors intended without missing out on any of the framework features or options. C3 then adds to your application everything necessary for integrating and deploying to Cloudflare so that you don’t have to configure it yourself.

With our application scaffolded, let’s get it to display a list of products stored in a database with just a few steps. First, we add the configuration for our database to our wrangler.toml config file:

binding = "DB"
database_name = "blog-products-db"
database_id = "XXXXXXXXXXXXXXXX"

Yes, that’s right! You can now configure your bound resources via the wrangler.toml file, even for full-stack apps deployed to Pages. We’ll share much more about configuration enhancements to Pages in a dedicated announcement.

Now let’s create a simple schema.sql file representing our database schema:

CREATE TABLE products(product_id INTEGER PRIMARY KEY, name TEXT, price INTEGER);
INSERT INTO products (product_id, name, price) VALUES (1, 'Apple', 250), (2, 'Banana', 100), (3, 'Cherry', 375);

And initialize our database:

$ npx wrangler d1 execute blog-products-db --local --file schema.sql

Notice that we used the –local flag of wrangler d1 execute to apply the changes to our local D1 database. This is the database that our dev server will connect to.

Next, if you use TypeScript, let TypeScript know about your database by running:

$ npm run build-cf-types

This command is preconfigured for all full-stack applications created via C3 and executes wrangler types to update the interface of Cloudflare’s environment containing all configured bindings.

We can now start the dev server provided by your framework via a handy shortcut:

$ npm run dev

This shortcut will start your framework’s dev server, whether it’s powered by next dev, nitro, or vite.

Now to access our database and list the products, we can now use a framework specific approach. For example, in a Next.js application that uses the App router, we could update app/api/hello/route.ts with the following:

const db = getRequestContext().env.DB;
 const productsResults = await db.prepare('SELECT * FROM products').all();
 return Response.json(productsResults.results);

Or in a Nuxt application, we can create a server/api/hello.ts file and populate it with:

export default defineEventHandler(async ({ context }) => {
   const db = context.cloudflare.env.DB;
   const productsResults = await db.prepare('SELECT * FROM products').all();
   return productsResults.results;

Assuming that the framework dev server is running on port 3000, you can test the new API route in either framework by navigating to http://localhost:3000/api/hello. For simplicity, we picked API routes in these examples, but the same applies to any UI-generating routes as well.

Each web framework has its own way to define routes and pass contextual information about the request throughout the application, so how you access your databases, object stores, and other resources will depend on your framework. You can read our updated full-stack framework guides to learn more:

Now that you know how to access Cloudflare’s resources in the framework of your choice, everything else you know about your framework remains the same. You can now develop your application locally, using the development server optimized for your framework, which often includes support for hot module replacement (HMR), custom dev tools, enhanced debugging support and more, all while still benefiting from Cloudflare-specific APIs and features. Win-win!

What has actually changed to enable these development workflows?

To decrease the development latency and preserve the custom framework-specific experiences, we needed to enable web frameworks and their dev servers to integrate with wrangler and miniflare in a seamless, almost invisible way.

Miniflare is a key component in this puzzle. It is our local simulator for Cloudflare-specific resources, which is powered by workerd, our JavaScript (JS) runtime. By relying on workerd, we ensure that Cloudflare’s JavaScript APIs run locally in a way that faithfully simulates our production environment. The trouble is that framework dev servers already rely on Node.js to run the application, so bringing another JS runtime into the mix breaks many assumptions in how these dev servers have been architected.

Our team however came up with an interesting approach to bridging the gap between these two JS runtimes. We call it the getPlatformProxy() API, which is now part of wrangler and is super-powered by miniflare’s magic proxy. This API exposes a JS proxy object that behaves just like the usual Workers env object containing all bound resources. The proxy object enables code from Node.js to transparently invoke JavaScript code running in workerd, as well access Cloudflare-specific runtime APIs.

With this bridge between the Node.js and workerd runtimes, your application can now access Cloudflare simulators for D1, R2, KV and other storage solutions directly while running in a dev server powered by Node.js. Or you could even write an Node.js script to do the same:

 import {getPlatformProxy} from 'wrangler';

 const {env} = getPlatformProxy();
 const db = env.DB;

 // Now let’s execute a DB query that runs in a local D1 db
 // powered by miniflare/workerd and access the result from Node.js
 const productsResults = await db.prepare('SELECT * FROM products').all();

With the getPlatformProxy() API available, the remaining work was all about updating all framework adapters, plugins, and in some cases frameworks themselves to make use of this API. We are grateful for the support we received from framework teams on this journey, especially Alex from Astro, pi0 from Nuxt, Pedro from Remix, Ryan from Solid, Ben and Rich from Svelte, and our collaborator on the next-on-pages project, James Anderson.

Future improvements to development workflows with Vite

While the getPlatformProxy() API is a good solution for many scenarios, we can do better. If we could run the entire application in our JS runtime rather than Node.js, we could even more faithfully simulate the production environment and reduce developer friction and production surprises.

In the ideal world, we’d like you to develop against the same runtime that you deploy to in production, and this can only be achieved by integrating workerd directly into the dev servers of all frameworks, which is not a small feat considering the number of frameworks out there and the differences between them.

We however got a bit lucky. As we kicked off this effort, we quickly realized that Vite, a popular dev server used by many full-stack frameworks, was gaining increasingly greater adoption. In fact, Remix switched over to Vite just recently and confirmed the popularity of Vite as the common foundation for web development today.

If Vite had first-class support for running a full-stack application in an alternative JavaScript runtime, we could enable anyone using Vite to develop their applications locally with complete access to the Cloudflare developer platform. No more framework specific custom integrations and workarounds — all the features of a full-stack framework, Vite, and Cloudflare accessible to all developers.

Sounds too good to be true? Maybe. We are very stoked to be working with the Vite team on the Vite environments proposal, which could enable just that. This proposal is still evolving, so stay tuned for updates.

What will you build today?

We aim to make Cloudflare the best development platform for web developers. Making it quick and easy to develop your application with frameworks and tools you are already familiar with is a big part of our story. Start your journey with us by running a single command:

$ npm create cloudflare@latest

We’ve added JavaScript-native RPC to Cloudflare Workers

Post Syndicated from Kenton Varda original https://blog.cloudflare.com/javascript-native-rpc

Cloudflare Workers now features a built-in RPC (Remote Procedure Call) system enabling seamless Worker-to-Worker and Worker-to-Durable Object communication, with almost no boilerplate. You just define a class:

export class MyService extends WorkerEntrypoint {
  sum(a, b) {
    return a + b;

And then you call it:

let three = await env.MY_SERVICE.sum(1, 2);

No schemas. No routers. Just define methods of a class. Then call them. That’s it.

But that’s not it

This isn’t just any old RPC. We’ve designed an RPC system so expressive that calling a remote service can feel like using a library – without any need to actually import a library! This is important not just for ease of use, but also security: fewer dependencies means fewer critical security updates and less exposure to supply-chain attacks.

To this end, here are some of the features of Workers RPC:

  • For starters, you can pass Structured Clonable types as the params or return value of an RPC. (That means that, unlike JSON, Dates just work, and you can even have cycles.)
  • You can additionally pass functions in the params or return value of other functions. When the other side calls the function you passed to it, they make a new RPC back to you.
  • Similarly, you can pass objects with methods. Method calls become further RPCs.
  • RPC to another Worker (over a Service Binding) usually does not even cross a network. In fact, the other Worker usually runs in the very same thread as the caller, reducing latency to zero. Performance-wise, it’s almost as fast as an actual function call.
  • When RPC does cross a network (e.g. to a Durable Object), you can invoke a method and then speculatively invoke further methods on the result in a single network round trip.
  • You can send a byte stream over RPC, and the system will automatically stream the bytes with proper flow control.
  • All of this is secure, based on the object-capability model.
  • The protocol and implementation are fully open source as part of workerd.

Workers RPC is a JavaScript-native RPC system. Under the hood, it is built on Cap’n Proto. However, unlike Cap’n Proto, Workers RPC does not require you to write a schema. (Of course, you can use TypeScript if you like, and we provide tools to help with this.)

In general, Workers RPC is designed to “just work” using idiomatic JavaScript code, so you shouldn’t have to spend too much time looking at docs. We’ll give you an overview in this blog post. But if you want to understand the full feature set, check out the documentation.

Why RPC? (And what is RPC anyway?)

Remote Procedure Calls (RPC) are a way of expressing communications between two programs over a network. Without RPC, you might communicate using a protocol like HTTP. With HTTP, though, you must format and parse your communications as an HTTP request and response, perhaps designed in REST style. RPC systems try to make communications look like a regular function call instead, as if you were calling a library rather than a remote service. The RPC system provides a “stub” object on the client side which stands in for the real server-side object. When a method is called on the stub, the RPC system figures out how to serialize and transmit the parameters to the server, invoke the method on the server, and then transmit the return value back.

The merits of RPC have been subject to a great deal of debate. RPC is often accused of committing many of the fallacies of distributed computing.

But this reputation is outdated. When RPC was first invented some 40 years ago, async programming barely existed. We did not have Promises, much less async and await. Early RPC was synchronous: calls would block the calling thread waiting for a reply. At best, latency made the program slow. At worst, network failures would hang or crash the program. No wonder it was deemed “broken”.

Things are different today. We have Promise and async and await, and we can throw exceptions on network failures. We even understand how RPCs can be pipelined so that a chain of calls takes only one network round trip. Many large distributed systems you likely use every day are built on RPC. It works.

The fact is, RPC fits the programming model we’re used to. Every programmer is trained to think in terms of APIs composed of function calls, not in terms of byte stream protocols nor even REST. Using RPC frees you from the need to constantly translate between mental models, allowing you to move faster.

Example: Authentication Service

Here’s a common scenario: You have one Worker that implements an application, and another Worker that is responsible for authenticating user credentials. The app Worker needs to call the auth Worker on each request to check the user’s cookie.

This example uses a Service Binding, which is a way of configuring one Worker with a private channel to talk to another, without going through a public URL. Here, we have an application Worker that has been configured with a service binding to the Auth worker.

Before RPC, all communications between Workers needed to use HTTP. So, you might write code like this:

// OLD STYLE: HTTP-based service bindings.
export default {
  async fetch(req, env, ctx) {
    // Call the auth service to authenticate the user's cookie.
    // We send it an HTTP request using a service binding.

    // Construct a JSON request to the auth service.
    let authRequest = {
      cookie: req.headers.get("Cookie")

    // Send it to env.AUTH_SERVICE, which is our service binding
    // to the auth worker.
    let resp = await env.AUTH_SERVICE.fetch(
        "https://auth/check-cookie", {
      method: "POST",
      headers: {
        "Content-Type": "application/json; charset=utf-8",
      body: JSON.stringify(authRequest)

    if (!resp.ok) {
      return new Response("Internal Server Error", {status: 500});

    // Parse the JSON result.
    let authResult = await resp.json();

    // Use the result.
    if (!authResult.authorized) {
      return new Response("Not authorized", {status: 403});
    let username = authResult.username;

    return new Response(`Hello, ${username}!`);

Meanwhile, your auth server might look like:

// OLD STYLE: HTTP-based auth server.
export default {
  async fetch(req, env, ctx) {
    // Parse URL to decide what endpoint is being called.
    let url = new URL(req.url);
    if (url.pathname == "/check-cookie") {
      // Parse the request.
      let authRequest = await req.json();

      // Look up cookie in Workers KV.
      let cookieInfo = await env.COOKIE_MAP.get(
          hash(authRequest.cookie), "json");

      // Construct the response.
      let result;
      if (cookieInfo) {
        result = {
          authorized: true,
          username: cookieInfo.username
      } else {
        result = { authorized: false };

      return Response.json(result);
    } else {
      return new Response("Not found", {status: 404});

This code has a lot of boilerplate involved in setting up an HTTP request to the auth service. With RPC, we can instead express this as a function call:

// NEW STYLE: RPC-based service bindings
export default {
  async fetch(req, env, ctx) {
    // Call the auth service to authenticate the user's cookie.
    // We invoke it using a service binding.
    let authResult = await env.AUTH_SERVICE.checkCookie(

    // Use the result.
    if (!authResult.authorized) {
      return new Response("Not authorized", {status: 403});
    let username = authResult.username;

    return new Response(`Hello, ${username}!`);

And the server side becomes:

// NEW STYLE: RPC-based auth server.
import { WorkerEntrypoint } from "cloudflare:workers";

export class AuthService extends WorkerEntrypoint {
  async checkCookie(cookie) {
    // Look up cookie in Workers KV.
    let cookieInfo = await this.env.COOKIE_MAP.get(
        hash(cookie), "json");

    // Return result.
    if (cookieInfo) {
      return {
        authorized: true,
        username: cookieInfo.username
    } else {
      return { authorized: false };

This is a pretty nice simplification… but we can do much more!

Let’s get fancy! Or should I say… classy?

Let’s say we want our auth service to do a little more. Instead of just checking cookies, it provides a whole API around user accounts. In particular, it should let you:

  • Get or update the user’s profile info.
  • Send the user an email notification.
  • Append to the user’s activity log.

But, these operations should only be allowed after presenting the user’s credentials.

Here’s what the server might look like:

import { WorkerEntrypoint, RpcTarget } from "cloudflare:workers";

// `User` is an RPC interface to perform operations on a particular
// user. This class is NOT exported as an entrypoint; it must be
// received as the result of the checkCookie() RPC.
class User extends RpcTarget {
  constructor(uid, env) {

    // Note: Instance members like these are NOT exposed over RPC.
    // Only class (prototype) methods and properties are exposed.
    this.uid = uid;
    this.env = env;

  // Get/set user profile, backed by Worker KV.
  async getProfile() {
    return await this.env.PROFILES.get(this.uid, "json");
  async setProfile(profile) {
    await this.env.PROFILES.put(this.uid, JSON.stringify(profile));

  // Send the user a notification email.
  async sendNotification(message) {
    let addr = await this.env.EMAILS.get(this.uid);
    await this.env.EMAIL_SERVICE.send(addr, message);

  // Append to the user's activity log.
  async logActivity(description) {
    // (Please excuse this somewhat problematic implementation,
    // this is just a dumb example.)
    let timestamp = new Date().toISOString();
    await this.env.ACTIVITY.put(
        `${this.uid}/${timestamp}`, description);

// Now we define the entrypoint service, which can be used to
// get User instances -- but only by presenting the cookie.
export class AuthService extends WorkerEntrypoint {
  async checkCookie(cookie) {
    // Look up cookie in Workers KV.
    let cookieInfo = await this.env.COOKIE_MAP.get(
        hash(cookie), "json");

    if (cookieInfo) {
      return {
        authorized: true,
        user: new User(cookieInfo.uid, this.env),
    } else {
      return { authorized: false };

Now we can write a Worker that uses this API while displaying a web page:

export default {
  async fetch(req, env, ctx) {
    // `using` is a new JavaScript feature. Check out the
    // docs for more on this:
    // https://developers.cloudflare.com/workers/runtime-apis/rpc/lifecycle/
    using authResult = await env.AUTH_SERVICE.checkCookie(
    if (!authResult.authorized) {
      return new Response("Not authorized", {status: 403});

    let user = authResult.user;
    let profile = await user.getProfile();

    await user.logActivity("You visited the site!");
    await user.sendNotification(
        `Thanks for visiting, ${profile.name}!`);

    return new Response(`Hello, ${profile.name}!`);

Finally, this worker needs to be configured with a service binding pointing at the AuthService class. Its wrangler.toml may look like:

name = "app-worker"
main = "./src/app.js"

# Declare a service binding to the auth service.
binding = "AUTH_SERVICE"    # name of the binding in `env`
service = "auth-service"    # name of the worker in the dashboard
entrypoint = "AuthService"  # name of the exported RPC class

Wait, how?

What exactly happened here? The Server created an instance of the class User and returned it to the client. It has methods that the client can then just call? Are we somehow transferring code over the wire?

No, absolutely not! All code runs strictly in the isolate where it was originally loaded. What actually happens is, when the return value is passed over RPC, all class instances are replaced with RPC stubs. The stub, when called, makes a new RPC back to the server, where it calls the method on the original User object that was created there:

But then you might ask: how does the RPC stub know what methods are available? Is a list of methods passed over the wire?

In fact, no. The RPC stub is a special object called a “Proxy“. It implements a “wildcard method”, that is, it appears to have an infinite number of methods of every possible name. When you try to call a method, the name you called is sent to the server. If the original object has no such method, an exception is thrown.

Did you spot the security?

In the above example, we see that RPC is easy to use. We made an object! We called it! It all just felt natural, like calling a local API! Hooray!

But there’s another extremely important property that the AuthService API has which you may have missed: As designed, you cannot perform any operation on a user without first checking the cookie. This is true despite the fact that the individual method calls do not require sending the cookie again, and the User object itself doesn’t store the cookie.

The trick is, the initial checkCookie() RPC is what returns a User object in the first place. The AuthService API does not provide any other way to obtain a User instance. The RPC client cannot create a User object out of thin air, and cannot call methods of an object without first explicitly receiving a reference to it.

This is called capability-based security: we say that the User reference received by the client is a “capability”, because receiving it grants the client the ability to perform operations on the user. The getProfile() method grants this capability only when the client has presented the correct cookie.

Capability-based security is often like this: security can be woven naturally into your APIs, rather than feel like an additional concern bolted on top.

More security: Named entrypoints

Another subtle but important detail to call out: in the above example, the auth service’s RPC API is exported as a named class:

export class AuthService extends WorkerEntrypoint {

And in our wrangler.toml for the calling worker, we had to specify an “entrypoint”, matching the class name:

entrypoint = "AuthService"  # name of the exported RPC class

In the past, service bindings would bind to the “default” entrypoint, declared with export default {. But, the default entrypoint is also typically exposed to the Internet, e.g. automatically mapped to a hostname under workers.dev (unless you explicitly turn that off). It can be tricky to safely assume that requests arriving at this entrypoint are in any way trusted.

With named entrypoints, this all changes. A named entrypoint is only accessible to Workers which have explicitly declared a binding to it. By default, only Workers on your own account can declare such bindings. Moreover, the binding must be declared at deploy time; a Worker cannot create new service bindings at runtime.

Thus, you can trust that requests arriving at a named entrypoint can only have come from Workers on your account and for which you explicitly created a service binding. In the future, we plan to extend this pattern further with the ability to lock down entrypoints, audit which Workers have bindings to them, tell the callee information about who is calling at runtime, and so on. With these tools, there is no need to write code in your app itself to authenticate access to internal APIs; the system does it for you.

What about type safety?

Workers RPC works in an entirely dynamically-typed way, just as JavaScript itself does. But just as you can apply TypeScript on top of JavaScript in general, you can apply it to Workers RPC.

The @cloudflare/workers-types package defines the type Service<MyEntrypointType>, which describes the type of a service binding. MyEntrypointType is the type of your server-side interface. Service<MyEntrypointType> applies all the necessary transformations to turn this into a client-side type, such as converting all methods to async, replacing functions and RpcTargets with (properly-typed) stubs, and so on.

It is up to you to share the definition of MyEntrypointType between your server app and its clients. You might do this by defining the interface in a separate shared TypeScript file, or by extracting a .d.ts type declaration file from your server code using tsc --declaration.

With that done, you can apply types to your client:

import { WorkerEntrypoint } from "cloudflare:workers";

// The interface that your server-side entrypoint implements.
// (This would probably be imported from a .d.ts file generated
// from your server code.)
declare class MyEntrypointType extends WorkerEntrypoint {
  sum(a: number, b: number): number;

// Define an interface Env specifying the bindings your client-side
// worker expects.
interface Env {
  MY_SERVICE: Service<MyEntrypointType>;

// Define the client worker's fetch handler with typed Env.
export default <ExportedHandler<Env>> {
  async fetch(req, env, ctx) {
    // Now env.MY_SERVICE is properly typed!
    const result = await env.MY_SERVICE.sum(1, 2);
    return new Response(result.toString());

RPC to Durable Objects

Durable Objects allow you to create a “named” worker instance somewhere on the network that multiple other workers can then talk to, in order to coordinate between them. Each Durable Object also has its own private on-disk storage where it can store state long-term.

Previously, communications with a Durable Object had to take the form of HTTP requests and responses. With RPC, you can now just declare methods on your Durable Object class, and call them on the stub. One catch: to opt into RPC, you must declare your Durable Object class with extends DurableObject, like so:

import { DurableObject } from "cloudflare:workers";

export class Counter extends DurableObject {
  async increment() {
    // Increment our stored value and return it.
    let value = await this.ctx.storage.get("value");
    value = (value || 0) + 1;
    this.ctx.storage.put("value", value);
    return value;

Now we can call it like:

let stub = env.COUNTER_NAMEPSACE.get(id);
let value = await stub.increment();

TypeScript is supported here too, by defining your binding with type DurableObjectNamespace<ServerType>:

interface Env {
  COUNTER_NAMESPACE: DurableObjectNamespace<Counter>;

Eliding awaits with speculative calls

When talking to a Durable Object, the object may be somewhere else in the world from the caller. RPCs must cross the network. This takes time: despite our best efforts, we still haven’t figured out how to make information travel faster than the speed of light.

When you have a complex RPC interface where one call returns an object on which you wish to make further method calls, it’s easy to end up with slow code that makes too many round trips over the network.

// Makes three round trips.
let foo = await stub.foo();
let baz = await foo.bar.baz();
let corge = await baz.qux[3].corge();

Workers RPC features a way to avoid this: If you know that a call will return a value containing a stub, and all you want to do with it is invoke a method on that stub, you can skip awaiting it:

// Same thing, only one round trip.
let foo = stub.foo();
let baz = foo.bar.baz();
let corge = await baz.qux[3].corge();

Whoa! How does this work?

RPC methods do not return normal promises. Instead, they return special RPC promises. These objects are “custom thenables“, which means you can use them in all the ways you’d use a regular Promise, like awaiting it or calling .then() on it.

But an RPC promise is more than just a thenable. It is also a proxy. Like an RPC stub, it has a wildcard property. You can use this to express speculative RPC calls on the eventual result, before it has actually resolved. These speculative calls will be sent to the server immediately, so that they can begin executing as soon as the first RPC has finished there, before the result has actually made its way back over the network to the client.

This feature is also known as “Promise Pipelining”. Although it isn’t explicitly a security feature, it is commonly provided by object-capability RPC systems like Cap’n Proto.

The future: Custom Bindings Marketplace?

For now, Service Bindings and Durable Objects only allow communication between Workers running on the same account. So, RPC can only be used to talk between your own Workers.

But we’d like to take it further.

We have previously explained why Workers environments contain live objects, also known as “bindings”. But today, only Cloudflare can add new binding types to the Workers platform – like Queues, KV, or D1. But what if anyone could invent their own binding type, and give it to other people?

Previously, we thought this would require creating a way to automatically load client libraries into the calling Workers. That seemed scary: it meant using someone’s binding would require trusting their code to run inside your isolate. With RPC, there’s no such trust. The binding only sees exactly what you explicitly pass to it. It cannot compromise the rest of your Worker.

Could Workers RPC provide the basis for a “bindings marketplace”, where people can offer rich JavaScript APIs to each other in an easy and secure way? We’re excited to explore and find out.

Try it now

Workers RPC is available today for all Workers users. To get started, check out the docs.

Browser Rendering API GA, rolling out Cloudflare Snippets, SWR, and bringing Workers for Platforms to all users

Post Syndicated from Tanushree Sharma original https://blog.cloudflare.com/browser-rendering-api-ga-rolling-out-cloudflare-snippets-swr-and-bringing-workers-for-platforms-to-our-paygo-plans

Browser Rendering API is now available to all paid Workers customers with improved session management

In May 2023, we announced the open beta program for the Browser Rendering API. Browser Rendering allows developers to programmatically control and interact with a headless browser instance and create automation flows for their applications and products.

At the same time, we launched a version of the Puppeteer library that works with Browser Rendering. With that, developers can use a familiar API on top of Cloudflare Workers to create all sorts of workflows, such as taking screenshots of pages or automatic software testing.

Today, we take Browser Rendering one step further, taking it out of beta and making it available to all paid Workers’ plans. Furthermore, we are enhancing our API and introducing a new feature that we’ve been discussing for a long time in the open beta community: session management.

Session Management

Session management allows developers to reuse previously opened browsers across Worker’s scripts. Reusing browser sessions has the advantage that you don’t need to instantiate a new browser for every request and every task, drastically increasing performance and lowering costs.

Before, to keep a browser instance alive and reuse it, you’d have to implement complex code using Durable Objects. Now, we’ve simplified that for you by keeping your browsers running in the background and extending the Puppeteer API with new session management methods that give you access to all of your running sessions, activity history, and active limits.

Here’s how you can list your active sessions:

const sessions = await puppeteer.sessions(env.RENDERING);
      "connectionId": "2a2246fa-e234-4dc1-8433-87e6cee80145",
      "connectionStartTime": 1711621704607,
      "sessionId": "478f4d7d-e943-40f6-a414-837d3736a1dc",
      "startTime": 1711621703708
      "sessionId": "565e05fb-4d2a-402b-869b-5b65b1381db7",
      "startTime": 1711621703808

We have added a Worker script example on how to use session management to the Developer Documentation.

Analytics and logs

Observability is an essential part of any Cloudflare product. You can find detailed analytics and logs of your Browser Rendering usage in the dashboard under your account’s Worker & Pages section.

Browser Rendering is now available to all customers with a paid Workers plan. Each account is limited to running two new browsers per minute and two concurrent browsers at no cost during this period. Check our developers page to get started.

We are rolling out access to Cloudflare Snippets

Powerful, programmable, and free of charge, Snippets are the best way to perform complex HTTP request and response modifications on Cloudflare. What was once too advanced to achieve using Rules products is now possible with Snippets. Since the initial announcement during Developer Week 2022, the promise of extending out-of-the-box Rules functionality by writing simple JavaScript code is keeping the Cloudflare community excited.

During the first 3 months of 2024 alone, the amount of traffic going through Snippets increased over 7x, from an average of 2,200 requests per second in early January to more than 17,000 in March.

However, instead of opening the floodgates and letting millions of Cloudflare users in to test (and potentially break) Snippets in the most unexpected ways, we are going to pace ourselves and opt for a phased rollout, much like the newly released Gradual Rollouts for Workers.

In the next few weeks, 5% of Cloudflare users will start seeing “Snippets” under the Rules tab of the zone-level menu in their dashboard. If you happen to be part of the first 5%, snip into action and try out how fast and powerful Snippets are even for advanced use cases like dynamically changing the date in headers or A / B testing leveraging the `math.random` function. Whatever you use Snippets for, just keep one thing in mind: this is still an alpha, so please do not use Snippets for production traffic just yet.

Until then, keep your eyes out for the new Snippets tab in the Cloudflare dashboard and learn more how powerful and flexible Snippets are at the developer documentation in the meantime.

Coming soon: asynchronous revalidation with stale-while-revalidate

One of the features most requested by our customers is the asynchronous revalidation with stale-while-revalidate (SWR) cache directive, and we will be bringing this to you in the second half of 2024.  This functionality will be available by design as part of our new CDN architecture that is being built using Rust with performance and memory safety at top of mind.

Currently, when a client requests a resource, such as a web page or an image, Cloudflare checks to see if the asset is in cache and provides a cached copy if available. If the file is not in the cache or has expired and become stale, Cloudflare connects to the origin server to check for a fresh version of the file and forwards this fresh version to the end user. This wait time adds latency to these requests and impacts performance.

Stale-while-revalidate is a cache directive that allows the expired or stale version of the asset to be served to the end user while simultaneously allowing Cloudflare to check the origin to see if there’s a fresher version of the resource available. If an updated version exists, the origin forwards it to Cloudflare, updating the cache in the process. This mechanism allows the client to receive a response quickly from the cache while ensuring that it always has access to the most up-to-date content. Stale-while-revalidate strikes a balance between serving content efficiently and ensuring its freshness, resulting in improved performance and a smoother user experience.

Customers who want to be part of our beta testers and “cache” in on the fun can register here, and we will let you know when the feature is ready for testing!

Coming on April 16, 2024: Workers for Platforms for our pay-as-you-go plan

Today, we’re excited to share that on April 16th, Workers for Platforms will be available to all developers through our new $25 pay-as-you-go plan!

Workers for Platforms is changing the way we build software – it gives you the ability to embed personalization and customization directly into your product. With Workers for Platforms, you can deploy custom code on behalf of your users or let your users directly deploy their own code to your platform, without you or your users having to manage any infrastructure. You can use Workers for Platforms with all the exciting announcements that have come out this Developer Week – it supports all the bindings that come with Workers (including Workers AI, D1 and Durable Objects) as well as Python Workers.  

Here’s what some of our customers – ranging from enterprises to startups – are building on Workers for Platforms:

  • Shopify Oxygen is a hosting platform for their Remix-based eCommerce framework Hydrogen, and it’s built on Workers for Platforms! The Hydrogen/Oxygen combination gives Shopify merchants control over their buyer experience without the restrictions of generic storefront templates.
  • Grafbase is a data platform for developers to create a serverless GraphQL API that unifies data sources across a business under one endpoint. They use Workers for Platforms to give their developers the control and flexibility to deploy their own code written in JavaScript/TypeScript or WASM.
  • Triplit is an open-source database that syncs data between server and browser in real-time. It allows users to build low latency, real-time applications with features like relational querying, schema management and server-side storage built in. Their query and sync engine is built on top of Durable Objects, and they’re using Workers for Platforms to allow their customers to package custom Javascript alongside their Triplit DB instance.

Tools for observability and platform level controls

Workers for Platforms doesn’t just allow you to deploy Workers to your platform – we also know how important it is to have observability and control over your users’ Workers. We have a few solutions that help with this:

  • Custom Limits: Set CPU time or subrequest caps on your users’ Workers. Can be used to set limits in order to control your costs on Cloudflare and/or shape your own pricing and packaging model. For example, if you run a freemium model on your platform, you can lower the CPU time limit for customers on your free tier.
  • Tail Workers: Tail Worker events contain metadata about the Worker, console.log() messages, and capture any unhandled exceptions. They can be used to provide your developers with live logging in order to monitor for errors and troubleshoot in real time.
  • Outbound Workers: Get visibility into all outgoing requests from your users’ Workers. Outbound Workers sit between user Workers and the fetch() requests they make, so you get full visibility over the request before it’s sent out to the Internet.


We wanted to make sure that Workers for Platforms was affordable for hobbyists, solo developers, and indie developers. Workers for Platforms is part of a new $25 pay-as-you-go plan, and it includes the following:

Included Amounts
Requests 20 million requests/month
+$0.30 per additional million
CPU time 60 million CPU milliseconds/month
+$0.02 per additional million CPU milliseconds
Scripts 1000 scripts
+0.02 per additional script/month

Workers for Platforms will be available to purchase on April 16, 2024!

The Workers for Platforms will be available to purchase under the Workers for Platforms tab on the Cloudflare Dashboard on April 16, 2024.

In the meantime, to learn more about Workers for Platforms, check out our starter project and developer documentation.

Community Update: empowering startups building on Cloudflare and creating an inclusive community

Post Syndicated from Ricky Robinett original https://blog.cloudflare.com/2024-community-update

With millions of developers around the world building on Cloudflare, we are constantly inspired by what you all are building with us. Every Developer Week, we’re excited to get your hands on new products and features that can help you be more productive, and creative, with what you’re building. But we know our job doesn’t end when we put new products and features in your hands during Developer Week. We also need to cultivate welcoming community spaces where you can come get help, share what you’re building, and meet other developers building with Cloudflare.

We’re excited to close out Developer Week by sharing updates on our Workers Launchpad program, our latest Developer Challenge, and the work we’re doing to ensure our community spaces – like our Discord and Community forums – are safe and inclusive for all developers.

Helping startups go further with Workers Launchpad

In late 2022, we initiated the $2 billion Workers Launchpad Funding Program aimed at aiding the more than one million developers who use Cloudflare’s Developer Platform. This initiative particularly benefits startups that are investing in building on Cloudflare to propel their business growth.

The Workers Launchpad Program offers a variety of resources to help builders scale faster and reach more customers. The program includes, but is not limited to:

  • Fostering a community of like-minded founders
  • Facilitating introductions to the Launchpad’s VC partner network of 40+ leading investors
  • Company-building support and mentorship through virtual Founders Bootcamp sessions
  • Organizing technical office hours with our engineers
  • Access to preview upcoming Cloudflare products and Product Managers
  • Culminating in a Demo Day, for participants to share their stories globally with investors and prospective customers.

So far, 50 amazing startups from 13 countries have successfully graduated from the Workers Launchpad program. We finished up Cohort #1 in March 2023, and Cohort #2 wrapped up August 2023.

Meet Cohort #3 of the Workers Launchpad!

Since the end of Cohort #2, we have received hundreds of new applications from startups across the globe. Startup applicants showcased incredible tools and software across a variety of industries, including AI, SaaS, Supply Chain, Media, Gaming, Hospitality, and Developer Productivity. While we were encouraged by this wave of applicants’ ability to build amazing technology, there were a few that stood out that are leveraging Cloudflare’s Developer Suite to scale their business.

With that being said, we would like to introduce you to the 29 startups that have been chosen to participate in Cohort #3 of Workers Launchpad:

Below, you will find a brief summary of what problems these startups are looking to solve:

Autoblocks AI Evaluation & testing platform to improve AI product quality.
BEAM (By Mass Luminosity) A next-gen live streaming platform that elevates creator-viewer interactions to the next level.
BentoML Run any AI model in your cloud.
bohr.io An easy and fast development platform.
Cloneable Provides low/no-code tools to build and deploy applications to any device, instantly.
CleverEV Manage EV charging infrastructure and experience for clients.
Dulia Managed edge powered serverless AI platform.
Erxes Open-source experience operating system empowering businesses.
Exporio AI-first A/B testing and personalization platform.
Helicone GenAI observability platform built for developers.
Houdini An end-to-end solution for building and deploying GraphQL applications.
Intelligage Humanize your AI for customers.
Langbase Ship hyper-personalized AI apps in seconds — any LLM, any data, any developer.
Milkshake Create websites via mobile within minutes.
Nadrama Kubernetes PaaS in your cloud account, in minutes.
NuxtHub (by NuxtLabs) Build full-stack applications on Cloudflare with zero configuration.
Panaptico High performance networking fabrics for specialized workloads.
Playroom Platform for game developers to build multiplayer games in minutes.
Puzzle Labs P2P, prompt-first knowledge base for teams to collaborate with AI.
Resilis Intelligent edge caching for REST APIs.
Scrappi A better way to collect, create and collaborate.
Starlight Labs AI native game studio.
T4 Stack Ship feature parity on universal apps.
TextCortex AI AI copilot platform to leverage the power of easy customization and integration.
Toothless Build GenAI-powered workflow automation and internal tools in minutes.
Unfetch Generate and run scripts with AI to complete tasks within seconds.
Unkey Redefines API management for developers. Add authentication, analytics, and rate-limiting to your APIs in minutes.
Unnug Transformative cloud compiler with an emphasis on user on-premises, cloud, and edge resources.
Wope AI-powered marketing agent that leverages Gen AI to optimize businesses’ online presence and drive more traffic.

The Cloudflare team is looking forward to working with Cohort #3 participants and sharing what they are building on Cloudflare. To follow along with Cohort #3 of Workers Launchpad, follow @CloudflareDev and join our Developer Discord server.

Are you a startup and interested in joining Cohort #4? Apply here!

AI developer challenge

Now that Workers AI is GA, we’re excited to see what our community can build.  We’ve teamed up with our friends at DEV who will be running an AI Developer challenge, which officially launched on Wednesday, April 3, and runs until Sunday, April 14, 2024, when submissions close.

For this challenge, you will build a Workers AI application that makes use of AI task types from Cloudflare’s growing catalog of Open Models. Apps will be evaluated on innovation, creativity, and demonstration of underlying technology with prizes awarded by DEV for the best overall app, as well as projects leveraging multiple models and tasks. For more information and details on how to participate, including DEV’s rules and requirements, head over to the official challenge page.

Creating an inclusive community

Our community has been growing really fast over the past year, so fast that it’s becoming more difficult to welcome each new member that joins our Discord server every day, and Developer Week has always been one of the main drivers of this growth.

When you come into the Cloudflare developer community, it’s important to us that you’re entering a space that is safe and welcoming. Even though we already have rules for the server and community forums, we needed guidelines for our community programs, so that’s why we’ve created a new Code of Conduct that promotes inclusivity, respect, and will help us create a better community for everyone.

Do you want to be part of this and help us create a more inclusive and helpful community? Then please share your feedback and tell us what you would like to see improved in our community and our Discord server in this thread.

What’s new with Cloudflare Media: updates for Calls, Stream, and Images

Post Syndicated from Deanna Lam original https://blog.cloudflare.com/whats-next-for-cloudflare-media

Our customers use Cloudflare Calls, Stream, and Images to build live, interactive, and real-time experiences for their users. We want to reduce friction by making it easier to get data into our products. This also means providing transparent pricing, so customers can be confident that costs make economic sense for their business, especially as they scale.

Today, we’re introducing four new improvements to help you build media applications with Cloudflare:

  • Cloudflare Calls is in open beta with transparent pricing
  • Cloudflare Stream has a Live Clipping API to let your viewers instantly clip from ongoing streams
  • Cloudflare Images has a pre-built upload widget that you can embed in your application to accept uploads from your users
  • Cloudflare Images lets you crop and resize images of people at scale with automatic face cropping

Build real-time video and audio applications with Cloudflare Calls

Cloudflare Calls is now in open beta, and you can activate it from your dashboard. Your usage will be free until May 15, 2024. Starting May 15, 2024, customers with a Calls subscription will receive the first terabyte each month for free, with any usage beyond that charged at $0.05 per real-time gigabyte. Additionally, there are no charges for inbound traffic to Cloudflare.

To get started, read the developer documentation for Cloudflare Calls.

Live Instant Clipping: create clips from live streams and recordings

Live broadcasts often include short bursts of highly engaging content within a longer stream. Creators and viewers alike enjoy being able to make a “clip” of these moments to share across multiple channels. Being able to generate that clip rapidly enables our customers to offer instant replays, showcase key pieces of recordings, and build audiences on social media in real-time.

Today, Cloudflare Stream is launching Live Instant Clipping in open beta for all customers. With the new Live Clipping API, you can let your viewers instantly clip and share moments from an ongoing stream – without re-encoding the video.

When planning this feature, we considered a typical user flow for generating clips from live events. Consider users watching a stream of a video game: something wild happens and users want to save and share a clip of it to social media. What will they do?

First, they’ll need to be able to review the preceding few minutes of the broadcast, so they know what to clip. Next, they need to select a start time and clip duration or end time, possibly as a visualization on a timeline or by scrubbing the video player. Finally, the clip must be available quickly in a way that can be replayed or shared across multiple platforms, even after the original broadcast has ended.

That ideal user flow implies some heavy lifting in the background. We now offer a manifest to preview recent live content in a rolling window, and we provide the timing information in that response to determine the start and end times of the requested clip relative to the whole broadcast. Finally, on request, we will generate on-the-fly that clip as a standalone video file for easy sharing as well as an HLS manifest for embedding into players.

Live Instant Clipping is available in beta to all customers starting today! Live clips are free to make; they do not count toward storage quotas, and playback is billed just like minutes of video delivered. To get started, check out the Live Clipping API in developer documentation.

Integrate Cloudflare Images into your application with only a few lines of code

Building applications with user-uploaded images is even easier with the upload widget, a pre-built, interactive UI that lets users upload images directly into your Cloudflare Images account.

Many developers use Cloudflare Images as an end-to-end image management solution to support applications that center around user-generated content, from AI photo editors to social media platforms. Our APIs connect the frontend experience – where users upload their images – to the storage, optimization, and delivery operations in the backend.

But building an application can take time. Our team saw a huge opportunity to take away as much extra work as possible, and we wanted to provide off-the-shelf integration to speed up the development process.

With the upload widget, you can seamlessly integrate Cloudflare Images into your application within minutes. The widget can be integrated in two ways: by embedding a script into a static HTML page or by installing a package that works with your favorite framework. We provide a ready-made Worker template that you can deploy directly to your account to connect your frontend application with Cloudflare Images and authorize users to upload through the widget.

To try out the upload widget, sign up for our closed beta.

Optimize images of people with automatic face cropping for Cloudflare Images

Cloudflare Images lets you dynamically manipulate images in different aspect ratios and dimensions for various use cases. With face cropping for Cloudflare Images, you can now crop and resize images of people’s faces at scale. For example, if you’re building a social media application, you can apply automatic face cropping to generate profile picture thumbnails from user-uploaded images.

Our existing gravity parameter uses saliency detection to set the focal point of an image based on the most visually interesting pixels, which determines how the image will be cropped. We expanded this feature by using a machine learning model called RetinaFace, which classifies images that have human faces. We’re also introducing a new zoom parameter that you can combine with face cropping to specify how closely an image should be cropped toward the face.

To apply face cropping to your image optimization, sign up for our closed beta.

Photo by Eye for Ebony on Unsplash

Meet the Media team over Discord

As we’re working to build the next set of media tools, we’d love to hear what you’re building for your users. Come say hi to us on Discord. You can also learn more by visiting our developer documentation for Calls, Stream, and Images.

Cloudflare Calls: millions of cascading trees all the way down

Post Syndicated from Renan Dincer original https://blog.cloudflare.com/cloudflare-calls-anycast-webrtc

Following its initial announcement in September 2022, Cloudflare Calls is now in open beta and available in your Cloudflare Dashboard. Cloudflare Calls lets developers build real-time audio/video apps using WebRTC, and it abstracts away the complexity by turning the Cloudflare network into a singular SFU. In this post, we dig into how we make this possible.

WebRTC growing pains

WebRTC is the only way to send UDP traffic out of a web browser – everything else uses TCP.

As a developer, you need a UDP-based transport layer for applications demanding low latency and real-time feedback, such as audio/video conferencing and interactive gaming. This is because unlike WebSocket and other TCP-based solutions, UDP is not subject to head-of-line blocking, a frequent topic on the Cloudflare Blog.

When building a new video conferencing app, you typically start with a peer-to-peer web application using WebRTC, where clients exchange data directly. This approach is efficient for small-scale demos, but scalability issues arise as the number of participants increases. This is because the amount of data each client must transmit grows substantially, following an almost exponential increase relative to the number of participants, as each client needs to send data to n-1 other clients.

Selective Forwarding Units (SFUs) play pivotal roles in scaling WebRTC applications. An SFU functions by receiving multiple media or data flows from participants and deciding which streams should be forwarded to other participants, thus acting as a media stream routing hub. This mechanism significantly reduces bandwidth requirements and improves scalability by managing stream distribution based on network conditions and participant needs. Even though it hasn’t always been this way from when video calling on computers first became popular, SFUs are often found in the cloud, rather than home computers of clients, because of superior connectivity offered in a data center.

A modern audio/video application thus quickly becomes complicated with the addition of this server side element. Since all clients connect to this central SFU server, there are numerous things to consider when you’re architecting and scaling a real-time application:

  • How close is the SFU server location(s) to the end user clients, how is a client assigned to a server?
  • Where is the SFU hosted, and if it’s hosted in the cloud, what are the egress costs from VMs?
  • How many participants can fit in a “room”? Are all participants sending and receiving data? With cameras on? Audio only?
  • Some SFUs require the use of custom SDKs. Which platforms do these run on and are they compatible with the application you’re trying to build?
  • Monitoring/reliability/other issues that come with running infrastructure

Some of these concerns, and the complexity of WebRTC infrastructure in general, has made the community look in different directions. However, it is clear that in 2024, WebRTC is alive and well with plenty of new and old uses. AI startups build characters that converse in real time, cars leverage WebRTC to stream live footage of their cameras to smartphones, and video conferencing tools are going strong.

WebRTC has been interesting to us for a while. Cloudflare Stream implemented WHIP and WHEP WebRTC video streaming protocols in 2022, which remain the lowest latency way to broadcast video. OBS Studio implemented WHIP broadcasting support as have a variety of software and hardware vendors alongside Cloudflare. In late 2022, we launched Cloudflare Calls in closed beta. When we blogged about it back then, we were very impressed with how WebRTC fared, and spoke to many customers about their pain points as well as creative ideas the existing browser APIs can foster. We also saw other WebRTC-based apps like Clubhouse rise in popularity and Twitter Spaces play a role in popular culture. Today, we see real-time applications of a different sort. Many AI projects have impressive demos with voice/video interactions. All of these apps are built with the same WebRTC APIs and system architectures.

We are confident that Cloudflare Calls is a new kind of WebRTC infrastructure you should try. When we set out to build Cloudflare Calls, we had a few ideas that we weren’t sure would work, but were worth trying:

  • Build every WebRTC component on Anycast with a single IP address for DTLS, ICE, STUN, SRTP, SCTP, etc.
  • Don’t force an SDK – WebRTC APIs by themselves are enough, and allow for the most novel uses to shine, because best developers always find ways to hit the limits of SDKs.
  • Deploy in all 310+ cities Cloudflare operates in – use every Cloudflare server, not just a subset
  • Exchange offer and answer over HTTP between Cloudflare and the WebRTC client. This way there is only a single PeerConnection to manage.

Now we know this is all possible, because we made it happen, and we think it’s the best experience a developer can get with pure WebRTC.

Is Cloudflare Calls a real SFU?

Cloudflare is in the business of having computers in numerous places. Historically, our core competency was operating a caching HTTP reverse proxy, and we are very good at this. With Cloudflare Calls, we asked ourselves “how can we build a large distributed system that brings together our global network to form one giant stateful system that feels like a single machine?”

When using Calls, every PeerConnection automatically connects to the closest Cloudflare data center instead of a single server. Rather than connecting every client that needs to communicate with each other to a single server, anycast spreads out connections as much as possible to minimize last mile latency sourced from your ISP between your client and Cloudflare.

It’s good to minimize last mile latency because after the data enters Cloudflare’s control, the underlying media can be managed carefully and routed through the Cloudflare backbone. This is crucial for WebRTC applications where millisecond delays can significantly impact user experience. To give you a sense about latency between Cloudflare’s data centers and end-users, about 95% of the Internet connected population is within 50ms of a Cloudflare data center. As I write this, I am about 20ms away, but in the past, I have been lucky enough to be connected to a **great** home Wi-Fi network less than 1ms away in Manhattan. “But you are just one user!” you might be thinking, so here is a chart from Cloudflare Radar showing recent global latency measurements:

This setup allows more opportunities for packets lost to be replied with retransmissions closer to users, more opportunities for bandwidth adjustments.

Eliminating SFU region selection

A traditional challenge in WebRTC infrastructure involves the manual selection of Selective Forwarding Units (SFUs) based on geographic location to minimize latency. Some systems solve this problem by selecting a location for the SFU after the first user joins the “room”. This makes routing inefficient when the rest of the participants in the conversation are clustered elsewhere. The anycast architecture of Calls eliminates this issue. When a client initiates a connection, BGP dynamically determines the closest data center. Each selected server only becomes responsible for the PeerConnection of the clients closest to it.

One might see this is actually a simpler way of managing servers, as there is no need to maintain a layer of WebRTC load balancing for traffic or CPU capacity between servers. However, anycast has its own challenges, and we couldn’t take a laissez-faire approach.

Steps to establishing a PeerConnection

One of the challenging parts in assigning a server to a client PeerConnection is supporting dual stack networking for backwards compatibility with clients that only support the old version of the Internet Protocol, IPv4.

Cloudflare Calls uses a single IP address per protocol, and our L4 load balancer directs packets to a single server per client by using the 4-tuple {client IP, client port, destination IP, destination port} hashing. This means that every ICE connectivity check packet arrives at different servers: one for IPv4 and one for IPv6.

ICE is not the only protocol used for WebRTC; there is also STUN and TURN for connectivity establishment. Actual media bits are encrypted using DTLS, which carries most of the data during a session.

DTLS packets don’t have any identifiers in them that would indicate they belong to a specific connection (unlike QUIC’s connection ID field), so every server should be able to handle DTLS packets and get the necessary certificates to be able to decrypt them for processing. DTLS encryption is negotiated at the SDP layer using the HTTPS API.

The HTTPS API for Calls also lands on a different server than DTLS and ICE connectivity checks. Since DTLS packets need information from the SDP exchanged using the HTTPS API, and ICE connectivity checks depend on the HTTPS API for userFragment and password fields in the connectivity check packets, it would be very useful for all of these to be available in one server. Yet in our setup, they’re not.

Fippo and Gustavo of WebRTCHacks complained (gracefully noted) about slow replies to ICE connectivity checks in their great article as they were digging into our WHIP implementation right around our announcement in 2022:

Looking at the Wireshark dumps we see a surprisingly large amount of time pass between the first STUN request and the first STUN response – it was 1.8 seconds in the screenshot below.

In other tests, it was shorter, but still 600ms long.

After that, the DTLS packets do not get an immediate response, requiring multiple attempts. This ultimately leads to a call setup time of almost three seconds – way above the global average of 800ms Fippo has measured previously (for the complete handshake, 200ms for the DTLS handshake). For Cloudflare with their extensive network, we expected this to be way below that average.

Gustavo and Fippo observed our solution to this problem of different parts of the WebRTC negotiation landing on different servers. Since Cloudflare Calls unbundles the WebRTC protocol to make the entire network act like a single computer, at this critical moment, we need to form consensus across the network. We form consensus by configuring every server to handle any incoming PeerConnection just in time. When a packet arrives, if the server doesn’t know about it, it quickly learns about the negotiated parameters from another server, such as the ufrag and the DTLS fingerprint from the SDP, and responds with the appropriate response.

Getting faster

Even though we’ve sped up the process of forming consensus across the Cloudflare network, any delays incurred can still have weird side effects. For example, up until a few months ago, delays of a few hundred milliseconds caused slow connections in Chrome.

A connectivity check packet delayed by a few hundred milliseconds signals to Chrome that this is a high latency network, even though every other STUN message after that was replied to in less than 5-10ms. Chrome thus delays sending a USE-CANDIDATE attribute in the responses for a few seconds, degrading the user experience.

Fortunately, Chrome also sends DTLS ClientHello before USE-CANDIDATE (behavior we’ve seen only on Chrome), so to help speed up Chrome, Calls uses DTLS packets in place of STUN packets with USE-CANDIDATE attributes.

After solving this issue with Chrome, PeerConnections globally now take about 100-250ms to get connected. This includes all consensus management, STUN packets, and a complete DTLS handshake.

Sessions and Tracks are the building blocks of Cloudflare’s SFU, not rooms

Once a PeerConnection is established to Cloudflare, we call this a Session. Many media Tracks or DataChannels can be published using a single Session, which returns a unique ID for each. These then can be subscribed to over any other PeerConnection anywhere around the world using the unique ID. The tracks can be published or subscribed anytime during the lifecycle of the PeerConnection.

In the background, Cloudflare takes care of scaling through a fan-out architecture with cascading trees that are unique per track. This structure works by creating a hierarchy of nodes where the root node distributes the stream to intermediate nodes, which then fan out to end-users. This significantly reduces the bandwidth required at the source and ensures scalability by distributing the load across the network. This simple but powerful architecture allows developers to build anything from 1:1 video calls to large 1:many or many:many broadcasting scenarios with Calls.

There is no “room” concept in Cloudflare Calls. Each client can add as many tracks into a PeerConnection as they’d like. The limit is the bandwidth available between Cloudflare and the client, which is practically limited by the client side every time. The signaling or the concept of a “room” is left to the application developer, who can choose to pull as many tracks as they’d like from the tracks they have pushed elsewhere into a PeerConnection. This allows developers to move participants into breakout rooms and then back into a plenary room, and then 1:1 rooms while keeping the same PeerConnection and MediaTracks active.

Cloudflare offers an unopinionated approach to bandwidth management, allowing for greater control in customizing logic to suit your business needs. There is no active bandwidth management or restriction on the number of tracks. The WebRTC Stats API provides a standardized way to access data on packet loss and possible congestion, enabling you to incorporate client-side logic based on this information. For instance, if poor Wi-Fi connectivity leads to degraded service, your front-end could inform the user through a notice and automatically reduce the number of video tracks for that client.

“NACK shield” at the edge

The Internet can’t guarantee timely and orderly delivery of packets, leading to the necessity of retransmission mechanisms, particularly in protocols like TCP. This ensures data eventually reaches its destination, despite possible delays. Real-time systems, however, need special consideration of these delays. A packet that is delayed past its deadline for rendering on the screen is worthless, but a packet that is lost can be recovered if it can be retransmitted within a very short period of time, on the order of milliseconds. This is where NACKs come to play.

A WebRTC client receiving data constantly checks for packet loss. When one or more packets don’t arrive at the expected time or a sequence number discontinuity is seen on the receiving buffer, a special NACK packet is sent back to the source in order to ask for a packet retransmission.

In a peer-to-peer topology, if it receives a NACK packet, the source of the data has to retransmit packets for every participant. When an SFU is used, the SFU could send NACKs back to source, or keep a complex buffer for each client to handle retransmissions.

This gets more complicated with Cloudflare Calls, since both the publisher and the subscriber connect to Cloudflare, likely to different servers and also probably in different locations. In addition, there is a possibility of other Cloudflare data centers in the middle, either through Argo, or just as part of scaling to many subscribers on the same track.

It is common for SFUs to backpropagate NACK packets back to the source, losing valuable time to recover packets. Calls goes beyond this and can handle NACK packets in the location closest to the user, which decreases overall latency. The latency advantage gives more chance for the packet to be recovered compared to a centralized SFU or no NACK handling at all.

Since there is possibly a number of Cloudflare data centers between clients, packet loss within the Cloudflare network is also possible. We handle this by generating NACK packets in the network. With each hop that is taken with the packets, the receiving end can generate NACK packets. These packets are then recovered or backpropagated to the publisher to be recovered.

Cloudflare Calls does TURN over Anycast too

Separately from the SFU, Calls also offers a TURN service. TURN relays act as relay points for traffic between WebRTC clients like the browser and SFUs, particularly in scenarios where direct communication is obstructed by NATs or firewalls. TURN maintains an allocation of public IP addresses and ports for each session, ensuring connectivity even in restrictive network environments.

Cloudflare Calls’ TURN service supports a few ports to help with misbehaving middleboxes and firewalls:

  • TURN-over-UDP over port 3748 (standard), and also port 53
  • TURN-over-TCP over ports 3748 and 80
  • TURN-over-TLS over ports 5349 and 443

TURN works the same way as Calls, available over anycast and always connecting to the closest datacenter.

Pricing and how to get started

Cloudflare Calls is now in open beta and available in your Cloudflare Dashboard. Depending on your use case, you can set up an SFU application and/or a TURN service with only a few clicks.

To kick off its open beta phase, Calls is available at no cost for a limited time. Starting May 15, 2024, customers will receive the first terabyte each month for free, with any usage beyond that charged at $0.05 per real-time gigabyte. Beta customers will be provided at least 30 days to upgrade from the free beta to a paid subscription. Additionally, there are no charges for in-bound traffic to Cloudflare. For volume pricing, talk to your account manager.

Cloudflare Calls is ideal if you are building new WebRTC apps. If you have existing SFUs or TURN infrastructure, you may still consider using Calls alongside your existing infrastructure. Building a bridge to Calls from other places is not difficult as Cloudflare Calls supports standard WebRTC APIs and acts like just another WebRTC peer.

We understand that getting started with a new platform is difficult, so we’re also open sourcing our internal video conferencing app, Orange Meets. Orange Meets supports small and large conference calls by maintaining room state in Workers Durable Objects. It has screen sharing, client-side noise-canceling, and background blur. It is written with TypeScript and React and is available on GitHub.

We’re hiring

We think the current state of Cloudflare Calls enables many use cases. Calls already supports publishing and subscribing to media tracks and DataChannels. Soon, it will support features like simulcasting.

But we’re just scratching the surface and there is so much more to build on top of this foundation.

If you are passionate about WebRTC (and other real-time protocols!!), the Media Platform team building the Calls product at Cloudflare is hiring and would love to talk to you.

Improving Cloudflare Workers and D1 developer experience with Prisma ORM

Post Syndicated from Jon Harrell (Guest Author) original https://blog.cloudflare.com/prisma-orm-and-d1

Working with databases can be difficult. Developers face increasing data complexity and needs beyond simple create, read, update, and delete (CRUD) operations. Unfortunately, these issues also compound on themselves: developers have a harder time iterating in an increasingly complex environment. Cloudflare Workers and D1 help by reducing time spent managing infrastructure and deploying applications, and Prisma provides a great experience for your team to work and interact with data.  

Together, Cloudflare and Prisma make it easier than ever to deploy globally available apps with a focus on developer experience. To further that goal, Prisma Object Relational Mapper (ORM) now natively supports Cloudflare Workers and D1 in Preview. With version 5.12.0 of Prisma ORM you can now interact with your data stored in D1 from your Cloudflare Workers with the convenience of the Prisma Client API. Learn more and try it out now.

What is Prisma?

From writing to debugging, SQL queries take a long time and slow developer productivity. Even before writing queries, modeling tables can quickly become unwieldy, and migrating data is a nerve-wracking process. Prisma ORM looks to resolve all of these issues by providing an intuitive data modeling language, an automated migration workflow, and a developer-friendly and type-safe client for JavaScript and TypeScript, allowing developers to focus on what they enjoy: developing!

Prisma is focused on making working with data easy. Alongside an ORM, Prisma offers Accelerate and Pulse, products built on Cloudflare that cover needs from connection pooling, to query caching, to real-time type-safe database subscriptions.

How to get started with Prisma ORM, Cloudflare Workers, and D1

To get started with Prisma ORM and D1, first create a basic Cloudflare Workers app. This guide will start with the ”Hello World” Worker example app, but any Workers example app will work. If you don’t have a project yet, start by creating a new one. Name your project something memorable, like my-d1-prisma-app and select “Hello World” worker and TypeScript. For now, we will choose to not deploy and will wait until after we have set up D1 and Prisma ORM.

npm create cloudflare@latest

Next, move into your newly created project and make sure that dependencies are installed:

cd my-d1-prisma-app && npm install

After dependencies are installed, we can move on to the D1 setup.

First, create a new D1 database for your app.

npx wrangler d1 create prod-prisma-d1-app

binding = "DB" # i.e. available in your Worker on env.DB
database_name = "prod-prisma-d1-app"
database_id = "<unique-ID-for-your-database>"

The section starting with [[d1_databases]] is the binding configuration needed in your wrangler.toml for your Worker to communicate with D1. Add that now:

// wrangler.toml
main = "src/index.ts"
compatibility_date = "2024-03-20"
compatibility_flags = ["nodejs_compat"]

binding = "DB" # i.e. available in your Worker on env.DB
database_name = "prod-prisma-d1-app"
database_id = "<unique-ID-for-your-database>"

Your application now has D1 available! Next, add Prisma ORM to manage your queries, schema and migrations! To add Prisma ORM, first make sure the latest version is installed. Prisma ORM versions 5.12.0 and up support Cloudflare Workers and D1.

npm install prisma@latest @prisma/client@latest @prisma/adapter-d1

Now run npx prisma init in order to create the necessary files to start with. Since D1 uses SQLite’s SQL dialect, we set the provider to be sqlite.

npx prisma init --datasource-provider sqlite

This will create a few files, but the one to look at first is your Prisma schema file, available at prisma/schema.prisma

// schema.prisma
// This is your Prisma schema file,
// learn more about it in the docs: https://pris.ly/d/prisma-schema

generator client {
  provider = "prisma-client-js"

datasource db {
  provider = "sqlite"
  url  = env("DATABASE_URL")

Before you can create any models, first enable the driverAdapters Preview feature. This will allow the Prisma Client to use an adapter to communicate with D1.

// schema.prisma
// This is your Prisma schema file,
// learn more about it in the docs: https://pris.ly/d/prisma-schema

generator client {
  provider = "prisma-client-js"
+ previewFeatures = ["driverAdapters"]

datasource db {
  provider = "sqlite"
  url      = env("DATABASE_URL")

Now you are ready to create your first model! In this app, you will be creating a “ticker”, a mainstay of many classic Internet sites.

Add a new model to your schema, Visit, which will track that an individual visited your site. A Visit is a simple model that will have a unique ID and the time at which an individual visited your site.

// This is your Prisma schema file,
// learn more about it in the docs: https://pris.ly/d/prisma-schema

generator client {
  provider        = "prisma-client-js"
  previewFeatures = ["driverAdapters"]

datasource db {
  provider = "sqlite"
  url      = env("DATABASE_URL")

+ model Visit {
+   id        Int      @id @default(autoincrement())
+   visitTime DateTime @default(now())
+ }

Now that you have a schema and a model, let’s create a migration. First use wrangler to generate an empty migration file and prisma migrate to fill it. If prompted, select “yes” to create a migrations folder at the root of your project.

npx wrangler d1 migrations create prod-prisma-d1-app init
 ⛅️ wrangler 3.36.0
✔ No migrations folder found. Set `migrations_dir` in wrangler.toml to choose a different path.
Ok to create /path/to/your/project/my-d1-prisma-app/migrations? … yes
✅ Successfully created Migration '0001_init.sql'!

The migration is available for editing here
npx prisma migrate diff --script --from-empty --to-schema-datamodel ./prisma/schema.prisma >> migrations/0001_init.sql

The npx prisma migrate diff command takes the difference between your database (which is currently empty) and the Prisma schema. It then saves this difference to a new file in the migrations directory.

// 0001_init.sql
-- Migration number: 0001 	 2024-03-21T22:15:50.184Z
-- CreateTable

Now you can migrate your local and remote D1 database instances using wrangler and re-generate your Prisma Client to begin making queries.

npx wrangler d1 migrations apply prod-prisma-d1-app --local
npx wrangler d1 migrations apply prod-prisma-d1-app --remote
npx prisma generate

Make sure to import PrismaClient and PrismaD1, define the binding for your D1 database, and you’re ready to use Prisma in your application.

// src/index.ts
import { PrismaClient } from "@prisma/client";
import { PrismaD1 } from "@prisma/adapter-d1";

export interface Env {
  DB: D1Database,

export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext): Promise<Response> {
    const adapter = new PrismaD1(env.DB);
    const prisma = new PrismaClient({ adapter });
    const { pathname } = new URL(request.url);

    if (pathname === '/') {
      const numVisitors = await prisma.visit.count();
      return new Response(
        `You have had ${numVisitors} visitors!`

    return new Response('');

You may notice that there’s always 0 visitors. Add another route to create a new visitor whenever someone visits the /visit route

// src/index.ts
import { PrismaClient } from "@prisma/client";
import { PrismaD1 } from "@prisma/adapter-d1";

export interface Env {
  DB: D1Database,

export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext): Promise<Response> {
    const adapter = new PrismaD1(env.DB);
    const prisma = new PrismaClient({ adapter });
    const { pathname } = new URL(request.url);

    if (pathname === '/') {
      const numVisitors = await prisma.visit.count();
      return new Response(
        `You have had ${numVisitors} visitors!`
    } else if (pathname === '/visit') {
      const newVisitor = await prisma.visit.create({ data: {} });
      return new Response(
        `You visited at ${newVisitor.visitTime}. Thanks!`

    return new Response('');

Your app is now set up to record visits and report how many visitors you have had!

Summary and further reading

We were able to build a simple app easily with Cloudflare Workers, D1 and Prisma ORM, but the benefits don’t stop there! Check the official documentation for information on using Prisma ORM with D1 along with workflows for migrating your data, and even extending the Prisma Client for your specific needs.

Data Anywhere with Pipelines, Event Notifications, and Workflows

Post Syndicated from Matt Silverlock original https://blog.cloudflare.com/data-anywhere-events-pipelines-durable-execution-workflows

Data is fundamental to any real-world application: the database storing your user data and inventory, the analytics tracking sales events and/or error rates, the object storage with your web assets and/or the Parquet files driving your data science team, and the vector database enabling semantic search or AI-powered recommendations for your users.

When we first announced Workers back in 2017, and then Workers KV, Cloudflare R2, and D1, it was obvious that the next big challenge to solve for developers would be in making it easier to ingest, store, and query the data needed to build scalable, full-stack applications.

To that end, as part of our quest to make building stateful, distributed-by-default applications even easier, we’re launching our new Event Notifications service; a preview of our upcoming streaming ingestion product, Pipelines; and a sneak peek into our take on durable execution, Workflows.

Event-based architectures

When you’re writing data — whether that’s new data, changing existing data, or deleting old data — you often want to trigger other, asynchronous work to run in response. That could be processing user-driven uploads, updating search indexes as the underlying data changes, or removing associated rows in your SQL database when content is removed.

In order to make these event-driven workflows far easier to build across Cloudflare, we’re launching the first step towards a wider Event Notifications platform across Cloudflare, starting with notifications support in R2.

You can read more in the deep-dive on Event Notifications for R2, but in a nutshell: you can configure changes to content in any R2 bucket to write directly to a Queue, allowing you to reliably consume those events in a Worker or to pull from compute in a legacy cloud.

Event Notifications for R2 are just the beginning, though. There are many kinds of events you might want to trigger as a developer — these are just some of the event types we’re planning to support:

  • Changes (writes) to key-value pairs in your Workers KV namespaces.
  • Updates to your D1 databases, including changed rows or triggers.
  • Deployments to your Cloudflare Workers

Consuming event notifications from a single Worker is just one approach, though. As you start to consume events, you may want to trigger multi-step workflows that execute reliably, resume from errors or exceptions, and ensure that previous steps aren’t duplicated or repeated unnecessarily. An event notification framework turns out to be just the thing needed to drive a workflow engine that executes durably

Making it even easier to ingest data

When we launched Cloudflare R2, our object storage service, we knew that supporting the de facto-standard S3 API was critical in order to allow developers to bring the tooling and services they already had over to R2. But the S3 API is designed to be simple: at its core, it provides APIs for upload, download, multipart and metadata operations, and many tools don’t support the S3 API.

What if you want to batch clickstream data from your web services so that it’s efficient (and cost-effective) to query by your analytics team? Or partition data by customer ID, merchant ID, or locale within a structured data format like JSON?

Well, we want to help solve this problem too, and so we’re announcing Pipelines, an upcoming streaming ingestion service designed to ingest data at scale, aggregate it, and write it directly to R2, without you having to manage infrastructure, partitions, runners, or worry about durability.

With Pipelines, creating a globally scalable ingestion endpoint that can ingest tens-of-thousands of events per second doesn’t require any code:

$ wrangler pipelines create clickstream-ingest-prod --batch-size="1MB" --batch-timeout-secs=120 --batch-on-json-key=".merchantId" --destination-bucket="prod-cs-data"

✅ Successfully created new pipeline "clickstream-ingest-prod"
📥 Created endpoints:
➡ HTTPS: https://d458dbe698b8eef41837f941d73bc5b3.pipelines.cloudflarestorage.com/clickstream-ingest-prod
➡ WebSocket: wss://d458dbe698b8eef41837f941d73bc5b3.pipelines.cloudflarestorage.com:8443/clickstream-ingest-prod
➡ Kafka: d458dbe698b8eef41837f941d73bc5b3.pipelines.cloudflarestorage.com:9092 (topic: clickstream-ingest-prod)

As you can see here, we’re already thinking about how to make Pipelines protocol-agnostic: write from a HTTP client, stream events over a WebSocket, and/or redirect your existing Kafka producer (and stop having to manage and scale Kafka) directly to Pipelines.

But that’s just the beginning of our vision here. Scalable ingestion and simple batching is one thing, but what about if you have more complex needs? Well, we have a massively scalable compute platform (Cloudflare Workers) that can help address this too.

The code below is just an initial exploration for how we’re thinking about an API for running transforms over streaming data. If you’re aware of projects like Apache Beam or Flink, this programming model might even look familiar:

export default {    
   // Pipeline handler is invoked when batch criteria are met
   async pipeline(stream: StreamPipeline, env: Env, ctx: ExecutionContext): Promise<StreamingPipeline> {
      // ...
      return stream
         // Type: transform(label: string, transformFunc: TransformFunction): Promise<StreamPipeline>
         // Each transform has a label that is used in metrics to provide
    // per-transform observability and debugging
         .transform("human readable label", (events: Array<StreamEvent>) => {
            return events.map((e) => ...)
         .transform("another transform", (events: Array<StreamEvent>) => {
            return events.map((e) => ...)
            format: "json",
            bucket: "MY_BUCKET_NAME",
            prefix: somePrefix,
            batchSize: "10MB"


  • The Worker describes a pipeline of transformations (mapping, reducing, filtering) that operates over each subset of events (records)
  • You can call out to other services — including D1 or KV — in order to synchronously or asynchronously hydrate data or lookup values during your stream processing
  • We take care of scaling horizontally based on records-per-second and/or any concurrency settings you configure based on processing latency requirements.

We’ll be bringing Pipelines into open beta later in 2024, and it will initially launch with support for HTTP ingestion and R2 as a destination (sink), but we’re already thinking bigger.

We’ll be sharing more as Pipelines gets closer to release. In the meantime, you can register your interest and share your use-case, and we’ll reach out when Pipelines reaches open beta.

Durable Execution

If the term “Durable Execution” is new to you, don’t worry: the term comes from the desire to run applications that can resume execution from where they left off, even if the underlying host or compute fails (where the “durable” part comes from).

As we’ve continued to build out our data and AI platforms, we’ve been acutely aware that developers need ways to create reliable, repeatable workflows that operate over that data, turn unstructured data into structured data, trigger on fresh data (or periodically), and automatically retry, restart, and export metrics for each step along the way. The industry calls this Durable Execution: we’re just calling it Workflows.

What makes Workflows different from other takes on Durable Execution is that we provide the underlying compute as part of the platform. You don’t have to bring-your-own compute, or worry about scaling it or provisioning it in the right locations. Workflows runs on top of Cloudflare Workers – you write the workflow, and we take care of the rest.

Here’s an early example of writing a Workflow that generates text embeddings using Workers AI and stores them (ready to query) in Vectorize as new content is written to (or updated within) R2.

  • Each Workflow run is triggered by an Event Notification consumed from a Queue, but could also be triggered by a HTTP request, another Worker, or even scheduled on a timer.
  • Individual steps within the Workflow allow us to define individually retriable units of work: in this case, we’re reading the new objects from R2, creating text embeddings using Workers AI, and then inserting.
  • State is durably persisted between steps: each step can emit state, and Workflows will automatically persist that so that any underlying failures, uncaught exceptions or network retries can resume execution from the last successful step.
  • Every call to step() automatically emits metrics associated with the unique Workflow run, making it easier to debug within each step and/or break down your application into its smallest units of execution, without having to worry about observability.

Step-by-step, it looks like this:

Transforming this series of steps into real code, here’s what this would look like with Workflows:

import { Ai } from "@cloudflare/ai";
import { Workflow } from "cloudflare:workers";

export interface Env {
  R2: R2Bucket;
  AI: any;
  VECTOR_INDEX: VectorizeIndex;

export default class extends Workflow {
  async run(event: Event) {
    const ai = new Ai(this.env.AI);

    // List of keys to fetch from our incoming event notification
    const keysToFetch = event.messages.map((val) => {
      return val.object.key;

    // The return value of each step is stored (the "durable" part
    // of "durable execution")
    // This ensures that state can be persisted between steps, reducing
    // the need to recompute results ($$, time) should subsequent
    // steps fail.
    const inputs = await this.ctx.run(
      // Each step has a user-defined label
      // Metrics are emitted as each step runs (to success or failure)
// with this label attached and available within per-Workflow
// analytics in near-real-time.
"read objects from R2", async () => {
      const objects = [];

      for (const key of keysToFetch) {
        const object = await this.env.R2.get(key);
        objects.push(await object.text());

      return objects;

    // Persist the output of this step.
    const embeddings = await this.ctx.run(
      "generate embeddings",
      async () => {
        const { data } = await ai.run("@cf/baai/bge-small-en-v1.5", {
          text: inputs,

        if (data.length) {
          return data;
        } else {
          // Uncaught exceptions trigger an automatic retry of the step
          // Retries and timeouts have sane defaults and can be overridden
    // per step
          throw new Error("Failed to generate embeddings");
        retries: {
          limit: 5,
          delayMs: 1000,
          backoff: "exponential",

    await this.ctx.run("insert vectors", async () => {
      const vectors = [];

      keysToFetch.forEach((key, index) => {
          id: crypto.randomUUID(),
          // Our embeddings from the previous step
          values: embeddings[index].values, 
          // The path to each R2 object to map back to during
 	    // vector search
          metadata: { r2Path: key },

      return this.env.VECTOR_INDEX.upsert();

This is just one example of what a Workflow can do. The ability to durably execute an application, modeled as a series of steps, applies to a wide number of domains. You can apply this model of execution to a number of use-cases, including:

  • Deploying software: each step can define a build step and subsequent health check, gating further progress until your deployment meets your criteria for “healthy”.
  • Post-processing user data: triggering a workflow based on user uploads (e.g. to Cloudflare R2) that then subsequently parses that data asynchronously, redacts PII or sensitive data, writes the sanitized output, and triggers a notification via email, webhook, or mobile push.
  • Payment and batch workflows: aggregating raw customer usage data on a periodic schedule by querying your data warehouse (or Workers Analytics Engine), triggering usage or spend alerts, and/or generating PDF invoices.

Each of these use cases model tasks that you want to run to completion, minimize redundant retries by persisting intermediate state, and (importantly) easily observe success and failure.

We’ll be sharing more about Workflows during the second quarter of 2024 as we work towards an open (public!) beta. This includes how we’re thinking about idempotency and interactions with our storage, per-instance observability and metrics, local development, and templates to bootstrap common workflows.

Putting it together

We’ve often thought of Cloudflare’s own network as one massively scalable parallel data processing cluster: data centers in 310+ cities, with the ability to run compute close to users and/or close to data, keep it within the bounds of regulatory or compliance requirements, and most importantly, use our massive scale to enable our customers to scale as well.

Recapping, a fully-fledged data platform needs to enable three things:

  1. Ingesting data: getting data into the platform (in the right format, from the right sources)
  2. Storing data: securely, reliably, and durably.
  3. Querying data: understanding and extracting insights from the data, and/or transforming it for use by other tools.

When we launched R2 we tackled the second part, but knew that we’d need to follow up with the first and third parts in order to make it easier for developers to get data in and make use of it.

If we look at how we can build a system that helps us solve each of these three parts together with Pipelines, Event Notifications, R2, and Workflows, we end up with an architecture that resembles this:

Specifically, we have Pipelines (1) scaling out to ingest data, batch it, filter it, and then durably store it in R2 (2) in a format that’s ready and optimized for querying. Workflows, ClickHouse, Databricks, or the query engine of your choice can then query (3) that data as soon as it’s ready — with “ready” being automatically triggered by an Event Notification as soon as the data is ingested and written to R2.

There’s no need to poll, no need to batch after the fact, no need to have your query engine slow down on data that wasn’t pre-aggregated or filtered, and no need to manage and scale infrastructure in order to keep up with load or data jurisdiction requirements. Create a Pipeline, write your data directly to R2, and query directly from it.

If you’re also looking at this and wondering about the costs of moving this data around, then we’re holding to one important principle: zero egress fees across all of our data products. Just as we set the stage for this with our R2 object storage, we intend to apply this to every data product we’re building, Pipelines included.

Start Building

We’ve shared a lot of what we’re building so that developers have an opportunity to provide feedback (including via our Developer Discord), share use-cases, and think about how to build their next application on Cloudflare.

R2 adds event notifications, support for migrations from Google Cloud Storage, and an infrequent access storage tier

Post Syndicated from Matt DeBoard original https://blog.cloudflare.com/r2-events-gcs-migration-infrequent-access

We’re excited to announce three new features for Cloudflare R2, our zero egress fee object storage platform:

Event Notifications Open Beta

The lifecycle of data often doesn’t stop immediately after upload to an R2 bucket – event data may need to be transformed and loaded into a data warehouse, media files may need to go through a post-processing step, etc. We’re releasing event notifications for R2 in open beta to enable building applications and workflows driven by your changing data.

Event notifications work by sending messages to your queue each time there is a change to your data. These messages are then received by a consumer Worker where you can then define any subsequent action that needs to be taken.

To get started enabling event notifications on your R2 bucket, you can run the following Wrangler command (replacing bucket_name and queue_name with your bucket and queue names respectively):

wrangler r2 bucket notification create <bucket_name> --event-type object-create --queue <queue_name>

For more information on how to set up event notifications on your R2 buckets today and limitations during beta, please refer to the documentation.

Super Slurper for Google Cloud Storage

Super Slurper can now migrate data from Google Cloud Storage (GCS) to Cloudflare R2. We released Super Slurper last year with the goal of making one-time comprehensive data migrations fast, reliable, and easy: there’s no need to spin up migration VMs and implement complicated retry logic. Since then, thousands of developers have used Super Slurper to migrate petabytes of data from AWS S3 to R2. Now Google Cloud Storage customers can migrate data to Cloudflare R2 to benefit from Cloudflare’s zero egress fees, whether you are permanently moving data to another provider or not.

To get started migrating data from GCS:

  1. From the Cloudflare dashboard, select R2 > Data Migration.
  2. Select Migrate files.
  3. Select Google Cloud Storage for the source bucket provider.
  4. Enter your bucket name and associated credentials and select Next.
  5. Enter your R2 bucket name and associated credentials and select Next.
  6. After you finish reviewing the details of your migration, select Migrate files.

You can view the status of your migration job at any time on the dashboard. For more information on how to use Super Slurper, please refer to the documentation here.

Infrequent Access Private Beta

We’re excited to introduce the private beta of our new Infrequent Access storage class. For use cases that involve data that isn’t frequently accessed (long tail user-generated content, logs, etc), Infrequent Access gives you the ability to pay less for storage while maintaining performance and durability.

Here’s an example of how you can upload an object to your R2 bucket with the new Infrequent Access storage class using Workers:

# wrangler.toml
binding = 'MY_BUCKET'
bucket_name = '<YOUR_BUCKET_NAME>'

# index.ts
export default {
   async fetch(request: Request, env: Env): Promise<Response> {
      if (request.method === "PUT") {
         await env.MY_BUCKET.put("myobject", request.body, storageClass: "InfrequentAccess");
         return new Response("Put object successfully!");
      return new Response("Not a PUT!");

In addition to uploading objects directly to Infrequent Access, you can define an object lifecycle policy to move data to Infrequent Access after a period of time goes by and you no longer need to access your data as often. In the future, we plan to automatically optimize storage classes for data so you can avoid manually creating rules and better adapt to changing data access patterns.

For data stored in the Infrequent Access storage class, the pricing components will be similar to what you’re used to with R2: storage, Class A operations (writes, lists), Class B operations (reads), and data retrieval (processing). Data retrieval is charged per GB when data in the Infrequent Access storage class is retrieved and is what allows us to provide storage at a lower price. It reflects the additional computational resources required to fetch data from underlying storage optimized for less frequent access. And when the time comes, and you do need to use your data, there are still no egress fees.

Component Price
Storage $0.01 / GB-month
Class A Operations $9.00 / million requests
Class B Operations $0.90 / million requests
Data Retrieval (Processing) $0.01 / GB
Egress (or Data Transfer) $0 – No Charge

Are you interested in participating in the private beta for Infrequent Access?

Join the private beta waitlist to get access.

Have any feedback?

We would love to hear from you! To share your feedback about R2 and our data migration services, please join the Cloudflare Developer Discord. If you’re interested in learning more about R2, get started by visiting R2’s developer documentation or see how much you could save with our pricing calculator.

How Picsart leverages Cloudflare’s Developer Platform to build globally performant services

Post Syndicated from Mark Dembo original https://blog.cloudflare.com/picsart-move-to-workers-huge-performance-gains

Delivering great user experiences with a global user base can be challenging. While serving requests quickly when you start out in a local market is straightforward, doing so for a global audience is much more difficult. Why? Even under optimal conditions, you cannot be faster than the speed of light, which brings single data center solutions to their performance limits.

In this post, we will cover how Picsart improved the performance of one of its most critical services by moving from a centralized architecture to a globally distributed service built on Cloudflare. Our serverless compute platform, Workers, distributed throughout 310+ cities around the world, and our globally distributed Workers KV storage allowed them to improve their performance significantly and drive real business impact.

Success driven by data-driven insights

Picsart is one of the world’s largest digital creation platforms and a long-standing Cloudflare partner. At its core, an advanced tech stack powers its comprehensive features, including AI-driven photo and video editing tools and community-driven content sharing. With its infrastructure spanning across multiple cloud environments and on-prem deployments, Picsart is engineered to handle billions of daily requests from its huge mobile and web user base and API integrations. For over a decade, Cloudflare has been integral to Picsart, providing support for performant content delivery and securing its digital ecosystem.  

Similar to many other tech giants, Picsart approaches product development in a data-driven way. At the core of the innovation is Picsart’s remote configuration and experimentation platform, which enables product managers, UX researchers, and others to segment their user base into different test groups. These test groups might get to see slightly different implementations of features or designs of the Picsart app. Users might also get early access to experimental features or see different in-app promotions. In combination with constant monitoring of relevant KPIs, this allows for informed product decisions based on user preference and business impact.

On each app start, the client device sends a request to the remote configuration service for the latest setup tailored to the user’s session. The assignment of experiments relies on factors like the operating system and previous sessions, making each request unique and uncachable. Picsart’s app showcases extensive remote configuration capabilities, enabling adjustments to nearly every element. This results in a response containing a 1.5 MB configuration file for mobile clients. While the long-term solution is to reduce the file size, which has grown over time as more teams adopted the powerful service, this is not possible in the near or mid-term as it requires a major rewrite of all clients.

This setup request is blocking in the “hot path” during app start, as the results of this request will decide how the app itself looks and behaves. Hence, performance is critical. To ensure users are not waiting for too long, Picsart apps will wait for 1500ms on mobile for the request to complete – if it does not, the user will not be assigned a test group and the app will fallback to default settings.

The clock is ticking

While a 1500ms round trip time seems like a sufficiently large time budget, the data suggested otherwise. Before the improvements were implemented, a staggering 50% of devices could not complete the requests in time. How come? In these 1.5 seconds the following steps need to complete:

  1. The request must travel from the users’ devices to the centralized backend servers
  2. The server processes the request based on dozens of user attributes provided in the request and thousands of defined remote configuration variations, running experiments, and segments metadata. Using all the info, the server selects the right variation of each remote setting entry and builds the response payload.
  3. The response must travel from the centralized backend servers to the user devices.

Looking at the data, it was clear to the Picsart team that their backend service was already well-optimized, taking only 30 milliseconds, a tiny fraction of the available time budget, to process each of the billions of monthly requests. The bulk of the request time came from network latency. Especially with mobile devices, last mile performance can be very volatile, eating away a significant amount of the available time budget. Not only that, but the data was clear: users closer to the origin server had a much higher chance of making the round trip in time versus users out of region. It quickly became obvious that Picsart, fueled by its global success, had outgrown a single-region setup.

To the drawing board

A solution that comes to mind would be to replicate the existing cloud infrastructure in multiple regions and use global load balancing to minimize the distance a request needs to travel. However, this introduces significant overhead and cost. On the infrastructure side, it is not only the additional compute instances and database clusters that incur cost, but also cross-region data transfer to keep data in sync. Moreover, technical teams would need to operate and monitor infrastructure in multiple regions, which can add a lot to the complexity and cognitive load, leading to decreased development velocity and productivity loss.

Picsart instead looked to Cloudflare – we already had a long-lasting relationship for Application Performance and Security, and they aimed to use our Developer Platform to tackle the problem.

Workers and Workers KV seemed like the ideal solution. Both compute and data are globally distributed in 310+ locations around the world, resulting in a shorter distance between end users and the experimentation service. Not only that, but Cloudflare’s global-by-default approach allows for deployment with minimal overhead, and in contrast to other considered solutions, no additional fees to distribute the data around the globe.

No race without a clock

The objective for the refactor of the experimentation service was to increase the share of devices that successfully receive experimentation configuration within the set time budget.

But how to measure success? While synthetic testing can be useful in many situations, Picsart opted to come up with another clever solution:

During development, the Picsart engineers had already added a testing endpoint to the web and mobile versions of their app that sends a duplicate request to the new endpoint, discarding the response and swallowing all potential errors. This allows them to collect timing data based on real-user metrics without impacting the app’s performance and reliability.

A simplified version of this pattern for a web client could look like this:

// API endpoint URLs
const prodUrl = 'https://prod.example.com/';
const devUrl = 'https://new.example.com/';

// Function to collect metrics
const collectMetrics = (duration) => {
    console.log('Request duration:', duration);
    // …

// Function to fetch data from an endpoint and call collectMetrics
const fetchData = async (url, options) => {
    const startTime = performance.now();
    try {
        const response = await fetch(url, options);
        const endTime = performance.now();
        const duration = endTime - startTime;
        return await response.json();
    } catch (error) {
        console.error('Error fetching data:', error);

// Fetching data from both endpoints
async function fetchDataFromBothEndpoints() {
    try {
        const result1 = await fetchData(prodUrl, { method: 'POST', ... });
        console.log('Result from endpoint 1:', result1);

        // Fetching data from the second endpoint without awaiting its completion
        fetchData(devUrl, { method: 'POST', ... });
    } catch (error) {
        console.error('Error fetching data from both endpoints:', error);


Using existing data analytics tools, Picsart was able to analyze the performance of the new services from day one, starting with a dummy endpoint and a ‘hello world’ response. And with that a v0 was created that did not have the correct logic just yet, but simulated reading multiple values from KV and returning a response of a realistic size back to the end user.

The need for a do-over

In the initial phase, outcomes fell short of expectations. Surprisingly, requests were slower despite the service’s proximity to end users. What caused this setback?  Subsequent investigation unveiled multiple culprits and design patterns in need for optimization.

Data segmentation

The previous, stateful solution operated on a single massive “blob” of data exceeding 100MB in value. Loading this into memory incurred a few seconds of initial startup time, but once the VM completed the task, request handling was fast, benefiting from the readily available data in memory.

However, this approach doesn’t seamlessly transition to the serverless realm. Unlike long-running VMs, Worker isolates have short lifespans. Repeatedly parsing large JSON objects led to prolonged compute durations. Simply parsing four KV entries of 25MB each (KV maximum value size is 25MB) on each request was not a feasible option.

The Picsart team went back to solution design and embarked on a journey to optimize their system’s execution time, resulting in a series of impactful improvements.

The fundamental insight that guided the solution was the unnecessary overhead that was involved in loading and parsing data irrelevant to the user’s specific context. The 100MB configuration file contained configurations for all platforms and locations worldwide – a setup that was far from efficient in a globally distributed, serverless compute environment. For instance, when processing requests from users in the United States, there was no need to fetch configurations targeted for users in other countries, or for different platforms.

To address this inefficiency, the Picsart team stored the configuration of each platform and country in separate KV records. This targeted strategy meant that for a request originating from a US user on an Android device, our system would only fetch and parse the KV record specific to Android users in the US, thereby excluding all irrelevant data. This resulted in approximately 600 KV records, each with a maximum size of 10MB. While this leads to data duplication on the KV storage side, it decreases the amount of data that needs to be parsed upon request. As Cloudflare operates in over 120 countries around the world, only a subset of records were needed in each location. Hence, the increase in cardinality had minimal impact on KV cache performance, as demonstrated by more than 99.5% of KV reads being served from local cache.

Key Size
settings_part1.json 25MB
settings_part2.json 25MB

Before (simplified)

Key Size
com.picsart.studio_apple_us.json 6.1MB
com.picsart.studio_apple_de.json 6.1MB
com.picsart.studio_android_us.json 5.9MB

After (simplified)

This approach was a significant move for Picsart as they transitioned from a regional cloud setup to Cloudflare’s globally distributed connectivity cloud. By serving data from close proximity to end user locations, they were able to combat the high network latency from their previous setup. This strategy radically transformed the data-handling process. which unlocked two major benefits:

  • Performance Gains: By ensuring that only the relevant subset of data is fetched and parsed based on the user’s platform and geographical location, wall time and compute resources required for these operations could be significantly reduced.
  • Scalability and Flexibility: the granular segmentation of data enables effortless scaling of the service for new features or regional content. Adding support for new applications now only requires inserting new, standalone KV records in contrast to the previous solution where this would require increasing the size of the single record.

Immutable updates

Now that changes to the configuration were segmented by app, country, and platform, this also allowed for individual updates of the configuration in KV. KV storage showcases its best performance when records are updated infrequently but read very often. This pattern leverages KV’s fundamental design to cache values at edge locations upon reads, ensuring that subsequent queries for the same record are swiftly served by local caches rather than requiring a trip back to KV’s centralized data centers. This architecture is fundamental for minimizing latency and maximizing the speed of data retrieval across a globally distributed platform.

A crucial requirement for Picsart’s experimentation system was the ability to propagate updates of remote configuration values immediately. Updating existing records would require very short cache TTLs and even the minimum KV cache TTL of 60 seconds was considered unacceptable for the dynamic nature of the feature flagging. Moreover, setting short TTLs also impacts the cache hit ratio and the overall KV performance, specifically in regions with low traffic.

To reconcile the need for both rapid updates and efficient caching, Picsart adopted an innovative approach: making KV records immutable. Instead of modifying existing records, they opted to create new records with each configuration change. By appending the content hash to the KV key and writing new records after each update, Picsart ensured that each record was unique and immutable. This allowed them to leverage higher cache TTLs, as these records would never be updated.

Key Size
com.picsart.studio_apple_us.json 60s

Before (simplified)

Key Size
com.picsart.studio_apple_us_b58b59.json 86400s
com.picsart.studio_apple_us_273678.json 86400s

After (simplified)

There was a catch, though. The service must now keep track of the correct KV keys to use. The Picsart team addressed this challenge by storing references to the latest KV keys in the environment variables of the Worker.

Each configuration change triggers a new KV pair to be written and the services’ environment variables to be updated. As global Workers deployments take mere seconds, changes to the experimentation and configuration data are near-instantaneously globally available.

JSON serialization & alternatives

Following the previous improvements, the Picsart team made another significant discovery: only a small fraction of configuration data is needed to assign the experiments, while the remaining majority of the data comprises JSON values for the remote configuration payloads. While the service must deliver the latter in the response, the data is not required during the initial processing phase.

The initial implementation used KV’s get() method to retrieve the configuration data with the parameter type=json, which converts the KV value to an object. This process is very compute-intensive compared to using the get() method with parameter type= text, which simply returns the value as a string. In the context of Picsart’s data, the bulk of the CPU cycles were wasted on serializing JSON data that is not needed to perform the required business logic.

What if the data structure and code could be changed in such a way that only the data needed to assign experiments was parsed as JSON, while the configuration values were treated as text? Picsart went ahead with a new approach: splitting the KV records into two, creating a small 300KB record for the metadata, which can be quickly parsed to an object, and a 9.7MB record of configuration values. The extracted configuration values are delimited by newline characters. The respective line number is used as reference in the metadata entry, so that the respective configuration value for an experiment can be merged back into the payload response later.

  "name": "shape_replace_items",
  "default_value": "<large json object>",
  "segments": [
      "id": "f1244",
      "value": "<Another json object
json object>"
      "id": "a2lfd",
      "value": "<Yet another large json
Before: Metadata and Values in one JSON object (simplified)

// com.picsart.studio_apple_am_metadata

1 {
2   "name": "shape_replace_items",
3   "default_value": 1,
4   "segments": [
5     {
6       "id": "f1244",
7       "value": 2
8     },
9     {
10       "id": "a2lfd",
11      "value": 3
12     }
13   ]
14 }

// com.picsart.studio_apple_am_values

1 "<large json object>"
2 "<Another json object>"
3 "<Yet another json object>"

After: Metadata and Values are split (simplified)

After calculating the experiments and selecting the correct variants based solely on the small metadata entry, the service constructs a JSON string for the response containing placeholders for the actual values that reference the corresponding line numbers in the separate text file. To finalize the response, the server replaces the placeholders with the corresponding serialized JSON strings from the text file. This approach circumvents the need for parsing and re-serializing large JSON objects and helps to avoid a significant computational overhead.

Note that the process of parsing the metadata JSON and determining the correct experiments as well as the loading of the large file with configuration values are executed in parallel, saving additional milliseconds.

By minimizing the size of the JSON data that needed to be parsed and leveraging a more efficient method for constructing the final response, the Picsart team managed to not only reduce the response times but also optimize the compute resource usage. This approach reflects a broader principle applicable across the tech industry: that efficiency, particularly in serverless architectures, can often be dramatically improved by rethinking data structure and utilization.

Getting a head start

The changes on the server-side, moving from a single region setup to Cloudflare’s global architecture, paid off massively. Median response times globally dropped by more than 1 second, which was already a huge improvement for the team. However, in looking at the new data, two more paths for client-side optimizations were found.

As the web and mobile app would call the service at startup, most of the time no active connections to the servers were alive and establishing that connection at request time costs valuable milliseconds.

For the web version, setting a pre-connect header on initial page load showed a positive impact. For the mobile app version, the Picsart team took it a step further. Investigation showed that before the connection could be established, three modules had to complete initialization: the error tracker, the HTTP client, and the SDK. Reordering of the modules to initialize the HTTP client first allowed for connection establishment in parallel to the initialization of the SDK and error tracker, again saving time. This resulted in another 200ms improvement for end users.

Setting a new personal best

The day had come and it was time for the phased rollout, web first and the mobile apps second. With suspense, the team looked at the dashboards, and were pleasantly surprised. The rollout was successful and billions of requests were handled with ease.

Share of successfully delivered experiments

The result? The Picsart apps are loading faster than ever for millions of users worldwide, while the share of successfully delivered experiments increased from 50% to 85%. Median response time dropped from 1500 ms to 280 ms. The response time dropped to 70 ms on the web since the response size is smaller compared to mobile. This translates to a real business impact for Picsart as they can now deliver more personalized and data-driven experiences to even more of their users.

A bright future ahead

Picsart is already thinking of the next generation of experimentation. To integrate with Cloudflare even further, the plan is to use Durable Objects to store hundreds of millions of user data records in a decentralized fashion, enabling even more powerful experiments without impacting performance. This is possible thanks to Durable Objects’ underlying architecture that stores the user data in-region, close to the respective end user device.

Beyond that, Picsart’s experimentation team is also planning to onboard external B2B customers to their experimentation platform as Cloudflare’s developer platform provides them with the scale and global network to handle more traffic and data with ease.

Get started yourself

If you’re also working on or with an application that would benefit from Cloudflare’s speed and scale, check out our developer documentation and tutorials, and join our developer Discord to get community support and inspiration.

Running fine-tuned models on Workers AI with LoRAs

Post Syndicated from Michelle Chen original https://blog.cloudflare.com/fine-tuned-inference-with-loras

Inference from fine-tuned LLMs with LoRAs is now in open beta

Today, we’re excited to announce that you can now run fine-tuned inference with LoRAs on Workers AI. This feature is in open beta and available for pre-trained LoRA adapters to be used with Mistral, Gemma, or Llama 2, with some limitations. Take a look at our product announcements blog post to get a high-level overview of our Bring Your Own (BYO) LoRAs feature.

In this post, we’ll do a deep dive into what fine-tuning and LoRAs are, show you how to use it on our Workers AI platform, and then delve into the technical details of how we implemented it on our platform.

What is fine-tuning?

Fine-tuning is a general term for modifying an AI model by continuing to train it with additional data. The goal of fine-tuning is to increase the probability that a generation is similar to your dataset. Training a model from scratch is not practical for many use cases given how expensive and time consuming they can be to train. By fine-tuning an existing pre-trained model, you benefit from its capabilities while also accomplishing your desired task. Low-Rank Adaptation (LoRA) is a specific fine-tuning method that can be applied to various model architectures, not just LLMs. It is common that the pre-trained model weights are directly modified or fused with additional fine-tune weights in traditional fine-tuning methods. LoRA, on the other hand, allows for the fine-tune weights and pre-trained model to remain separate, and for the pre-trained model to remain unchanged. The end result is that you can train models to be more accurate  at specific tasks, such as generating code, having a specific personality, or generating images in a specific style. You can even fine-tune an existing LLM to understand additional information about a specific topic.

The approach of maintaining the original base model weights means that you can create new fine-tune weights with relatively little compute. You can take advantage of existing foundational models (such as Llama, Mistral, and Gemma), and adapt them for your needs.

How does fine-tuning work?

To better understand fine-tuning and why LoRA is so effective, we have to take a step back to understand how AI models work. AI models (like LLMs) are neural networks that are trained through deep learning techniques. In neural networks, there are a set of parameters that act as a mathematical representation of the model’s domain knowledge, made up of weights and biases – in simple terms, numbers. These parameters are usually represented as large matrices of numbers. The more parameters a model has, the larger the model is, so when you see models like llama-2-7b, you can read “7b” and know that the model has 7 billion parameters.

A model’s parameters define its behavior. When you train a model from scratch, these parameters usually start off as random numbers. As you train the model on a dataset, these parameters get adjusted bit-by-bit until the model reflects the dataset and exhibits the right behavior. Some parameters will be more important than others, so we apply a weight and use it to show more or less importance. Weights play a crucial role in the model’s ability to capture patterns and relationships in the data it is trained on.

Traditional fine-tuning will adjust all the parameters in the trained model with a new set of weights. As such, a fine-tuned model requires us to serve the same amount of parameters as the original model, which means it can take a lot of time and compute to train and run inference for a fully fine-tuned model. On top of that, new state-of-the-art models, or versions of existing models, are regularly released, meaning that fully fine-tuned models can become costly to train, maintain, and store.

LoRA is an efficient method of fine-tuning

In the simplest terms, LoRA avoids adjusting parameters in a pre-trained model and instead allows us to apply a small number of additional parameters. These additional parameters are applied temporarily to the base model to effectively control model behavior. Relative to traditional fine-tuning methods it takes a lot less time and compute to train these additional parameters, which are referred to as a LoRA adapter. After training, we package up the LoRA adapter as a separate model file that can then plug in to the base model it was trained from. A fully fine-tuned model can be tens of gigabytes in size, while these adapters are usually just a few megabytes. This makes it a lot easier to distribute, and serving fine-tuned inference with LoRA only adds ms of latency to total inference time.

If you’re curious to understand why LoRA is so effective, buckle up — we first have to go through a brief lesson on linear algebra. If that’s not a term you’ve thought about since university, don’t worry, we’ll walk you through it.

Show me the math

With traditional fine-tuning, we can take the weights of a model (W0) and tweak them to output a new set of weights — so the difference between the original model weights and the new weights is ΔW, representing the change in weights. Therefore, a tuned model will have a new set of weights which can be represented as the original model weights plus the change in weights, W0 + ΔW.

Remember, all of these model weights are actually represented as large matrices of numbers. In math, every matrix has a property called rank (r), which describes the number of linearly independent columns or rows in a matrix. When matrices are low-rank, they have only a few columns or rows that are “important”, so we can actually decompose or split them into two smaller matrices with the most important parameters  (think of it like factoring in algebra). This technique is called rank decomposition, which allows us to greatly reduce and simplify matrices while keeping the most important bits. In the context of fine-tuning, rank determines how many parameters get changed from the original model – the higher the rank, the stronger the fine-tune, giving you more granularity over the output.

According to the original LoRA paper, researchers have found that when a model is low-rank, the matrix representing the change in weights is also low-rank. Therefore, we can apply rank decomposition to our matrix representing the change in weights ΔW to create two smaller matrices A, B, where ΔW = BA. Now, the change in the model can be represented by two smaller low-rank matrices. This is why this method of fine-tuning is called Low-Rank Adaptation.

When we run inference, we only need the smaller matrices A, B to change the behavior of the model. The model weights in A, B constitute our LoRA adapter (along with a config file). At runtime, we add the model weights together, combining the original model (W0) and the LoRA adapter (A, B). Adding and subtracting are simple mathematical operations, meaning that we can quickly swap out different LoRA adapters by adding and subtracting A, B from W0.. By temporarily adjusting the weights of the original model, we modify the model’s behavior and output and as a result, we get fine-tuned inference with minimal added latency.

According to the original LoRA paper, “LoRA can reduce the number of trainable parameters by 10,000 times and the GPU memory requirement by 3 times”. Because of this, LoRA is one of the most popular methods of fine-tuning since it’s a lot less computationally expensive than a fully fine-tuned model, doesn’t add any material inference time, and is much smaller and portable.

How can you use LoRAs with Workers AI?

Workers AI is very well-suited to run LoRAs because of the way we run serverless inference. The models in our catalog are always pre-loaded on our GPUs, meaning that we keep them warm so that your requests never encounter a cold start. This means that the base model is always available, and we can dynamically load and swap out LoRA adapters as needed. We can actually plug in multiple LoRA adapters to one base model, so we can serve multiple different fine-tuned inference requests at once.

When you fine-tune with LoRA, your output will be two files: your custom model weights (in safetensors format) and an adapter config file (in json format). To create these weights yourself, you can train a LoRA on your own data using the Hugging Face PEFT (Parameter-Efficient Fine-Tuning) library combined with the Hugging Face AutoTrain LLM library. You can also run your training tasks on services such as Auto Train and Google Colab. Alternatively, there are many open-source LoRA adapters available on Hugging Face today that cover a variety of use cases.

Eventually, we want to support the LoRA training workloads on our platform, but we’ll need you to bring your trained LoRA adapters to Workers AI today, which is why we’re calling this feature Bring Your Own (BYO) LoRAs.

For the initial open beta release, we are allowing people to use LoRAs with our Mistral, Llama, and Gemma models. We have set aside versions of these models which accept LoRAs, which you can access by appending -lora to the end of the model name. Your adapter must have been fine-tuned from one of our supported base models listed below:

  • @cf/meta-llama/llama-2-7b-chat-hf-lora
  • @cf/mistral/mistral-7b-instruct-v0.2-lora
  • @cf/google/gemma-2b-it-lora
  • @cf/google/gemma-7b-it-lora

As we are launching this feature in open beta, we have some limitations today to take note of: quantized LoRA models are not yet supported, LoRA adapters must be smaller than 100MB and have up to a max rank of 8, and you can try up to 30 LoRAs per account during our initial open beta. To get started with LoRAs on Workers AI, read the Developer Docs.

As always, we expect people to use Workers AI and our new BYO LoRA feature with our Terms of Service in mind, including any model-specific restrictions on use contained in the models’ license terms.

How did we build multi-tenant LoRA serving?

Serving multiple LoRA models simultaneously poses a challenge in terms of GPU resource utilization. While it is possible to batch inference requests to a base model, it is much more challenging to batch requests with the added complexity of serving unique LoRA adapters. To tackle this problem, we leverage the Punica CUDA kernel design in combination with global cache optimizations in order to handle the memory intensive workload of multi-tenant LoRA serving while offering low inference latency.

The Punica CUDA kernel was introduced in the paper Punica: Multi-Tenant LoRA Serving as a method to serve multiple, significantly different LoRA models applied to the same base model. In comparison to previous inference techniques, the method offers substantial throughput and latency improvements. This optimization is achieved in part through enabling request batching even across requests serving different LoRA adapters.

The core of the Punica kernel system is a new CUDA kernel called Segmented Gather Matrix-Vector Multiplication (SGMV). SGMV allows a GPU to store only a single copy of the pre-trained model while serving different LoRA models. The Punica kernel design system consolidates the batching of requests for unique LoRA models to improve performance by parallelizing the feature-weight multiplication of different requests in a batch. Requests for the same LoRA model are then grouped to increase operational intensity. Initially, the GPU loads the base model while reserving most of its GPU memory for KV Cache. The LoRA components (A and B matrices) are then loaded on demand from remote storage (Cloudflare’s cache or R2) when required by an incoming request. This on demand loading introduces only milliseconds of latency, which means that multiple LoRA adapters can be seamlessly fetched and served with minimal impact on inference performance. Frequently requested LoRA adapters are cached for the fastest possible inference.

Once a requested LoRA has been cached locally, the speed it can be made available for inference is constrained only by PCIe bandwidth. Regardless, given that each request may require its own LoRA, it becomes critical that LoRA downloads and memory copy operations are performed asynchronously. The Punica scheduler tackles this exact challenge, batching only requests which currently have required LoRA weights available in GPU memory, and queueing requests that do not until the required weights are available and the request can efficiently join a batch.

By effectively managing KV cache and batching these requests, it is possible to handle significant multi-tenant LoRA-serving workloads. A further and important optimization is the use of continuous batching. Common batching methods require all requests to the same adapter to reach their stopping condition before being released. Continuous batching allows a request in a batch to be released early so that it does not need to wait for the longest running request.

Given that LLMs deployed to Cloudflare’s network are available globally, it is important that LoRA adapter models are as well. Very soon, we will implement remote model files that are cached at Cloudflare’s edge to further reduce inference latency.

A roadmap for fine-tuning on Workers AI

Launching support for LoRA adapters is an important step towards unlocking fine-tunes on our platform. In addition to the LLM fine-tunes available today, we look forward to supporting more models and a variety of task types, including image generation.

Our vision for Workers AI is to be the best place for developers to run their AI workloads — and this includes the process of fine-tuning itself. Eventually, we want to be able to run the fine-tuning training job as well as fully fine-tuned models directly on Workers AI. This unlocks many use cases for AI to be more relevant in organizations by empowering models to have more granularity and detail for specific tasks.

With AI Gateway, we will be able to help developers log their prompts and responses, which they can then use to fine-tune models with production data. Our vision is to have a one-click fine-tuning service, where log data from AI Gateway can be used to retrain a model (on Cloudflare) and then the fine-tuned model can be redeployed on Workers AI for inference. This will allow developers to personalize their AI models to fit their applications, allowing for granularity as low as a per-user level. The fine-tuned model can then be smaller and more optimized, helping users save time and money on AI inference – and the magic is that all of this can all happen within our very own Developer Platform.

We’re excited for you to try the open beta for BYO LoRAs! Read our Developer Docs for more details, and tell us what you think on Discord.

Leveling up Workers AI: general availability and more new capabilities

Post Syndicated from Michelle Chen original https://blog.cloudflare.com/workers-ai-ga-huggingface-loras-python-support

Welcome to Tuesday – our AI day of Developer Week 2024! In this blog post, we’re excited to share an overview of our new AI announcements and vision, including news about Workers AI officially going GA with improved pricing, a GPU hardware momentum update, an expansion of our Hugging Face partnership, Bring Your Own LoRA fine-tuned inference, Python support in Workers, more providers in AI Gateway, and Vectorize metadata filtering.

Workers AI GA

Today, we’re excited to announce that our Workers AI inference platform is now Generally Available. After months of being in open beta, we’ve improved our service with greater reliability and performance, unveiled pricing, and added many more models to our catalog.

Improved performance & reliability

With Workers AI, our goal is to make AI inference as reliable and easy to use as the rest of Cloudflare’s network. Under the hood, we’ve upgraded the load balancing that is built into Workers AI. Requests can now be routed to more GPUs in more cities, and each city is aware of the total available capacity for AI inference. If the request would have to wait in a queue in the current city, it can instead be routed to another location, getting results back to you faster when traffic is high. With this, we’ve increased rate limits across all our models – most LLMs now have a of 300 requests per minute, up from 50 requests per minute during our beta phase. Smaller models have a limit of 1500-3000 requests per minute. Check out our Developer Docs for the rate limits of individual models.

Lowering costs on popular models

Alongside our GA of Workers AI, we published a pricing calculator for our 10 non-beta models earlier this month. We want Workers AI to be one of the most affordable and accessible solutions to run inference, so we added a few optimizations to our models to make them more affordable. Now, Llama 2 is over 7x cheaper and Mistral 7B is over 14x cheaper to run than we had initially published on March 1. We want to continue to be the best platform for AI inference and will continue to roll out optimizations to our customers when we can.

As a reminder, our billing for Workers AI started on April 1st for our non-beta models, while beta models remain free and unlimited. We offer 10,000 neurons per day for free to all customers. Workers Free customers will encounter a hard rate limit after 10,000 neurons in 24 hours while Workers Paid customers will incur usage at $0.011 per 1000 additional neurons.  Read our Workers AI Pricing Developer Docs for the most up-to-date information on pricing.

New dashboard and playground

Lastly, we’ve revamped our Workers AI dashboard and AI playground. The Workers AI page in the Cloudflare dashboard now shows analytics for usage across models, including neuron calculations to help you better predict pricing. The AI playground lets you quickly test and compare different models and configure prompts and parameters. We hope these new tools help developers start building on Workers AI seamlessly – go try them out!

Run inference on GPUs in over 150 cities around the world

When we announced Workers AI back in September 2023, we set out to deploy GPUs to our data centers around the world. We plan to deliver on that promise and deploy inference-tuned GPUs almost everywhere by the end of 2024, making us the most widely distributed cloud-AI inference platform. We have over 150 cities with GPUs today and will continue to roll out more throughout the year.

We also have our next generation of compute servers with GPUs launching in Q2 2024, which means better performance, power efficiency, and improved reliability over previous generations. We provided a preview of our Gen 12 Compute servers design in a December 2023 blog post, with more details to come. With Gen 12 and future planned hardware launches, the next step is to support larger machine learning models and offer fine-tuning on our platform. This will allow us to achieve higher inference throughput, lower latency and greater availability for production workloads, as well as expanding support to new categories of workloads such as fine-tuning.

Hugging Face Partnership

We’re also excited to continue our partnership with Hugging Face in the spirit of bringing the best of open-source to our customers. Now, you can visit some of the most popular models on Hugging Face and easily click to run the model on Workers AI if it is available on our platform.

We’re happy to announce that we’ve added 4 more models to our platform in conjunction with Hugging Face. You can now access the new Mistral 7B v0.2 model with improved context windows, Nous Research’s Hermes 2 Pro fine-tuned version of Mistral 7B, Google’s Gemma 7B, and Starling-LM-7B-beta fine-tuned from OpenChat. There are currently 14 models that we’ve curated with Hugging Face to be available for serverless GPU inference powered by Cloudflare’s Workers AI platform, with more coming soon. These models are all served using Hugging Face’s technology with a TGI backend, and we work closely with the Hugging Face team to curate, optimize, and deploy these models.

“We are excited to work with Cloudflare to make AI more accessible to developers. Offering the most popular open models with a serverless API, powered by a global fleet of GPUs is an amazing proposition for the Hugging Face community, and I can’t wait to see what they build with it.”
Julien Chaumond, Co-founder and CTO, Hugging Face

You can find all of the open models supported in Workers AI in this Hugging Face Collection, and the “Deploy to Cloudflare Workers AI” button is at the top of each model card. To learn more, read Hugging Face’s blog post and take a look at our Developer Docs to get started. Have a model you want to see on Workers AI? Send us a message on Discord with your request.

Supporting fine-tuned inference – BYO LoRAs

Fine-tuned inference is one of our most requested features for Workers AI, and we’re one step closer now with Bring Your Own (BYO) LoRAs. Using the popular Low-Rank Adaptation method, researchers have figured out how to take a model and adapt some model parameters to the task at hand, rather than rewriting all model parameters like you would for a fully fine-tuned model. This means that you can get fine-tuned model outputs without the computational expense of fully fine-tuning a model.

We now support bringing trained LoRAs to Workers AI, where we apply the LoRA adapter to a base model at runtime to give you fine-tuned inference, at a fraction of the cost, size, and speed of a fully fine-tuned model. In the future, we want to be able to support fine-tuning jobs and fully fine-tuned models directly on our platform, but we’re excited to be one step closer today with LoRAs.

const response = await ai.run(
  "@cf/mistralai/mistral-7b-instruct-v0.2-lora", //the model supporting LoRAs
      messages: [{"role": "user", "content": "Hello world"],
      raw: true, //skip applying the default chat template
      lora: "00000000-0000-0000-0000-000000000", //the finetune id OR name 

BYO LoRAs is in open beta as of today for Gemma 2B and 7B, Llama 2 7B and Mistral 7B models with LoRA adapters up to 100MB in size and max rank of 8, and up to 30 total LoRAs per account. As always, we expect you to use Workers AI and our new BYO LoRA feature with our Terms of Service in mind, including any model-specific restrictions on use contained in the models’ license terms.

Read the technical deep dive blog post and developer docs to get started.

Write Workers in Python

Python is the second most popular programming language in the world (after JavaScript) and the language of choice for building AI applications. And starting today, in open beta, you can now write Cloudflare Workers in Python. Python Workers support all bindings to resources on Cloudflare, including Vectorize, D1, KV, R2 and more.

LangChain is the most popular framework for building LLM‑powered applications, and like how Workers AI works with langchain-js, the Python LangChain library works on Python Workers, as do other Python packages like FastAPI.

Workers written in Python are just as simple as Workers written in JavaScript:

from js import Response

async def on_fetch(request, env):
    return Response.new("Hello world!")

…and are configured by simply pointing at a .py file in your wrangler.toml:

name = "hello-world-python-worker"
main = "src/entry.py"
compatibility_date = "2024-03-18"
compatibility_flags = ["python_workers"]

There are no extra toolchain or precompilation steps needed. The Pyodide Python execution environment is provided for you, directly by the Workers runtime, mirroring how Workers written in JavaScript already work.

There’s lots more to dive into — take a look at the docs, and check out our companion blog post for details about how Python Workers work behind the scenes.

AI Gateway now supports Anthropic, Azure, AWS Bedrock, Google Vertex, and Perplexity

Our AI Gateway product helps developers better control and observe their AI applications, with analytics, caching, rate limiting, and more. We are continuing to add more providers to the product, including Anthropic, Google Vertex, and Perplexity, which we’re excited to announce today. We quietly rolled out Azure and Amazon Bedrock support in December 2023, which means that the most popular providers are now supported via AI Gateway, including Workers AI itself.

Take a look at our Developer Docs to get started with AI Gateway.

Coming soon: Persistent Logs

In Q2 of 2024, we will be adding persistent logs so that you can push your logs (including prompts and responses) to object storage, custom metadata so that you can tag requests with user IDs or other identifiers, and secrets management so that you can securely manage your application’s API keys.

We want AI Gateway to be the control plane for your AI applications, allowing developers to dynamically evaluate and route requests to different models and providers. With our persistent logs feature, we want to enable developers to use their logged data to fine-tune models in one click, eventually running the fine-tune job and the fine-tuned model directly on our Workers AI platform. AI Gateway is just one product in our AI toolkit, but we’re excited about the workflows and use cases it can unlock for developers building on our platform, and we hope you’re excited about it too.

Vectorize metadata filtering and future GA of million vector indexes

Vectorize is another component of our toolkit for AI applications. In open beta since September 2023, Vectorize allows developers to persist embeddings (vectors), like those generated from Workers AI text embedding models, and query for the closest match to support use cases like similarity search or recommendations. Without a vector database, model output is forgotten and can’t be recalled without extra costs to re-run a model.

Since Vectorize’s open beta, we’ve added metadata filtering. Metadata filtering lets developers combine vector search with filtering for arbitrary metadata, supporting the query complexity in AI applications. We’re laser-focused on getting Vectorize ready for general availability, with an target launch date of June 2024, which will include support for multi-million vector indexes.

// Insert vectors with metadata
const vectors: Array<VectorizeVector> = [
    id: "1",
    values: [32.4, 74.1, 3.2],
    metadata: { url: "/products/sku/13913913", streaming_platform: "netflix" }
    id: "2",
    values: [15.1, 19.2, 15.8],
    metadata: { url: "/products/sku/10148191", streaming_platform: "hbo" }
let upserted = await env.YOUR_INDEX.upsert(vectors);

// Query with metadata filtering
let metadataMatches = await env.YOUR_INDEX.query(<queryVector>, { filter: { streaming_platform: "netflix" }} )

The most comprehensive Developer Platform to build AI applications

On Cloudflare’s Developer Platform, we believe that all developers should be able to quickly build and ship full-stack applications  – and that includes AI experiences as well. With our GA of Workers AI, announcements for Python support in Workers, AI Gateway, and Vectorize, and our partnership with Hugging Face, we’ve expanded the world of possibilities for what you can build with AI on our platform. We hope you are as excited as we are – take a look at all our Developer Docs to get started, and let us know what you build.

Bringing Python to Workers using Pyodide and WebAssembly

Post Syndicated from Hood Chatham original https://blog.cloudflare.com/python-workers

Starting today, in open beta, you can now write Cloudflare Workers in Python.

This new support for Python is different from how Workers have historically supported languages beyond JavaScript — in this case, we have directly integrated a Python implementation into workerd, the open-source Workers runtime. All bindings, including bindings to Vectorize, Workers AI, R2, Durable Objects, and more are supported on day one. Python Workers can import a subset of popular Python packages including FastAPI, Langchain, Numpy and more. There are no extra build steps or external toolchains.

To do this, we’ve had to push the bounds of all of our systems, from the runtime itself, to our deployment system, to the contents of the Worker bundle that is published across our network. You can read the docs, and start using it today.

We want to use this post to pull back the curtain on the internal lifecycle of a Python Worker, share what we’ve learned in the process, and highlight where we’re going next.

Beyond “Just compile to WebAssembly”

Cloudflare Workers have supported WebAssembly since 2018 — each Worker is a V8 isolate, powered by the same JavaScript engine as the Chrome web browser. In principle, it’s been possible for years to write Workers in any language — including Python — so long as it first compiles to WebAssembly or to JavaScript.

In practice, just because something is possible doesn’t mean it’s simple. And just because “hello world” works doesn’t mean you can reliably build an application. Building full applications requires supporting an ecosystem of packages that developers are used to building with. For a platform to truly support a programming language, it’s necessary to go much further than showing how to compile code using external toolchains.

Python Workers are different from what we’ve done in the past. It’s early, and still in beta, but we think it shows what providing first-class support for programming languages beyond JavaScript can look like on Workers.

The lifecycle of a Python Worker

With Pyodide now built into workerd, you can write a Worker like this:

from js import Response

async def on_fetch(request, env):
    return Response.new("Hello world!")

…with a wrangler.toml file that points to a .py file:

name = "hello-world-python-worker"
main = "src/entry.py"
compatibility_date = "2024-03-18"

…and when you run npx wrangler@latest dev, the Workers runtime will:

  1. Determine which version of Pyodide is required, based on your compatibility date
  2. Create an isolate for your Worker, and automatically inject Pyodide
  3. Serve your Python code using Pyodide

This all happens under the hood — no extra toolchain or precompilation steps needed. The Python execution environment is provided for you, mirroring how Workers written in JavaScript already work.

A Python interpreter built into the Workers runtime

Just as JavaScript has many engines, Python has many implementations that can execute Python code. CPython is the reference implementation of Python. If you’ve used Python before, this is almost certainly what you’ve used, and is commonly referred to as just “Python”.

Pyodide is a port of CPython to WebAssembly. It interprets Python code, without any need to precompile the Python code itself to any other format. It runs in a web browser — check out this REPL. It is true to the CPython that Python developers know and expect, providing most of the Python Standard Library. It provides a foreign function interface (FFI) to JavaScript, allowing you to call JavaScript APIs directly from Python — more on this below. It provides popular open-source packages, and can import pure Python packages directly from PyPI.

Pyodide struck us as the perfect fit for Workers. It is designed to allow the core interpreter and each native Python module to be built as separate WebAssembly modules, dynamically linked at runtime. This allows the code footprint for these modules to be shared among all Workers running on the same machine, rather than requiring each Worker to bring its own copy. This is essential to making WebAssembly work well in the Workers environment, where we often run thousands of Workers per machine — we need Workers using the same programming language to share their runtime code footprint. Running thousands of Workers on every machine is what makes it possible for us to deploy every application in every location at a reasonable price.

Just like with JavaScript Workers, with Python Workers we provide the runtime for you:

Pyodide is currently the exception — most languages that target WebAssembly do not yet support dynamic linking, so each application ends up bringing its own copy of its language runtime. We hope to see more languages support dynamic linking in the future, so that we can more effectively bring them to Workers.

How Pyodide works

Pyodide executes Python code in WebAssembly, which is a sandboxed environment, separated from the host runtime. Unlike running native code, all operations outside of pure computation (such as file reads) must be provided by a runtime environment, then imported by the WebAssembly module.

LLVM provides three target triples for WebAssembly:

  1. wasm32-unknown-unknown – this backend provides no C standard library or system call interface; to support this backend, we would need to manually rewrite every system or library call to make use of imports we would define ourselves in the runtime.
  2. wasm32-wasi – WASI is a standardized system interface, and defines a standard set of imports that are implemented in WASI runtimes such as wasmtime.
  3. wasm32-unknown-emscripten – Like WASI, Emscripten defines the imports that a WebAssembly program needs to execute, but also outputs an accompanying JavaScript library that implements these imported functions.

Pyodide uses Emscripten, and provides three things:

  1. A distribution of the CPython interpreter, compiled using Emscripten
  2. A foreign function interface (FFI) between Python and JavaScript
  3. A set of third-party Python packages, compiled using Emscripten’s compiler to WebAssembly.

Of these targets, only Emscripten currently supports dynamic linking, which, as we noted above, is essential to providing a shared language runtime for Python that is shared across isolates. Emscripten does this by providing implementations of dlopen and dlsym, which use the accompanying JavaScript library to modify the WebAssembly program’s table to link additional WebAssembly-compiled modules at runtime. WASI does not yet support the dlopen/dlsym dynamic linking abstractions used by CPython.

Pyodide and the magic of foreign function interfaces (FFI)

You might have noticed that in our Hello World Python Worker, we import Response from the js module:

from js import Response

async def on_fetch(request, env):
    return Response.new("Hello world!")

Why is that?

Most Workers are written in JavaScript, and most of our engineering effort on the Workers runtime goes into improving JavaScript Workers. There is a risk in adding a second language that it might never reach feature parity with the first language and always be a second class citizen. Pyodide’s foreign function interface (FFI) is critical to avoiding this by providing access to all JavaScript functionality from Python. This can be used by the Worker author directly, and it is also used to make packages like FastAPI and Langchain work out-of-the-box, as we’ll show later in this post.

An FFI is a system for calling functions in one language that are implemented in another language. In most cases, an FFI is defined by a “higher-level” language in order to call functions implemented in a systems language, often C. Python’s ctypes module is such a system. These sorts of foreign function interfaces are often difficult to use because of the nature of C APIs.

Pyodide’s foreign function interface is an interface between Python and JavaScript, which are two high level object-oriented languages with a lot of design similarities. When passed from one language to another, immutable types such as strings and numbers are transparently translated. All mutable objects are wrapped in an appropriate proxy.

When a JavaScript object is passed into Python, Pyodide determines which JavaScript protocols the object supports and dynamically constructs an appropriate Python class that implements the corresponding Python protocols. For example, if the JavaScript object supports the JavaScript iteration protocol then the proxy will support the Python iteration protocol. If the JavaScript object is a Promise or other thenable, the Python object will be an awaitable.

from js import JSON

js_array = JSON.parse("[1,2,3]")

for entry in js_array:

The lifecycle of a request to a Python Worker makes use of Pyodide’s FFI, wrapping the incoming JavaScript Request object in a JsProxy object that is accessible in your Python code. It then converts the value returned by the Python Worker’s handler into a JavaScript Response object that can be delivered back to the client:

Why dynamic linking is essential, and static linking isn’t enough

Python comes with a C FFI, and many Python packages use this FFI to import native libraries. These libraries are typically written in C, so they must first be compiled down to WebAssembly in order to work on the Workers runtime. As we noted above, Pyodide is built with Emscripten, which overrides Python’s C FFI — any time a package tries to load a native library, it is instead loaded from a WebAssembly module that is provided by the Workers runtime. Dynamic linking is what makes this possible — it is what lets us override Python’s C FFI, allowing Pyodide to support many Python packages that have native library dependencies.

Dynamic linking is “pay as you go”, while static linking is “pay upfront” — if code is statically linked into your binary, it must be loaded upfront in order for the binary to run, even if this code is never used.

Dynamic linking enables the Workers runtime to share the underlying WebAssembly modules of packages across different Workers that are running on the same machine.

We won’t go too much into detail on how dynamic linking works in Emscripten, but the main takeaway is that the Emscripten runtime fetches WebAssembly modules from a filesystem abstraction provided in JavaScript. For each Worker, we generate a filesystem at runtime, whose structure mimics a Python distribution that has the Worker’s dependencies installed, but whose underlying files are shared between Workers. This makes it possible to share Python and WebAssembly files between multiple Workers that import the same dependency. Today, we’re able to share these files across Workers, but copy them into each new isolate. We think we can go even further, by employing copy-on-write techniques to share the underlying resource across many Workers.

Supporting Server and Client libraries

Python has a wide variety of popular HTTP client libraries, including httpx, urllib3, requests and more. Unfortunately, none of them work out of the box in Pyodide. Adding support for these has been one of the longest running user requests for the Pyodide project. The Python HTTP client libraries all work with raw sockets, and the browser security model and CORS do not allow this, so we needed another way to make them work in the Workers runtime.

Async Client libraries

For libraries that can make requests asynchronously, including aiohttp and httpx, we can use the Fetch API to make requests. We do this by patching the library, instructing it to use the Fetch API from JavaScript — taking advantage of Pyodide’s FFI. The httpx patch ends up quite simple —fewer than 100 lines of code. Simplified even further, it looks like this:

from js import Headers, Request, fetch

def py_request_to_js_request(py_request):
    js_headers = Headers.new(py_request.headers)
    return Request.new(py_request.url, method=py_request.method, headers=js_headers)

def js_response_to_py_response(js_response):
  ... # omitted

async def do_request(py_request):
  js_request = py_request_to_js_request(py_request)
    js_response = await fetch(js_request)
    py_response = js_response_to_py_response(js_response)
    return py_response

Synchronous Client libraries

Another challenge in supporting Python HTTP client libraries is that many Python APIs are synchronous. For these libraries, we cannot use the fetch API directly because it is asynchronous.

Thankfully, Joe Marshall recently landed a contribution to urllib3 that adds Pyodide support in web browsers by:

  1. Checking if blocking with Atomics.wait() is possible
    a. If so, start a fetch worker thread
    b. Delegate the fetch operation to the worker thread and serialize the response into a SharedArrayBuffer
    c. In the Python thread, use Atomics.wait to block for the response in the SharedArrayBuffer
  2. If Atomics.wait() doesn’t work, fall back to a synchronous XMLHttpRequest

Despite this, today Cloudflare Workers do not support worker threads or synchronous XMLHttpRequest, so neither of these two approaches will work in Python Workers. We do not support synchronous requests today, but there is a way forward…

WebAssembly Stack Switching

There is an approach which will allow us to support synchronous requests. WebAssembly has a stage 3 proposal adding support for stack switching, which v8 has an implementation of. Pyodide contributors have been working on adding support for stack switching to Pyodide since September of 2022, and it is almost ready.

With this support, Pyodide exposes a function called run_sync which can block for completion of an awaitable:

from pyodide.ffi import run_sync

def sync_fetch(py_request):
   js_request = py_request_to_js_request(py_request)
   js_response  = run_sync(fetch(js_request))
   return js_response_to_py_response(js_response)

FastAPI and Python’s Asynchronous Server Gateway Interface

FastAPI is one of the most popular libraries for defining Python servers. FastAPI applications use a protocol called the Asynchronous Server Gateway Interface (ASGI). This means that FastAPI never reads from or writes to a socket itself. An ASGI application expects to be hooked up to an ASGI server, typically uvicorn. The ASGI server handles all of the raw sockets on the application’s behalf.

Conveniently for us, this means that FastAPI works in Cloudflare Workers without any patches or changes to FastAPI itself. We simply need to replace uvicorn with an appropriate ASGI server that can run within a Worker. Our initial implementation lives here, in the fork of Pyodide that we maintain. We hope to add a more comprehensive feature set, add test coverage, and then upstream this implementation into Pyodide.

You can try this yourself by cloning cloudflare/python-workers-examples, and running npx wrangler@latest dev in the directory of the FastAPI example.

Importing Python Packages

Python Workers support a subset of Python packages, which are provided directly by Pyodide, including numpy, httpx, FastAPI, Langchain, and more. This ensures compatibility with the Pyodide runtime by pinning package versions to Pyodide versions, and allows Pyodide to patch internal implementations, as we showed above in the case of httpx.

To import a package, simply add it to your requirements.txt file, without adding a version number. A specific version of the package is provided directly by Pyodide. Today, you can use packages in local development, and in the coming weeks, you will be able to deploy Workers that define dependencies in a requirements.txt file. Later in this post, we’ll show how we’re thinking about managing new versions of Pyodide and packages.

We maintain our own fork of Pyodide, which allows us to provide patches specific to the Workers runtime, and to quickly expand our support for packages in Python Workers, while also committing to upstreaming our changes back to Pyodide, so that the whole ecosystem of developers can benefit.

Python packages are often big and memory hungry though, and they can do a lot of work at import time. How can we ensure that you can bring in the packages you need, while mitigating long cold start times?

Making cold starts faster with memory snapshots

In the example at the start of this post, in local development, we mentioned injecting Pyodide into your Worker. Pyodide itself is 6.4MB — and Python packages can also be quite large.

If we simply shoved Pyodide into your Worker and uploaded it to Cloudflare, that’d be quite a large Worker to load into a new isolate — cold starts would be slow. On a fast computer with a good network connection, Pyodide takes about two seconds to initialize in a web browser, one second of network time and one second of cpu time. It wouldn’t be acceptable to initialize it every time you update your code for every isolate your Worker runs in across Cloudflare’s network.

Instead, when you run npx wrangler@latest deploy, the following happens:

  1. Wrangler uploads your Python code and your requirements.txt file to the Workers API
  2. We send your Python code, and your requirements.txt file to the Workers runtime to be validated
  3. We create a new isolate for your Worker, and automatically inject Pyodide plus any packages you’ve specified in your requirements.txt file.
  4. We scan the Worker’s code for import statements, execute them, and then take a snapshot of the Worker’s WebAssembly linear memory. Effectively, we perform the expensive work of importing packages at deploy time, rather than at runtime.
  5. We deploy this snapshot alongside your Worker’s Python code to Cloudflare’s network.
  6. Just like a JavaScript Worker, we execute the Worker’s top-level scope.

When a request comes in to your Worker, we load this snapshot and use it to bootstrap your Worker in an isolate, avoiding expensive initialization time:

This takes cold starts for a basic Python Worker down to below 1 second. We’re not yet satisfied with this though. We’re confident that we can drive this down much, much further. How? By reusing memory snapshots.

Reusing Memory Snapshots

When you upload a Python Worker, we generate a single memory snapshot of the Worker’s top-level imports, including both Pyodide and any dependencies. This snapshot is specific to your Worker. It can’t be shared, even though most of its contents are the same as other Python Workers.

Instead, we can create a single, shared snapshot ahead of time, and preload it into a pool of “pre-warmed” isolates. These isolates would already have the Pyodide runtime loaded and ready — making a Python Worker work just like a JavaScript Worker. In both cases, the underlying interpreter and execution environment is provided by the Workers runtime, and available on-demand without delay. The only difference is that with Python, the interpreter runs in WebAssembly, within the Worker.

Snapshots are a common pattern across runtimes and execution environments. Node.js uses V8 snapshots to speed up startup time. You can take snapshots of Firecracker microVMs and resume execution in a different process. There’s lots more we can do here — not just for Python Workers, but for Workers written in JavaScript as well, caching snapshots of compiled code from top-level scope and the state of the isolate itself. Workers are so fast and efficient that to-date we haven’t had to take snapshots in this way, but we think there are still big performance gains to be had.

This is our biggest lever towards driving cold start times down over the rest of 2024.

Future proofing compatibility with Pyodide versions and Compatibility Dates

When you deploy a Worker to Cloudflare, you expect it to keep running indefinitely, even if you never update it again. There are Workers deployed in 2018 that are still running just fine in production.

We achieve this using Compatibility Dates and Compatibility Flags, which provide explicit opt-in mechanisms for new behavior and potentially backwards-incompatible changes, without impacting existing Workers.

This works in part because it mirrors how the Internet and web browsers work. You publish a web page with some JavaScript, and rightly expect it to work forever. Web browsers and Cloudflare Workers have the same type of commitment of stability to developers.

There is a challenge with Python though — both Pyodide and CPython are versioned. Updated versions are published regularly and can contain breaking changes. And Pyodide provides a set of built-in packages, each with a pinned version number. This presents a question — how should we allow you to update your Worker to a newer version of Pyodide?

The answer is Compatibility Dates and Compatibility Flags.

A new version of Python is released every year in August, and a new version of Pyodide is released six (6) months later. When this new version of Pyodide is published, we will add it to Workers by gating it behind a Compatibility Flag, which is only enabled after a specified Compatibility Date. This lets us continually provide updates, without risk of breaking changes, extending the commitment we’ve made for JavaScript to Python.

Each Python release has a five (5) year support window. Once this support window has passed for a given version of Python, security patches are no longer applied, making this version unsafe to rely on. To mitigate this risk, while still trying to hold as true as possible to our commitment of stability and long-term support, after five years any Python Worker still on a Python release that is outside of the support window will be automatically moved forward to the next oldest Python release. Python is a mature and stable language, so we expect that in most cases, your Python Worker will continue running without issue. But we recommend updating the compatibility date of your Worker regularly, to stay within the support window.

In between Python releases, we also expect to update and add additional Python packages, using the same opt-in mechanism. A Compatibility Flag will be a combination of the Python version and the release date of a set of packages. For example, python_3.17_packages_2025_03_01.

How bindings work in Python Workers

We mentioned earlier that Pyodide provides a foreign function interface (FFI) to JavaScript — meaning that you can directly use JavaScript objects, methods, functions and more, directly from Python.

This means that from day one, all binding APIs to other Cloudflare resources are supported in Cloudflare Workers. The env object that is provided by handlers in Python Workers is a JavaScript object that Pyodide provides a proxy API to, handling type translations across languages automatically.

For example, to write to and read from a KV namespace from a Python Worker, you would write:

from js import Response

async def on_fetch(request, env):
    await env.FOO.put("bar", "baz")
    bar = await env.FOO.get("bar")
    return Response.new(bar) # returns "baz"

This works for Web APIs too — see how Response is imported from the js module? You can import any global from JavaScript this way.

Get this JavaScript out of my Python!

You’re probably reading this post because you want to write Python instead of JavaScript. from js import Response just isn’t Pythonic. We know — and we have actually tackled this challenge before for another language (Rust). And we think we can do this even better for Python.

We launched workers-rs in 2021 to make it possible to write Workers in Rust. For each JavaScript API in Workers, we, alongside open-source contributors, have written bindings that expose a more idiomatic Rust API.

We plan to do the same for Python Workers — starting with the bindings to Workers AI and Vectorize. But while workers-rs requires that you use and update an external dependency, the APIs we provide with Python Workers will be built into the Workers runtime directly. Just update your compatibility date, and get the latest, most Pythonic APIs.

This is about more than just making bindings to resources on Cloudflare more Pythonic though — it’s about compatibility with the ecosystem.

Similar to how we recently converted workers-rs to use types from the http crate, which makes it easy to use the axum crate for routing, we aim to do the same for Python Workers. For example, the Python standard library provides a raw socket API, which many Python packages depend on. Workers already provides connect(), a JavaScript API for working with raw sockets. We see ways to provide at least a subset of the Python standard library’s socket API in Workers, enabling a broader set of Python packages to work on Workers, with less of a need for patches.

But ultimately, we hope to kick start an effort to create a standardized serverless API for Python. One that is easy to use for any Python developer and offers the same capabilities as JavaScript.

We’re just getting started with Python Workers

Providing true support for a new programming language is a big investment that goes far beyond making “hello world” work. We chose Python very intentionally — it’s the second most popular programming language after JavaScript — and we are committed to continuing to improve performance and widen our support for Python packages.

We’re grateful to the Pyodide maintainers and the broader Python community — and we’d love to hear from you. Drop into the Python Workers channel in the Cloudflare Developers Discord, or start a discussion on Github about what you’d like to see next and which Python packages you’d like us to support.

Building D1: a Global Database

Post Syndicated from Vy Ton original https://blog.cloudflare.com/building-d1-a-global-database

Developers who build Worker applications focus on what they’re creating, not the infrastructure required, and benefit from the global reach of Cloudflare’s network. Many applications require persistent data, from personal projects to business-critical workloads. Workers offer various database and storage options tailored to developer needs, such as key-value and object storage.

Relational databases are the backbone of many applications today. D1, Cloudflare’s relational database complement, is now generally available. Our journey from alpha in late 2022 to GA in April 2024 focused on enabling developers to build production workloads with the familiarity of relational data and SQL.

What’s D1?

D1 is Cloudflare’s built-in, serverless relational database. For Worker applications, D1 offers SQL’s expressiveness, leveraging SQLite’s SQL dialect, and developer tooling integrations, including object-relational mappers (ORMs) like Drizzle ORM. D1 is accessible via Workers or an HTTP API.

Serverless means no provisioning, default disaster recovery with Time Travel, and usage-based pricing. D1 includes a generous free tier that allows developers to experiment with D1 and then graduate those trials to production.

How to make data global?

D1 GA has focused on reliability and developer experience. Now, we plan on extending D1 to better support globally-distributed applications.

In the Workers model, an incoming request invokes serverless execution in the closest data center. A Worker application can scale globally with user requests. Application data, however, remains stored in centralized databases, and global user traffic must account for access round trips to data locations. For example, a D1 database today resides in a single location.

Workers support Smart Placement to account for frequently accessed data locality. Smart Placement invokes a Worker closer to centralized backend services like databases to lower latency and improve application performance. We’ve addressed Workers placement in global applications, but need to solve data placement.

The question, then, is how can D1, as Cloudflare’s built-in database solution, better support data placement for global applications? The answer is asynchronous read replication.

What is asynchronous read replication?

In a server-based database management system, like Postgres, MySQL, SQL Server, or Oracle, a read replica is a separate database server that serves as a read-only, almost up-to-date copy of the primary database server. An administrator creates a read replica by starting a new server from a snapshot of the primary server and configuring the primary server to send updates asynchronously to the replica server. Since the updates are asynchronous, the read replica may be behind the current state of the primary server. The difference between the primary server and a replica is called replica lag. It’s possible to have more than one read replica.

Asynchronous read replication is a time-proven solution for improving the performance of databases:

  • It’s possible to increase throughput by distributing load across multiple replicas.
  • It’s possible to lower query latency when the replicas are close to the users making queries.

Note that some database systems also offer synchronous replication. In a synchronous replicated system, writes must wait until all replicas have confirmed the write. Synchronous replicated systems can run only as fast as the slowest replica and come to a halt when a replica fails. If we’re trying to improve performance on a global scale, we want to avoid synchronous replication as much as possible!

Consistency models & read replicas

Most database systems provide read committed, snapshot isolation, or serializable consistency models, depending on their configuration. For example, Postgres defaults to read committed but can be configured to use stronger modes. SQLite provides snapshot isolation in WAL mode. Stronger modes like snapshot isolation or serializable are easier to program against because they limit the permitted system concurrency scenarios and the kind of concurrency race conditions the programmer has to worry about.

Read replicas are updated independently, so each replica’s contents may differ at any moment. If all of your queries go to the same server, whether the primary or a read replica, your results should be consistent according to whatever consistency model your underlying database provides. If you’re using a read replica, the results may just be a little old.

In a server-based database with read replicas, it’s important to stick with the same server for all of the queries in a session. If you switch among different read replicas in the same session, you compromise the consistency model provided by your application, which may violate your assumptions about how the database acts and cause your application to return incorrect results!

For example, there are two replicas, A and B. Replica A lags the primary database by 100ms, and replica B lags the primary database by 2s. Suppose a user wishes to:

  1. Execute query 1
    1a. Do some computation based on query 1 results
  2. Execute query 2 based on the results of the computation in (1a)

At time t=10s, query 1 goes to replica A and returns. Query 1 sees what the primary database looked like at t=9.9s. Suppose it takes 500ms to do the computation, so at t=10.5s, query 2 goes to replica B. Remember, replica B lags the primary database by 2s, so at t=10.5s, query 2 sees what the database looks like at t=8.5s. As far as the application is concerned, the results of query 2 look like the database has gone backwards in time!

Formally, this is read committed consistency since your queries will only see committed data, but there’s no other guarantee – not even that you can read your own writes. While read committed is a valid consistency model, it’s hard to reason about all of the possible race conditions the read committed model allows, making it difficult to write applications correctly.

D1’s consistency model & read replicas

By default, D1 provides the snapshot isolation that SQLite provides.

Snapshot isolation is a familiar consistency model that most developers find easy to use. We implement this consistency model in D1 by ensuring at most one active copy of the D1 database and routing all HTTP requests to that single database. While ensuring that there’s at most one active copy of the D1 database is a gnarly distributed systems problem, it’s one that we’ve solved by building D1 using Durable Objects. Durable Objects guarantee global uniqueness, so once we depend on Durable Objects, routing HTTP requests is easy: just send them to the D1 Durable Object.

This trick doesn’t work if you have multiple active copies of the database since there’s no 100% reliable way to look at a generic incoming HTTP request and route it to the same replica 100% of the time. Unfortunately, as we saw in the previous section’s example, if we don’t route related requests to the same replica 100% of the time, the best consistency model we can provide is read committed.

Given that it’s impossible to route to a particular replica consistently, another approach is to route requests to any replica and ensure that the chosen replica responds to requests according to a consistency model that “makes sense” to the programmer. If we’re willing to include a Lamport timestamp in our requests, we can implement sequential consistency using any replica. The sequential consistency model has important properties like “read my own writes” and “writes follow reads,” as well as a total ordering of writes. The total ordering of writes means that every replica will see transactions commit in the same order, which is exactly the behavior we want in a transactional system. Sequential consistency comes with the caveat that any individual entity in the system may be arbitrarily out of date, but that caveat is a feature for us because it allows us to consider replica lag when designing our APIs.

The idea is that if D1 gives applications a Lamport timestamp for every database query and those applications tell D1 the last Lamport timestamp they’ve seen, we can have each replica determine how to make queries work according to the sequential consistency model.

A robust, yet simple, way to implement sequential consistency with replicas is to:

  • Associate a Lamport timestamp with every single request to the database. A monotonically increasing commit token works well for this.
  • Send all write queries to the primary database to ensure the total ordering of writes.
  • Send read queries to any replica, but have the replica delay servicing the query until the replica receives updates from the primary database that are later than the Lamport timestamp in the query.

What’s nice about this implementation is that it’s fast in the common case where a read-heavy workload always goes to the same replica and will work even if requests get routed to different replicas.

Sneak Preview: bringing read replication to D1 with Sessions

To bring read replication to D1, we will expand the D1 API with a new concept: Sessions. A Session encapsulates all the queries representing one logical session for your application. For example, a Session might represent all requests coming from a particular web browser or all requests coming from a mobile app. If you use Sessions, your queries will use whatever copy of the D1 database makes the most sense for your request, be that the primary database or a nearby replica. D1’s Sessions implementation will ensure sequential consistency for all queries in the Session.

Since the Sessions API changes D1’s consistency model, developers must opt-in to the new API. Existing D1 API methods are unchanged and will still have the same snapshot isolation consistency model as before. However, only queries made using the new Sessions API will use replicas.

Here’s an example of the D1 Sessions API:

export default {
  async fetch(request: Request, env: Env) {
    // When we create a D1 Session, we can continue where we left off
    // from a previous Session if we have that Session's last commit
    // token.  This Worker will return the commit token back to the
    // browser, so that it can send it back on the next request to
    // continue the Session.
    // If we don't have a commit token, make the first query in this
    // session an "unconditional" query that will use the state of the
    // database at whatever replica we land on.
    const token = request.headers.get('x-d1-token') ?? 'first-unconditional'
    const session = env.DB.withSession(token)

    // Use this Session for all our Workers' routes.
    const response = await handleRequest(request, session)

    if (response.status === 200) {
      // Set the token so we can continue the Session in another request.
      response.headers.set('x-d1-token', session.latestCommitToken)
    return response

async function handleRequest(request: Request, session: D1DatabaseSession) {
  const { pathname } = new URL(request.url)

  if (pathname === '/api/orders/list') {
    // This statement is a read query, so it will execute on any
    // replica that has a commit equal or later than `token` we used
    // to create the Session.
    const { results } = await session.prepare('SELECT * FROM Orders').all()

    return Response.json(results)
  } else if (pathname === '/api/orders/add') {
    const order = await request.json<Order>()

    // This statement is a write query, so D1 will send the query to
    // the primary, which always has the latest commit token.
    await session
      .prepare('INSERT INTO Orders VALUES (?, ?, ?)')
      .bind(order.orderName, order.customer, order.value)

    // In order for the application to be correct, this SELECT
    // statement must see the results of the INSERT statement above.
    // The Session API keeps track of commit tokens for queries
    // within the session and will ensure that we won't execute this
    // query until whatever replica we're using has seen the results
    // of the INSERT.
    const { results } = await session
      .prepare('SELECT COUNT(*) FROM Orders')

    return Response.json(results)

  return new Response('Not found', { status: 404 })

D1’s implementation of Sessions makes use of commit tokens.  Commit tokens identify a particular committed query to the database.  Within a session, D1 will use commit tokens to ensure that queries are sequentially ordered.  In the example above, the D1 session ensures that the “SELECT COUNT(*)” query happens after the “INSERT” of the new order, even if we switch replicas between the awaits.  

There are several options on how you want to start a session in a Workers fetch handler.  db.withSession(<condition>) accepts these arguments:

condition argument



(1) starts Session as of given commit token

(2) subsequent queries have sequential consistency


(1) if the first query is read, read whatever current replica has and use the commit token of that read as the basis for subsequent queries.  If the first query is a write, forward the query to the primary and use the commit token of the write as the basis for subsequent queries.

(2) subsequent queries have sequential consistency


(1) runs first query, read or write, against the primary

(2) subsequent queries have sequential consistency

null or missing argument

treated like first-unconditional 

It’s possible to have a session span multiple requests by “round-tripping” the commit token from the last query of the session and using it to start a new session.  This enables individual user agents, like a web app or a mobile app, to make sure that all of the queries the user sees are sequentially consistent.

D1’s read replication will be built-in, will not incur extra usage or storage costs, and will require no replica configuration. Cloudflare will monitor an application’s D1 traffic and automatically create database replicas to spread user traffic across multiple servers in locations closer to users. Aligned with our serverless model, D1 developers shouldn’t worry about replica provisioning and management. Instead, developers should focus on designing applications for replication and data consistency tradeoffs.

We’re actively working on global read replication and realizing the above proposal (share feedback In the #d1 channel on our Developer Discord). Until then, D1 GA includes several exciting new additions.

Check out D1 GA

Since D1’s open beta in October 2023, we’ve focused on D1’s reliability, scalability, and developer experience demanded of critical services. We’ve invested in several new features that allow developers to build and debug applications faster with D1.

Build bigger with larger databases
We’ve listened to developers who requested larger databases. D1 now supports up to 10GB databases, with 50K databases on the Workers Paid plan. With D1’s horizontal scaleout, applications can model database-per-business-entity use cases. Since beta, new D1 databases process 40x more requests than D1 alpha databases in a given period.

Import & export bulk data
Developers import and export data for multiple reasons:

  • Database migration testing to/from different database systems
  • Data copies for local development or testing
  • Manual backups for custom requirements like compliance

While you could execute SQL files against D1 before, we’re improving wrangler d1 execute –file=<filename> to ensure large imports are atomic operations, never leaving your database in a halfway state. wrangler d1 execute also now defaults to local-first to protect your remote production database.

To import our Northwind Traders demo database, you can download the schema & data and execute the SQL files.

npx wrangler d1 create northwind-traders

# omit --remote to run on a local database for development
npx wrangler d1 execute northwind-traders --remote --file=./schema.sql

npx wrangler d1 execute northwind-traders --remote --file=./data.sql

D1 database data & schema, schema-only, or data-only can be exported to a SQL file using:

# database schema & data
npx wrangler d1 export northwind-traders --remote --output=./database.sql

# single table schema & data
npx wrangler d1 export northwind-traders --remote --table='Employee' --output=./table.sql

# database schema only
npx wrangler d1 export <database_name> --remote --output=./database-schema.sql --no-data=true

Debug query performance
Understanding SQL query performance and debugging slow queries is a crucial step for production workloads. We’ve added the experimental wrangler d1 insights to help developers analyze query performance metrics also available via GraphQL API.

# To find top 10 queries by average execution time:
npx wrangler d1 insights <database_name> --sort-type=avg --sort-by=time --count=10

Developer tooling
Various community developer projects support D1. New additions include Prisma ORM, in version 5.12.0, which now supports Workers and D1.

Next steps

The features available now with GA and our global read replication design are just the start of delivering the SQL database needs for developer applications. If you haven’t yet used D1, you can get started right now, visit D1’s developer documentation to spark some ideas, or join the #d1 channel on our Developer Discord to talk to other D1 developers and our product engineering team.

Why Workers environment variables contain live objects

Post Syndicated from Kenton Varda original https://blog.cloudflare.com/workers-environment-live-object-bindings

If you’ve ever written a Cloudflare Worker using Workers KV for storage, you may have noticed something unsettling.

// A simple Worker that always returns the value named "content",
// read from Workers KV storage.
export default {
  async fetch(request, env, ctx) {
    return new Response(await env.MY_KV.get("content"));

Do you feel something is… missing? Like… Where is the setup? The authorization keys? The client library instantiation? Aren’t environment variables normally strings? How is it that env.MY_KV seems to be an object with a get() method that is already hooked up?

Coming from any other platform, you might expect to see something like this instead:

// How would a "typical cloud platform" do it?

// Import KV client library?
import { KV } from "cloudflare:kv";

export default {
  async fetch(request, env, ctx) {
    // Connect to the database?? Using my secret auth key???
    // Which comes from an environment variable????
    let myKv = KV.connect("my-kv-namespace", env.MY_KV_AUTHKEY);

    return new Response(await myKv.get("content"));

As another example, consider service bindings, which allow a Worker to send requests to another Worker.

// A simple Worker that greets an authenticated user, delegating to a
// separate service to perform authentication.
export default {
  async fetch(request, env, ctx) {
    // Forward headers to auth service to get user info.
    let authResponse = await env.AUTH_SERVICE.fetch(
        {headers: request.headers});
    let userInfo = await authResponse.json();
    return new Response("Hello, " + userInfo.name);

Notice in particular the use of env.AUTH_SERVICE.fetch() to send the request. This sends the request directly to the auth service, regardless of the hostname we give in the URL.

On “typical” platforms, you’d expect to use a real (perhaps internal) hostname to route the request instead, and also include some credentials proving that you’re allowed to use the auth service API:

// How would a "typical cloud platform" do it?
export default {
  async fetch(request, env, ctx) {
    // Forward headers to auth service, via some internal hostname?
    // Hostname needs to be configurable, so get it from an env var.
    let authRequest = new Request(
        "https://" + env.AUTH_SERVICE_HOST + "/getUser",
        {headers: request.headers});

    // We also need to prove that our service is allowed to talk to
    // the auth service API. Add a header for that, containing a
    // secret token from our environment.

    // Now we can make the request.
    let authResponse = await fetch(authRequest);
    let userInfo = await authResponse.json();
    return new Response("Hello, " + userInfo.name);

As you can see, in Workers, the “environment” is not just a bunch of strings. It contains full-fledged objects. We call each of these objects a “binding“, because it binds the environment variable name to a resource. You configure exactly what resource a name is bound to when you deploy your Worker – again, just like a traditional environment variable, but not limited to strings.

We can clearly see above that bindings eliminate a little bit of boilerplate, which is nice. But, there’s so much more.

Bindings don’t just reduce boilerplate. They are a core design feature of the Workers platform which simultaneously improve developer experience and application security in several ways. Usually these two goals are in opposition to each other, but bindings elegantly solve for both at the same time.


It may not be obvious at first glance, but bindings neatly solve a number of common security problems in distributed systems.

SSRF is Not A Thing

Bindings, when used properly, make Workers immune to Server-Side Request Forgery (SSRF) attacks, one of the most common yet deadly security vulnerabilities in application servers today. In an SSRF attack, an attacker tricks a server into making requests to other internal services that only it can see, thus giving the attacker access to those internal services.

As an example, imagine we have built a social media application where users are able to set their avatar image. Imagine that, as a convenience, instead of uploading an image from their local disk, a user can instead specify the URL of an image on a third-party server, and the application server will fetch that image to use as the avatar. Sounds reasonable, right? We can imagine the app contains some code like:

let resp = await fetch(userAvatarUrl);
let data = await resp.arrayBuffer();
await setUserAvatar(data);

One problem: What if the user claims their avatar URL is something like “https://auth-service.internal/status”? Whoops, now the above code will actually fetch a status page from the internal auth service, and set it as the user’s avatar. Presumably, the user can then download their own avatar, and it’ll contain the content of this status page, which they were not supposed to be able to access!

But using bindings, this is impossible: There is no URL that the attacker can specify to reach the auth service. The application must explicitly use the binding env.AUTH_SERVICE to reach it. The global fetch() function cannot reach the auth service no matter what URL it is given; it can only make requests to the public Internet.

A legacy caveat: When we originally designed Workers in 2017, the primary use case was implementing a middleware layer in front of an origin server, integrated with Cloudflare’s CDN. At the time, bindings weren’t a thing yet, and we were primarily trying to implement the Service Workers interface. To that end, we made a design decision: when a Worker runs on Cloudflare in front of some origin server, if you invoke the global fetch() function with a URL that is within your zone’s domain, the request will be sent directly to the origin server, bypassing most logic Cloudflare would normally apply to a request received from the Internet. Sadly, this means that Workers which run in front of an origin server are not immune to SSRF – they must worry about it just like traditional servers on private networks must. Although this puts Workers in the same place as most servers, we now see a path to make SSRF a thing you never have to worry about when writing Workers. We will be introducing “origin bindings”,  where the origin server is represented by an explicit binding. That is, to send a request to your origin, you’d need to do env.ORIGIN.fetch(). Then, the global fetch() function can be restricted to only talk to the public Internet, fully avoiding SSRF. This is a big change and we need to handle backwards-compatibility carefully – expect to see more in the coming months. Meanwhile, for Workers that do not have an origin server behind them, or where the origin server does not rely on Cloudflare for security, global fetch() is SSRF-safe today.

And a reminder: Requests originating from Workers have a header, CF-Worker, identifying the domain name that owns the Worker. This header is intended for abuse mitigation: if your server is receiving abusive requests from a Worker, it tells you who to blame and gives you a way to filter those requests. This header is not intended for authorization. You should not implement a private API that grants access to your Workers based solely on the CF-Worker header matching your domain. If you do, you may re-open the opportunity for SSRF vulnerabilities within any Worker running on that domain.

You can’t leak your API key if there is no API key

Usually, if your web app needs access to a protected resource, you will have to obtain some sort of an API key that grants access to the resource. But typically anyone who has this key can access the resource as if they were the Worker. This makes handling auth keys tricky. You can’t put it directly in a config file, unless the entire config file is considered a secret. You can’t check it into source control – you don’t want to publish your keys to GitHub! You probably shouldn’t even store the key on your hard drive – what if your laptop is compromised? And so on.

Even if you have systems in place to deliver auth keys to services securely (like Workers Secrets), if the key is just a string, the service itself can easily leak it. For instance, a developer might carelessly insert a log statement for debugging which logs the service’s configuration – including keys. Now anyone who can access your logs can discover the secret, and there’s probably no practical way to tell if such a leak has occurred.

With Workers bindings, we endeavor for bindings to be live objects, not secret keys. For instance, as seen in the first example in this post, when using a Workers KV binding, you never see a key at all. It’s therefore impossible for a Worker to accidentally leak access to a KV namespace.

No certificate management

This is similar to the API key problem, but arguably worse. When internal services talk to each other over a network, you presumably want them to use secure transports, but typically that requires that every service have a certificate and a private key signed by some CA, and clients must be configured to trust that CA. This is all a big pain to manage, and often the result is that developers don’t bother; they set up a VPC and assume the network is trusted.

In Workers, since all intra-service communications happen over a binding, the system itself can take on all the work of ensuring the transport is secure and goes to the right place.

No frustrating ACL management – but also no lazy “allow all”

At this point you might be thinking: Why are we talking about API keys at all? Cloudflare knows which Worker is sending any request. Can’t it handle the authentication that way?

Consider the earlier example where we imagined that KV namespaces could be opened by name:

// Imagine KV namespaces could be open by name?
let myKv = KV.connect("my-kv-namespace", env.MY_KV_AUTHKEY);

What if we made it simply:

// No authkey, because the system knows whether the Worker has
// permission?
let myKv = KV.connect("my-kv-namespace");

We could then imagine that we could separately configure each KV namespace with an Access Control List (ACL) that specifies which Workers can access it.

Of course, the first problem with this is that it’s vulnerable to SSRF. But, we discussed that already, so let’s discuss another problem.

Many platforms use ACLs for security, but have you ever noticed how everyone hates them? You end up with two choices:

  • Tediously maintain ACLs on every resource. Inevitably, this is always a huge pain. First you deploy your code, which you think is properly configured. Then you discover that it’s failing with permissions errors causing a production outage! So you go fiddle with the IAM system. There are 533,291 roles to choose from and none of them are actually what you want. It turns out you’re supposed to create a custom role, but that’s not obvious, and once you get there, the UI is confusing. Also it’s easy to confuse your team’s service account with your team’s email group, so you give the permissions to the wrong principal, but it takes you an hour of staring at it to realize what you did wrong. Then somehow you manage to remove your own access to the resource and you can’t add it back even though you’re a project admin? (Why yes, all this did in fact happen to me, while using a cloud provider that shall remain nameless.)
  • Give up and grant everything access to everything. Just put all your services in a single VPC where they can all freely talk to each other. This is what most developers are inclined to do, if their security team doesn’t step in to stop them.

Much of this pain comes about because connecting a server to a resource today involves two steps that should really be one step:

  1. Configure the server to point at the resource.
  2. Configure the resource to accept requests from the server.

Developers are primarily concerned with step 1, and forget that step 2 exists until it blows up in their faces. Then it’s a mad scramble to learn how step 2 even works.

What if step 1 just implied step 2? Obviously, if you’re trying to configure a service to access a resource, then you also want the resource to allow access to the service. As long as the person trying to set this up has permissions to both, then there is no reason for this to be a two-step process.

But in typical platforms, the platform itself has no way of knowing that a service has been configured to talk to a resource, because the configuration is just a string.

Bindings fix that. When you define a binding from a Worker to a particular KV namespace, the platform inherently understands that you are telling the Worker to use the KV namespace. Therefore, it can implicitly ensure that the correct permissions are granted. There is no step 2.

And conversely, if no binding is configured, then the Worker does not have access. That means that every Worker starts out with no access by default, and only receives access to exactly the things it needs. Secure by default.

As a related benefit, you can always accurately answer the question “What services are using this resource?” based on bindings. Since the system itself understands bindings and what they point to, the system can answer the query without knowing anything about the service’s internals.

Developer Experience

We’ve seen that bindings improve security in a number of ways. Usually, people expect security and developer friendliness to be a trade-off, with each security measure making life harder for developers. Bindings, however, are entirely the opposite! They actually make life easier!

Easier setup

As we saw in the intro, using a binding reduces setup boilerplate. Instead of receiving an environment variable containing an API key which must be passed into some sort of library, the environment variable itself is an already-initialized client library.


Because the system understands what bindings a Worker has, and even exactly when those bindings are exercised, the system can answer a lot of questions that would normally require more manual instrumentation or analysis to answer, such as:

  • For a given Worker, what resources does it use? Since the system understands the types of all bindings and what they point to (it doesn’t just see them as opaque strings), it can answer this question.
  • For a given resource, which Workers use it? This is the reverse query. The system can maintain an index of bindings in order to find ones pointing at a given resource.
  • How often does a particular Worker use a particular resource? Since bindings are invoked by calling methods on the binding itself, the system can observe these calls, log them, collect metrics, etc.

Testability via dependency injection

When you deploy a test version of your service, you probably want it to operate on test resources rather than real production resources. For instance, you might have a separate testing KV namespace for storage. But, you probably want to deploy exactly the same code to test that you will eventually deploy to production. That means the names of these resources cannot be hard-coded.

On traditional platforms, the obvious way to avoid hard-coding resource names is to put the name in an environment variable. Going back to our example from the intro, if KV worked in a traditional way not using bindings, you might end up with code like this:

// Hypothetical non-binding-based KV.
let myKv = KV.connect(env.MY_KV_NAMESPACE, env.MY_KV_AUTHKEY);

At best, you now have two environment variables (which had better stay in sync) just to specify what namespace to use.

But at worst, developers might forget to parameterize their resources this way.

  • A developer may write new code that is hard-coded to use a test database, and then forget to update it before pushing it to production, accidentally using the test database in prod.
  • A developer might prototype a new service using production resources from the start (or using new resources which become production resources), only later on deciding that they need to create a new deployment for testing. But by then, it may be a pain to find and parameterize all the different resources used.

With bindings, it’s impossible to have this problem. Since you can only connect to a KV namespace through a binding, it’s always possible to make a separate deployment of the same code which talks to a test namespace instead of production, e.g. using Wrangler Environments.

In the testing world, this is sometimes called “dependency injection”. With bindings, dependencies are always injectable.


Dependency injection isn’t just for tests. A service whose dependencies can be changed out easily will be easier to deploy into new environments, including new production environments.

Say, for instance, you have a service that authenticates users. Now you are launching a new product, which, for whatever reason, has a separate userbase from the original product. You need to deploy a new version of the auth service that uses a different database to implement a separate user set. As long as all dependencies are injectable, this should be easy.

Again, bindings are not the only way to achieve dependency injection, but a bindings-based system will tend to lead developers to write dependency-injectable code by default.


Has anyone done this before?

You have. Every time you write code.

As it turns out, this approach is used all the time at the programming language level. Bindings are analogous to parameters of a function, or especially parameters to a class constructor. In a memory-safe programming language, you can’t access an object unless someone has passed you a pointer or reference to that object. Objects in memory don’t have URLs that you use to access them.

Programming languages work this way because they are designed to manage complexity, and this proves to be an elegant way to do so. Yet, this style which we’re used to using at the programming language level is much less common at the distributed system level. The Cloudflare Workers platform aims to treat the network as one big computer, and so it makes sense to extend programming language concepts across the network.

Of course, we’re not the first to apply this to distributed systems, either. The paradigm is commonly called “capability-based security”, which brings us to the next question…

Is this capability-based security?

Bindings are very much inspired by capability-based security.

At present, bindings are not a complete capability system. In particular, there is currently no particular mechanism for a Worker to pass a binding to another Worker. However, this is something we can definitely imagine adding in the future.

Imagine, for instance, you want to call another Worker through a service binding, and as you do, you want to give that other Worker temporary access to a KV namespace for it to operate on. Wouldn’t it be nice if you could just pass the object, and have it auto-revoked at the end of the request? In the future, we might introduce a notion of dynamic bindings which can bind to different resources on a per-request basis, where a calling Worker can pass in a particular value to use for a given request.

For the time being, bindings cannot really be called object capabilities. However, many of the benefits of bindings are the same benefits commonly attributed to capability systems. This is because of some basic similarities:

  • Like a capability, a binding simultaneously designates a resource and also confers permission to access that resource, without referencing any separate ACL.
  • Like capabilities, bindings do not exist in any global namespace: they are scoped to the env object passed to a specific Worker.
  • Like a capability, to use a binding, the application must explicitly specify which binding it is trying to use, and only specifies the binding. In particular, the application does not separately specify the name of the resource in any other namespace (no URL, no global ID, etc.). The existence of the binding only affects the application’s behavior when the application explicitly invokes that binding.

Why is env a parameter to fetch(), not global?

This is a bit wonky, but the goal is to enable composition of Workers.

Imagine you have two Workers, one which implements your API, mapped to api.example.com, and one which serves static assets, mapped to assets.example.com. One day, for whatever reason, you decide you want to combine these two Workers into a single Worker. So you write this code:

import apiWorker from "api-worker.js";
import assetWorker from "asset-worker.js";

export default {
  async fetch(req, env, ctx) {
    let url = new URL(req.url);
    if (url.hostname == "api.example.com") {
      return apiWorker.fetch(req, env, ctx);
    } else if (url.hostname == "assets.example.com") {
      return assetWorker.fetch(req, env, ctx);
    } else {
      return new Response("Not found", {status: 404});

This is great! No code from either Worker needed to be modified at all. We just create a new file containing a router Worker that delegates to one or the other.

But, you discover a problem: both the API Worker and the assets Worker use a KV namespace binding, and it turns out that they both decided to name the binding env.KV, but these bindings are meant to point to different namespaces used for different purposes. Does this mean I have to go edit the Workers to change the name of the binding before I can merge them?

No, it doesn’t, because I can just remap the environments before delegating:

import apiWorker from "api-worker.js";
import assetWorker from "asset-worker.js";

export default {
  async fetch(req, env, ctx) {
    let url = new URL(req.url);
    if (url.hostname == "api.example.com") {
      let subenv = {KV: env.API_KV};
      return apiWorker.fetch(req, subenv, ctx);
    } else if (url.hostname == "assets.example.com") {
      let subenv = {KV: env.ASSETS_KV};
      return assetWorker.fetch(req, subenv, ctx);
    } else {
      return new Response("Not found", {status: 404});

If environments were globals, this remapping would not be possible.

In fact, this benefit goes much deeper than this somewhat-contrived example. The fact that the environment is not a global essentially forces code to be internally designed for dependency injection (DI). Designing code to be DI-friendly sometimes seems tedious, but every time I’ve done it, I’ve been incredibly happy that I did. Such code tends to be much easier to test and to adapt to new circumstances, for the same reasons mentioned when we discussed dependency injection earlier, but applying at the level of individual modules rather than whole Workers.

With that said, if you really insist that you don’t care about making your code explicitly DI-friendly, there is an alternative: Put your env into AsyncLocalStorage. That way it is “ambiently” available anywhere in your code, but you can still get some composability.

import { AsyncLocalStorage } from 'node:async_hooks';

// Allocate a new AsyncLocalStorage to store the value of `env`.
const ambientEnv = new AsyncLocalStorage();

// We can now define a global function that reads a key from env.MY_KV,
// without having to pass `env` down to it.
function getFromKv(key) {
  // Get the env from AsyncLocalStorage.
  return ambientEnv.getStore().MY_KV.get(key);

export default {
  async fetch(req, env, ctx) {
    // Put the env into AsyncLocalStorage while we handle the request,
    // so that calls to getFromKv() work.
    return ambientEnv.run(env, async () => {
      // Handle request, including calling functions that may call
      // getFromKv().

      // ... (code) ...

How does a KV binding actually work?

Under the hood, a Workers KV binding encapsulates a secret key used to access the corresponding KV namespace. This key is actually the encryption key for the namespace. The key is distributed to the edge along with the Worker’s code and configuration, using encrypted storage to keep it safe.

Although the key is distributed with the Worker, the Worker itself has no way to access the key. In fact, even the owner of the Cloudflare account cannot see the key – it is simply never revealed outside of Cloudflare’s systems. (Cloudflare employees are also prevented from viewing these keys.)

Even if an attacker somehow got ahold of the key, it would not be useful to them as-is. Cloudflare’s API does not provide any way for a user to upload a raw key to use in a KV binding. The API instead has the client specify the public ID of the namespace they want to use. The deployment system verifies that the KV namespace in question is on the same account as the Worker being uploaded (and that the client is authorized to deploy Workers on said account).

Get Started

To learn about all the types of bindings offered by Workers and how to use them, check out the documentation.