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Embracing passwordless authentication with Grab’s Passkey

Post Syndicated from Grab Tech original https://engineering.grab.com/embracing-passwordless-authentication-with-passkey

Abstract

This blog post introduces Passkey — our latest addition to the Grab app — a step towards a secure, passwordless future. It provides an in-depth look at this innovative authentication method that allows users to have full control over their security, making authentication seamless and phishing-resistant. By the end of this piece, you will understand why we developed Passkey, how it works, the challenges we overcame, and the benefits brought to us post-launch. Whether you’re a tech enthusiast, a cybersecurity follower, or a Grab user, this piece offers valuable insights into the passwordless authentication sphere and Grab’s commitment to user safety and comfort.

Introduction

In the evolving world of digital security, Grab has always prioritised user account safety. A significant part of this involves exploring more secure and user-friendly authentication methods. Enter Grab’s Passkey — a major step towards passwordless authentication that leverages the Fast IDentity Online (FIDO) standard, giving users full control over their security, and making authentication seamless.

Background

Traditionally, the authentication process primarily relies on passwords — a precarious practice given the vulnerability to various security threats, such as phishing, keystroke logging, and brute-force attacks. This downside leads to the pursuit of safer, more user-friendly alternatives. Among these is the introduction of passwordless authentication.

A passwordless authentication method eliminates the need for users to enter traditional passwords during the verification process. Instead, it employs alternatives like:

  • Email link: A one-time clickable link sent via email.
  • One-Time Passcodes (OTPs): Temporary codes sent to users.
  • Social logins: Using existing profiles on platforms like Facebook or Google to sign in.
  • Authenticator apps: Software that generates time-sensitive codes.

Solution

Recognising the limitations and security issues of traditional password-based authentication, we turned to a more secure, user-friendly solution – the passwordless authentication system. Among other methods, we are also enabling Passkey, built on the FIDO standard. This global standard fosters wider adoption and support from consumer brands, making Passkey a secure and convenient choice.

Why Passkey?

Given the rapidly evolving security threats in the digital space, we selected Passkey for its unique benefits in providing both enhanced security and a seamless user experience. Passkey offers enhanced security as it is phishing-resistant and doesn’t require secrets to be stored in Grab’s database. Instead, secrets are securely kept within the user’s device, putting the control in their hands and significantly reducing the chances of exposure.

Fast-paced adoption of Passkey

Passkey technology is not only promising in theory but also successful in practice, as evidenced by its wider industry adoption. Consumers are adopting passkeys at a rapid pace in 2024. With large global consumer brands, such as Adobe, Amazon, Apple, Google, Hyatt, Nintendo, PayPal, Playstation, Shopify and TikTok enabling passkey technology for their users, more than 13 billion accounts can now leverage passkeys for sign-in.

In a recent FIDO Alliance independent study conducted on World Password Day 2024 across the U.S. and UK, findings reveal:

  • A majority of people are aware of passkey technology (62%).
  • Over half have enabled passkeys on at least one of their accounts (53%).
  • Once they adopt a passkey, nearly a quarter enable a passkey whenever possible (23%).
  • A large number believe passkeys are more secure (61%) and more convenient than passwords (58%).

These trends clearly illustrate why we chose to implement Passkey as our passwordless solution.

Architecture details

How do passkeys work?

There are three components of the passkey flow:

  • Backend: Holds the accounts database storing the public key and other metadata about the passkey.
  • Frontend: Communicates with the authenticator and sends requests to the backend.
  • Authenticator: The user’s authenticator creates and stores the passkey. This may be implemented in the operating system underlying the user agent, in external hardware, or a combination of both.
Figure 1. A high-level overview of the passkey authentication.

Supported environments

Google Password Manager: Stores, serves and synchronises passkeys on Android and Chrome. Passkeys are securely backed up and synced between Android devices where the user is signed using the same Google account, and available passkeys are listed.

iCloud Keychain: Synchronises the saved passkey to other Apple devices that run macOS, iOS, or iPadOS where the user is signed in using the same iCloud account.

Implementation

In this section, we illustrate the usage of passkeys in several scenarios.

Creating a new passkey

Figure 2. Passkey registration steps in Grab app.
  1. The user signs into the Grab app and selects Enable Passkey.
  2. Frontend requests user details and a challenge from Backend.
  3. Authenticator creates the user’s passkey upon their consent using their device’s screen lock.
  4. This passkey, along with other data, is sent back to Frontend.
  5. Frontend sends the public key credential to Backend for storage and future authentications.
Figure 3. Sequence diagram of Passkey registration.

Creating a passkey – notable Webauthn parameters

  1. When the user selects Enable Passkey, Frontend fetches the following information to call navigator.credentials.create() from Backend:
    • challenge: server-generated challenge.
    • user.id: user’s unique ID, stored as ArrayBuffer.
    • user.name: unique username or email for account recognition.
    • user.displayName: user-friendly name for the account.
    • excludeCredentials: to prevent registering the same device multiple times.
    • rp.id: Domain or a registrable suffix of an RP’s origin.
    • rp.name: Name of the RP.
    • pubKeyCredParams: Specifies RP’s public-key algorithms.
    • authenticatorSelection.authenticatorAttachment: Indicates type of authenticator attachment desired.
    • authenticatorSelection.requireResidentKey: Indicates if resident key is needed.
    • authenticatorSelection.userVerification: Indicates if user verification is required, preferred, or discouraged.
  2. Frontend invokes WebAuthn API to create a passkey.

     const publicKeyCredentialCreationOptions = {
       challenge: *****,
       rp: {
         name: "Example",
         id: "example.com",
       },
       user: {
         id: *****,
         name: "john78",
         displayName: "John",
       },
       pubKeyCredParams: [{alg: -7, type: "public-key"},{alg: -257, type: "public-key"}],
       excludeCredentials: [{
         id: *****,
         type: 'public-key',
         transports: ['internal'],
       }],
       authenticatorSelection: {
         authenticatorAttachment: "platform",
         requireResidentKey: true,
       }
     };
    
     const credential = await navigator.credentials.create({
       publicKey: publicKeyCredentialCreationOptions
     });
    
     // Encode and send the credential to the server for verification.
    
  3. Post user consent, passkey is created and returned along with relevant data to the frontend.
  4. Frontend sends the public key credential to Backend where it gets stored for future authentication.
  5. Backend receives and processes the object, and information is stored in the database for future use.

Signing in with a passkey

Figure 4. Passkey authentication steps in Grab app.
  1. The user launches the Grab app and opts to login using their passkey.
  2. Frontend requests a challenge from Backend for passkey authentication.
  3. The user is shown their available passkeys.
  4. Upon choosing a passkey, the user consents to using their device’s lock screen.
  5. Frontend receives the public key credential and some data.
  6. Frontend forwards these to the backend, which verifies them against the database and logs the user in.

Thus, Passkey enhances the login experience, providing an optimal blend of security and seamless usability.

Figure 5. Sequence diagram of the Passkey authentication.

Signing in with a passkey – notable Webauthn parameters

  1. Frontend fetches a challenge from Backend.
    • challenge: server-generated challenge, crucial to prevent replay attacks.
    • allowCredentials: array of acceptable credentials for authentication.
    • userVerification: indicates whether user verification is required, preferred, or discouraged.
  2. Frontend calls navigator.credentials.get() to initiate user authentication.

     // To abort a WebAuthn call, instantiate an `AbortController`.
    
     const abortController = new AbortController();
    
     const publicKeyCredentialRequestOptions = {
       // Server generated challenge
       challenge: ****,
       // The same RP ID as used during registration
       rpId: 'example.com',
     };
    
     const credential = await navigator.credentials.get({
       publicKey: publicKeyCredentialRequestOptions,
       signal: abortController.signal,
       // Specify 'conditional' to activate conditional UI
       mediation: 'conditional'
     });
    
  3. Post user consent through their device’s screen lock, a PublicKeyCredential object is returned to Frontend.
  4. The returned PublicKeyCredential is sent to Backend for verification. Backend looks up matching credential ID and verifies the signature against the stored public key.

Impact

A frictionless login paints a positive picture for our users. No more waiting for OTPs or struggling with cumbersome two-factor authentication. With the implementation of Passkey, users will enjoy a smoother, faster, and more secure login process.

In addition to delivering a frictionless user experience, passkeys provide heightened security compared to conventional authentication methods such as OTPs and passwords, which demand active credential management.

Using passkeys for authentication can lead to cost savings by cutting down or eliminating fees related to third-party authentication services, communication expenses, and messaging platforms. This strategy not only boosts security and user experience but also enhances the financial efficiency of the authentication process.

Moving forward, our focus is on enhancing, streamlining, and extending the capabilities of Passkey. We are enthusiastic about the evolution of passwordless authentication and are dedicated to ongoing investments in technologies that deliver the utmost user satisfaction and experience.

Conclusion

Leveraging passkeys for authentication provides heightened security, enhanced user experience, cost-effectiveness, decreased vulnerabilities, multi-factor authentication support, and simplified credential management. The future direction involves enhancing and broadening Passkey capabilities, with a dedication to investing in user-centric technologies that advance passwordless authentication. This commitment underscores the focus on delivering secure, efficient, and user-friendly authentication solutions for both existing and prospective users.

What’s next

Looking ahead, based on the user adoption of Passkey and its anticipated impact on improving login convenience, we aim to explore the expansion of this feature to web login as well. We envision a scenario where users can leverage the power of their existing phone Passkey, no matter the operating system, thereby creating a truly seamless and secure login experience.
As we gather user feedback, analyse usage data, and delve into Passkey’s impact, we aim to identify growth opportunities and further enhance our understanding of this innovative feature’s transformative effect on app security. Stay tuned for updates on how we are revolutionising our approach to authentication, with a continuous focus on enhancing user convenience and security.

References

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Turbocharging GrabUnlimited with Temporal

Post Syndicated from Grab Tech original https://engineering.grab.com/turbocharging-grabunlimited-with-temporal

Welcome to the behind-the-scenes story of GrabUnlimited, Grab’s flagship membership program. We undertook the mammoth task of migrating from our legacy system to a Temporal1 workflow-based system, enhancing our ability to handle millions of subscribers with increased efficiency and resilience. The result? A whopping 80% reduction in open production incidents, and most importantly – an improved membership experience for our users. In this first part of the series, you will learn how to design a robust and scalable membership system as we delve into our own experience building one.

What is GrabUnlimited?

The idea behind GrabUnlimited, is pretty simple: you pay a monthly fee, you get monthly benefits as a member (e.g discounted food delivery fee). A membership system plays a key role in enhancing user experience by giving them more value for money, but also by building loyalty, making Grab their go-to app for everyday needs. However, as this program grew and evolved, it brought along unique challenges and opportunities.

With the initial triumph and significant surge in subscriber count by over 1000% from January 2022 to June 2023 – which we were super proud of! – the architecture that supported GrabUnlimited was starting to show signs of strain. Common subscriber concerns such as not receiving their membership benefits, along with developer issues marked by an increase in service outages highlighted the system’s low resiliency. The culprit? A backend service that, while functional, was not built to efficiently manage the complexities of a rapidly scaling membership model.

Deep dive into our previous system design

As engineers, we know that deciding to migrate any system to a new one is like changing the engine of a running car. It requires meticulous evaluation of the existing systems, a deep dive into the issues and their root causes, and a thorough analysis of potential solutions and their trade-offs.

How was GrabUnlimited designed?

Initially, GrabUnlimited systems were designed for an experiment and not a full-fledged regional product. The idea was to try it out as a minimum viable product over a restricted segment of a few hundred thousand users. Let’s first have a look at how the membership program works.

Figure 1. GrabUnlimited life of a membership flowchart.

Under the hood, our membership system relies on two main flows

  • Membership purchase: The user enrols for a certain duration (e.g 3 months), completes the payment through our Payment service, and receives benefits via our Reward service.
  • Membership renewal: A daily cron job2 checks which memberships need renewal, processes the payment, and delivers the benefits.

We employed a state machine3 approach to break down the membership process into smaller chunks called state handlers. For instance, a membership might transition through ‘Init’, ‘Charged’, ‘Rewarded’, and ‘Active’ states. To operate these states, we used Amazon’s Simple Queue Service (SQS). SQS acts as a manager, delegating state handlers to workers (our service) and monitoring the status of the state handler. If a worker fails to complete a task, SQS reassigns the task to another worker, ensuring no task is lost. The load is also spread across multiple workers, helping with scalability.

To safeguard our system against duplicate tasks such as charging the user twice, when a worker takes up a task, it would use a Redis lock4 mechanism with a time-to-live (TTL) of five minutes preventing any other worker from picking up the same task. If a worker fails or crashes, the lock expires and another worker can pick up the job.

So far, so good.

Figure 2. GrabUnlimited previous system design overview.

With our success came many challenges

As our subscriber base grew, we experienced an increase in system outages. To address this, we scrutinised metrics like the number of support tickets and gauged the toll on our engineering team. This included the time spent patching up issues and the opportunity cost of not developing new features or improvements.

From our subscribers’ point of view, we saw a steady increase in reported incidents.

  • Users were blocked because their membership status was corrupted in our database.
  • Memberships were not automatically renewed, or users were not able to resubscribe.
  • Users were not receiving their benefits after renewing their membership.

From the engineering team’s perspective, we were dedicating one engineer every week to battle these incidents full time. The on-call engineers were not only tasked with manually fixing all customer reports but were also swamped with frequent system alerts. This situation had three detrimental impacts on our team:

  • We were constantly putting out fires instead of addressing the root causes.
  • We were spending resources that could have been used to enhance our customers’ experience.
  • Our team’s motivation and confidence was taking a big hit.

Finding the architectural culprit

The first step was to clearly identify and understand the issues within our systems. We looked at the frequency of failures and their root cause. From there, we were able to detect recurring patterns, which led us to four major issues in our architecture.

Scalability

Our system’s cron job, which retrieves all daily memberships due for renewal from our database, becomes slower and more resource-intensive as the number of members increases. Despite our attempt to alleviate high database usage by dividing the process into multiple batches and running several cron jobs, we were still experiencing significant surges each time a cron job runs. So our only viable solution was vertical scaling5 of the database. In other words, we had a serious bottleneck in our system.

Figure 3. Database queries per second during membership renewals at night.

Concurrency6

Picture this – A user tries to cancel their membership in the middle of the auto-renewal process, and voila, we have what we call a “zombie” state where the membership is both cancelled and renewed. This situation happens due to the limitations of our 5-minute Redis lock. If the renewal process holding the lock doesn’t complete within the timeout, the lock is released, enabling the cancel process to obtain the lock and run concurrently.

Resiliency7

What happens when the Rewards service faces an outage? The user buys a membership but doesn’t receive the rewards. It’s like throwing a party but the guests never arrive. We had three issues here:

  • In the event where upstream services had an outage, we relied on SQS’s maximum number of retries without exponential backoff8, causing potential overloads on recovering services.
  • Our cron job being housed within the service itself was susceptible to interruptions during outages or service restarts.
  • Over time, the logic to transition between states in our state machine became complex and multi-responsibility as more states were added. This made our retry mechanism unreliable due to potential risks of double charging or double awarding users. Which leads us to our fourth culprit.

Idempotency9

Even when some steps could be retried, our system lacked idempotency guarantees – a safety net to ensure that a step could be repeated without unintended side effects. Although our critical upstream systems like Payments and Rewards support idempotency via idempotency keys, our service wasn’t originally designed with this in mind.

  • Users could be stuck in a state where the payment succeeded but they didn’t receive their benefits or received them twice, requiring manual intervention from engineers.
  • We were not able to auto-retry membership renewals if the cron job, database, or any service had an outage.
Figure 4. Example of Idempotency issue in our old system design. If a single task fails in a state handler, the whole step would be retried which could lead to a double awarding.

For example, consider a state handler “BenefitsAwarding” that follows these steps:

  1. Generate an idempotency key.
  2. Calls Reward service to award the first set of benefits to the subscriber using the key.
  3. Calls Reward service to award the second set of benefits to the subscriber using the key.

If step 3 fails due to an outage, and the step is retried and re-queued in SQS, it would restart from step 1. This generates a new idempotency key, meaning the Reward system wouldn’t recognize the retry and will award Benefits1 twice. One way to fix this with our current design is to substantially increase the number of states in our SQS state machine, to isolate tasks further rather than handling too much logic in a state handler. However, that would mean having hundreds of states making the whole process difficult to maintain.

Ultimately, most incidents traced back to one fundamental issue: Our systems were relying on a sequential process that couldn’t be easily replayed if any incident or disturbance happened during execution. We were placing all our bets on the happy path, a risky gamble indeed.

The Solution: Migrating our system to Temporal

Armed with a clear understanding of the problems and their impacts, we set out to explore potential solutions. This journey led us to consider refactoring our existing system or migrating to a new architecture that another team introduced to us: Temporal.

Enter Temporal

Temporal is an open-source workflow orchestration engine. Think of it as a more robust and battle-tested implementation of our previous SQS architecture. It’s designed to run millions of workflows concurrently and can recover/resume the state of a workflow execution at the exact point of failure even in the event of an outage. It has features like infinite retries, exponential backoff, rate limiting, and observability out of the box. This sounded exactly like what we needed! By using Temporal, we could offload the complexity of managing state transitions, retries, and task concurrency, allowing us to focus on our core business logic.

In order to make the right decision, we meticulously assessed our options over the following criteria: scalability10, reliability11, resiliency12, performance, development effort, cost, security, flexibility13, and testability14. We realised that most of what we needed to build to compensate for our system design gaps was already built into Temporal. Let’s have a sneak peek on how the architecture looks and how it solves all four major culprits we discussed.

Figure 5. GrabUnlimited new system design architecture.

Fixing our architecture culprits

Scalability

Let’s start with the easiest fix, remember our old cron job for membership renewals? We replaced it with Timer which allows a workflow to sleep and automatically wake up. Instead of renewing membership by batches, they are now renewed throughout the entire day based on the hour and minute when the user subscribed. What does this mean for us? We no longer need to fetch memberships from our database to trigger renewals. The workflow will resume at the due date to process the renewal, eliminating the database as a bottleneck.

Figure 6. Total queries per second (QPS) on database before and after the migration to Temporal.

Concurrency

Our legacy Redis lock mechanism was clearly not enough. However, with Temporal, we have alternative solutions to avoid race conditions. What happens if a user tries to cancel while the membership renewal workflow is being triggered? Temporal allows us to assign the same workflow ID to multiple workflows running mutually exclusive operations, ensuring only one operation runs at a time. Basically, we assigned the same workflow ID to both cancellation and renewal workflows, either cancellation happens first, removing the need to renew the consumer membership, or renewal takes the lead, and cancellation only happens after.

Figure 7. Total corrupted membership states (zombies) manually handled by engineers significantly decreased during our migration which started in February.

Resiliency

Out of the box, Temporal allowed us to put in place a few key resilience mechanisms like exponential backoff and infinite retry which was a key gap in our previous SQS architecture. That was great because we didn’t have to implement these mechanisms on our own and it meant that when calling key upstream services like Payment, we were able to precisely set our retry policies without overwhelming the service in case of an outage on their end.

Idempotency

Remember our fourth culprit from above? Our state handlers with SQS were performing too many tasks simultaneously, which made it risky to trust the retry process. This multi-responsibility nature introduced significant risks, including potential database corruption, double charging, and double awarding of benefits. Further breaking down these steps would result in hundreds of intermediary steps, each requiring careful maintenance and correct sequencing. With Temporal, you can imagine a membership as an ever-running workflow consisting of a sequence of steps that are automatically managed and retried in case of failures.

While this approach didn’t directly resolve idempotency issues, it made the system and the code more readable and allowed us to design steps with single responsibilities. This, in turn, made it simpler for us to develop and ensure these steps were idempotent.

Let’s take a look at our previous example with Temporal.

Figure 8. Temporal workflow: If a single task fails, only that task is retried.

Let’s consider the same use case where a member needs to receive their benefits. The tasks remain the same except we don’t need to persist the idempotency key as it will be in the Temporal workflow state instead.

  1. Generate idempotency keys.
  2. Calls Reward service to award the first set of benefits to the subscriber using the key abc1.
  3. Calls Reward service to award the second set of benefits to the subscriber using the second key xyz1.

If the “AssignBenefits2” step fails, and the process is retried by Temporal, it will restart directly from that step, thus preventing the double awarding we were experiencing with SQS. Thanks to this approach, we largely improved idempotency and resiliency in our system, which also led to great results in decreasing user reported incidents.

Figure 9. Total open production incidents reported by users related to membership issues from January to October 2024.

Embracing Temporal: Challenges and mindset shift

Transitioning to Temporal was quite a paradigm shift for our team. Rather than managing SQS state transitions, we could now focus on our core business logic while Temporal handled the complexities of state management, error handling, and retries. This change allowed us to streamline development, making our processes more intuitive.

However, this shift wasn’t without its challenges. Temporal features such as Workflow and Activity design, deterministic execution, and built-in retry mechanisms required a steep learning curve. We had to quickly adapt to Temporal’s new way of thinking, and while it took some time to master these tools, they ultimately led to a more robust and scalable system. The transition to Temporal brought not only technical improvements but also a new mindset for solving problems efficiently.

Key takeaways and conclusion

After a thorough analysis, we decided to transition our architecture to Temporal, as it outperformed on nearly every evaluation criteria. Here are the key takeaways from our experience:

  • Understand the problem, fix it for the future: Migrating legacy systems requires more than just patching up issues; it demands a deep dive into the root causes. For us, that meant addressing challenges in scalability, resiliency, and concurrency head-on to prevent future headaches.
  • Focusing on what matters: By adopting Temporal workflow orchestration, we could shift our focus to what really counts, core business logic. The result? An 80% reduction in production incidents and a much smoother post-migration experience.
  • Resilience and flexibility at scale: Temporal provided the infrastructure we needed to handle millions of subscribers with more robust processes for retries, idempotency, and state management. These features played a key role in ensuring the system remained stable and flexible as our user base grew.
  • The learning curve pays off: Every system migration has its challenges, but the payoff was transformative. Despite the initial hiccups, moving to Temporal allowed us to scale GrabUnlimited seamlessly while significantly improving both our development processes and the overall user experience.

Stay tuned for Part 2, where we dive into the challenges of the migration and the lessons learned along the way. How did we seamlessly migrate millions of users to this new architecture without disrupting their memberships? How did we implement Temporal without pausing development for months? And what roadblocks did we encounter as we scaled this solution to all our users? We’ll answer these questions and more in the next post.

Nothing would have been possible without the unwavering support of Abegail Nato Alcantara, Andrys Silalahi, Pavel Sidlo, and Renu Yadav.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Definition of terms

  1. Temporal: Temporal is an open-source workflow orchestration platform. It allows developers to build scalable and reliable applications using familiar development patterns and easy-to-use tools. ↩

  2. Cron job: A cron job is a time-based job scheduler in Unix-like operating systems. Users can schedule jobs (commands or scripts) to run periodically at fixed times, dates, or intervals. ↩

  3. State machine: A state machine is a behavioural model used in computer science. It represents a system in terms of states and transitions between those states. ↩

  4. Redis lock mechanism: Redis is an in-memory data structure store that can be used as a database, cache, and message broker. A Redis lock mechanism is a way to ensure that only one computer in a distributed network can process a certain piece of code at a time. ↩

  5. Vertical scaling: also known as “scaling up”, is the process of adding more resources (such as memory, CPUs, or storage) to an existing server or database to enhance its performance and capacity. Which is different from Horizontal scaling, also known as “scaling out”, the process of adding more servers or nodes to a system to handle increased load. ↩

  6. Concurrency: In computing, concurrency is the ability of different parts or units of a program, algorithm, or problem to be executed out-of-order or in partial order, without affecting the final outcome. ↩

  7. Resiliency: refers to the ability of a system or application to quickly recover from failures and continue its intended operation without significant interruption. ↩

  8. Exponential backoff: Exponential backoff is an algorithm that uses feedback to multiplicatively decrease the rate of some process, in order to gradually find an acceptable rate. In the context of the article, it refers to a strategy for retrying failed tasks with increasing wait times between retries. ↩

  9. Idempotency: An operation is idempotent if the result of performing it once is exactly the same as the result of performing it repeatedly without any intervening actions. ↩

  10. Scalability: The ability of a system to handle increased workload or demand by adding resources. ↩

  11. Reliability: The capacity of a system to consistently perform its intended functions without failure. ↩

  12. Resiliency: The ability of a system to recover quickly and effectively from failures or disruptions, ensuring continuity of service. ↩

  13. Flexibility: The architecture should be flexible enough to accommodate future changes in requirements. ↩

  14. Testability: The architecture should allow for effective testing to ensure the system works as expected. ↩

How we seamlessly migrated high volume real-time streaming traffic from one service to another with zero data loss and duplication

Post Syndicated from Grab Tech original https://engineering.grab.com/seamless-migration

At Grab, we continuously enhance our systems to improve scalability, reliability and cost-efficiency. Recently, we undertook a project to split the read and write functionalities of one of our backend services into separate services. This was motivated by the need to independently scale these operations based on their distinct scalability requirements.

In this post, we will dive deep into how we migrated the stream processing (write) functionality to a new service with zero data loss and duplication. This was accomplished while handling a high volume of real-time traffic averaging 20,000 reads per second from 16 source Kafka streams writing to other output streams and several DynamoDB tables.

Migration challenges and strategy

Migrating the stream processing to the new service while ensuring zero data loss and duplication posed some interesting challenges, especially given the high volume of real-time data. We needed a strategy that would enable us to:

  • Migrate streams one by one gradually.
  • Validate the new service’s processing in production before fully switching over.
  • Perform the switchover with no downtime or data inconsistencies.

We considered various options for the switchover such as using feature flags via our unified config management and experimental rollout platform. However, these approaches had some limitations:

  • There could be some data loss or duplication during the deployment time when toggling the flags, which can be up to a few minutes.
  • There might be data inconsistencies as the flag value could be updated on the services (the existing and and the new one) at slightly different times.

Ultimately, we decided on a custom time-based switchover logic implemented in shared code between the two services leveraging our monorepo structure. In the following sections, we will walk you through the steps we took to achieve this seamless migration.

Step 1: Preparation

First, since both the existing and new services reside in our monorepo, we moved the stream processing code from the existing service to a shared /commons directory. This allowed both the old and new services to import and use the same code. We added logic in this commons package to selectively turn stream processing on or off based on the service processing them.

Next, we created temporary “sink” resources such as streams and DynamoDB tables for the new service to write the processed data. This allowed us to monitor and validate the new service’s behavior in production without impacting the main resources.

Figure 1. For a short period, both services consumed the incoming streams, but only the old service continued to write to the actual sink resources while the new service wrote to validation sink resources.

Step 2: Scheduling the switchover

In the shared /commons code, we added a map[string]time.Time to schedule the switchover for each stream.

map[string]time.Time{
  "streamA": time.Date(2024, 2, 28, 12, 0, 0, 0, time.UTC),
  "streamB": time.Date(2024, 3, 10, 12, 0, 0, 0, time.UTC),
  // ...
}

When a stream is added to this map, it means it is scheduled for switchover at the specified time. This logic is shared between both services, so the switchover happens simultaneously. The new service starts writing to the main resources while the old service stops, with no overlap or gap.

Step 3: Deployment and monitoring

To perform the switchover, we:

  1. Updated the switchover times for the streams.
  2. Deployed both services with enough buffer time before the scheduled switch.
  3. Closely monitored the process by creating dedicated monitors for the migration process using our observability tools.
Figure 2. This timeseries graph shows the stream received at the old and the new service (dotted line), facilitating real time monitoring of the stream processing volume across both services during the validation period.

The old service continued consuming the streams for a short monitoring period post-switchover, but without writing anywhere, ensuring no loss or duplication at the output sink resources. Then, the stream consumption was removed from the old service altogether, completing the entire migration process.

Results and learnings

Using this time-based approach, we were able to seamlessly migrate the high-volume stream processing to the new service with:

  • Zero data loss or duplication.
  • No downtime or production issues.

The whole migration, including the gradual stream-by-stream switchover, was completed in about three weeks.

One learning was that such custom time-based logic, while effective for our use case, has limitations. If a rollback was needed for any of the two services for some unexpected reasons, some data inconsistency would be unavoidable. Generally, such time-based logic should be used with caution as it can lead to unexpected scenarios if the systems fall out of sync. We went ahead with this approach as it was a temporary measure and we had thoroughly tested it before carrying out the switchover.

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Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Supercharging LLM Application Development with LLM-Kit

Post Syndicated from Grab Tech original https://engineering.grab.com/supercharging-llm-application-development-with-llm-kit

Introduction

At Grab, we are committed to leveraging the power of technology to deliver the best services to our users and partners. As part of this commitment, we have developed the LLM-Kit, a comprehensive framework designed to supercharge the setup of production-ready Generative AI applications. This blog post will delve into the features of the LLM-Kit, the problems it solves, and the value it brings to our organisation.

Challenges

The introduction of the LLM-Kit has significantly addressed the challenges encountered in LLM application development. The involvement of sensitive data in AI applications necessitates that security remains a top priority, ensuring data safety is not compromised during AI application development.

Concerns such as scalability, integration, monitoring, and standardisation are common issues that any organisation will face in their LLM and AI development efforts.

The LLM-Kit has empowered Grab to pursue LLM application development and the rollout of Generative AI efficiently and effectively in the long term.

Introducing the LLM-Kit

The LLM-Kit is our solution to these challenges. Since the introduction of the LLM Kit, it has helped onboard hundreds of GenAI applications at Grab and has become the de facto choice for developers. It is a comprehensive framework designed to supercharge the setup of production-ready LLM applications. The LLM-Kit provides:

  • Pre-configured structure: The LLM-Kit comes with a pre-configured structure containing an API server, configuration management, a sample LLM Agent, and tests.
  • Integrated tech stack: The LLM-Kit integrates with Poetry, Gunicorn, FastAPI, LangChain, LangSmith, Hashicorp Vault, Amazon EKS, and Gitlab CI pipelines to provide a robust and end-to-end tech stack for LLM application development.
  • Observability: The LLM-Kit features built-in observability with Datadog integration and LangSmith, enabling real-time monitoring of LLM applications.
  • Config & secret management: The LLM-Kit utilises Python’s configparser and Vault for efficient configuration and secret management.
  • Authentication: The LLM-Kit provides built-in OpenID Connect (OIDC) auth helpers for authentication to Grab’s internal services.
  • API documentation: The LLM-Kit features comprehensive API documentation using Swagger and Redoc.
  • Redis & vector databases integration: The LLM-Kit integrates with Redis and Vector databases for efficient data storage and retrieval.
  • Deployment pipeline: The LLM-Kit provides a deployment pipeline for staging and production environments.
  • Evaluations: The LLM-Kit seamlessly integrates with LangSmith, utilising its robust evaluations framework to ensure the quality and performance of the LLM applications.

In addition to these features, the team has also included a cookbook with many commonly used examples within the organisation providing a valuable resource for developers. Our cookbook includes a diverse range of examples, such as persistent memory agents, Slackbot LLM agents, image analysers and full-stack chatbots with user interfaces, showcasing the versatility of the LLM-Kit.

The value of the LLM-Kit

The LLM-Kit brings significant value to our teams at Grab:

  • Increased development velocity: By providing a pre-configured structure and integrated tech stack, the LLM-Kit accelerates the development of LLM applications.
  • Improved observability: With built-in LangSmith and Datadog integration, teams can monitor their LLM applications in real-time, enabling faster issue detection and resolution.
  • Enhanced security: The LLM-Kit’s built-in OIDC auth helpers and secret management using Vault ensure the secure development and deployment of LLM applications.
  • Efficient data management: The integration with Vector databases facilitates efficient data storage and retrieval, crucial for the performance of LLM applications.
  • Standardisation: The LLM-Kit provides a paved-road framework for building LLM applications, promoting best practices and standardisation across teams.

Through the LLM-Kit, we can save an estimate of 1.5 weeks before teams start working on their first feature.

Figure 1. Project development process before LLM-Kit
Figure 2. Project development process after LLM-Kit

Architecture design and technical implementation

The LLM-Kit is designed with a modular architecture that promotes scalability, flexibility, and ease of use.

Figure 3. LLM-Kit modules

Automated steps

To better illustrate the technical implementation of the LLM-Kit, let’s take a look at figure 4 which outlines the step-by-step process of how an LLM application is generated with the LLM-Kit:

Figure 4. Process of generating LLM apps using LLM-Kit

The process begins when an engineer submits a form with the application name and other relevant details. This triggers the creation of a GitLab project, followed by the generation of a code scaffold specifically designed for the LLM application. GitLab CI files are then generated within the same repository to handle continuous integration and deployment tasks. The process continues with the creation of staging infrastructure, including components like Elastic Container Registry (ECR) and Elastic Kubernetes Service (EKS). Additionally, a Terraform folder is created to provision the necessary infrastructure, eventually leading to the deployment of production infrastructure. At the end of the pipeline, a GPT token is pushed to a secure Vault path, and the engineer is notified upon the successful completion of the pipeline.

Scaffold code structure

The scaffolded code is broken down into multiple folders:

  1. Agents: Contains the code to initialise an agent. We have gone ahead with LangChain as the agent framework; essentially the entry point for the endpoint defined in the Routes folder.
  2. Auth: Authentication and authorisation module for executing some of the APIs within Grab.
  3. Core: Includes extracting all configurations (i.e. GPT token) and secret decryption for running the LLM application.
  4. Models: Used to define the structure for the core LLM APIs within Grab.
  5. Routes: REST API endpoint definitions for the LLM Applications. It comes with health check, authentication, authorisation, and a simple agent by default.
  6. Storage: Includes connectivity with PGVector, our managed vector database within Grab and database schemas.
  7. Tools: Functions which are used as tools for the LLM Agent.
  8. Tracing: Integration with our tracing and monitoring tools to monitor various metrics for a production application.
  9. Utils: Default folder for utility functions.
Figure 5. Scaffold code structure

Infrastructure provisioning and deployment

Within the same codebase, we have integrated a comprehensive pipeline that automatically scaffolds the necessary code for infrastructure provisioning, deployment, and build processes. Using Terraform, the pipeline provisions the required infrastructure seamlessly. The deployment pipelines are defined in the .gitlab-ci.yml file, ensuring smooth and automated deployments. Additionally, the build process is specified in the Dockerfile, allowing for consistent builds. This automated scaffolding streamlines the development workflow, enabling developers to focus on writing business logic without worrying about the underlying infrastructure and deployment complexities.

Figure 6. Pipeline infrastructure

RAG scaffolding

At Grab, we’ve established a streamlined process for setting up a vector database (PGVector) and whitelisting the service using the LLM-Kit. Once the form (figure 7) is submitted, you can access the credentials and database host path. The secrets will be automatically added to the Vault path. Engineers will then only need to include the DB host path in the configuration file of the scaffolded LLM-Kit application.

Figure 7. Form submitted to access credentials and database host path

Conclusion

The LLM-Kit is a testament to Grab’s commitment to fostering innovation and growth in AI and ML. By addressing the challenges faced by our teams and providing a comprehensive, scalable, and flexible framework for LLM application development, the LLM-Kit is paving the way for the next generation of AI applications at Grab.

Growth and future plans

Looking ahead, the LLM-Kit team aims to significantly enhance the web server’s concurrency and scalability while providing reliable and easy-to-use SDKs. The team plans to offer reusable and composable LLM SDKs, including evaluation and guardrails frameworks, to enable service owners to build feature-rich Generative AI programs with ease. Key initiatives also include the development of a CLI for version updates and dev tooling, as well as a polling-based agent serving function. These advancements are designed to drive innovation and efficiency within the organisation, ultimately providing a more seamless and efficient development experience for engineers.

We would like to acknowledge and thank Pak Zan Tan, Han Su, and Jonathan Ku from the Yoshi team and Chen Fei Lee from the MEKS team for their contribution to this project under the leadership of Padarn George Wilson.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

How we reduced initialisation time of Product Configuration Management SDK

Post Syndicated from Grab Tech original https://engineering.grab.com/how-we-reduced-grabx-sdk-initialisation-time

Introduction

GrabX serves as Grab’s central platform for product configuration management. GrabX client services read product configurations through an SDK. This SDK reads the configurations in a way that’s eventually consistent, meaning it takes about a minute for any configuration updates to reach the client SDKs.

However, some GrabX SDK clients, particularly those that need to read larger configuration data (~400 MB), reported that the SDK takes an extended amount of time to initialise, approximately four minutes. This blog post details how we analysed and addressed this issue.

SDK Observations

GrabX clients have observed that the GrabX SDK requires several minutes to initialise. This results in what is known as ‘cold starts’, where the SDK takes an extended time to begin supporting the reading of configurations at startup. This challenge highlights the importance of efficient SDK start-up management, especially when a service handling a high volume of incoming traffic initiates new SDK instances to manage the load better. However, due to the extended SDK initialisation time, these instances continue to experience stress, potentially leading to service throttling.

SDK Initialisation Workflow

The SDK initialisation flow described below is based on the improvements we proposed to the SDK design in our previous post. In that post, we suggested enhancing the SDK design by:

A. Implementing service-based data partitioning and storage in the AWS S3 bucket
B. Allowing service-based subscription of data for the SDK

The following diagram provides a high-level overview of the initialisation process of the GrabX SDK, which can be divided into the following sequential steps:

  1. Set options that drive the behaviour of the SDK.
  2. Initialise dependent module clients.
  3. Initialise the GrabX client. (Highlighted as A in the diagram below)
  4. Download data for the SDK’s subscribed list of services from the AWS S3 bucket and store this data on the SDK instance disk. (Highlighted as B in the diagram below)
  5. Download common data needed by the SDK from the AWS S3 bucket and store this data on the SDK instance disk. This data is referred to as ‘common’ because it is required by all different client services. (Highlighted as C in the diagram below)
  6. Download data for the SDK’s subscribed list of services from the AWS S3 bucket and load this data into the SDK instance memory. (Highlighted as D in the diagram below)
  7. Download common data needed by the SDK from the AWS S3 bucket and load this data into the SDK instance memory. (Highlighted as E in the diagram below)
  8. Initialise dependent modules for resolving the configuration value. (Highlighted as F in the diagram below)

Proposed Solution

In order to address the issue of extended SDK initialisation time, we have decided to enhance the SDK initialisation design in multiple phases. Each phase focused on improving a specific part of the workflow.

Improvement Phase 1

As discussed in the previous section, the GrabX SDK needs to load two separate sets of data: the subscribed services data and the common data. These two data sets are currently downloaded from the AWS S3 bucket and sequentially loaded into disk and memory.

In the first phase of our improvement plan, we decided to change the sequential data load to a concurrent data load for these two data sets, as illustrated in the following diagram. This alteration in the SDK initialisation workflow reduced the initialisation time by approximately 80%.


Improvement Phase 2

Building on the progress made in Phase 1, we next turned our attention to the issue of large configuration file sizes. As mentioned in the introduction, the extended SDK initialisation time was particularly noticeable for client services that needed to load larger amounts of data.

In this phase, we decided to implement an SDK design change that allows the SDK to concurrently download data from the AWS S3 bucket and load it into memory for all these large configurations within a subscribed service, as illustrated in the following diagram. This modification to the SDK initialisation workflow further reduced the initialisation time by approximately 6%.


Improvement Phase 3

Upon examining the SDK’s behaviour, we observed that the SDK is both persisting configuration data downloaded from the AWS S3 bucket to disk and loading the data into memory. We understand that the data is loaded into memory to reduce the latency of configuration reads. The data is stored on disk to support a fallback mechanism, which is activated in a very specific use case: when the client SDK instance restarts and there is a connectivity issue with AWS S3 for downloading configuration files. In this scenario, the SDK will read the configuration data stored on disk. However, this data could be outdated as it is not freshly downloaded from the AWS S3 bucket, and most client services require the most recent data.

Therefore, we realised that the fallback mechanism, for which data is persisted on disk, actually conflicts with the desired SDK behaviour for most client services. As a result, we decided to eliminate the SDK initialisation step that downloads configuration data from AWS S3 and persists it on disk. If the SDK initialisation fails to connect to the AWS S3 bucket and download data, client services can then take the necessary action, such as retrying initialisation. This modification further reduced the initialisation time by approximately 50% compared to the improvement achieved in Phase 2.


Conclusion

We benchmarked the proposed solution with a variety of services, each having different configuration data sizes. Our findings suggest that the proposed solution has the potential to reduce initialisation time by up to 90%.

The following chart illustrates the phase-wise reduction in initialisation time achieved through the improvements made to the GrabX SDK.


Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Metasense V2: Enhancing, improving and productionisation of LLM powered data governance

Post Syndicated from Grab Tech original https://engineering.grab.com/metasense-v2

Introduction

In the initial article, LLM Powered Data Classification, we addressed how we integrated Large Language Models (LLM) to automate governance-related metadata generation. The LLM integration enabled us to resolve challenges in Gemini, such as restrictions on the customisation of machine learning classifiers and limitations of resources to train a customised model. Gemini is a metadata generation service built internally to automate the tag generation process using a third-party data classification service. We also focused on LLM-powered column-level tag classifications. The classified tags, combined with Grab’s data privacy rules, allowed us to determine sensitivity tiers of data entities. The affordability of the model also enables us to scale it to cover more data entities in the company. The initial model scanned more than 20,000 data entries, at an average of 300-400 entities per day. Despite its remarkable performance, we were aware that there was room for improvement in the areas of data classification and prompt evaluation.

Improving the model post-rollout

Since its launch in early 2024, our model has gradually grown to cover the entire data lake. To date, the vast majority of our data lake tables have undergone analysis and classification by our model. This has significantly reduced the workload for Grabbers. Instead of manually classifying all new or existing tables, Grabbers can now rely on our model to assign the appropriate classification tier accurately.

Despite table classification being automated, the data pipeline still requires owners to manually perform verification to prevent any misclassifications. While it is impossible to entirely eliminate human oversight from critical machine learning workflows, the team has dedicated substantial time post-launch to refining the model, thereby safely minimising the need for human intervention.

Utilising post-rollout data

Following the deployment of our model and receipt of extensive feedback from table owners, we have accumulated a large dataset to further enhance the model. This data, coupled with the dataset of manual classifications from the Data Governance Office to ensure compliance with information classification protocols, serves as the training and testing datasets for the second iteration of our model.

Model improvements with prompt engineering

Expanding the evaluation and testing data allowed us to uncover weaknesses in the previous model. For instance, we discovered that seemingly innocuous table columns like “business email” could contain entries with Personal Identifiable Information (PII) data.

An example of this would be a business that uses a personal email address containing a legal name—a discrepancy that would be challenging for even human reviewers to detect. Additionally, we discovered nested JSON structures occasionally included personal names, phone numbers, and email addresses hidden among other non-PII metadata. Lastly, we identified passenger communications with Grab occasionally mentioning legal names, phone numbers, and other PII, despite most of the content being non-PII.

Ultimately, we hypothesised the model’s main issue was model capacity. The model displayed difficulty focusing on large data samples containing a mixture of PII and non-PII data despite having a good understanding of what constitutes PII. Just like humans, when given high volumes of tasks to work on simultaneously, the model’s effectiveness is reduced. In the original model, 13 out of 21 tags were aimed at distinguishing different types of non-PII data. This took up significant model capacity and distracted the model from its actual task: identifying PII data.

To prevent the model from being overwhelmed, large tasks are divided into smaller, more manageable tasks, allowing the model to dedicate more attention to each task. The following measures were taken to free up model capacity:

  1. Splitting the model into two parts to make problem solving more manageable.
    • One part for adding PII tags.
    • Another part for adding all other types of tags.
  2. Reducing the number of tags for the first part from 21 to 8 by removing all non-PII tags. This simplifies the task of differentiating types of data.

  3. Using clear and concise language, removing unnecessary detail. This was done by reducing word count in prompt from 1,254 to 737 words for better data analysis.

  4. Splitting tables with more than 150 columns into smaller tables. Fewer table rows means that the LLM has sufficient capacity to focus on each column.

Enabling rapid prompt experimentation and deployment

In our quest to facilitate swift experimentation with various prompt versions, we have empowered a diverse team of data scientists and engineers to work together effectively on the prompts and service. This has been made possible by upgrading our model architecture to incorporate the LangChain and LangSmith frameworks.

LangChain introduces a novel framework that streamlines the process from raw input to the desired outcome by chaining interoperable components. LangSmith, on the other hand, is a unified DevOps platform that fosters collaboration among various team members and developers, including product managers, data scientists, and software engineers. It simplifies the processes of development, collaboration, testing, deployment, and monitoring for all involved.

Our new backend leverages LangChain to construct an updated model that supports classification tasks for both non-PII and PII tagging. Integration with LangSmith enables data scientists to directly develop prompt templates and conduct experiments via the LangSmith user interface. In addition, managing the evaluation dataset on LangSmith provides a clear view of the performance of prompts across multiple custom metrics.

The integration of LangChain and LangSmith has significantly improved our model architecture, fostering collaboration and continuous improvement. This has not only streamlined our processes but also enhanced the transparency of our performance metrics. By harnessing the power of these innovative tools, we are better equipped to deliver high-quality, efficient solutions.

The benefits of the LangChain and LangSmith framework enhancements in Metasense are summarised as follows:

Streamlined prompt optimisation process.

Data scientists can create, update, and evaluate prompts directly on the LangSmith user interface and save them in commit mode. For rapid deployment, the prompt identifier in service configurations can be easily adjusted.

Figure 1: Streamlined prompt optimisation process.

Transparent prompt performance metrics.

LangSmith’s capabilities allow us to effortlessly run evaluations on a dataset and obtain performance metrics across multiple dimensions, such as accuracy, latency, and error rate.

Assuring quality in perpetuity

With exceptionally low misclassification rates recorded, table owners can place greater trust in the model’s outputs and spend less time reviewing them. Nevertheless, as a prudent safety measure, we have set up alerts to monitor misclassification rates periodically, sounding an internal alarm if the rate crosses a defined threshold. A model improvement protocol has also been set in place for such alarms.

Conclusion

The integration of LLM into our metadata generation process has significantly improved our data classification capabilities, reducing manual workloads and increasing accuracy. Continuous improvements, including the adoption of LangChain and LangSmith frameworks, have streamlined prompt optimisation and enhanced collaboration among our team. With low misclassification rates and robust safety measures, our system is both reliable and scalable, fostering trust and efficiency. In conclusion, these advancements ensure we remain at the forefront of data governance, delivering high-quality solutions and valuable insights to our stakeholders.

We would like to express our sincere gratitude to Infocomm Media Development Authority (IMDA) for supporting this initative.

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Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

How we reduced peak memory and CPU usage of the product configuration management SDK

Post Syndicated from Grab Tech original https://engineering.grab.com/reduced-memory-cpu-usage-grabx-sdk

Introduction

GrabX is Grab’s central platform for product configuration management. It has the capacity to control any component within Grab’s backend systems through configurations that are hosted directly on GrabX.

GrabX clients read these configurations through an SDK, which reads the configurations in a way that’s asynchronous and eventually consistent. As a result, it takes about a minute for any updates to the configurations to reach the client SDKs.

In this article, we discuss our analysis and the steps we took to reduce the peak memory and CPU usage of the SDK.

Observations on potential SDK improvements

Our GrabX clients noticed that the GrabX SDK tended to require high memory and CPU usage. From this, we saw opportunities for further improvements that could:

  • Optimise the tail latencies of client services.
  • Enable our clients to use their resources more effectively.
  • Reduce operation costs and improve the efficiency of using the GrabX SDK.
  • Accelerate the adoption of GrabX by Grab’s internal services.

SDK design

At a high-level, creating, updating, and serving configuration values via the GrabX SDK involved the following process:

Figure 1. Previous GrabX SDK design.
  1. The process begins when GrabX clients either create or update configurations. This is done through the GrabX web portal or by making an API call.
  2. Once the configurations are created or updated, the GrabX backend module takes over. It stores the new configuration into an SQL database table.
  3. The GrabX backend ensures that the latest configuration data is available to client SDKs.

    a. The GrabX backend checks every minute for any newly created or updated configurations.

    b. If there are new or updated configurations, GrabX backend creates a new JSON file. This file contains all existing and newly created configurations. It’s important to note that all configurations across all services are stored in a single JSON file.

    c. The backend module uploads this newly created JSON file to an AWS S3 bucket.

    d. The backend module assigns a version number to the new JSON file and updates a text file in the AWS S3 bucket. This text file stores the latest JSON file version number. The client SDK refers to this version file to check if a newer version of the configuration data is available.

  4. The client SDK performs a check on the version file every minute to determine if a newer version is available. This mechanism is crucial to maintain data consistency across all instances of a service. If any instance fell out of sync, it would be brought back in sync within a minute.
  5. If a new version of the configuration JSON file is available, the client SDK downloads this new file. Following the download, it loads the configuration data into memory. Storing the configuration data in memory reduces the read latency for the configurations.

Areas of improvement for existing SDK design

In this section we outline the areas of improvement we identified within the SDK design.

Service-based data partitioning

We saw an opportunity for service-based data partitioning. The configuration data for all services was consolidated into a single JSON file. Upon studying the data read patterns of client services, we observed that most services primarily needed to access configuration data specific to their own service. However, the present design required storing configuration data for all other services. This resulted in unnecessary memory consumption.

Retaining only new version of configuration in the same file

By using a single JSON file for storing old and new configuration data, we saw a significant increase in the size of the JSON file.

The SDK only needs the full data when it starts; the more common case is that it needs to stay updated with the latest configuration. Even in that scenario, the SDK needed to fetch a complete new JSON file every minute no matter the size of the updates. Consequently, the process of downloading, decoding, and loading high volumes of data at a high frequency (every minute) caused the client SDK to spike in memory and CPU usage.

More efficient JSON decoding

An additional factor which contributed to memory and CPU usage during the decoding phase was the inefficiency of the default JSON decode library to decode this large (>100MB) JSON file. Decoding this JSON file was heavy on available CPU resources, which tended to starve the service of its ability to handle incoming requests. This manifested as increasing the P99 latency of the service.

Figure 2. Graph illustrating the increased P99 latency due to CPU throttling for a service.

Implemented solution

We proposed modifications to the existing SDK design, which we discuss in this section.

Partition data by service

The proposed solution involved partitioning the data based on services. We chose this approach because a single configuration typically belonged to a single service, and most services primarily needed to read configurations that pertained to their own service.

Upon analysing the distribution of service-configuration, we discovered that 98% of client services required less than 1% of the total configuration data. Despite this, they were required to maintain and reload 100% of the configuration data. Furthermore, the service with the largest number of configurations only required 20% of the total configuration data.

Therefore, we proposed a shift towards service-based partitioning of configuration data. This allowed individual client services to access only the data they needed to read.

Figure 3. Graph showing the number of services with varying amounts of configurations.

Create separate JSON files for each configuration

Our proposal also included creating a separate JSON file for each configuration in a service. Previously, all data was stored in a single JSON file housed in an AWS S3 bucket, which supported a maximum of 3,500 write/update requests and 5,500 read requests per second.

By storing each configuration in a separate JSON file, we were able to create a different S3 prefix for each configuration file. These S3 prefixes helped us to maximise S3 throughput by enhancing the read/write performance for each configuration. AWS S3 can handle at least 3,500 PUT/COPY/POST/DELETE requests or 5,500 GET/HEAD requests per second for each partitioned Amazon S3 prefix.

Therefore, with each configuration’s data stored in a separate S3 file with a different prefix, the GrabX platform could achieve a throughput of 5,500 read requests and 3,500 write/update requests per second per configuration. This was beneficial for boosting read/write capacity when needed.

Implement a service-level changelog

We proposed to create a changelog file at the service level. In other words, a changelog file was created for each service. This file was used to keep track of the latest update version, as well as previous service configuration update versions. This file also recorded the configurations which were created or updated in each version. This enables the SDK to accurately identify the configurations that were created or updated in each update version. This was useful to update the specific configurations belonging to a service on the client side.

Implement service-based SDK

We proposed that SDK client services should be allowed to subscribe to a list of services for which they need to read configuration data. The SDK was initialised with data of the subscribed services and received updates only for configurations corresponding to the subscribed services.

Figure 4. This flowchart shows our proposed service-based SDK implementation.

The SDK only sought updates for the subscribed services. The client SDK needed to read the changelog file for each of the subscribed services, comparing the latest changelog version against the SDK version number. Whenever a newer changelog version was available, the SDK updated the variables with the latest version.

This approach significantly reduced the volume of data that the SDK needed to download, decode, and load into memory during both initialisation and each subsequent update.

Conclusion

In summary, we identified ways to optimise CPU and memory usage in the GrabX SDK. Our analysis revealed that frequent high resource consumption hindered the wider adoption of GrabX. We proposed a series of modifications, including partitioning data by service and creating separate JSON files for each configuration.

After benchmarking the proposed solution with a variety of configuration data sizes, we found that the solution has the potential to reduce memory utilisation by up to 70% and decrease the maximum CPU utilisation by more than 50%. These improvements significantly enhance the performance and scalability of the GrabX SDK.

Figure 5. Bar charts showcasing memory(MB) & CPU(%) utilisation for Service A before and after using the discussed solution.

Moving forward, we plan to continue optimising the GrabX SDK by exploring additional improvements, such as reducing its initialisation time. These efforts aim to make GrabX an even more robust and reliable solution for product configuration management within Grab’s ecosystem.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

LLM-assisted vector similarity search

Post Syndicated from Grab Tech original https://engineering.grab.com/llm-assisted-vector-similarity-search

Introduction

As the complexity of data retrieval requirements continue to grow, traditional search methods often struggle to provide relevant and accurate results, especially for nuanced or conceptual queries. Vector similarity search has emerged as a powerful technique for finding semantically similar information. It refers to finding vectors in a large dataset that are most similar to a given query vector, typically using some distance or similarity measure. The concept originated in the 1960s with the work by Minsky and Papert on nearest neighbour search 1. Since then, the idea has evolved substantially with modern approaches often using approximate methods to enable fast search in high-dimensional spaces, such as locality-sensitive hashing 2 and graph-based indexing 3.

Recently, vector similarity search has become a crucial component in many machine learning and information retrieval applications. It is one of the key technologies that popularised the idea of Retrieval Augmented Generation (RAG) 4 which increased the applicability of Transformer 5 based Generative Large Language Models (LLMs) 6 in domain-specific tasks without requiring any further training or fine-tuning. However, the effectiveness of the vector search can be limited when dealing with intricate queries or contextual nuances. For example, from a typical vector similarity search perspective, “I like fishing” and “I do not like fishing” may be quite close to each other, while in reality, they are the exact opposite. In this blog post, we discuss an approach that we experimented with that combines vector similarity search with LLMs to enhance the relevance and accuracy of search results for such complex and nuanced queries. We leverage the strengths of both techniques: vector similarity search for efficient shortlisting of potential matches, and LLMs for their ability to understand natural language queries and rank the shortlisted results based on their contextual relevance.

Proposed solution

The proposed solution involves a two-step process:

  1. Vector similarity search: We first perform a vector similarity search on the dataset to obtain a shortlist of potential matches (e.g., top 10-50 results) for the given query. This step leverages the efficiency of vector similarity search to quickly narrow down the search space.

  2. LLM-assisted ranking: The shortlisted results from the vector similarity search are then fed into an LLM, which ranks the results based on their relevance to the original query. The LLM’s ability to understand natural language queries and contextual information helps in identifying the most relevant results from the shortlist.

By combining these two steps, we aim to achieve the best of both worlds: the efficiency of vector similarity search for initial shortlisting, and the contextual understanding and ranking capabilities of LLMs for refining the final results.

Figure 1. Similarity search and the proposed LLM-assisted similarity search.

Experiment

Datasets

To evaluate the effectiveness of our proposed solution, we conducted experiments on two small synthetic datasets in CSV format that we curated using GPT-4o 7.

  • Food dataset: A collection of 100 dishes with their titles and descriptions.
  • Tourist spots dataset: A collection of 100 tourist spots in Asia, including their names, cities, countries, and descriptions.

It is important to note that we primarily focus on performing similarity search on structured data such as description of various entities in a relational database.

Setup

Our experimental setup included a Python script for vector similarity search leveraging Facebook AI Similarity Search (FAISS) 8, a library developed by Facebook that offers efficient similarity search, and OpenAI’s embeddings (i.e., text-embedding-ada-002) 9 to generate the vector embeddings needed for facilitating the vector search. For our proposed solution, an LLM component (i.e., GPT-4o) was included in the setup in addition to the FAISS-based similarity search component.

Observations

To compare the performance of the proposed approach of LLM-assisted vector similarity search as outlined in the “Proposed solution” section with the raw vector similarity search, we conducted both techniques on our two synthetic datasets. With the raw vector search, we get the top three matches for a given query. For our proposed technique, we first get a shortlist of 15 entity matches from FAISS for the same query, and supply the shortlist and the original query to LLM with some descriptive instructions in the prompt to find the top three matches from the provided shortlist.

From the experiments, in simpler cases where the queries were straightforward and directly aligned with the textual content of the data, both the raw similarity search and the LLM-assisted similarity search demonstrated comparable performance. However, as the queries became more complex, involving additional constraints, negations, or conceptual requirements, the LLM-assisted search exhibited a clear advantage over the raw similarity search. The LLM’s ability to understand context and capture subtleties in the queries allowed it to filter out irrelevant results and rank the most appropriate ones higher, leading to improved accuracy.

Here are a few examples where the LLM-assisted similarity search performed better:

Food dataset

Query: “food with no fish or shrimp”

Raw similarity search result:

- title: Tempura, description: A Japanese dish of seafood or vegetables that have been battered and deep fried.
- title: Ceviche, description: A seafood dish popular in Latin America, made from fresh raw fish cured in citrus juices.
- title: Sushi, description: A Japanese dish consisting of vinegared rice accompanied by various ingredients such as seafood and vegetables.

LLM-assisted similarity search result:

- title: Chicken Piccata, description: Chicken breasts cooked in a sauce of lemon, butter, and capers.
- title: Chicken Alfredo, description: An Italian-American dish of pasta in a creamy sauce made from butter and Parmesan cheese.
- title: Chicken Satay, description: Grilled chicken skewers served with peanut sauce.

Observation: The LLM correctly filtered out dishes containing fish or shrimp, while the raw similarity search failed to do so, presumably due to the presence of negation in the query.

Tourist spots dataset

Query: “exposure to wildlife”

Raw similarity search result:

- name: Ocean Park, city: Hong Kong, country: Hong Kong, description: Marine mammal park and oceanarium.
- name: Merlion Park, city: Singapore, country: Singapore, description: Iconic statue with the head of a lion and body of a fish.
- name: Manila Bay, city: Manila, country: Philippines, description: A natural harbor known for its sunset views.

LLM-assisted similarity search result:

- name: Ocean Park, city: Hong Kong, country: Hong Kong, description: Marine mammal park and oceanarium.
- name: Chengdu Research Base, city: Chengdu, country: China, description: A research center for giant panda breeding.
- name: Mount Hua, city: Shaanxi, country: China, description: Mountain known for its dangerous hiking trails.

Observation: Two out of the top three matches by the LLM-assisted technique seem relevant to the query while only one result from the raw similarity search is relevant and the other two being somewhat irrelevant to the query. The LLM identified the relevance of a research base for giant panda breeding to the “exposure to wildlife”, which the raw similarity search ignored in its ranking.

These examples provide a glimpse into the utility of LLMs in finding more relevant matches in scenarios where the queries involved additional context, constraints, or conceptual requirements beyond simple keyword matching. On the other hand, when the queries were more straightforward and focused on specific keywords or phrases present in the data, both approaches demonstrated comparable performance. For instance, queries like “Japanese food” or “beautiful mountains” yielded similar results from both the raw similarity search and the proposed LLM-assisted approach.

Overall, the LLM-assisted vector search exhibited a clear advantage in handling complex queries, leveraging its ability to understand natural language and contextual information. However, for simpler queries, the raw similarity search remained a viable option, especially when computational efficiency is a concern.

Conclusion

The experiments demonstrated the potential of combining vector similarity search with LLMs to enhance the relevance and accuracy of search results, particularly for complex and nuanced queries. While vector similarity search alone can provide reasonable results for straightforward queries, the LLM-assisted approach shines when dealing with queries that require a deeper understanding of context, nuances, and conceptual relationships. By leveraging the natural language understanding capabilities of LLMs, this approach can better capture the intent behind complex queries and provide more relevant search results.

Our experiment was limited to using a small volume of structured data (100 data points in each dataset) with a limited number of queries. However, we have witnessed similar enhancement in search result relevance when we deployed this solution internally within Grab for larger datasets, for example, 4500+ rows of data stored in a relational database.

Nevertheless, it is important to note that the effectiveness of this approach may still depend on the quality and complexity of the data, as well as the specific use case and query patterns. We believe it is still worthwhile to evaluate the proposed approach for more diverse (e.g., beyond CSV) and larger datasets. An interesting future work can be varying the size of the shortlist from the similarity search and observing how it impacts the overall search relevance when using the proposed approach. In addition, for real world applications, the performance implications in terms of additional latency introduced by the additional LLM query must also be considered.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

References

  1. M. Minsky and S. Papert, Perceptrons: An Introduction to Computational Geometry. MIT Press, 1969. ↩

  2. P. Indyk and R. Motwani, “Approximate nearest neighbors: Towards removing the curse of dimensionality,” in Proceedings of the Thirtieth Annual ACM Symposium on Theory of Computing, 1998. ↩

  3. Y. Malkov and D. Yashunin, “Efficient and robust approximate nearest neighbor search using hierarchical navigable small world graphs,” IEEE Transactions on Pattern Analysis and Machine Intelligence, 2020. ↩

  4. P. Lewis, E. Perez, A. Piktus, F. Petroni, V. Karpukhin, N. Goyal, and D. Kiela, “Retrieval-augmented generation for knowledge-intensive NLP tasks,” in Advances in Neural Information Processing Systems, 2020. ↩

  5. A. Vaswani, “Attention is all you need,” in Advances in Neural Information Processing Systems, 2017. ↩

  6. A. Radford, “Improving language understanding by generative pre-training,” 2018. ↩

  7. “Hello GPT-4o,” OpenAI, May 2024. [Online]. Available: https://openai.com/index/hello-gpt-4o/. [Accessed: Oct. 6, 2024]. ↩

  8. M. Douze, A. Guzhva, C. Deng, J. Johnson, G. Szilvasy, P. E. Mazaré, and H. Jégou, “The faiss library,” arXiv preprint arXiv:2401.08281, 2024. ↩

  9. “Embeddings,” OpenAI API. [Online]. Available: https://platform.openai.com/docs/guides/embeddings. [Accessed: Oct. 6, 2024]. ↩

Leveraging RAG-powered LLMs for Analytical Tasks

Post Syndicated from Grab Tech original https://engineering.grab.com/transforming-the-analytics-landscape-with-RAG-powered-LM

Introduction

Retrieval-Augmented Generation (RAG) is a powerful process that is designed to integrate direct function calling to answer queries more efficiently by retrieving relevant information from a broad database. In the rapidly evolving business landscape, Data Analysts (DAs) are struggling with the growing number of data queries from stakeholders. The conventional method of manually writing and running similar queries repeatedly is time-consuming and inefficient. This is where RAG-powered Large Language Models (LLMs) step in, offering a transformative solution to streamline the analytics process and empower DAs to focus on higher value tasks.

In this article, we will share how the Integrity Analytics team has built out a data solution using LLMs to help automate tedious analytical tasks like generating regular metric reports and performing fraud investigations.

While LLMs are known for their proficiency in data interpretation and insight generation, they represent just a fragment of the entire solution. For a comprehensive solution, LLMs must be integrated with other essential tools. The following is required in assembling a solution:

  • Internally facing LLM tool – Spellvault is a platform within Grab that stores, shares, and refines LLM prompts. It features low/no-code RAG capabilities that lower the barrier of entry for people to create LLM applications.
  • Data – with real time or close to real-time latency to ensure accuracy. It has to be in a standardised format to ensure that all LLM data inputs are accurate.
  • Scheduler – runs LLM applications at regular intervals. Useful for automating routine tasks.
  • Messaging Tool – a user interface where users can interact with LLM by entering a command to receive reports and insights.

Introducing Data-Arks, the data middleware serving up relevant data to the LLM agents

For most data use cases, DAs are usually running the same set of SQL queries with minor changes to parameters like dates, age or other filter conditions. In most instances, we already have a clear understanding of the required data and format to accomplish a task. Therefore, we need a tool that can execute the exact SQL query and channel the data output to the LLM.

Figure 1. Data-Arks hosts various APIs which can be called to serve data to applications like SpellVault.

What is Data-Arks?

Data-Arks is an in-house Python-based API platform housing several frequently used SQL queries and python functions packaged into individual APIs. Data-Arks is also integrated with Slack, Wiki, and JIRA APIs, allowing users to parse and fetch information and data from these tools as well. The benefits of Data-Arks are summarised as follows:

  • Integration: Data-Arks service allows users to upload any SQL query or Python script on the platform. These queries are then surfaced as APIs, which can be called to serve data to the LLM agent.

  • Versatility: Data-Arks can be extended to everyone. Employees from various teams and functions at Grab can self-serve to upload any SQL query that they want onto the platform, allowing this tool to be used for different teams’ use cases.

Automating regular report generation and summarisation using Data-Arks and Spellvault

LLMs are just one piece of the puzzle, to build a comprehensive solution, they must be integrated with other tools. Figure 2 shows how different tools are used in executing report summaries in Slack.

Figure 2 shows how different tools are used in executing report summaries in Slack.

Figure 2. Report Summarizer uses various tools to summarise queries and deliver a summarised report through Slack.

Figure 3 is an example of a summarised report generated by the Report Summarizer using dummy data. Report Summarizer calls a Data-Arks API to generate the data in a tabular format and LLM helps summarise and generate a short paragraph of key insights. This automated report generation has helped save an estimated 3-4 hours per report.

Figure 3. Sample of a report generated using dummy data extracted from [https://data.gov.my/](https://data.gov.my/).

LLM bots for fraud investigations

LLMs also excel in helping to streamline fraud investigations, as LLMs are able to contextualise several different data points and information and derive useful insights from them.

Introducing A* bot, the team’s very own LLM fraud investigation helper.

A set of frequently used queries for fraud investigation is made available as Data-Arks APIs. Upon a user prompt or query, SpellVault selects the most relevant queries using RAG, executes them and provides a summary of the results to users through Slack.

Figure 4. A* bot uses Data-Arks and Spellvault to get information for fraud investigations.

Figure 5 shows a sample of fraud investigation responses from A* bot. Scaling to multiple queries for a fraud investigation process, what was once a time-consuming fraud investigation can now be reduced to a matter of minutes, as the A* bot is capable of providing all the necessary information simultaneously.

Figure 5. Sample of fraud investigation responses.

RAG vs fine-tuning

On deciding between RAG or fine-tuning to improve LLM accuracy, three key factors tipped the scales in favour of the RAG approach:

  • Effort and cost considerations
    Fine-tuning requires significant computational cost as it involves taking a base model and further training it with smaller, domain specific data and context. RAG is computationally less expensive as it relies on retrieving only relevant data and context to augment a model’s response. As the same base model can be used for different use cases, RAG is the preferred choice due to its flexibility and cost efficiency.

  • Ability to respond with the latest information
    Fine-tuning requires model re-training with each new information update, whereas RAG simply retrieves required context and data from a knowledge base to enhance its response. Thus, by using RAG, LLM is able to answer questions using the most current information from our production database, eliminating the need for model re-training.

  • Speed and scalability
    Without the burden of model re-training, the team can rapidly scale and build out new LLM applications with a well managed knowledge base.

What’s next?

The potential of using RAG-powered LLM can be limitless as the ability of GPT is correlated with the tools it equips. Hence, the process does not stop here and we will try to onboard more tools or integration to GPT. In the near future, we plan to utilise Data-Arks to provide images to GPT as GPT-4o is a multimodal model that has vision capabilities. We are committed to pushing the boundaries of what’s possible with RAG-powered LLM, and we look forward to unveiling the exciting advancements that lie ahead.

Figure 6. What’s next?

We would like to express our sincere gratitude to the following individuals and teams whose invaluable support and contributions have made this project a reality:
– Meichen Lu, a senior data scientist at Grab, for her guidance and assistance in building the MVP and testing the concept.
– The data engineering team, particularly Jia Long Loh and Pu Li, for setting up the necessary services and infrastructure.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Leveraging RAG-powered LLMs for Analytical Tasks

Post Syndicated from Grab Tech original https://engineering.grab.com/transforming-the-analytics-landscape-with-RAG-powered-LLM

Introduction

Retrieval-Augmented Generation (RAG) is a powerful process that is designed to integrate direct function calling to answer queries more efficiently by retrieving relevant information from a broad database. In the rapidly evolving business landscape, Data Analysts (DAs) are struggling with the growing number of data queries from stakeholders. The conventional method of manually writing and running similar queries repeatedly is time-consuming and inefficient. This is where RAG-powered Large Language Models (LLMs) step in, offering a transformative solution to streamline the analytics process and empower DAs to focus on higher value tasks.

In this article, we will share how the Integrity Analytics team has built out a data solution using LLMs to help automate tedious analytical tasks like generating regular metric reports and performing fraud investigations.

While LLMs are known for their proficiency in data interpretation and insight generation, they represent just a fragment of the entire solution. For a comprehensive solution, LLMs must be integrated with other essential tools. The following is required in assembling a solution:

  • Internally facing LLM tool – Spellvault is a platform within Grab that stores, shares, and refines LLM prompts. It features low/no-code RAG capabilities that lower the barrier of entry for people to create LLM applications.
  • Data – with real time or close to real-time latency to ensure accuracy. It has to be in a standardised format to ensure that all LLM data inputs are accurate.
  • Scheduler – runs LLM applications at regular intervals. Useful for automating routine tasks.
  • Messaging Tool – a user interface where users can interact with LLM by entering a command to receive reports and insights.

Introducing Data-Arks, the data middleware serving up relevant data to the LLM agents

For most data use cases, DAs are usually running the same set of SQL queries with minor changes to parameters like dates, age or other filter conditions. In most instances, we already have a clear understanding of the required data and format to accomplish a task. Therefore, we need a tool that can execute the exact SQL query and channel the data output to the LLM.

Figure 1. Data-Arks hosts various APIs which can be called to serve data to applications like SpellVault.

What is Data-Arks?

Data-Arks is an in-house Python-based API platform housing several frequently used SQL queries and python functions packaged into individual APIs. Data-Arks is also integrated with Slack, Wiki, and JIRA APIs, allowing users to parse and fetch information and data from these tools as well. The benefits of Data-Arks are summarised as follows:

  • Integration: Data-Arks service allows users to upload any SQL query or Python script on the platform. These queries are then surfaced as APIs, which can be called to serve data to the LLM agent.

  • Versatility: Data-Arks can be extended to everyone. Employees from various teams and functions at Grab can self-serve to upload any SQL query that they want onto the platform, allowing this tool to be used for different teams’ use cases.

Automating regular report generation and summarisation using Data-Arks and Spellvault

LLMs are just one piece of the puzzle, to build a comprehensive solution, they must be integrated with other tools. Figure 2 shows how different tools are used in executing report summaries in Slack.

Figure 2 shows how different tools are used in executing report summaries in Slack.

Figure 2. Report Summarizer uses various tools to summarise queries and deliver a summarised report through Slack.

Figure 3 is an example of a summarised report generated by the Report Summarizer using dummy data. Report Summarizer calls a Data-Arks API to generate the data in a tabular format and LLM helps summarise and generate a short paragraph of key insights. This automated report generation has helped save an estimated 3-4 hours per report.

Figure 3. Sample of a report generated using dummy data extracted from [https://data.gov.my/](https://data.gov.my/).

LLM bots for fraud investigations

LLMs also excel in helping to streamline fraud investigations, as LLMs are able to contextualise several different data points and information and derive useful insights from them.

Introducing A* bot, the team’s very own LLM fraud investigation helper.

A set of frequently used queries for fraud investigation is made available as Data-Arks APIs. Upon a user prompt or query, SpellVault selects the most relevant queries using RAG, executes them and provides a summary of the results to users through Slack.

Figure 4. A* bot uses Data-Arks and Spellvault to get information for fraud investigations.

Figure 5 shows a sample of fraud investigation responses from A* bot. Scaling to multiple queries for a fraud investigation process, what was once a time-consuming fraud investigation can now be reduced to a matter of minutes, as the A* bot is capable of providing all the necessary information simultaneously.

Figure 5. Sample of fraud investigation responses.

RAG vs fine-tuning

On deciding between RAG or fine-tuning to improve LLM accuracy, three key factors tipped the scales in favour of the RAG approach:

  • Effort and cost considerations
    Fine-tuning requires significant computational cost as it involves taking a base model and further training it with smaller, domain specific data and context. RAG is computationally less expensive as it relies on retrieving only relevant data and context to augment a model’s response. As the same base model can be used for different use cases, RAG is the preferred choice due to its flexibility and cost efficiency.

  • Ability to respond with the latest information
    Fine-tuning requires model re-training with each new information update, whereas RAG simply retrieves required context and data from a knowledge base to enhance its response. Thus, by using RAG, LLM is able to answer questions using the most current information from our production database, eliminating the need for model re-training.

  • Speed and scalability
    Without the burden of model re-training, the team can rapidly scale and build out new LLM applications with a well managed knowledge base.

What’s next?

The potential of using RAG-powered LLM can be limitless as the ability of GPT is correlated with the tools it equips. Hence, the process does not stop here and we will try to onboard more tools or integration to GPT. In the near future, we plan to utilise Data-Arks to provide images to GPT as GPT-4o is a multimodal model that has vision capabilities. We are committed to pushing the boundaries of what’s possible with RAG-powered LLM, and we look forward to unveiling the exciting advancements that lie ahead.

Figure 6. What’s next?

We would like to express our sincere gratitude to the following individuals and teams whose invaluable support and contributions have made this project a reality:
– Meichen Lu, a senior data scientist at Grab, for her guidance and assistance in building the MVP and testing the concept.
– The data engineering team, particularly Jia Long Loh and Pu Li, for setting up the necessary services and infrastructure.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Evolution of Catwalk: Model serving platform at Grab

Post Syndicated from Grab Tech original https://engineering.grab.com/catwalk-evolution

Introduction

As Southeast Asia’s leading super app, Grab serves millions of users across multiple countries every day. Our services range from ride-hailing and food delivery to digital payments and much more. The backbone of our operations? Machine Learning (ML) models. They power our real-time decision-making capabilities, enabling us to provide a seamless and personalised experience to our users. Whether it’s determining the most efficient route for a ride, suggesting a food outlet based on a user’s preference, or detecting fraudulent transactions, ML models are at the forefront.

However, serving these ML models at Grab’s scale is no small feat. It requires a robust, efficient, and scalable model serving platform, which is where our ML model serving platform, Catwalk, comes in.

Catwalk has evolved over time, adapting to the growing needs of our business and the ever-changing tech landscape. It has been a journey of continuous learning and improvement, with each step bringing new challenges and opportunities.

Evolution of the platform

Phase 0: The need for a model serving platform

Before Catwalk’s debut as our dedicated model serving platform, data scientists across the company employed various ad-hoc approaches to serve ML models. These included:

  • Shipping models online using custom solutions.
  • Relying on backend engineering teams to deploy and manage trained ML models.
  • Embedding ML logic within Go backend services.

These methods, however, led to several challenges, undercovering the need for a unified, company-wide platform for serving machine learning models:

  • Operational overhead: Data scientists often lacked the necessary expertise to handle the operational aspects of their models, leading to service outages.
  • Resource wastage: There was frequently low resource utilisation (e.g., 1%) for data science services, leading to inefficient use of resources.
  • Friction with engineering teams: Differences in release cycles and unclear ownership when code was embedded into backend systems resulted in tension between data scientists and engineers.
  • Reinventing the wheel: Multiple teams independently attempted to solve model serving problems, leading to a duplication of effort.

​​These challenges highlighted the need for a company-wide, centralised platform for serving machine learning models.

Phase 1: No-code, managed platform for TensorFlow Serving models

Our initial foray into model serving was centred around creating a managed platform for deploying TensorFlow Serving models. The process involved data scientists submitting their models to the platform’s engineering admin, who could then deploy the model with an endpoint. Infrastructure and networking were managed using Amazon Elastic Kubernetes Service (EKS) and Helm Charts as illustrated below.


This phase of our platform, which we also detailed in our previous article, was beneficial for some users. However, we quickly encountered scalability challenges:

  • Codebase maintenance: Applying changes to every TensorFlow Serving (TFS) version was cumbersome and difficult to maintain.
  • Limited scalability: The fully managed nature of the platform made it difficult to scale.
  • Admin bottleneck: The engineering admin’s limited bandwidth became a bottleneck for onboarding new models.
  • Limited serving types: The platform only supported TensorFlow, limiting its usefulness for data scientists using other frameworks like LightGBM, XGBoost, or PyTorch.

After a year of operation, only eight models were onboarded to the platform, highlighting the need for a more scalable and flexible solution.

Phase 2: From models to model serving applications

To address the limitations of Phase 1, we transitioned from deploying individual models to self-contained model serving applications. This “low-code, self-serving” strategy introduced several new components and changes as illustrated in the points and diagram below:

  • Support for multiple serving types: Users gained the ability to deploy models trained with a variety of frameworks like Open Neural Network Exchange (ONNX), PyTorch, and TensorFlow.
  • Self-served platform through CI/CD pipelines: Data scientists could self-serve and independently manage their model serving applications through CI/CD pipelines.
  • New components: We introduced these new components to support the self-serving approach:
    • Catwalk proxy, a managed reverse proxy to various serving types.
    • Catwalk transformer, a low-code component to transform input and output data.
    • Amphawa, a feature fetching component to augment model inputs.

API request flow

The Catwalk proxy acts as the orchestration layer. Clients send requests to Catwalk proxy then it orchestrates calls to different components like transformers, feature-store, and so on. A typical end to end request flow is illustrated below.


Within a year of implementing these changes, the number of models on the platform increased from 8 to 300, demonstrating the success of this approach. However, new challenges emerged:

  • Complexity of maintaining Helm chart: As the platform continued to grow with new components and functionalities, maintaining the Helm chart became increasingly complex. The readability and flow control became more challenging, making the helm chart updating process prone to errors.
  • Process-level mistakes: The self-serving approach led to errors such as pushing empty or incompatible models to production, setting too few replicas, or allocating insufficient resources, which resulted in service crashes.

We knew that our work was nowhere near done. We had to keep iterating and explore ways to address the new challenges.

Phase 3: Replacing Helm charts with Kubernetes CRDs

To tackle the deployment challenges and gain more control, we made the significant decision to replace Helm charts with Kubernetes Custom Resource Definitions (CRDs). This required substantial engineering effort, but the outcomes have been rewarding. This transition gave us improved control over deployment pipelines, enabling customisations such as:

  • Smart defaults for AutoML
  • Blue-green deployments
  • Capacity management
  • Advanced scaling
  • Application set groupings

Below is an example of a simple model serving CRD manifest:

apiVersion: ml.catwalk.kubebuilder.io/v1
kind: ModelServing
spec:
  hpa:
    desired: 1
    max: 1
    min: 1
  modelMeta:
    modelName: "my-model"
    modelOwner: john.doe
  proxyLayer:
    enableLogging: true
    logHTTPBody: true
  servingLayer:
    servingType: "tensorflow-serving"
    version: "20"

Model serving CRD deployment state machine

Every model serving CRD submission follows a sequence of steps. If there are failures at any step, the controller keeps retrying after small intervals. The major steps on the deployment cycle are described below:

  1. Validate whether the new CRD specs are acceptable. Along with sanity checks, we also enforce a lot of platform constraints through this step.
  2. Clean up previous non-ready deployment resources. Sometimes a deployment submission might keep crashing and hence it doesn’t proceed to a ready state. On every submission, it’s important to check and clean up such previous deployments.
  3. Create resources for the new deployment and ensure that the new deployment is ready.
  4. Switch traffic from old deployment to the new deployment.
  5. Clean up resources for old deployment. At this point, traffic is already being served by the new deployment resources. So, we can clean up the old deployment.

Phase 4: Transition to a high-code, self-served, process-managed platform

As the number of model serving applications and use cases multiplied, clients sought greater control over orchestrations between different models, experiment executions, traffic shadowing, and responses archiving. To cater to these needs, we introduced several changes and components with the Catwalk Orchestrator, a high code orchestration solution, leading the pack.

Catwalk orchestrator

The Catwalk Orchestrator is a highly abstracted framework for building ML applications that replaced the catwalk-proxy from previous phases. The key difference is that users can now write their own business/orchestration logic. The orchestrator offers a range of utilities, reducing the need for users to write extensive boilerplate code. Key components of the Catwalk Orchestrator include HTTP server, gRPC server, clients for different model serving flavours (TensorFlow, ONNX, PyTorch, etc), client for fetching features from the feature bank, and utilities for logging, metrics, and data lake ingestion.

The Catwalk Orchestrator is designed to streamline the deployment of machine learning models. Here’s a typical user journey:

  1. Scaffold a model serving application: Users begin by scaffolding a model serving application using a command-line tool.
  2. Write business logic: Users then write the business logic for the application.
  3. Deploy to staging: The application is then deployed to a staging environment for testing.
  4. Complete load testing: Users test the application in the staging environment and complete load testing to ensure it can handle the expected traffic.
  5. Deploy to production: Once testing is completed, the application is deployed to the production environment.

Bundled deployments

To support multiple ML models as part of a single model serving application, we introduced the concept of bundled deployments. Multiple Kubernetes deployments are bundled together as a single model serving application deployment, allowing each component (e.g., models, catwalk-orchestrator, etc) to have its own Kubernetes deployment and to scale independently.


In addition to the major developments, we implemented other changes to enhance our platform’s efficiency. We made load testing mandatory for all ML application updates to ensure robust performance. This testing process was streamlined with a single command that runs the load test in the staging environment, with the results directly shared with the user.

Furthermore, we boosted deployment transparency by sharing deployment details through Slack and Datadog. This empowered users to diagnose issues independently, reducing the dependency on on-call support. This transparency not only improved our issue resolution times but also enhanced user confidence in our platform.

The results of these changes speak for themselves. The Catwalk Orchestrator has evolved into our flagship product. In just two years, we have deployed 200 Catwalk Orchestrators serving approximately 1,400 ML models.

What’s next?

As we continue to innovate and enhance our model serving platform, we are venturing into new territories:

  • Catwalk serverless: We aim to further abstract the model serving experience, making it even more user-friendly and efficient.
  • Catwalk data serving: We are looking to extend Catwalk’s capabilities to serve data online, providing a more comprehensive service.
  • LLM serving: In line with the trend towards generative AI and large language models (LLMs), we’re pivoting Catwalk to support these developments, ensuring we stay at the forefront of the AI and machine learning field.

Stay tuned as we continue to advance our technology and bring these exciting developments to life.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Bringing Grab’s Live Activity to Android: Enhancing user experience through custom notifications

Post Syndicated from Grab Tech original https://engineering.grab.com/live-activity-2

In May 2023, Grab unveiled the Live Activity feature for iOS, which received positive feedback from users. Live Activity is a feature that enhances user experience by displaying a user interface (UI) outside of the app, delivering real-time updates and interactive content. At Grab, we leverage this feature to keep users informed about their order updates without requiring them to manually open the app.

While Live Activity is a native iOS feature provided by Apple, there is currently no official Android equivalent. However, we are determined to bring this immersive experience to Android users. Inspired by the success of Live Activity on iOS, we have embarked on design explorations and feasibility studies to ensure the seamless integration of Live Activity into the Android platform. Our ultimate goal is to provide Android users with the same level of convenience and real-time updates, elevating their Grab experience.

Product Exploration

In July 2023, we took a proactive step by forming a dedicated working group with the specific goal of exploring Live Activity on the Android platform. Our mindset was focused on quickly enabling the MVP (Minimum Viable Product) of this feature for Android users. We focused on enabling Grab users to track food and mart orders on Live Activity as our first use-case. We also designed the Live Activity module as an extendable platform, allowing easy adoption by other Grab internal verticals such as the Express and Transport teams.

The team kicked off by analysing the current solution and end-to-end flow of Live Activity on iOS. The objective was to uncover opportunities on how we could leverage the existing platform approach.

Figure 1. Grab iOS Live Activity flow.

The first thing that caught our attention was that there is no Live Activity Token (also known as Push Token) concept on Android. Push Token is a token generated from the ActivityKit framework and used to remotely start, update, and end Live Activity notifications on iOS.

Our goal was to match the Live Activity set-up of iOS in Android, which was a challenge due to the missing Push Token. This required us to think outside the box and develop an innovative workaround. After multiple brainstorming sessions, the team developed two potential solutions, Solution 1 and Solution 2, as illustrated below:

Figure 2. Proposed solutions for Live Activity for Android.

We evaluated the two solutions. The first solution is to substitute the Push Token with a placeholder value, serving as a distinctive notification identifier. Whereas, the second solution involves the Hedwig service, our in-house message delivery service. We proposed to bypass the Live Activity token check process specifically for Android devices. Following extensive discussions, we decided to proceed with the first solution, which ensures consistency in the technical approach between Android and iOS platforms. Additionally, this solution allows us to ensure that notifications are only pushed to the devices that support the Live Activity feature. This decision strikes a good balance between efficiency and compatibility.

UI Components

Starting with a kick-off project meeting where we showcased our plans and proposed solutions to our stakeholders, the engineering team presented two native Android UI components that could be utilised to replicate Live Activity: the Notification View and the Floating View.

The Notification View is a component located in the notification drawer (and potentially on the Lock Screen) that fulfils the most basic use-case of the Live Activity feature. It enables Android users to access information without the need to open the app. Since the standard notification template only allows developers to display a single content title, a content subtitle, and one image, it falls short of meeting our Live Activity UI requirements. To overcome this limitation, custom notifications with custom layouts are needed.

Figure 3. Early design spec of Grab’s LA using custom notification.

One of the key advantages of custom notifications is that they do not require any additional new permissions, ensuring a smooth user experience. Additionally, Android users are accustomed to checking their notifications from the notification tray, making it a familiar and intuitive interaction. However, it is important to acknowledge that custom notifications rely on a remote view, which can pose restrictions on rendering only specific views. On top of that, custom notifications provide a limited space for content – limited to 48dp when collapsed and 252dp when expanded.

The Floating View is a component that will appear above all the applications in Android. It adds the convenience of accessing the information when the device is unlocked or when the user is on another app.

Figure 4. Early design spec of Grab’s LA using floating view.

The use of a Floating View offers greater flexibility to the view by eliminating the reliance on a remote view. However, it’s important to be aware of the potential limitations associated with this approach. These limitations include the requirement for screen space, which can potentially impact other app functionalities and cause frustration for users. Additionally, if we intend to display multiple order updates, we may require even more space, taking into account that Grab allows users to place multiple orders. Furthermore, the Floating View feature requires an extra “Draw over other apps” permission, a setting that allows an app to display information on top of other apps on your screen.

After thoughtful deliberation, we concluded that custom notifications provide a more consistent and user-friendly solution for implementing Grab’s Live Activity feature on Android. They offer compatibility, non-intrusiveness, no extra permissions, and the flexibility of silent notifications, ensuring an optimised user experience.

Building Grab Android’s “Live Activity”

We began developing the Live Activity feature by focusing on Food and Mart for the MVP. However, we prioritised potential future use cases for other verticals by examining the existing functionality of the Grab iOS Live Activity feature. By considering these factors from the start, we need to make sure that we build an extendable and flexible solution that caters to different verticals and their various use-cases.

Figure 5. Grab’s Android Live Activity.

As we set out to design Grab’s Android Live Activity module, we broke down the task into three key components:

  1. Registering Live Activity Token

In order to enable Hedwig services to send Live Activity notifications to devices, it is necessary to register a Live Activity Token for a specific order to Grab Devices services (refer to figure 1 for the iOS flow). As this use-case is applicable across various verticals in iOS, we have designed a LiveActivityIntegrationManager class specifically to handle this functionality.

interface LiveActivityIntegrationManager {  
    /\*\*  
     \* To start live activity journey  
     \* @param vertical refers to vertical name  
     \* @param id refers to unique id which is used to differentiate live activity UI instances  
     \* eg: Food will use orderID as id, transport can pass rideID  
     \*\*/  
    fun startLiveActivity(vertical: Vertical, id: String): Completable

    fun updateLiveActivity(id: String, attributes: LiveActivityAttributes)

    fun cancelLiveActivity(id: String)  
}  

Our goal is to provide developers with an easy implementation of Live Activity in the Grab app. Developers can simply utilize the startLiveActivity() function to register the token to Grab Devices by passing the vertical name and unique ID as parameters.

  1. Notification Listener and Payload Mapping

To handle Live Activity notifications in Android, it is necessary to listen to the Live Activity notification payload and map it to LiveActivityAttributes. Taking into consideration the initial Live Activity design (refer to figure 3), we need to analyse the variables necessary for this process. As a result, we break down the Live Activity UI into different UI elements and layouts, as follows:

Figure 6. Android Live Activity view breakdown.
  1. App Icon – labeled as 1 in Figure 6.
    This view always shows the Grab app icon.
  2. Header Icon – labeled as 2 in Figure 6.
    This view is an image view that could be set with icon resources.
  3. Content Title View – labeled as 3 in Figure 6.
    This view is a placeholder that could be set with a text or custom remote view.
  4. Content Text View – labeled as 4 in Figure 6.
    This view is a placeholder that could be set with a text or custom remote view.
  5. Footer View – labeled as 5 in Figure 6.
    This view is a placeholder that could be set with icon resources, bitmap, or custom remote view.

Decomposing the UI into different parts allows us to clearly understand of the UI components that need to maintain consistency across different use-cases, as well as the elements that can be easily customised and configured based on specific requirements. As a result, we have designed the LiveActivityAttributes class that serves as a container that encompasses all the necessary configurations required for rendering the Live Activity.

 
class LiveActivityAttributes private constructor(  
    val iconRes: Int?,  
    val headerIconRes: Int?,  
    val contentTitle: CharSequence?,  
    val contentTitleStyle: ContentStyle.TitleStyle?,  
    val customContentTitleView: LiveActivityCustomView?,  
    val contentText: CharSequence?,  
    val contentTextStyle: ContentStyle.TextStyle?,  
    val customContentTextView: LiveActivityCustomView?,  
    val footerIconRes: Int?,  
    val footerBitmap: Bitmap?,  
    val footerProgressBarProgress: Float?,  
    val footerProgressBarStyle: ProgressBarStyle?,  
    val footerRatingBarAttributes: RatingBarAttributes?,  
    val customFooterView: LiveActivityCustomView?,  
    val contentIntent: PendingIntent?,  
    …  
)  

  1. Payload Rendering

To ensure a clear separation of responsibilities, we have designed a separate class called LiveActivityManager. This dedicated class is responsible for the mapping of LiveActivityAttributes to Notifications. The generated notifications are then utilised by Android’s NotificationManager class to be posted and displayed accordingly.


interface LiveActivityManager {  
    /\*\*  
     \* Post a Live Activity to be shown in the status bar, stream, etc.  
     \*  
     \* @param id           the ID of the Live Activity  
     \* @param attributes the LiveActivity to post to the system  
     \*/  
    fun notify(id: Int, attributes: LiveActivityAttributes)

    fun cancel(id: Int)  
}

What’s Next?

We are delighted to announce that we have successfully implemented Grab’s Android version of the Live Activity feature for Express and Transport products. Furthermore, we plan to extend this feature to the Driver and Merchant applications as well. We understand the value this feature brings to our users and are committed to enhancing it further. Stay tuned for upcoming updates and enhancements to the Live Activity feature as we continue to improve and expand its capabilities across various verticals.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 428 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Enabling conversational data discovery with LLMs at Grab

Post Syndicated from Grab Tech original https://engineering.grab.com/hubble-data-discovery

Imagine a world where finding the right data is like searching for a needle in a haystack. In today’s data-driven landscape, companies are drowning in a sea of information, struggling to navigate through countless datasets to uncover valuable insights. At Grab, we faced a similar challenge. With over 200,000 tables in our data lake, along with numerous Kafka streams, production databases, and ML features, locating the most suitable dataset for our Grabber’s use cases promptly has historically been a significant hurdle.

Problem Space

Our internal data discovery tool, Hubble, built on top of the popular open-source platform Datahub, was primarily used as a reference tool. While it excelled at providing metadata for known datasets, it struggled with true data discovery due to its reliance on Elasticsearch, which performs well for keyword searches but cannot accept and use user-provided context (i.e., it can’t perform semantic search, at least in its vanilla form). The Elasticsearch parameters provided by Datahub out of the box also had limitations: our monthly average click-through rate was only 82%, meaning that in 18% of sessions, users abandoned their searches without clicking on any dataset. This suggested that the search results were not meeting their needs.

Another indispensable requirement for efficient data discovery that was missing at Grab was documentation. Documentation coverage for our data lake tables was low, with only 20% of the most frequently queried tables (colloquially referred to as P80 tables) having existing documentation. This made it difficult for users to understand the purpose and contents of different tables, even when browsing through them on the Hubble UI.

Consequently, data consumers heavily relied on tribal knowledge, often turning to their colleagues via Slack to find the datasets they needed. A survey conducted last year revealed that 51% of data consumers at Grab took multiple days to find the dataset they required, highlighting the inefficiencies in our data discovery process.

To address these challenges and align with Grab’s ongoing journey towards a data mesh architecture, the Hubble team recognised the importance of improving data discovery. We embarked on a journey to revolutionise the way our employees find and access the data they need, leveraging the power of AI and Large Language Models (LLMs).

Vision

Given the historical context, our vision was clear: to remove humans in the data discovery loop by automating the entire process using LLM-powered products. We aimed to reduce the time taken for data discovery from multiple days to mere seconds, eliminating the need for anyone to ask their colleagues data discovery questions ever again.


Goals

To achieve our vision, we set the following goals for ourselves for the first half of 2024:

  • Build HubbleIQ: An LLM-based chatbot that could serve as the equivalent of a Lead Data Analyst for data discovery. Just as a lead is an expert in their domain and can guide data consumers to the right dataset, we wanted HubbleIQ to do the same across all domains at Grab. We also wanted HubbleIQ to be accessible where data consumers hang out the most: Slack.
  • Improve documentation coverage: A new Lead Analyst joining the team would require extensive documentation coverage of very high quality. Without this, they wouldn’t know what data exists and where. Thus, it was important for us to improve documentation coverage.
  • Enhance Elasticsearch: We aimed to tune our Elasticsearch implementation to better meet the requirements of Grab’s data consumers.

A Systematic Path to Success

Step 1: Enhance Elasticsearch

Through clickstream analysis and user interviews, the Hubble team identified four categories of data search queries that were seen either on the Hubble UI or in Slack channels:

  • Exact search: Queries belonging to this category were a substring of an existing dataset’s name at Grab, with the query length being at least 40% of the dataset’s name.
  • Partial search: The Levenshtein distance between a query in this category and any existing dataset’s name was greater than 80. This category usually comprised queries that closely resembled an existing dataset name but likely contained spelling mistakes or were shorter than the actual name.

Exact and partial searches accounted for 75% of searches on Hubble (and were non-existent on Slack: as a human, receiving a message that just had the name of a dataset would feel rather odd). Given the effectiveness of vanilla Elasticsearch for these categories, the click rank was close to 0.


  • Inexact search: This category comprised queries that were usually colloquial keywords or phrases that may be semantically related to a given table, column, or piece of documentation (e.g., “city” or “taxi type”). Inexact searches accounted for the remaining 25% of searches on Hubble. Vanilla Elasticsearch did not perform well in this category since it relied on pure keyword matching and did not consider any additional context.

  • Semantic search: These were free text queries with abundant contextual information supplied by the user. Hubble did not see any such queries as users rightly expected that Hubble would not be able to fulfil their search needs. Instead, these queries were sent by data consumers to data producers via Slack. Such queries were numerous, but usually resulted in data hunting journeys that spanned multiple days – the root of frustration amongst data consumers.

The first two search types can be seen as “reference” queries, where the data consumer already knows what they are looking for. Inexact and contextual searches are considered “discovery” queries. The Hubble team noticed drop-offs in inexact searches because users learned that Hubble could not fulfil their discovery needs, forcing them to search for alternatives.

Through user interviews, the team discovered how Elasticsearch should be tuned to better fit the Grab context. They implemented the following optimisations:

  • Tagging and boosting P80 tables
  • Boosting the most relevant schemas
  • Hiding irrelevant datasets like PowerBI dataset tables
  • Deboosting deprecated tables
  • Improving the search UI by simplifying and reducing clutter
  • Adding relevant tags
  • Boosting certified tables

As a result of these enhancements, the click-through rate rose steadily over the course of the half to 94%, a 12 percentage point increase.

While this helped us make significant improvements to the first three search categories, we knew we had to build HubbleIQ to truly automate the last category – semantic search.

Step 2: Build a Context Store for HubbleIQ

To support HubbleIQ, we built a documentation generation engine that used GPT-4 to generate documentation based on table schemas and sample data. We refined the prompt through multiple iterations of feedback from data producers.

We added a “generate” button on the Hubble UI, allowing data producers to easily generate documentation for their tables. This feature also supported the ongoing Grab-wide initiative to certify tables.


In conjunction, we took the initiative to pre-populate docs for the most critical tables, while notifying data producers to review the generated documentation. Such docs were visible to data consumers with an “AI-generated” tag as a precaution. When data producers accepted or edited the documentation, the tag was removed.


As a result, documentation coverage for P80 tables increased by 70 percentage points to ~90%. User feedback showed that ~95% of users found the generated docs useful.

Step 3: Build and Launch HubbleIQ

With high documentation coverage in place, we were ready to harness the power of LLMs for data discovery. To speed up go-to-market, we decided to leverage Glean, an enterprise search tool used by Grab.

First, we integrated Hubble with Glean, making all data lake tables with documentation available on the Glean platform. Next, we used Glean Apps to create the HubbleIQ bot, which was essentially an LLM with a custom system prompt that could access all Hubble datasets that were catalogued on Glean. Finally, we integrated this bot into Hubble search, such that for any search that is likely to be a semantic search, HubbleIQ results are shown on top, followed by regular search results.


Recently, we integrated HubbleIQ with Slack, allowing data consumers to discover datasets without breaking their flow. Currently, we are working with analytics teams to add the bot to their “ask” channels (where data consumers come to ask contextual search queries for their domains). After integration, HubbleIQ will act as the first line of defence for answering questions in these channels, reducing the need for human intervention.


The impact of these improvements was significant. A follow-up survey revealed that 73% of respondents found it easy to discover datasets, marking a substantial 17 percentage point increase from the previous survey. Moreover, Hubble reached an all-time high in monthly active users, demonstrating the effectiveness of the enhancements made to the platform.

Next Steps

We’ve made significant progress towards our vision, but there’s still work to be done. Looking ahead, we have several exciting initiatives planned to further enhance data discovery at Grab.

On the documentation generation front, we aim to enrich the generator with more context, enabling it to produce even more accurate and relevant documentation. We also plan to streamline the process by allowing analysts to auto-update data docs based on Slack threads directly from Slack. To ensure the highest quality of documentation, we will develop an evaluator model that leverages LLMs to assess the quality of both human and AI-written docs. Additionally, we will implement Reflexion, an agentic workflow that utilises the outputs from the doc evaluator to iteratively regenerate docs until a quality benchmark is met or a maximum try-limit is reached.

As for HubbleIQ, our focus will be on continuous improvement. We’ve already added support for metric datasets and are actively working on incorporating other types of datasets as well. To provide a more seamless user experience, we will enable users to ask follow-up questions to HubbleIQ directly on the HubbleUI, with the system intelligently pulling additional metadata when a user mentions a specific dataset.

Conclusion

By harnessing the power of AI and LLMs, the Hubble team has made significant strides in improving documentation coverage, enhancing search capabilities, and drastically reducing the time taken for data discovery. While our efforts so far have been successful, there are still steps to be taken before we fully achieve our vision of completely replacing the reliance on data producers for data discovery. Nonetheless, with our upcoming initiatives and the groundwork we have laid, we are confident that we will continue to make substantial progress in the right direction over the next few production cycles.

As we forge ahead, we remain dedicated to refining and expanding our AI-powered data discovery tools, ensuring that Grabbers have every dataset they need to drive Grab’s success at their fingertips. The future of data discovery at Grab is brimming with possibilities, and the Hubble team is thrilled to be at the forefront of this exciting journey.

To our readers, we hope that our journey has inspired you to explore how you can leverage the power of AI to transform data discovery within your own organisations. The challenges you face may be unique, but the principles and strategies we have shared can serve as a foundation for your own data discovery revolution. By embracing innovation, focusing on user needs, and harnessing the potential of cutting-edge technologies, you too can unlock the full potential of your data and propel your organisation to new heights. The future of data-driven innovation is here, and we invite you to join us on this exhilarating journey.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Unveiling the process: The creation of our powerful campaign builder

Post Syndicated from Grab Tech original https://engineering.grab.com/the-creation-of-our-powerful-campaign-builder

In a previous blog, we introduced Trident, Grab’s internal marketing campaign platform. Trident empowers our marketing team to configure If This, Then That (IFTTT) logic and processes real-time events based on that.

While we mainly covered how we scaled up the system to handle large volumes of real-time events, we did not explain the implementation of the event processing mechanism. This blog will fill up this missing piece. We will walk you through the various processing mechanisms supported in Trident and how they were built.

Base building block: Treatment

In our system, we use the term “treatment” to refer to the core unit of a full IFTTT data structure. A treatment is an amalgamation of three key elements – an event, conditions (which are optional), and actions. For example, consider a promotional campaign that offers “100 GrabPoints for completing a ride paid with GrabPay Credit”. This campaign can be transformed into a treatment in which the event is “ride completion”, the condition is “payment made using GrabPay Credit”, and the action is “awarding 100 GrabPoints”.

Data generated across various Kafka streams by multiple services within Grab forms the crux of events and conditions for a treatment. Trident processes these Kafka streams, treating each data object as an event for the treatments. It evaluates the set conditions against the data received from these events. If all conditions are met, Trident then executes the actions.

Figure 1. Trident processes Kafka streams as events for treatments.

When the Trident user interface (UI) was first established, campaign creators had to grasp the treatment concept and configure the treatments accordingly. As we improved the UI, it became more user-friendly.

Building on top of treatment

Campaigns can be more complex than the example we provided earlier. In such scenarios, a single campaign may need transformation into several treatments. All these individual treatments are categorised under what we refer to as a “treatment group”. In this section, we discuss features that we have developed to manage such intricate campaigns.

Counter

Let’s say we have a marketing campaign that “rewards users after they complete 4 rides”. For this requirement, it’s necessary for us to keep track of the number of rides each user has completed. To make this possible, we developed a capability known as counter.

On the backend, a single counter setup translates into two treatments.

Treatment 1:

  • Event: onRideCompleted
  • Condition: N/A
  • Action: incrementUserStats

Treatment 2:

  • Event: onProfileUpdate
  • Condition: Ride Count == 4
  • Action: awardReward

In this feature, we introduce a new event, onProfileUpdate. The incrementUserStats action in Treatment 1 triggers the onProfileUpdate event following the update of the user counter. This allows Treatment 2 to consume the event and perform subsequent evaluations.

Figure 2. The end-to-end evaluation process when using the Counter feature.

When the onRideCompleted event is consumed, Treatment 1 is evaluated which then executes the incrementUserStat action. This action increments the user’s ride counter in the database, gets the latest counter value, and publishes an onProfileUpdate event to Kafka.

There are also other consumers that listen to onProfileUpdate events. When this event is consumed, Treatment 2 is evaluated. This process involves verifying whether the Ride Count equals to 4. If the condition is satisfied, the awardReward action is triggered.

This feature is not limited to counting the number of event occurrences only. It’s also capable of tallying the total amount of transactions, among other things.

Delay

Another feature available on Trident is a delay function. This feature is particularly beneficial in situations where we want to time our actions based on user behaviour. For example, we might want to give a ride voucher to a user three hours after they’ve ordered a ride to a theme park. The intention for this is to offer them a voucher they can use for their return trip.

On the backend, a delay setup translates into two treatments. Given the above scenario, the treatments are as follows:

Treatment 1:

  • Event: onRideCompleted
  • Condition: Dropoff Location == Universal Studio
  • Action: scheduleDelayedEvent

Treatment 2:

  • Event: onDelayedEvent
  • Condition: N/A
  • Action: awardReward

We introduce a new event, onDelayedEvent, which Treatment 1 triggers during the scheduleDelayedEvent action. This is made possible by using Simple Queue Service (SQS), given its built-in capability to publish an event with a delay.

Figure 3. The end-to-end evaluation process when using the Delay feature.

The maximum delay that SQS supports is 15 minutes; meanwhile, our platform allows for a delay of up to x hours. To address this limitation, we publish the event multiple times upon receiving the message, extending the delay by another 15 minutes each time, until it reaches the desired delay of x hours.

Limit

The Limit feature is used to restrict the number of actions for a specific campaign or user within that campaign. This feature can be applied on a daily basis or for the full duration of the campaign.

For instance, we can use the Limit feature to distribute 1000 vouchers to users who have completed a ride and restrict it to only one voucher for one user per day. This ensures a controlled distribution of rewards and prevents a user from excessively using the benefits of a campaign.

In the backend, a limit setup translates into conditions within a single treatment. Given the above scenario, the treatment would be as follows:

  • Event: onRideCompleted
  • Condition: TotalUsageCount <= 1000 AND DailyUserUsageCount <= 1
  • Action: awardReward

Similar to the Counter feature, it’s necessary for us to keep track of the number of completed rides for each user in the database.

Figure 4. The end-to-end evaluation process when using the Limit feature.

A better campaign builder

As our campaigns grew more and more complex, the treatment creation quickly became overwhelming. A complex logic flow often required the creation of many treatments, which was cumbersome and error-prone. The need for a more visual and simpler campaign builder UI became evident.

Our design team came up with a flow-chart-like UI. Figure 5, 6, and 7 show examples of how certain imaginary campaign setup would look like in the new UI.

Figure 5. When users complete a food order, if they are a gold user, award them with A. However, if they are a silver user, award them with B.
Figure 6. When users complete a food or mart order, increment a counter. When the counter reaches 5, send them a message. Once the counter reaches 10, award them with points.
Figure 7. When a user confirms a ride booking, wait for 1 minute, and then conduct A/B testing by sending a message 50% of the time.

The campaign setup in the new UI can be naturally stored as a node tree structure. The following is how the example in figure 5 would look like in JSON format. We assign each node a unique number ID, and store a map of the ID to node content.

{
  "1": {
    "type": "scenario",
    "data": { "eventType": "foodOrderComplete"  },
    "children": ["2", "3"]
  },
  "2": {
    "type": "condition",
    "data": { "lhs": "var.user.tier", "operator": "eq", "rhs": "gold" },
    "children": ["4"]
  },
  "3": {
    "type": "condition",
    "data": { "lhs": "var.user.tier", "operator": "eq", "rhs": "silver" },
    "children": ["5"]
  },
  "4": {
    "type": "action",
    "data": {
      "type": "awardReward",
      "payload": { "rewardID": "ID-of-A"  }
    }
  },
  "5": {
    "type": "action",
    "data": {
      "type": "awardReward",
      "payload": { "rewardID": "ID-of-B"  }
    }
  }
}

Conversion to treatments

The question then arises, how do we execute this node tree as treatments? This requires a conversion process. We then developed the following algorithm for converting the node tree into equivalent treatments:

// convertToTreatments is the main function
func convertToTreatments(rootNode) -> []Treatment:
  output = []

  for each scenario in rootNode.scenarios:
    // traverse down each branch
    context = createConversionContext(scenario)
    for child in rootNode.children:
      treatments = convertHelper(context, child)
      output.append(treatments)

  return output

// convertHelper is a recursive helper function
func convertHelper(context, node) -> []Treatment:
  output = []
  f = getNodeConverterFunc(node.type)
  treatments, updatedContext = f(context, node)

  output.append(treatments)

  for child in rootNode.children:
    treatments = convertHelper(updatedContext, child)
    output.append(treatments)

  return output

The getNodeConverterFunc will return different handler functions according to the node type. Each handler function will either update the conversion context, create treatments, or both.

Table 1. The handler logic mapping for each node type.
Node type Logic
condition Add conditions into the context and return the updated context.
action Return a treatment with the event type, condition from the context, and the action itself.
delay Return a treatment with the event type, condition from the context, and a scheduleDelayedEvent action.
count Return a treatment with the event type, condition from the context, and an incrementUserStats action.
count condition Form a condition with the count key from the context, and return an updated context with the condition.

It is important to note that treatments cannot always be reverted to their original node tree structure. This is because different node trees might be converted into the same set of treatments.

The following is an example where two different node trees setups correspond to the same set of treatments:

  • Food order complete -> if gold user -> then award A
  • Food order complete -> if silver user -> then award B
Figure 8. An example of two node tree setups corresponding to the the same set of treatments.

Therefore, we need to store both the campaign node tree JSON and treatments, along with the mapping between the nodes and the treatments. Campaigns are executed using treatments, but displayed using the node tree JSON.

Figure 9. For each campaign, we store both the node tree JSON and treatments, along with their mapping.

How we handle campaign updates

There are instances where a marketing user updates a campaign after its creation. For such cases we need to identify:

  • Which existing treatments should be removed.
  • Which existing treatments should be updated.
  • What new treatments should be added.

We can do this by using the node-treatment mapping information we stored. The following is the pseudocode for this process:

func howToUpdateTreatments(oldTreatments []Treatment, newTreatments []Treatment):
  treatmentsUpdate = map[int]Treatment // treatment ID -> updated treatment
  treatmentsRemove = []int // list of treatment IDs
  treatmentsAdd = []Treatment // list of new treatments to be created

  matchedOldTreamentIDs = set()

  for newTreatment in newTreatments:
    matched = false

    // see whether the nodes match any old treatment
    for oldTreatment in oldTreatments:
      // two treatments are considered matched if their linked node IDs are identical
      if isSame(oldTreatment.nodeIDs, newTreatment.nodeIDs):
        matched = true
        treatmentsUpdate[oldTreament.ID] = newTreatment
        matchedOldTreamentIDs.Add(oldTreatment.ID)
        break

    // if no match, that means it is a new treatment we need to create
    if not matched:
      treatmentsAdd.Append(newTreatment)

  // all the non-matched old treatments should be deleted
  for oldTreatment in oldTreatments:
    if not matchedOldTreamentIDs.contains(oldTreatment.ID):
      treatmentsRemove.Append(oldTreatment.ID)

  return treatmentsAdd, treatmentsUpdate, treatmentsRemove

For a visual illustration, let’s consider a campaign that initially resembles the one shown in figure 10. The node IDs are highlighted in red.

Figure 10. A campaign in node tree structure.

This campaign will generate two treatments.

Table 2. The campaign shown in the figure 10 will generated two treatments.
ID Treatment Linked node IDs
1 Event: food order complete
Condition: gold user
Action: award A
1, 2, 3
2 Event: food order complete
Condition: silver user
Action: award B
1, 4, 5

After creation, the campaign creator updates the upper condition branch, deletes the lower branch, and creates a new branch. Note that after node deletion, the deleted node ID will not be reused.

Figure 11. An updated campaign in node tree structure.

According to our logic in figure 11, the following update will be performed:

  • Update action for treatment 1 to “award C”.
  • Delete treatment 2
  • Create a new treatment: food -> is promo used -> send push

Conclusion

This article reveals the workings of Trident, our bespoke marketing campaign platform. By exploring the core concept of a “treatment” and additional features like Counter, Delay and Limit, we illustrated the flexibility and sophistication of our system.

We’ve explained changes to the Trident UI that have made campaign creation more intuitive. Transforming campaign setups into executable treatments while preserving the visual representation ensures seamless campaign execution and adaptation.

Our devotion to improving Trident aims to empower our marketing team to design engaging and dynamic campaigns, ultimately providing excellent experiences to our users.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Chimera Sandbox: A scalable experimentation and development platform for Notebook services

Post Syndicated from Grab Tech original https://engineering.grab.com/chimera-sandbox

Key to innovation and improvement in machine learning (ML) models is the ability for rapid iteration. Our team, Chimera, part of the Artificial Intelligence (AI) Platform team, provides the essential compute infrastructure, ML pipeline components, and backend services. This support enables our ML engineers, data scientists, and data analysts to efficiently experiment and develop ML solutions at scale.

With a commitment to leveraging the latest Generative AI (GenAI) technologies, Grab is enhancing productivity tools for all Grabbers. Our Chimera Sandbox, a scalable Notebook platform, facilitates swift experimentation and development of ML solutions, offering deep integration with our AI Gateway. This enables easy access to various Large Language Models (LLMs) (both proprietary and open source), ensuring scalability, compliance, and access control are managed seamlessly.

What is Chimera Sandbox?

Chimera Sandbox is a Notebook service platform. It allows users to launch multiple notebook and visualisation services for experimentation and development. The platform offers an extremely quick onboarding process enabling any Grabber to start learning, exploring and experimenting in just a few minutes. This inclusivity and ease of use have been key in driving the adoption of the platform across different teams within Grab and empowering all Grabbers to be GenAI-ready.

One significant challenge in harnessing ML for innovation, whether for technical experts or non-technical enthusiasts, has been the accessibility of resources. This includes GPU instances and specialised services for developing LLM-powered applications. Chimera Sandbox addresses this head-on by offering an extensive array of compute instances, both with and without GPU support, thus removing barriers to experimentation. Its deep integration with Grab’s suite of internal ML tools transforms the way users approach ML projects. Users benefit from features like hyperparameter tuning, tracking ML training metadata, accessing diverse LLMs through Grab’s AI Gateway, and experimenting with rich datasets from Grab’s data lake. Chimera Sandbox ensures that users have everything they need at their fingertips. This ecosystem not only accelerates the development process but also encourages innovative approaches to solving complex problems.

The underlying compute infrastructure of the Chimera Sandbox platform is Grab’s very own battle-tested, highly scalable ML compute infrastructure running on multiple Kubernetes clusters. Each cluster can scale up to thousands of nodes at peak times gracefully. This scalability ensures that the platform can handle the high computational demands of ML tasks. The robustness of Kubernetes ensures that the platform remains stable, reliable, and highly available even under heavy load. At any point in time, there can be hundreds of data scientists, ML engineers and developers experimenting and developing on the Chimera Sandbox platform.

Figure 1. Chimera Sandbox Platform.
Figure 2. UI for Starting Chimera Sandbox.

Best of both worlds

Chimera Sandbox is suitable for both new users who want to explore and experiment ML solutions and advanced users who want to have full control over the Notebook services they run. Users can launch Notebook services using default Docker images provided by the Chimera Sandbox platform. These images come pre-loaded with popular data science and ML libraries and various Grab internal systems integrations. Chimera also provides basic Docker images from which the users can use as base images to build their own customised Notebook service Docker images. Once the images are built, the users can configure their Notebook services to use their custom Docker images. This ensures their Notebook environment can be exactly the way they want them to be.

Figure 3. Users are able to customise their Notebook service with additional packages.

Real-time collaboration

The Chimera Sandbox platform also features a real-time collaboration feature. This feature fosters a collaborative environment where users can exchange ideas and work together on projects.

CPU and GPU choices

Chimera Sandbox offers a wide variety of CPU and GPU choices to cater to specific needs, whether it is a CPU, memory, or GPU intensive experimentation. This flexibility allows users to choose the most suitable computational resources for their tasks, ensuring optimal performance and efficiency.

Deep integration with Spark

The platform is deeply integrated with internal Spark engines, enabling users to experiment building extract, transform, and load (ETL) jobs with data from Grab’s data lake. Integrated helpers such as SparkConnect Kernel and %%spark_sql magic cell, provide a faster developer experience, which can execute Spark SQL queries without needing to write additional code to start a Spark session and query.

Figure 4. %%spark_sql magic cell enables users to quickly explore data with Spark.

In addition to Magic Cell, the Chimera Sandbox offers advanced Spark functionalities. Users can write PySpark code using pre-configured and configurable Spark clients in the runtime environment. The underlying computation engine leverages Grab’s custom Spark-on-Kubernetes operator, enabling support for large-scale Spark workloads. This high-code capability complements the low-code Magic Cell feature, providing users with a versatile data processing environment.

Chimera Sandbox features an AI Gallery to guide and accelerate users to start experimenting with ML solutions or building GenAI-powered applications. This is especially useful for new or novice users who are keen to explore what they can do on the Chimera Sandbox platform. With Chimera Sandbox, users are not just presented with a bare bones compute solution but rather are provided with ways to do ML tasks right from Chimera Sandbox Notebooks. This approach saves users from the hassle of having to piece together the examples from the public internet, which may not work on the platform. These ready-to-run and comprehensive notebooks in the AI Gallery assure users that they can run end-to-end examples without a hitch. Based on these examples, the users can only extend their experimentations and development for their specific needs. Not only that, these tutorials and notebooks exhibit the platform capabilities and integrations available on the platform in an interactive manner rather than having the users refer to a separate documentation.

Lastly, the AI Gallery encourages contributions from other Grabbers, fostering a collaborative environment. Users who are enthusiastic about creating educational contents on Chimera Sandbox can effectively share their work with other Grabbers.

Figure 5. Including AI Gallery in user specified sandbox images.

Integration with various LLM services

Notebook users on Chimera Sandbox can easily tap into a plethora of LLMs, both open source and proprietary models, without any additional setup via our AI Gateway. The platform takes care of access mechanisms and endpoints for various LLM services so that the users can easily use their favourite libraries to create LLM-powered applications and conduct experimentations. This seamless integration with LLMs enables users to focus on their GAI-powered ideas rather than having to worry about underlying logistics and technicalities of using different LLMs.

More than a notebook service

While Notebook is the most popular service on the platform, Chimera Sandbox offers much more than just notebook capabilities. It serves as a comprehensive namespace workspace equipped with a suite of ML/AI tools. Alongside notebooks, users can access essential ML tools such as Optuna for hyperparameter tuning, MLflow for experiment tracking, and other tools including Zeppelin, RStudio, Spark history, Polynote, and LabelStudio. All these services use a shared storage system, creating a tailored workspace for ML and AI tasks.

Figure 6. A Sandbox namespace with its out-of-the-box services.

Additionally, the Sandbox framework allows for the seamless integration of more services into personal workspaces. This high level of flexibility significantly enhances the capabilities of the Sandbox platform, making it an ideal environment for diverse ML and AI applications.

Cost attribution

For a multi-tenanted platform such as Chimera Sandbox, it is crucial to provide users information on how much they have spent with their experimentations. Cost showback and chargeback capabilities are of utmost importance for a platform on which users can launch Notebook services that use accelerated instances with GPUs. The platform provides cost attribution to individual users, so each user knows exactly how much they are spending on their experimentations and can make budget-conscious decisions. This transparency in cost attribution encourages responsible usage of resources and helps users manage their budgets effectively.

Growth and future plans

In essence, Chimera Sandbox is more than just a tool; it’s a catalyst for innovation and growth, empowering Grabbers to explore the frontiers of ML and AI. By providing an inclusive, flexible, and powerful platform, Chimera Sandbox is helping shape the future of Grab, making every Grabber not just ready but excited to contribute to the AI-driven transformation of our products and services.

In July and August of this year, teams were given the opportunity to intensively learn and experiment with AI. Since then, we have observed hockey stick growth on the Chimera Sandbox platform. We are enabling massive experimentation across different teams at Grab to experiment and work on different GAI-powered applications.

Figure 7. Chimera Sandbox daily active users.

Our future plans include mechanisms for better notebook discovery, collaboration and usability, and the ability to enable users to schedule their notebooks right from Chimera Sandbox. These enhancements aim to improve the user experience and make the platform even more versatile and powerful.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 700 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

How we improved translation experience with cost efficiency

Post Syndicated from Grab Tech original https://engineering.grab.com/improved-translation-experience-with-cost-efficiency

Introduction

As COVID restrictions were fully lifted in 2023, the number of tourists grew dramatically. People began to explore the world again, frequently using the Grab app to make bookings outside of their home country. However, we noticed that communication posed a challenge for some users. Despite our efforts to integrate an auto-translation feature in the booking chat, we received feedback about occasional missed or inaccurate translations. You can refer to this blog for a better understanding of Grab’s chat system.

An example of a bad translation. The correct translation is: ‘ok sir’.

In an effort to enhance the user experience for travellers using the Grab app, we formed an engineering squad to tackle this problem. The objectives are as follows:

  • Ensure translation is provided when it’s needed.
  • Improve the quality of translation.
  • Maintain the cost of this service within a reasonable range.

Ensure translation is provided when it’s needed

Originally, we relied on users’ device language settings to determine if translation is needed. For example, if both the passenger and driver’s language setting is set to English, translation is not needed. Interestingly, it turned out that the device language setting did not reliably indicate the language in which a user would send their messages. There were numerous cases where despite having their device language set to English, drivers sent messages in another language.

Therefore, we needed to detect the language of user messages on the fly to make sure we trigger translation when it’s needed.

Language detection

Simple as it may seem, language detection is not that straightforward a task. We were unable to find an open-source language detector library that covered all Southeast Asian languages. We looked for Golang libraries as our service was written in Golang. The closest we could find were the following:

  • Whatlang: unable to detect Malay
  • Lingua: unable to detect Burmese and Khmer

We decided to choose Lingua over Whatlang as the base detector due to the following factors:

  • Overall higher accuracy.
  • Capability to provide detection confidence level.
  • We have more users using Malay than those using Burmese or Khmer.

When a translation request comes in, our first step is to use Lingua for language detection. If the detection confidence level falls below a predefined threshold, we fall back to call the third-party translation service as it can detect all Southeast Asian languages.

You may ask, why don’t we simply use the third-party service in the first place. It’s because:

  • The third-party service only has a translate API that also does language detection, but it does not provide a standalone language detection API.
  • Using the translate API is costly, so we need to avoid calling it when it’s unnecessary. We will cover more on this in a later section.

Another challenge we’ve encountered is the difficulty of distinguishing between Malay and Indonesian languages due to their strong similarities and shared vocabulary. The identical text might convey different meanings in these two languages, which the third-party translation service struggles to accurately detect and translate.

Differentiating Malay and Indonesian is a tough problem in general. However, in our case, the detection has a very specific context, and we can make use of the context to enhance our detection accuracy.

Making use of translation context

All our translations are for the messages sent in the context of a booking or order, predominantly between passenger and driver. There are two simple facts that can aid in our language detection:

  • Booking/order happens in one single country.
  • Drivers are almost always local to that country.

So, for a booking that happens in an Indonesian city, if the driver’s message is detected as Malay, it’s highly likely that the message is actually in Bahasa Indonesia.

Improve quality of translation

Initially, we were entirely dependent on a third-party service for translating our chat messages. While overall powerful, the third-party service is not perfect, and it does generate weird translations from time to time.

An example of a weird translation from a third-party service recorded on 19 Dec 2023.

Then, it came to us that we might be able to build an in-house translation model that could translate chat messages better than the third-party service. The reasons being:

  • The scope of our chat content is highly specific. All the chats are related to bookings or orders. There would not be conversations about life or work in the chat. Maybe a small Machine Learning (ML) model would suffice to do the job.
  • The third-party service is a general translation service. It doesn’t know the context of our messages. We, however, know the whole context. Having the right context gives us a great edge on generating the right translation.

Training steps

To create our own translation model, we took the following steps:

  • Perform topic modelling on Grab chat conversations.
  • Worked with the localisation team to create a benchmark set of translations.
  • Measured existing translation solutions against benchmarks.
  • Used an open source Large Language Model (LLM) to produce synthetic training data.
  • Used synthetic data to train our lightweight translation model.

Topic modelling

In this step, our aim was to generate a dataset which is both representative of the chat messages sent by our users and diverse enough to capture all of the nuances of the conversations. To achieve this, we took a stratified sampling approach. This involved a random sample of past chat conversation messages stratified by various topics to ensure a comprehensive and balanced representation.

Developing a benchmark

For this step we engaged Grab’s localisation team to create a benchmark for translations. The intention behind this step wasn’t to create enough translation examples to fully train or even finetune a model, but rather, it was to act as a benchmark for translation quality, and also as a set of few-shot learning examples for when we generate our synthetic data.

This second point was critical! Although LLMs can generate good quality translations, LLMs are highly susceptible to their training examples. Thus, by using a set of handcrafted translation examples, we hoped to produce a set of examples that would teach the model the exact style, level of formality, and correct tone for the context in which we plan to deploy the final model.

Benchmarking

From a theoretical perspective there are two ways that one can measure the performance of a machine translation system. The first is through the computation of some sort of translation quality score such as a BLEU or CHRF++ score. The second method is via subjective evaluation. For example, you could give each translation a score from 1 to 5 or pit two translations against each other and ask someone to assess which they prefer.

Both methods have their relative strengths and weaknesses. The advantage of a subjective method is that it corresponds better with what we want, a high quality translation experience for our users. The disadvantage of this method is that it is quite laborious. The opposite is true for the computed translation quality scores, that is to say that they correspond less well to a human’s subjective experience of our translation quality, but that they are easier and faster to compute.

To overcome the inherent limitations of each method, we decided to do the following:

  1. Set a benchmark score for the translation quality of various translation services using a CHRF++ score.
  2. Train our model until its CHRF++ score is significantly better than the benchmark score.
  3. Perform a manual A/B test between the newly trained model and the existing translation service.

Synthetic data generation

To generate the training data needed to create our model, we had to rely on an open source LLM to generate the synthetic translation data. For this task, we spent considerable effort looking for a model which had both a large enough parameter count to ensure high quality outputs, but also a model which had the correct tokenizer to handle the diverse sets of languages which Grab’s customers speak. This is particularly important for languages which use non-standard character sets such as Vietnamese and Thai. We settled on using a public model from Hugging Face for this task.

We then used a subset of the previously mentioned benchmark translations to input as few-shot learning examples to our prompt. After many rounds of iteration, we were able to generate translations which were superior to the benchmark CHRF++ scores which we had attained in the previous section.

Model fine tuning

We now had one last step before we had something that was production ready! Although we had successfully engineered a prompt capable of generating high quality translations from the public Hugging Face model, there was no way we’d be able to deploy such a model. The model was far too big for us to deploy it in a cost efficient manner and within an acceptable latency. Our solution to this was to fine-tune a smaller bespoke model using the synthetic training data which was derived from the larger model.

These models were language specific (e.g. English to Indonesian) and built solely for the purpose of language translation. They are 99% smaller than the public model. With approximately 10 Million synthetic training examples, we were able to achieve performance which was 98% as effective as our larger model.

We deployed our model and ran several A/B tests with it. Our model performed pretty well overall, but we noticed a critical problem: sometimes, numbers got mutated in the translation. These numbers can be part of an address, phone number, price etc. Showing the wrong number in a translation can cause great confusion to the users. Unfortunately, an ML model’s output can never be fully controlled; therefore, we added an additional layer of programmatic check to mitigate this issue.

Post-translation quality check

Our goal is to ensure non-translatable content such as numbers, special symbols, and emojis in the original message doesn’t get mutated in the translation produced by our in-house model. We extract all the non-translatable content from the original message, count the occurrences of each, and then try to match the same in the translation. If it fails to match, we discard the in-house translation and fall back to using the third-party translation service.

Keep cost low

At Grab, we try to be as cost efficient as possible in all aspects. In the case of translation, we tried to minimise cost by avoiding unnecessary on-the-fly translations.

As you would have guessed, the first thing we did was to implement caching. A cache layer is placed before both the in-house translation model and the third-party translation. We try to serve translation from the cache first before hitting the underlying translation service. However, given that translation requests are in free text and can be quite dynamic, the impact of caching is limited. There’s more we need to do.

For context, in a booking chat, other than the users, Grab’s internal services can also send messages to the chat room. These messages are called system messages. For example,our food service always sends a message with information on the food order when an order is confirmed.

System messages are all fairly static in nature, however, we saw a very high amount of translation cost attributed to system messages. Taking a deeper look, we noticed the following:

  • Many system messages were not sent in the recipient’s language, thus requiring on-the-fly translation.
  • Many system messages, though having the same static structure, contain quite a few variants such as passenger’s name and food order item name. This makes it challenging to utilise our translation cache effectively as each message is different.

Since all system messages are manually prepared, we should be able to get them all manually translated into all the required languages, and avoid on-the-fly translations altogether.

Therefore, we launched an internal campaign, mandating all internal services that send system messages to chat rooms to get manual translations prepared, and pass in the translated contents. This alone helped us save roughly US$255K a year!

Next steps

At Grab, we firmly believe that our proprietary in-house translation models are not only more cost-effective but cater more accurately to our unique use cases compared to third-party services. We will focus on expanding these models to more languages and countries across our operating regions.

Additionally, we are exploring opportunities to apply learnings of our chat translations to other Grab content. This strategy aims to guarantee a seamless language experience for our rapidly expanding user base, especially travellers. We are enthusiastically looking forward to the opportunities this journey brings!

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 428 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Profile-guided optimisation (PGO) on Grab services

Post Syndicated from Grab Tech original https://engineering.grab.com/profile-guided-optimisation

Profile-guided optimisation (PGO) is a technique where CPU profile data for an application is collected and fed back into the next compiler build of Go application. The compiler then uses this CPU profile data to optimise the performance of that build by around 2-14% currently (future releases could likely improve this figure further).

High level view of how PGO works

PGO is a widely used technique that can be implemented with many programming languages. When it was released in May 2023, PGO was introduced as a preview in Go 1.20.

Enabling PGO on a service

Profile the service to get pprof file

First, make sure that your service is built using Golang version v1.20 or higher, as only these versions support PGO.

Next, enable pprof in your service.

If it’s already enabled, you can use the following command to capture a 6-minute profile and save it to /tmp/pprof.

curl 'http://localhost:6060/debug/pprof/profile?seconds=360' -o /tmp/pprof

Enabled PGO on the service

TalariaDB: TalariaDB is a distributed, highly available, and low latency time-series database for Presto open sourced by Grab.

It is a service that runs on an EKS cluster and is entirely managed by our team, we will use it as an example here.

Since the cluster deployment relies on a Docker image, we only need to update the Docker image’s go build command to include -PGO=./talaria.PGO. The talaria.PGO file is a pprof profile collected from production services over a span of 360 seconds.

If you’re utilising a go plugin, as we do in TalariaDB, it’s crucial to ensure that the PGO is also applied to the plugin.

Here’s our Dockerfile, with the additions to support PGO.

FROM arm64v8/golang:1.21 AS builder

ARG GO111MODULE="on"
ARG GOOS="linux"
ARG GOARCH="arm64"
ENV GO111MODULE=${GO111MODULE}
ENV GOOS=${GOOS}
ENV GOARCH=${GOARCH}

RUN mkdir -p /go/src/talaria
COPY . src/talaria
#RUN cd src/talaria && go mod download  && go build && test -x talaria
RUN cd src/talaria && go mod download  && go build -PGO=./talaria.PGO && test -x talaria

RUN mkdir -p /go/src/talaria-plugin
COPY ./talaria-plugin  src/talaria-plugin
RUN cd src/talaria-plugin && make plugin && test -f talaria-plugin.so
FROM arm64v8/debian:latest AS base

RUN apt-get update && apt-get install -y ca-certificates && rm -rf /var/cache/apk/*

WORKDIR /root/ 
ARG GO_BINARY=talaria
COPY  --from=builder /go/src/talaria/${GO_BINARY} .
COPY  --from=builder /go/src/talaria-plugin/talaria-plugin.so .

ADD entrypoint.sh . 
RUN mkdir /etc/talaria/ && chmod +x /root/${GO_BINARY} /root/entrypoint.sh
ENV TALARIA_RC=/etc/talaria/talaria.rc 
EXPOSE 8027
ENTRYPOINT ["/root/entrypoint.sh"]

Result on enabling PGO on one GrabX service

It’s important to mention that the pprof utilised for PGO was not captured during peak hours and was limited to a duration of 360 seconds.

Service TalariaDB has three clusters and the time we enabled PGO for these clusters are:

  • We enabled PGO on cluster 0, and deployed on 4 Sep 11.16 AM.
  • We enabled PGO on cluster 1, and deployed on 5 Sep 15:00 PM.
  • We enabled PGO on cluster 2, and deployed on 6 Sep 16:00 PM.

The size of the instances, their quantity, and all other dependencies remained unchanged.

CPU metrics on cluster

Cluster CPU usage before enabling PGO
Cluster CPU usage after enabling PGO

It’s evident that enabling PGO resulted in at least a 10% reduction in CPU usage.

Memory metrics on cluster

Memory usage of the cluster before enabling PGO
Percentage of free memory after enabling PGO

It’s clear that enabling PGO led to a reduction of at least 10GB (30%) in memory usage.

Volume metrics on cluster

Persistent volume usage on cluster before enabling PGO
Volume usage after enabling PGO

Enabling PGO resulted in a reduction of at least 7GB (38%) in volume usage. This volume is utilised for storing events that are queued for ingestion.

Ingested event count/CPU metrics on cluster

To gauge the enhancements, I employed the metric of ingested event count per CPU unit (event count / CPU). This approach was adopted to account for the variable influx of events, which complicates direct observation of performance gains.

Count of ingested events on cluster after enabling PGO

Upon activating PGO, there was a noticeable increase in the ingested event count per CPU, rising from 1.1 million to 1.7 million, as depicted by the blue line in the cluster screenshot.

How we enabled PGO on a Catwalk service

We also experimented with enabling PGO on certain orchestrators in a Catwalk service. This section covers our findings.

Enabling PGO on the test-golang-orch-tfs orchestrator

Attempt 1: Take pprof for 59 seconds

  • Just 1 pod running with a constant throughput of 420 QPS.
  • Load test started with a non-PGO image at 5:39 PM SGT.
  • Take pprof for 59 seconds.
  • Image with PGO enabled deployed at 5:49 PM SGT.

Observation: CPU usage increased after enabling PGO with pprof for 59 seconds.

We suspected that taking pprof for just 59 seconds may not be sufficient to collect accurate metrics. Hence, we extended the duration to 6 minutes in our second attempt.

Attempt 2 : Take pprof for 6 minutes

  • Just 1 pod running with a constant throughput of 420 QPS.
  • Deployed non PGO image with custom pprof server at 6:13 PM SGT.
  • pprof taken at 6:19 PM SGT for 6 minutes.
  • Image with PGO enabled deployed at 6:29 PM SGT.

Observation: CPU usage decreased after enabling PGO with pprof for 6 minutes.

CPU usage after enabling PGO on Catwalk
Container memory utilisation after enabling PGO on Catwalk

Based on this experiment, we found that the impact of PGO is around 5% but the effort involved to enable PGO outweighs the impact. To enable PGO on Catwalk, we would need to create Docker images for each application through CI pipelines.

Additionally, the Catwalk team would require a workaround to pass the pprof dump, which is not a straightforward task. Hence, we decided to put off the PGO application for Catwalk services.

Looking into PGO for monorepo services

From the information provided above, enabling PGO for a service requires the following support mechanisms:

  • A pprof service, which is currently facilitated through Jenkins.
  • A build process that supports PGO arguments and can attach or retrieve the pprof file.

For services that are hosted outside the monorepo and are self-managed, the effort required to experiment is minimal. However, for those within the monorepo, we will require support from the build process, which is currently unable to support this.

Conclusion/Learnings

Enabling PGO has proven to be highly beneficial for some of our services, particularly TalariaDB. By using PGO, we’ve observed a clear reduction in both CPU usage and memory usage to the tune of approximately 10% and 30% respectively. Furthermore, the volume used for storing queued ingestion events has been reduced by a significant 38%. These improvements definitely underline the benefits and potential of utilising PGO on services.

Interestingly, applying PGO resulted in an increased rate of ingested event count per CPU unit on TalariaDB, which demonstrates an improvement in the service’s efficiency.

Experiments with the Catwalk service have however shown that the effort involved to enable PGO might not always justify the improvements gained. In our case, a mere 5% improvement did not appear to be worth the work required to generate Docker images for each application via CI pipelines and create a solution to pass the pprof dump.

On the whole, it is evident that the applicability and benefits of enabling PGO can vary across different services. Factors such as application characteristics, current architecture, and available support mechanisms can influence when and where PGO optimisation is feasible and beneficial.

Moving forward, further improvements to go-build and the introduction of PGO support for monorepo services may drive greater adoption of PGO. In turn, this has the potential to deliver powerful system-wide gains that translate to faster response times, lower resource consumption, and improved user experiences. As always, the relevance and impact of adopting new technologies or techniques should be considered on a case-by-case basis against operational realities and strategic objectives.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 428 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

How we evaluated the business impact of marketing campaigns

Post Syndicated from Grab Tech original https://engineering.grab.com/evaluate-business-impact-of-marketing-campaigns

In a previous post, we introduced our systems for running marketing campaigns. Although we sent millions of messages daily, we had little insight into their effectiveness. Did they engage our users with our promotions? Did they encourage more transactions and bookings?

As Grab’s business expanded and the number of marketing campaigns increased, understanding the impact of these campaigns became crucial. This knowledge enables campaign managers to design more effective campaigns and avoid wasteful ones that degrade user experience.

Initially, campaign managers had to consult marketing analysts to gauge the impact of campaigns. However, this approach soon proved unsustainable:

  • Manual analysis doesn’t scale with an increasing number of campaigns.
  • Different analysts might assess the business impact in slightly different ways, leading to inconsistent results over time.

Thus, we recognised the need for a centralised solution allowing campaign managers to view their campaign impact analyses.

Marketing attribution model

The marketing analyst team designed a Marketing attribution model (MAM) for estimating the business impact of any campaign that sends messages to users. It quantifies business impact in terms of generated gross merchandise value (GMV), revenue, etc.

Unlike traditional models that only credit the last touchpoint (i.e. the last message user reads before making a transaction), MAM offers a more nuanced view. It recognises that users are exposed to various marketing messages (emails, pushes, feeds, etc.) throughout their decision-making process. As shown in Fig 1, MAM assigns credit to each touchpoint that influences a conversion (e.g., Grab usage) based on two key factors:

  • Relevance: Content directly related to the conversion receives a higher weightage. Imagine a user opening a GrabFood push notification before placing a food order. This push would be considered highly relevant and receive significant credit.
  • Recency: Touchpoints closer in time to the conversion hold more weight. For instance, a brand awareness email sent weeks before the purchase would be less impactful than a targeted GrabFood promotion right before the order.
    By factoring in both relevance and recency, MAM avoids crediting the same touchpoint twice and provides a more accurate picture of which marketing campaigns are driving higher conversions.
Fig 1. How MAM does business attribution

While MAM is effective for comparing the impacts of different campaigns, it struggles with the assessment of a single campaign because it does not account for negative impacts. For example, consider a message stating, “Hey, don’t use Grab.” Clearly, not all messages positively impact business.

Hold-out group

To better evaluate the impact of a single campaign, we divide targeted users into two groups:

  • Hold-out (control): do not send any message
  • Treatment: send the message
Fig 2. Campaign setup with hold-out group

We then compare the business performance of sending versus not sending messages. For the treatment group, we ideally count only the user transactions potentially linked to the message (i.e., transactions occurring within X days of message receipt). However, since the hold-out group receives no messages, there are no equivalent metrics for comparison.

The only business metrics available for the hold-out group are the aggregated totals of GMV, revenue, etc., over a given time, divided by the number of users. We must calculate the same for the treatment group to ensure a fair comparison.

Fig 3. Metrics calculation for both hold-out and treatment group

The comparison might seem unreliable due to:

  • The metrics are raw aggregations, lacking attribution logic.
  • The aggregated GMV and revenue might be skewed by other simultaneous campaigns involving the same users.

Here, we have to admit that figuring out true business impact is difficult. All we can do is try our best to get as close to the truth as possible. To make the comparison more precise, we employed the following strategies:

  • Stratify the two groups, so that both groups contain roughly the same distribution of users.
  • Calculate statistical significance to rule out the difference caused by random factors.
  • Allow users to narrow down the business metrics to compare according to campaign set-up. For example, we don’t compare ride bookings if the campaign is promoting food.

Statistical significance is a common, yet important technique for evaluating the result of controlled experiments. Let’s see how it’s used in our case.

Statistical significance

When we do an A/B testing, we cannot simply conclude that A is better than B when A’s result is better than B. The difference could be due to other random factors. If you did an A/A test, you will still see differences in the results even without doing anything different to the two groups.

Statistical significance is a method to calculate the probability that the difference between two groups is really due to randomness. The lower the probability, the more confidently we can say our action is truly making some impact.

In our case, to derive statistical significance, we assume:

  • Our hold-out and treatment group are two sets of samples drawn from two populations, A and B.
  • A and B are the same except that B received our message. We can’t 100% prove this, but can reasonably guess this is close to true, since we split with stratification.

Assuming the business metrics we are comparing is food GMV, the base numbers can be formulated as shown in Fig 4.

Fig 4. Formulation for calculating statistical significance

To calculate the probability, we then use a formula derived from the central limit theorem (CLT). The mathematical derivation of the formula is beyond the scope of this post. Programmatically, we use the popular jStat library for the calculation.

The calculation result of statistical significance as a special notice to the campaign owners is shown in Fig 5.

Fig 5. Display of business impact analysis with statistical significance

What’s next

Evaluating the true business impact remains challenging. We continue to refine our methodology and address potential biases, such as the assumption that both groups are of the same distribution, which might not hold true, especially in smaller group sizes. Furthermore, consistently reserving a 10% hold-out in each campaign is impractical for some campaigns, as sometimes campaign owners require messages to reach all targeted users.

We are committed to advancing our business impact evaluation solutions and will continue improving our existing solutions. We look forward to sharing more insights in future blogs.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 428 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

No version left behind: Our epic journey of GitLab upgrades

Post Syndicated from Grab Tech original https://engineering.grab.com/no-version-left-behind-our-epic-journey-of-gitlab-upgrades

In a tech-driven field, staying updated isn’t an option—it’s essential. At Grab, we’re committed to providing top-notch technology services. However, keeping pace can be demanding. At one point in time, our GitLab instance was trailing by roughly 14 months of releases. This blog post recounts our experience updating and formulating a consistent upgrade routine.

Recognising the need to upgrade

Our team, while skilled, was still learning GitLab’s complexities. Regular stability issues left us little time for necessary upgrades. Understanding the importance of upgrades for our operations to get latest patches for important security fixes and vulnerabilities, we started preparing for GitLab updates while managing system stability. This meant a quick learning and careful approach to updates.

The following image illustrates the version discrepancy between our self-hosted GitLab instance and the official most recent release of GitLab as of July 2022. GitLab follows a set release schedule, issuing one minor update monthly and rolling out a major upgrade annually.

Fig 1. The difference between our hosted version and the latest available GitLab version by 22 July 2022

Addressing fears and concerns

We were concerned about potential downtime, data integrity, and the threat of encountering unforeseen issues. GitLab is critical for the daily activities of Grab engineers. It serves a critical user base of thousands of engineers actively using it, hosting multiple mono repositories with code bases ranging in size from 1GB to a sizable 15GB. When taking into account all its artefacts, the overall imprint of a monorepo can extend to an impressive 39TB.

Our self-hosted GitLab firmly intertwines with multiple critical components. We’ve aligned our systems with GitLab’s official reference architecture for 5,000 users. We use Terraform to configure complete infrastructure with immutable Amazon Machine Images (AMIs) built using Packer and Ansible. Our efficient GitLab setup is designed for reliable performance to serve our wide user base. However, any fault leading to outages can disrupt our engineers, resulting in a loss of productivity for hundreds of teams.

High-level GitLab Architecture Diagram

The above is the top level architecture diagram of our GitLab infrastructure. Here are the major components of the GitLab architecture and their functions: 

  • Gitaly: Handles low-level Git operations for GitLab, such as interacting directly with the code repository present on disk. It’s important to mention that these code repositories are also stored on the same Gitaly nodes, using the attached Amazon Elastic Block Store (Amazon EBS) disks.
  • Praefect: Praefect in GitLab acts as a manager, coordinating Gitaly nodes to maintain data consistency and high availability.
  • Sidekiq: The background processing framework for GitLab written in Ruby. It handles asynchronous tasks in GitLab, ensuring smooth operation without blocking the main application.
  • App Server: The core web application server that serves the GitLab user interface and interacts with other components.

The importance of preparation

Recognising the complexity of our task, we prioritised careful planning for a successful upgrade. We studied GitLab’s documentation, shared insights within the team, and planned to prevent data losses.

To minimise disruptions from major upgrades or database migrations, we scheduled these during weekends. We also developed a checklist and a systematic approach for each upgrade, which include the following:

  • Diligently go through the release notes for each version of GitLab that falls within the scope of our upgrade.
  • Read through all dependencies like RDS, Redis, and Elasticsearch to ensure version compatibility.
  • Create documentation outlining new features, any deprecated elements, and changes that could potentially impact our operations.
  • Generate immutable AMIs for various components reflecting the new version of GitLab.
  • Revisit and validate all the backup plans.
  • Refresh staging environment with production data for accurate, realistic testing and performance checks, and validation of migration scripts under conditions similar to the actual setup.
  • Upgrade the staging environment.
  • Conduct extensive testing, incorporating both automated and manual functional testing, as well as load testing.
  • Conduct rollback tests on the staging environment to the previous version to confirm the rollback procedure’s reliability.
  • Inform all impacted stakeholders, and provide a defined timeline for upcoming upgrades.

We systematically follow GitLab’s official documentation for each upgrade, ensuring compatibility across software versions and reviewing specific instructions and changes, including any deprecations or removals.

The first upgrade

Equipped with knowledge, backup plans, and a robust support system, we embarked on our first GitLab upgrade two years ago. We carefully followed our checklist, handling each important part systematically. GitLab comprises both stateful (Gitaly) and stateless (Praefect, Sidekiq, and App Server) components, all managed through auto-scaling groups. We use a ‘create before destroy’ strategy for deploying stateless components and an ‘in-place node rotation’ method via Terraform for stateful ones.

We deployed key parts like Gitaly, Praefect, Sidekiq, App Servers, Network File System (NFS) server, and Elasticsearch in a specific sequence. Starting with Gitaly, followed by Praefect, then Sidekiq and App Servers, and finally NFS and Elasticsearch. Our thorough testing showed this order to be the most dependable and safe.

However, the journey was full of challenges. For instance, we encountered issues such as the Gitaly cluster falling out of sync for monorepo and the Praefect server failing to distribute the load effectively. Praefect assigns a primary Gitaly node for each repository to host it. All write operations are sent to the repository’s primary node, while read requests are spread across all synced nodes in the Gitaly cluster. If the Gitaly nodes aren’t synced, Praefect will redirect all write and read operations to the repository’s primary node.

Gitaly is a stateful application, we upgraded each Gitaly node with the latest AMI using an in-place node rotation strategy. In older versions of GitLab (up to v14.0), if a Gitaly node is unhealthy, Praefect would immediately update the primary node for the repository to any healthy Gitaly node. After the rolling upgrade for a 3-node Gitaly cluster, repositories were mainly concentrated on only one Gitaly node.

In our situation, a very busy monorepo was assigned to a Gitaly node that was also the main node for many other repositories. When real traffic began after deployment, the Gitaly node had trouble syncing the monorepo with the other nodes in the cluster.

Because the Gitaly node was out of sync, Praefect started sending all changes and access requests for monorepo to this struggling Gitaly node. This increased the load on the Gitaly server, causing it to fail. We found this to be the main issue and decided to manually move our monorepo to a Gitaly node that was less crowded. We also added a step to validate primary node distribution to our deployment checklist.

This immediate failover behaviour changed in GitLab version 14.1. Now, a primary is only elected lazily when a write request arrives for any repository. However, since we enabled maintenance mode before the Gitaly deployment, we didn’t receive any write requests. As a result, we did not see a shift in the primary node of the monorepo with new GitLab versions.

Regular upgrades: Our new normal

Embracing the practice of consistent upgrades dramatically transformed the way we operate. We initiated frequent upgrades and implemented measures to reduce the actual deployment time.  

  • Perform all major testing in one day before deployment.
  • Prepare a detailed checklist to follow during the deployment activity.
  • Reduce the minimum number of App Server and Sidekiq Servers required just after we start the deployment.
  • Upgrade components like App Server and Sidekiq in parallel.
  • Automate smoke testing to examine all major workflows after deployment.

Leveraging the lessons learned and the experience gained with each upgrade, we successfully cut the time spent on the entire operation by 50%. The image-3 shows how we reduced our deployment time for major upgrades from 6 hours to 3 hours and our deployment time for minor upgrades from 4 to 1.5 hours.

Each upgrade enriched our comprehensive knowledge base, equipping us with insights into the possible behaviours of each component under varying circumstances. Our growing experience and enhanced knowledge helped us achieve successful upgrades with less downtime with each deployment.

Rather than moving up one minor version at a time, we learned about the feasibility of skipping versions. We began using the GitLab Upgrade Path. This method allowed us to skip several versions, closing the distance to the latest version with fewer deployments. This approach enabled us to catch up on 24 months’ worth of upgrades in just 11 months, even though we started 14 months behind. 

Time taken in hrs for each upgrade. The blue line depicts major and the red line is for minor upgrades

Overcoming challenges

Our journey was not without hurdles. We faced challenges in maintaining system stability during upgrades, navigating unexpected changes in functionality post upgrades, and ensuring data integrity.

However, these challenges served as an opportunity for our team to innovate and create robust workarounds. Here are a few highlights:

Unexpected project distribution: During upgrades and Gitaly server restarts, we observed unexpected migration of the monorepo to a crowded Gitaly server, resulting in higher rate limiting. We manually updated primary nodes for the monorepo and made this validation as a part of our deployment checklist.

NFS deprecation: We migrated all required data to S3 buckets and deprecated NFS to become more resilient and independent of Availability Zone (AZ).

Handling unexpected Continuous Integration (CI) operations: A sudden surge in CI operations sometimes resulted in rate limiting and interrupted more essential Git operations for developers. This is because GitLab uses different RPC calls and their concurrency for SSH and HTTP operations. We encouraged using HTTPS links for GitLab CI and automation script and SSH links for regular Git operations.

Right-sizing resources: We countered resource limitations by right-sizing our infrastructure, ensuring each component had optimal resources to function efficiently.

Performance testing: We conducted performance testing of our GitLab using the GitLab Performance Tool (GPT). In addition, we used our custom scripts to load test Grab specific use cases and mono repositories.

Limiting maintenance windows: Each deployment required a maintenance window or downtime. To minimise this, we structured our deployment processes more efficiently, reducing potential downtime and ensuring uninterrupted service for users.

Dependency on GitLab.com image registry: We introduced measures to host necessary images internally, which increased our resilience and allowed us to cut ties with external dependencies.

The results

Through careful planning, we’ve improved our upgrade process, ensuring system stability and timely updates. We’ve also reduced the delay in aligning with official GitLab releases. The image below displays how the time delay between release date and deployment has been reduced with each upgrade. It sharply brought down from 396 days (around 14 months) to 35 days. 

At the time of this article, we’re just two minor versions behind the latest GitLab release, with a strong focus on security and resilience. We are also seeing a reduced number of reported issues after each upgrade.

Our refined process has allowed us to perform regular updates without any service disruptions. We aim to leverage these learnings to automate our upgrade deployments, painting a positive picture for our future updates, marked by efficiency and stability.

Time delay between official release date and date of deployment

Looking ahead

Our dedication extends beyond staying current with the most recent GitLab versions. With stabilised deployment, we are now focusing on:

  • Automated upgrades: Our efforts extend towards bringing in more automation to enhance efficiency. We’re already employing zero-downtime automated upgrades for patch versions involving no database migrations, utilising GitLab pipelines. Looking forward, we plan to automate minor version deployments as well, ensuring minimal human intervention during the upgrade process.
  • Automated runner onboarding for service teams: We’ve developed a ‘Runner as a Service’ solution for our service teams. Service teams can create their dedicated runners by providing minimal details, while we manage these runners centrally. This setup allows the service team to stay focused on development, ensuring smooth operations.
  • Improved communication and data safety: We’re regularly communicating new features and potential issues to our service teams. We also ensure targeted solutions for any disruptions. Additionally, we’re focusing on developing automated data validation via our data restoration process. 
  • Focus on development: With stabilised updates, we’ve created an environment where our development teams can focus more on crafting new features and supporting ongoing work, rather than handling upgrade issues.

Key takeaways

The upgrade process taught us the importance of adaptability, thorough preparation, effective communication, and continuous learning. Our ‘No Version Left Behind’ motto underscores the critical role of regular tech updates in boosting productivity, refining processes, and strengthening security. These insights will guide us as we navigate ongoing technological advancements.

Below are the key areas in which we improved:

Enhanced testing procedures: We’ve fine-tuned our testing strategies, using both automated and manual testing for GitLab, and regularly conducting performance tests before upgrades.

Approvals: We’ve designed approval workflows that allow us to obtain necessary clearances or approvals before each upgrade efficiently, further ensuring the smooth execution of our processes.

Improved communication: We’ve improved stakeholder communication, regularly sharing updates and detailed documents about new features, deprecated items, and significant changes with each upgrade.

Streamlined planning: We’ve improved our upgrade planning, strictly following our checklist and rotating the role of Upgrade Ownership among team members.

Optimised activity time: We’ve significantly reduced the time for production upgrade activity through advanced planning, automation, and eliminating unnecessary steps.

Efficient issue management: We’ve improved our ability to handle potential GitLab upgrade issues, with minimal to no issues occurring. We’re prepared to handle any incidents that could cause an outage.

Knowledge base creation and automation: We’ve created a GitLab knowledge base and continuously enhanced it with rich content, making it even more invaluable for training new team members and for reference during unexpected situations. We’ve also automated routine tasks to improve efficiency and reduce manual errors.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 428 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!

Ensuring data reliability and observability in risk systems

Post Syndicated from Grab Tech original https://engineering.grab.com/data-observability

Grab has an in-house Risk Management platform called GrabDefence which relies on ingesting large amounts of data gathered from upstream services to power our heuristic risk rules and data science models in real time.

Fig 1. GrabDefence aggregates data from different upstream services

As Grab’s business grows, so does the amount of data. It becomes imperative that the data which fuels our risk systems is of reliable quality as any data discrepancy or missing data could impact fraud detection and prevention capabilities.

We need to quickly detect any data anomalies, which is where data observability comes in.

Data observability as a solution

Data observability is a type of data operation (DataOps; similar to DevOps) where teams build visibility over the health and quality of their data pipelines. This enables teams to be notified of data quality issues, and allows teams to investigate and resolve these issues faster.

We needed a solution that addresses the following issues:

  1. Alerts for any data quality issues as soon as possible – so this means the observability tool had to work in real time.
  2. With hundreds of data points to observe, we needed a neat and scalable solution which allows users to quickly pinpoint which data points were having issues.
  3. A consistent way to compare, analyse, and compute data that might have different formats.

Hence, we decided to use Flink to standardise data transformations, compute, and observe data trends quickly (in real time) and scalably.

Flink SQL is a powerful, flexible tool for performing real-time analytics on streaming data. It allows users to query continuous data streams using standard SQL syntax, enabling complex event processing and data transformation within the Apache Flink ecosystem, which is particularly useful for scenarios requiring low-latency insights and decisions.

In Grab, data comes from multiple sources and while most of the data is in JSON format, the actual JSON structure differs between services. Because of JSON’s nested and dynamic data structure, it is difficult to consistently analyse the data – posing a significant challenge for real-time analysis.

To help address this issue, Apache Flink SQL has the capability to manage such intricacies with ease. It offers specialised functions tailored for parsing and querying JSON data, ensuring efficient processing.

Another standout feature of Flink SQL is the use of custom table functions, such as JSONEXPLOAD, which serves to deconstruct and flatten nested JSON structures into tabular rows. This transformation is crucial as it enables subsequent aggregation operations. By implementing a 5-minute tumbling window, Flink SQL can easily aggregate these now-flattened data streams. This technique is pivotal for monitoring, observing, and analysing data patterns and metrics in near real-time.

Now that data is aggregated by Flink for easy analysis, we still needed a way to incorporate comprehensive monitoring so that teams could be notified of any data anomalies or discrepancies in real time.

How we interfaced the output with Datadog 

Datadog is the observability tool of choice in Grab, with many teams using Datadog for their service reliability observations and alerts. By aggregating data from Apache Flink and integrating it with Datadog, we can harness the synergy of real-time analytics and comprehensive monitoring. Flink excels in processing and aggregating data streams, which, when pushed to Datadog, can be further analysed and visualised. Datadog also provides seamless integration with collaboration tools like Slack, which enables teams to receive instant notifications and alerts.

With Datadog’s out-of-the-box features such as anomaly detection, teams can identify and be alerted to unusual patterns or outliers in their data streams. Taking a proactive approach to monitoring is crucial in maintaining system health and performance as teams can be alerted, then collaborate quickly to diagnose and address anomalies.

This integrated pipeline—from Flink’s real-time data aggregation to Datadog’s monitoring and Slack’s communication capabilities—creates a robust framework for real-time data operations. It ensures that any potential issues are quickly traced and brought to the team’s attention, facilitating a rapid response. Such an ecosystem empowers organisations to maintain high levels of system reliability and performance, ultimately enhancing the overall user experience.

Organising monitors and alerts using out-of-the-box solutions from Datadog

Once we integrated Flink data into Datadog, we realised that it could become unwieldy to try to identify the data point with issues from hundreds of other counters.

Fig 2. Hundreds of data points on a graph make it hard to decipher which ones have issues

We decided to organise the counters according to the service stream it was coming from, and create individual monitors for each service stream. We used Datadog’s Monitor Summary tool to help visualise the total number of service streams we are reading from and the number of underlying data points within each stream.  

Fig 3. Data is grouped according to their source stream

Within each individual stream, we used Datadog’s Anomaly Detection feature to create an alert whenever a data point from the stream exceeds a predefined threshold. This can be configured by the service teams on Datadog.

Fig 4. Datadog’s built-in Anomaly Detection function triggers alerts whenever a data point exceeds a threshold

These alerts are then sent to a Slack channel where the Data team is informed when a data point of interest starts throwing anomalous values.

Fig 5. Datadog integration with Slack to help alert users

Impact

Since the deployment of this data observability tool, we have seen significant improvement in the detection of anomalous values. If there are any anomalies or issues, we now get alerts within the same day (or hour) instead of days to weeks later.

Organising the alerts according to source streams have also helped simplify the monitoring load and allows users to quickly narrow down and identify which pipeline has failed.

What’s next?

At the moment, this data observability tool is only implemented on selected checkpoints in GrabDefence. We plan to expand the observability tool’s coverage to include more checkpoints, and continue to refine the workflows to detect and resolve these data issues.

Join us

Grab is the leading superapp platform in Southeast Asia, providing everyday services that matter to consumers. More than just a ride-hailing and food delivery app, Grab offers a wide range of on-demand services in the region, including mobility, food, package and grocery delivery services, mobile payments, and financial services across 428 cities in eight countries.

Powered by technology and driven by heart, our mission is to drive Southeast Asia forward by creating economic empowerment for everyone. If this mission speaks to you, join our team today!