All posts by Julian Wood

Caching data and configuration settings with AWS Lambda extensions

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/caching-data-and-configuration-settings-with-aws-lambda-extensions/

This post is written by Hari Ohm Prasath Rajagopal, Senior Modernization Architect and Vamsi Vikash Ankam, Technical Account Manager

In this post, I show how to build a flexible in-memory AWS Lambda caching layer using Lambda extensions. Lambda functions use REST API calls to access the data and configuration from the cache. This can reduce latency and cost when consuming data from AWS services such as Amazon DynamoDB, AWS Systems Manager Parameter Store, and AWS Secrets Manager.

Applications making frequent API calls to retrieve static data can benefit from a caching layer. This can reduce the function’s latency, particularly for synchronous requests, as the data is retrieved from the cache instead of an external service. The cache can also reduce costs by reducing the number of calls to downstream services.

There are two types of cache to consider in this situation:

Lambda extensions are a new way for tools to integrate more easily into the Lambda execution environment and control and participate in Lambda’s lifecycle. They use the Extensions API, a new HTTP interface, to register for lifecycle events during function initialization, invocation, and shutdown.

They can also use environment variables to add options and tools to the runtime, or use wrapper scripts to customize the runtime startup behavior. The Lambda cache uses Lambda extensions to run as a separate process.

To learn more about how to use extensions with your functions, read “Introducing AWS Lambda extensions”.

Creating a cache using Lambda extensions

To set up the example, visit the GitHub repo, and follow the instructions in the README.md file.

The demo uses AWS Serverless Application Model (AWS SAM) to deploy the infrastructure. The walkthrough requires AWS SAM CLI (minimum version 0.48) and an AWS account.

To install the example:

  1. Create an AWS account if you do not already have one and login.
  2. Clone the repo to your local development machine:
  3. git clone https://github.com/aws-samples/aws-lambda-extensions
    cd aws-lambda-extensions/cache-extension-demo/
  4. If you are not running in a Linux environment, ensure that your build architecture matches the Lambda execution environment by compiling with GOOS=linux and GOARCH=amd64.
  5. GOOS=linux GOARCH=amd64
  6. Build the Go binary extension with the following command:
  7. go build -o bin/extensions/cache-extension-demo main.go
  8. Ensure that the extensions files are executable:
  9. chmod +x bin/extensions/cache-extension-demo
  10. Update the parameters region value in ../example-function/config.yaml with the Region where you are deploying the function.
  11. parameters:
      - region: us-west-2
  12. Build the function dependencies.
  13. cd SAM
    sam build
    AWS SAM build

    AWS SAM build

  14. Deploy the AWS resources specified in the template.yml file:
  15. sam deploy --guided
  16. During the prompts:
  17. Enter a stack name cache-extension-demo.
  18. Enter the same AWS Region specified previously.
  19. Accept the default DatabaseName. You can specify a custom database name, and also update the ../example-function/config.yaml and index.js files with the new database name.
  20. Enter MySecret as the Secrets Manager secret.
  21. Accept the defaults for the remaining questions.
  22. AWS SAM Deploy

    AWS SAM Deploy

    AWS SAM deploys:

    • A DynamoDB table.
    • The Lambda function ExtensionsCache-DatabaseEntry, which puts a sample item into the DynamoDB table.
    • An AWS Systems Manager Parameter Store parameter called CacheExtensions_Parameter1 with a value of MyParameter.
    • An AWS Secrets Manager secret called secret_info with a value of MySecret.
    • A Lambda layer called Cache_Extension_Layer.
    • A Lambda function using Nodejs.12 called ExtensionsCache-SampleFunction. This reads the cached values via the extension from either the DynamoDB table, Parameter Store, or Secrets Manager.
    • IAM permissions

    The cache extension is delivered as a Lambda layer and added to ExtensionsCache-SampleFunction.

    It is written as a self-contained binary in Golang, which makes the extension compatible with all of the supported runtimes. The extension caches the data from DynamoDB, Parameter Store, and Secrets Manager, and then runs a local HTTP endpoint to service the data. The Lambda function retrieves the configuration data from the cache using a local HTTP REST API call.

    Here is the architecture diagram.

    Extensions cache architecture diagram

    Extensions cache architecture diagram

    Once deployed, the extension performs the following steps:

    1. On start-up, the extension reads the config.yaml file, which determines which resources to cache. The file is deployed as part of the Lambda function.
    2. The boolean CACHE_EXTENSION_INIT_STARTUP Lambda environment variable specifies whether to load into cache the items specified in config.yaml. If false, the extension initializes an empty map with the names.
    3. The extension retrieves the required data based on the resources in the config.yaml file. This includes the data from DynamoDB, the configuration from Parameter Store, and the secret from Secrets Manager. The data is stored in memory.
    4. The extension starts a local HTTP server using TCP port 4000, which serves the cache items to the function. The Lambda function accesses the local in-memory cache by invoking the following endpoint: http://localhost:4000/<cachetype>?name=<name>.
    5. If the data is not available in the cache, or has expired, the extension accesses the corresponding AWS service to retrieve the data. It is cached first and then returned to the Lambda function. The CACHE_EXTENSION_TTL Lambda environment variable defines the refresh interval (defined based on Go time format, for example: 30s, 3m, etc.)

    This sequence diagram explains the data flow:

    Extensions cache sequence diagram

    Extensions cache sequence diagram

    Testing the example application

    Once the AWS SAM template is deployed, navigate to the AWS Lambda console.

    1. Select the function starting with the name ExtensionsCache-SampleFunction. Within the function code, the options array specifies which data to return from the cache. This is initially set to path: '/dynamodb?name=DynamoDbTable-pKey1-sKey1'
    2. Choose Configure test events to configure a test event.
    3. Enter a name for the Event name, accept the default payload, and select Create.
    4. Select Test to invoke the function. This returns the cached data from DynamoDB and logs the output.
    5. Successfully retrieve DynamoDB data from cache

      Successfully retrieve DynamoDB data from cache

    6. In the index.js file, amend the path statement to retrieve the Parameter Store configuration:
    7. const options = {
        "hostname": "localhost",
        "port": 4000,
        "path": "/parameters?name=CacheExtensions_Parameter1",
        "method": "GET"
      }
    8. Select Deploy to save the function configuration and select Test. The function returns the Parameter Store configuration item:
    9. Successfully retrieve Parameter Store data from cache

      Successfully retrieve Parameter Store data from cache

    10. In the function code, amend the path statement to retrieve the Secrets Manager secret:
    11. const options = {
        "hostname": "localhost",
        "port": 4000,
        "path": "/parameters?name=/aws/reference/secretsmanager/secret_info",
        "method": "GET"
      }
    12. Select Deploy to save the function configuration and select Test. The function returns the secret:
    Successfully retrieve Secrets Manager data from cache

    Successfully retrieve Secrets Manager data from cache

    The benefits of using Lambda extensions

    There are a number of benefits to using a Lambda extension for this solution:

    1. Improved Lambda function performance as data is cached in memory by the extension during initialization.
    2. Fewer AWS API calls to external services, this can reduce costs and helps avoid throttling limits if services are accessed frequently.
    3. Cache data is stored in memory and not in a file within the Lambda execution environment. This means that no additional process is required to manage the lifecycle of the file. In-memory is also more secure, as data is not persisted to disk for subsequent function invocations.
    4. The function requires less code, as it only needs to communicate with the extension via HTTP to retrieve the data. The function does not have to have additional libraries installed to communicate with DynamoDB, Parameter Store, Secrets Manager, or the local file system.
    5. The cache extension is a Golang compiled binary and the executable can be shared with functions running other runtimes like Node.js, Python, Java, etc.
    6. Using a YAML template to store the details of what to cache makes it easier to configure and add additional services.

    Comparing the performance benefit

    To test the performance of the cache extension, I compare two tests:

    1. A Golang Lambda function that accesses a secret from AWS Secrets Manager for every invocation.
    2. The ExtensionsCache-SampleFunction, previously deployed using AWS SAM. This uses the cache extension to access the secrets from Secrets Manager, the function reads the value from the cache.

    Both functions are configured with 512 MB of memory and the function timeout is set to 30 seconds.

    I use Artillery to load test both Lambda functions. The load runs for 100 invocations over 2 minutes. I use Amazon CloudWatch metrics to view the function average durations.

    Test 1 shows a duration of 43 ms for the first invocation as a cold start. Subsequent invocations average 22 ms.

    Test 1 performance results

    Test 1 performance results

    Test 2 shows a duration of 16 ms for the first invocation as a cold start. Subsequent invocations average 3 ms.

    Test 2 performance results

    Test 2 performance results

    Using the Lambda extensions caching layer shows a significant performance improvement. Cold start invocation duration is reduced by 62% and subsequent invocations by 80%.

    In this example, the CACHE_EXTENSION_INIT_STARTUP environment variable flag is not configured. With the flag enabled for the extension, data is pre-fetched during extension initialization and the cold start time is further reduced.

    Conclusion

    Using Lambda extensions is an effective way to cache static data from external services in Lambda functions. This reduces function latency and costs. This post shows how to build both a data and configuration cache using DynamoDB, Parameter Store, and Secrets Manager.

    To set up the walkthrough demo in this post, visit the GitHub repo, and follow the instructions in the README.md file.

    The extension uses a local configuration file to determine which values to cache, and retrieves the items from the external services. A Lambda function retrieves the values from the local cache using an HTTP request, without having to communicate with the external services directly. In this example, this results in an 80% reduction in function invocation time.

    For more serverless learning resources, visit https://serverlessland.com.

Working with Lambda layers and extensions in container images

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/working-with-lambda-layers-and-extensions-in-container-images/

In this post, I explain how to use AWS Lambda layers and extensions with Lambda functions packaged and deployed as container images.

Previously, Lambda functions were packaged only as .zip archives. This includes functions created in the AWS Management Console. You can now also package and deploy Lambda functions as container images.

You can use familiar container tooling such as the Docker CLI with a Dockerfile to build, test, and tag images locally. Lambda functions built using container images can be up to 10 GB in size. You push images to an Amazon Elastic Container Registry (ECR) repository, a managed AWS container image registry service. You create your Lambda function, specifying the source code as the ECR image URL from the registry.

Lambda container image support

Lambda container image support

Lambda functions packaged as container images do not support adding Lambda layers to the function configuration. However, there are a number of solutions to use the functionality of Lambda layers with container images. You take on the responsible for packaging your preferred runtimes and dependencies as a part of the container image during the build process.

Understanding how Lambda layers and extensions work as .zip archives

If you deploy function code using a .zip archive, you can use Lambda layers as a distribution mechanism for libraries, custom runtimes, and other function dependencies.

When you include one or more layers in a function, during initialization, the contents of each layer are extracted in order to the /opt directory in the function execution environment. Each runtime then looks for libraries in a different location under /opt, depending on the language. You can include up to five layers per function, which count towards the unzipped deployment package size limit of 250 MB. Layers are automatically set as private, but they can be shared with other AWS accounts, or shared publicly.

Lambda Extensions are a way to augment your Lambda functions and are deployed as Lambda layers. You can use Lambda Extensions to integrate functions with your preferred monitoring, observability, security, and governance tools. You can choose from a broad set of tools provided by AWS, AWS Lambda Ready Partners, and AWS Partners, or create your own Lambda Extensions. For more information, see “Introducing AWS Lambda Extensions – In preview.”

Extensions can run in either of two modes, internal and external. An external extension runs as an independent process in the execution environment. They can start before the runtime process, and can continue after the function invocation is fully processed. Internal extensions run as part of the runtime process, in-process with your code.

Lambda searches the /opt/extensions directory and starts initializing any extensions found. Extensions must be executable as binaries or scripts. As the function code directory is read-only, extensions cannot modify function code.

It helps to understand that Lambda layers and extensions are just files copied into specific file paths in the execution environment during the function initialization. The files are read-only in the execution environment.

Understanding container images with Lambda

A container image is a packaged template built from a Dockerfile. The image is assembled or built from commands in the Dockerfile, starting from a parent or base image, or from scratch. Each command then creates a new layer in the image, which is stacked in order on top of the previous layer. Once built from the packaged template, a container image is immutable and read-only.

For Lambda, a container image includes the base operating system, the runtime, any Lambda extensions, your application code, and its dependencies. Lambda provides a set of open-source base images that you can use to build your container image. Lambda uses the image to construct the execution environment during function initialization. You can use the AWS Serverless Application Model (AWS SAM) CLI or native container tools such as the Docker CLI to build and test container images locally.

Using Lambda layers in container images

Container layers are added to a container image, similar to how Lambda layers are added to a .zip archive function.

There are a number of ways to use container image layering to add the functionality of Lambda layers to your Lambda function container images.

Use a container image version of a Lambda layer

A Lambda layer publisher may have a container image format equivalent of a Lambda layer. To maintain the same file path as Lambda layers, the published container images must have the equivalent files located in the /opt directory. An image containing an extension must include the files in the /opt/extensions directory.

An example Lambda function, packaged as a .zip archive, is created with two layers. One layer contains shared libraries, and the other layer is a Lambda extension from an AWS Partner.

aws lambda create-function –region us-east-1 –function-name my-function \

aws lambda create-function --region us-east-1 --function-name my-function \  
    --role arn:aws:iam::123456789012:role/lambda-role \
    --layers \
        "arn:aws:lambda:us-east-1:123456789012:layer:shared-lib-layer:1" \
        "arn:aws:lambda:us-east-1:987654321987:extensions-layer:1" \
    …

The corresponding Dockerfile syntax for a function packaged as a container image includes the following lines. These pull the container image versions of the Lambda layers and copy them into the function image. The shared library image is pulled from ECR and the extension image is pulled from Docker Hub.

FROM public.ecr.aws/myrepo/shared-lib-layer:1 AS shared-lib-layer
# Layer code
WORKDIR /opt
COPY --from=shared-lib-layer /opt/ .

FROM aws-partner/extensions-layer:1 as extensions-layer
# Extension  code
WORKDIR /opt/extensions
COPY --from=extensions-layer /opt/extensions/ .

Copy the contents of a Lambda layer into a container image

You can use existing Lambda layers, and copy the contents of the layers into the function container image /opt directory during docker build.

You need to build a Dockerfile that includes the AWS Command Line Interface to copy the layer files from Amazon S3.

The Dockerfile to add two layers into a single image includes the following lines to copy the Lambda layer contents.

FROM alpine:latest

ARG AWS_DEFAULT_REGION=${AWS_DEFAULT_REGION:-"us-east-1"}
ARG AWS_ACCESS_KEY_ID=${AWS_ACCESS_KEY_ID:-""}
ARG AWS_SECRET_ACCESS_KEY=${AWS_SECRET_ACCESS_KEY:-""}
ENV AWS_DEFAULT_REGION=${AWS_DEFAULT_REGION}
ENV AWS_ACCESS_KEY_ID=${AWS_ACCESS_KEY_ID}
ENV AWS_SECRET_ACCESS_KEY=${AWS_SECRET_ACCESS_KEY}

RUN apk add aws-cli curl unzip

RUN mkdir -p /opt

RUN curl $(aws lambda get-layer-version-by-arn --arn arn:aws:lambda:us-east-1:1234567890123:layer:shared-lib-layer:1 --query 'Content.Location' --output text) --output layer.zip
RUN unzip layer.zip -d /opt
RUN rm layer.zip

RUN curl $(aws lambda get-layer-version-by-arn --arn arn:aws:lambda:us-east-1:987654321987:extensions-layer:1 --query 'Content.Location' --output text) --output layer.zip
RUN unzip layer.zip -d /opt
RUN rm layer.zip

To run the AWS CLI, specify your AWS_ACCESS_KEY, and AWS_SECRET_ACCESS_KEY, and include the required AWS_DEFAULT_REGION as command-line arguments.

docker build . -t layer-image1:latest \
--build-arg AWS_DEFAULT_REGION=us-east-1 \
--build-arg AWS_ACCESS_KEY_ID=AKIAIOSFODNN7EXAMPLE \
--build-arg AWS_SECRET_ACCESS_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY

This creates a container image containing the existing Lambda layer and extension files. This can be pushed to ECR and used in a function.

Build a container image from a Lambda layer

You can repackage and publish Lambda layer file content as container images. Creating separate container images for different layers allows you to add them to multiple functions, and share them in a similar way as Lambda layers.

You can create a separate container image containing the files from a single layer, or combine the files from multiple layers into a single image. If you create separate container images for layer files, you then add these images into your function image.

There are two ways to manage language code dependencies. You can pre-build the dependencies and copy the files into the container image, or build the dependencies during docker build.

In this example, I migrate an existing Python application. This comprises a Lambda function and extension, from a .zip archive to separate function and extension container images. The extension writes logs to S3.

You can choose how to store images in repositories. You can either push both images to the same ECR repository with different image tags, or push to different repositories. In this example, I use separate ECR repositories.

To set up the example, visit the GitHub repo and follow the instructions in the README.md file.

The existing example extension uses a makefile to install boto3 using pip install with a requirements.txt file. This is migrated to the docker build process. I must add a Python runtime to be able to run pip install as part of the build process. I use python:3.8-alpine as a minimal base image.

I create separate Dockerfiles for the function and extension. The extension Dockerfile contains the following lines.

FROM python:3.8-alpine AS installer
#Layer Code
COPY extensionssrc /opt/
COPY extensionssrc/requirements.txt /opt/
RUN pip install -r /opt/requirements.txt -t /opt/extensions/lib

FROM scratch AS base
WORKDIR /opt/extensions
COPY --from=installer /opt/extensions .

I build, tag, login, and push the extension container image to an existing ECR repository.

docker build -t log-extension-image:latest  .
docker tag log-extension-image:latest 123456789012.dkr.ecr.us-east-1.amazonaws.com/log-extension-image:latest
aws ecr get-login-password --region us-east-1 | docker login --username AWS --password-stdin 123456789012.dkr.ecr.us-east-1.amazonaws.com
docker push 123456789012.dkr.ecr.us-east-1.amazonaws.com/log-extension-image:latest

The function Dockerfile contains the following lines, which add the files from the previously created extension image to the function image. There is no need to run pip install for the function as it does not require any additional dependencies.

FROM 123456789012.dkr.ecr.us-east-1.amazonaws.com/log-extension-image:latest AS layer
FROM public.ecr.aws/lambda/python:3.8
# Layer code
WORKDIR /opt
COPY --from=layer /opt/ .
# Function code
WORKDIR /var/task
COPY app.py .
CMD ["app.lambda_handler"]

I build, tag, and push the function container image to a separate existing ECR repository. This creates an immutable image of the Lambda function.

docker build -t log-extension-function:latest  .
docker tag log-extension-function:latest 123456789012.dkr.ecr.us-east-1.amazonaws.com/log-extension-function:latest
docker push 123456789012.dkr.ecr.us-east-1.amazonaws.com/log-extension-function:latest

The function requires a unique S3 bucket to store the logs files, which I create in the S3 console. I create a Lambda function from the ECR repository image, and specify the bucket name as a Lambda environment variable.

aws lambda create-function --region us-east-1  --function-name log-extension-function \
--package-type Image --code ImageUri=123456789012.dkr.ecr.us-east-1.amazonaws.com/log-extension-function:latest \
--role "arn:aws:iam:: 123456789012:role/lambda-role" \
--environment  "Variables": {"S3_BUCKET_NAME": "s3-logs-extension-demo-logextensionsbucket-us-east-1"}

For subsequent extension code changes, I need to update both the extension and function images. If only the function code changes, I need to update the function image. I push the function image as the :latest image to ECR. I then update the function code deployment to use the updated :latest ECR image.

aws lambda update-function-code --function-name log-extension-function --image-uri 123456789012.dkr.ecr.us-east-1.amazonaws.com/log-extension-function:latest

Using custom runtimes with container images

With .zip archive functions, custom runtimes are added using Lambda layers. With container images, you no longer need to copy in Lambda layer code for custom runtimes.

You can build your own custom runtime images starting with AWS provided base images for custom runtimes. You can add your preferred runtime, dependencies, and code to these images. To communicate with Lambda, the image must implement the Lambda Runtime API. We provide Lambda runtime interface clients for all supported runtimes, or you can implement your own for additional runtimes.

Running extensions in container images

A Lambda extension running in a function packaged as a container image works in the same way as a .zip archive function. You build a function container image including the extension files, or adding an extension image layer. Lambda looks for any external extensions in the /opt/extensions directory and starts initializing them. Extensions must be executable as binaries or scripts.

Internal extensions modify the Lambda runtime startup behavior using language-specific environment variables, or wrapper scripts. For language-specific environment variables, you can set the following environment variables in your function configuration to augment the runtime command line.

  • JAVA_TOOL_OPTIONS (Java Corretto 8 and 11)
  • NODE_OPTIONS (Node.js 10 and 12)
  • DOTNET_STARTUP_HOOKS (.NET Core 3.1)

An example Lambda environment variable for JAVA_TOOL_OPTIONS:

-javaagent:"/opt/ExampleAgent-0.0.jar"

Wrapper scripts delegate the runtime start-up to a script. The script can inject and alter arguments, set environment variables, or capture metrics, errors, and other diagnostic information. The following runtimes support wrapper scripts: Node.js 10 and 12, Python 3.8, Ruby 2.7, Java 8 and 11, and .NET Core 3.1

You specify the script by setting the value of the AWS_LAMBDA_EXEC_WRAPPER environment variable as the file system path of an executable binary or script, for example:

/opt/wrapper_script

Conclusion

You can now package and deploy Lambda functions as container images in addition to .zip archives. Lambda functions packaged as container images do not directly support adding Lambda layers to the function configuration as .zip archives do.

In this post, I show a number of solutions to use the functionality of Lambda layers and extensions with container images, including example Dockerfiles.

I show how to migrate an existing Lambda function and extension from a .zip archive to separate function and extension container images. Follow the instructions in the README.md file in the GitHub repository.

For more serverless learning resources, visit https://serverlessland.com.

Using AWS Lambda extensions to send logs to custom destinations

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/using-aws-lambda-extensions-to-send-logs-to-custom-destinations/

You can now send logs from AWS Lambda functions directly to a destination of your choice using AWS Lambda Extensions. Lambda Extensions are a new way for monitoring, observability, security, and governance tools to easily integrate with AWS Lambda. For more information, see “Introducing AWS Lambda Extensions – In preview”.

To help you troubleshoot failures in Lambda functions, AWS Lambda automatically captures and streams logs to Amazon CloudWatch Logs. This stream contains the logs that your function code and extensions generate, in addition to logs the Lambda service generates as part of the function invocation.

Previously, to send logs to a custom destination, you typically configure and operate a CloudWatch Log Group subscription. A different Lambda function forwards logs to the destination of your choice.

Logging tools, running as Lambda extensions, can now receive log streams directly from within the Lambda execution environment, and send them to any destination. This makes it even easier for you to use your preferred extensions for diagnostics.

Today, you can use extensions to send logs to Coralogix, Datadog, Honeycomb, Lumigo, New Relic, and Sumo Logic.

Overview

To receive logs, extensions subscribe using the new Lambda Logs API.

Lambda Logs API

Lambda Logs API

The Lambda service then streams the logs directly to the extension. The extension can then process, filter, and route them to any preferred destination. Lambda still sends the logs to CloudWatch Logs.

You deploy extensions, including ones that use the Logs API, as Lambda layers, with the AWS Management Console and AWS Command Line Interface (AWS CLI). You can also use infrastructure as code tools such as AWS CloudFormation, the AWS Serverless Application Model (AWS SAM), Serverless Framework, and Terraform.

Logging extensions from AWS Lambda Ready Partners and AWS Partners available at launch

Today, you can use logging extensions with the following tools:

  • The Datadog extension now makes it easier than ever to collect your serverless application logs for visualization, analysis, and archival. Paired with Datadog’s AWS integration, end-to-end distributed tracing, and real-time enhanced AWS Lambda metrics, you can proactively detect and resolve serverless issues at any scale.
  • Lumigo provides monitoring and debugging for modern cloud applications. With the open source extension from Lumigo, you can send Lambda function logs directly to an S3 bucket, unlocking new post processing use cases.
  • New Relic enables you to efficiently monitor, troubleshoot, and optimize your Lambda functions. New Relic’s extension allows you send your Lambda service platform logs directly to New Relic’s unified observability platform, allowing you to quickly visualize data with minimal latency and cost.
  • Coralogix is a log analytics and cloud security platform that empowers thousands of companies to improve security and accelerate software delivery, allowing you to get deep insights without paying for the noise. Coralogix can now read Lambda function logs and metrics directly, without using Cloudwatch or S3, reducing the latency, and cost of observability.
  • Honeycomb is a powerful observability tool that helps you debug your entire production app stack. Honeycomb’s extension decreases the overhead, latency, and cost of sending events to the Honeycomb service, while increasing reliability.
  • The Sumo Logic extension enables you to get instant visibility into the health and performance of your mission-critical applications using AWS Lambda. With this extension and Sumo Logic’s continuous intelligence platform, you can now ensure that all your Lambda functions are running as expected, by analyzing function, platform, and extension logs to quickly identify and remediate errors and exceptions.

You can also build and use your own logging extensions to integrate your organization’s tooling.

Showing a logging extension to send logs directly to S3

This demo shows an example of using a simple logging extension to send logs to Amazon Simple Storage Service (S3).

To set up the example, visit the GitHub repo and follow the instructions in the README.md file.

The example extension runs a local HTTP endpoint listening for HTTP POST events. Lambda delivers log batches to this endpoint. The example creates an S3 bucket to store the logs. A Lambda function is configured with an environment variable to specify the S3 bucket name. Lambda streams the logs to the extension. The extension copies the logs to the S3 bucket.

Lambda environment variable specifying S3 bucket

Lambda environment variable specifying S3 bucket

The extension uses the Extensions API to register for INVOKE and SHUTDOWN events. The extension, using the Logs API, then subscribes to receive platform and function logs, but not extension logs.

As the example is an asynchronous system, logs for one invoke may be processed during the next invocation. Logs for the last invoke may be processed during the SHUTDOWN event.

Testing the function from the Lambda console, Lambda sends logs to CloudWatch Logs. The logs stream shows logs from the platform, function, and extension.

Lambda logs visible in CloudWatch Logs

Lambda logs visible in CloudWatch Logs

The logging extension also receives the log stream directly from Lambda, and copies the logs to S3.

Browsing to the S3 bucket, the log files are available.

S3 bucket containing copied logs

S3 bucket containing copied logs.

Downloading the file shows the log lines. The log contains the same platform and function logs, but not the extension logs, as specified during the subscription.

[{'time': '2020-11-12T14:55:06.560Z', 'type': 'platform.start', 'record': {'requestId': '49e64413-fd42-47ef-b130-6fd16f30148d', 'version': '$LATEST'}},
{'time': '2020-11-12T14:55:06.774Z', 'type': 'platform.logsSubscription', 'record': {'name': 'logs_api_http_extension.py', 'state': 'Subscribed', 'types': ['platform', 'function']}},
{'time': '2020-11-12T14:55:06.774Z', 'type': 'platform.extension', 'record': {'name': 'logs_api_http_extension.py', 'state': 'Ready', 'events': ['INVOKE', 'SHUTDOWN']}},
{'time': '2020-11-12T14:55:06.776Z', 'type': 'function', 'record': 'Function: Logging something which logging extension will send to S3\n'}, {'time': '2020-11-12T14:55:06.780Z', 'type': 'platform.end', 'record': {'requestId': '49e64413-fd42-47ef-b130-6fd16f30148d'}}, {'time': '2020-11-12T14:55:06.780Z', 'type': 'platform.report', 'record': {'requestId': '49e64413-fd42-47ef-b130-6fd16f30148d', 'metrics': {'durationMs': 4.96, 'billedDurationMs': 100, 'memorySizeMB': 128, 'maxMemoryUsedMB': 87, 'initDurationMs': 792.41}, 'tracing': {'type': 'X-Amzn-Trace-Id', 'value': 'Root=1-5fad4cc9-70259536495de84a2a6282cd;Parent=67286c49275ac0ad;Sampled=1'}}}]

Lambda has sent specific logs directly to the subscribed extension. The extension has then copied them directly to S3.

For more example log extensions, see the Github repository.

How do extensions receive logs?

Extensions start a local listener endpoint to receive the logs using one of the following protocols:

  1. TCP – Logs are delivered to a TCP port in Newline delimited JSON format (NDJSON).
  2. HTTP – Logs are delivered to a local HTTP endpoint through PUT or POST, as an array of records in JSON format. http://sandbox:${PORT}/${PATH}. The $PATH parameter is optional.

AWS recommends using an HTTP endpoint over TCP because HTTP tracks successful delivery of the log messages to the local endpoint that the extension sets up.

Once the endpoint is running, extensions use the Logs API to subscribe to any of three different logs streams:

  • Function logs that are generated by the Lambda function.
  • Lambda service platform logs (such as the START, END, and REPORT logs in CloudWatch Logs).
  • Extension logs that are generated by extension code.

The Lambda service then sends logs to endpoint subscribers inside of the execution environment only.

Even if an extension subscribes to one or more log streams, Lambda continues to send all logs to CloudWatch.

Performance considerations

Extensions share resources with the function, such as CPU, memory, disk storage, and environment variables. They also share permissions, using the same AWS Identity and Access Management (IAM) role as the function.

Log subscriptions consume memory resources as each subscription opens a new memory buffer to store the logs. This memory usage counts towards memory consumed within the Lambda execution environment.

For more information on resources, security and performance with extensions, see “Introducing AWS Lambda Extensions – In preview”.

What happens if Lambda cannot deliver logs to an extension?

The Lambda service stores logs before sending to CloudWatch Logs and any subscribed extensions. If Lambda cannot deliver logs to the extension, it automatically retries with backoff. If the log subscriber crashes, Lambda restarts the execution environment. The logs extension re-subscribes, and continues to receive logs.

When using an HTTP endpoint, Lambda continues to deliver logs from the last acknowledged delivery. With TCP, the extension may lose logs if an extension or the execution environment fails.

The Lambda service buffers logs in memory before delivery. The buffer size is proportional to the buffering configuration used in the subscription request. If an extension cannot process the incoming logs quickly enough, the buffer fills up. To reduce the likelihood of an out of memory event due to a slow extension, the Lambda service drops records and adds a platform.logsDropped log record to the affected extension to indicate the number of dropped records.

Disabling logging to CloudWatch Logs

Lambda continues to send logs to CloudWatch Logs even if extensions subscribe to the logs stream.

To disable logging to CloudWatch Logs for a particular function, you can amend the Lambda execution role to remove access to CloudWatch Logs.

{
"Version": "2012-10-17",
"Statement": [
    {
        "Effect": "Deny",
        "Action": [
            "logs:CreateLogGroup",
            "logs:CreateLogStream",
            "logs:PutLogEvents"
        ],
        "Resource": [
            "arn:aws:logs:*:*:*"
        ]
    }
  ]
}

Logs are no longer delivered to CloudWatch Logs for functions using this role, but are still streamed to subscribed extensions. You are no longer billed for CloudWatch logging for these functions.

Pricing

Logging extensions, like other extensions, share the same billing model as Lambda functions. When using Lambda functions with extensions, you pay for requests served and the combined compute time used to run your code and all extensions, in 100 ms increments. To learn more about the billing for extensions, visit the Lambda FAQs page.

Conclusion

Lambda extensions enable you to extend the Lambda service to more easily integrate with your favorite tools for monitoring, observability, security, and governance.

Extensions can now subscribe to receive log streams directly from the Lambda service, in addition to CloudWatch Logs. Today, you can install a number of available logging extensions from AWS Lambda Ready Partners and AWS Partners. Extensions make it easier to use your existing tools with your serverless applications.

To try the S3 demo logging extension, follow the instructions in the README.md file in the GitHub repository.

Extensions are now available in preview in all commercial regions other than the China regions.

For more serverless learning resources, visit https://serverlessland.com.

Building Extensions for AWS Lambda – In preview

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/building-extensions-for-aws-lambda-in-preview/

AWS Lambda is announcing a preview of Lambda Extensions, a new way to easily integrate Lambda with your favorite monitoring, observability, security, and governance tools. Extensions enable tools to integrate deeply into the Lambda execution environment to control and participate in Lambda’s lifecycle. This simplified experience makes it easier for you to use your preferred tools across your application portfolio today.

In this post I explain how Lambda extensions work, the changes to the Lambda lifecycle, and how to build an extension. To learn how to use extensions with your functions, see the companion blog post “Introducing AWS Lambda extensions”.

Extensions are built using the new Lambda Extensions API, which provides a way for tools to get greater control during function initialization, invocation, and shut down. This API builds on the existing Lambda Runtime API, which enables you to bring custom runtimes to Lambda.

You can use extensions from AWS, AWS Lambda Ready Partners, and open source projects for use-cases such as application performance monitoring, secrets management, configuration management, and vulnerability detection. You can also build your own extensions to integrate your own tooling using the Extensions API.

There are extensions available today for AppDynamics, Check Point, Datadog, Dynatrace, Epsagon, HashiCorp, Lumigo, New Relic, Thundra, Splunk, AWS AppConfig, and Amazon CloudWatch Lambda Insights. For more details on these, see “Introducing AWS Lambda extensions”.

The Lambda execution environment

Lambda functions run in a sandboxed environment called an execution environment. This isolates them from other functions and provides the resources, such as memory, specified in the function configuration.

Lambda automatically manages the lifecycle of compute resources so that you pay for value. Between function invocations, the Lambda service freezes the execution environment. It is thawed if the Lambda service needs the execution environment for subsequent invocations.

Previously, only the runtime process could influence the lifecycle of the execution environment. It would communicate with the Runtime API, which provides an HTTP API endpoint within the execution environment to communicate with the Lambda service.

Lambda and Runtime API

Lambda and Runtime API

The runtime uses the API to request invocation events from Lambda and deliver them to the function code. It then informs the Lambda service when it has completed processing an event. The Lambda service then freezes the execution environment.

The runtime process previously exposed two distinct phases in the lifecycle of the Lambda execution environment: Init and Invoke.

1. Init: During the Init phase, the Lambda service initializes the runtime, and then runs the function initialization code (the code outside the main handler). The Init phase happens either during the first invocation, or in advance if Provisioned Concurrency is enabled.

2. Invoke: During the invoke phase, the runtime requests an invocation event from the Lambda service via the Runtime API, and invokes the function handler. It then returns the function response to the Runtime API.

After the function runs, the Lambda service freezes the execution environment and maintains it for some time in anticipation of another function invocation.

If the Lambda function does not receive any invokes for a period of time, the Lambda service shuts down and removes the environment.

Previous Lambda lifecycle

Previous Lambda lifecycle

With the addition of the Extensions API, extensions can now influence, control, and participate in the lifecycle of the execution environment. They can use the Extensions API to influence when the Lambda service freezes the execution environment.

AWS Lambda execution environment with the Extensions API

AWS Lambda execution environment with the Extensions API

Extensions are initialized before the runtime and the function. They then continue to run in parallel with the function, get greater control during function invocation, and can run logic during shut down.

Extensions allow integrations with the Lambda service by introducing the following changes to the Lambda lifecycle:

  1. An updated Init phase. There are now three discrete Init tasks: extensions Init, runtime Init, and function Init. This creates an order where extensions and the runtime can perform setup tasks before the function code runs.
  2. Greater control during invocation. During the invoke phase, as before, the runtime requests the invocation event and invokes the function handler. In addition, extensions can now request lifecycle events from the Lambda service. They can run logic in response to these lifecycle events, and respond to the Lambda service when they are done. The Lambda service freezes the execution environment when it hears back from the runtime and all extensions. In this way, extensions can influence the freeze/thaw behavior.
  3. Shutdown phase: we are now exposing the shutdown phase to let extensions stop cleanly when the execution environment shuts down. The Lambda service sends a shut down event, which tells the runtime and extensions that the environment is about to be shut down.
New Lambda lifecycle with extensions

New Lambda lifecycle with extensions

Each Lambda lifecycle phase starts with an event from the Lambda service to the runtime and all registered extensions. The runtime and extensions signal that they have completed by requesting the Next invocation event from the Runtime and Extensions APIs. Lambda freezes the execution environment and all extensions when there are no pending events.

Lambda lifecycle for execution environment, runtime, extensions, and function.png

Lambda lifecycle for execution environment, runtime, extensions, and function.png

For more information on the lifecycle phases and the Extensions API, see the documentation.

How are extensions delivered and run?

You deploy extensions as Lambda layers, which are ZIP archives containing shared libraries or other dependencies.

To add a layer, use the AWS Management Console, AWS Command Line Interface (AWS CLI), or infrastructure as code tools such as AWS CloudFormation, the AWS Serverless Application Model (AWS SAM), and Terraform.

When the Lambda service starts the function execution environment, it extracts the extension files from the Lambda layer into the /opt directory. Lambda then looks for any extensions in the /opt/extensions directory and starts initializing them. Extensions need to be executable as binaries or scripts. As the function code directory is read-only, extensions cannot modify function code.

Extensions can run in either of two modes, internal and external.

  • Internal extensions run as part of the runtime process, in-process with your code. They are not separate processes. Internal extensions allow you to modify the startup of the runtime process using language-specific environment variables and wrapper scripts. You can use language-specific environment variables to add options and tools to the runtime for Java Correto 8 and 11, Node.js 10 and 12, and .NET Core 3.1. Wrapper scripts allow you to delegate the runtime startup to your script to customize the runtime startup behavior. You can use wrapper scripts with Node.js 10 and 12, Python 3.8, Ruby 2.7, Java 8 and 11, and .NET Core 3.1. For more information, see “Modifying-the-runtime-environment”.
  • External extensions allow you to run separate processes from the runtime but still within the same execution environment as the Lambda function. External extensions can start before the runtime process, and can continue after the runtime shuts down. External extensions work with Node.js 10 and 12, Python 3.7 and 3.8, Ruby 2.5 and 2.7, Java Corretto 8 and 11, .NET Core 3.1, and custom runtimes.

External extensions can be written in a different language to the function. We recommend implementing external extensions using a compiled language as a self-contained binary. This makes the extension compatible with all of the supported runtimes. If you use a non-compiled language, ensure that you include a compatible runtime in the extension.

Extensions run in the same execution environment as the function, so share resources such as CPU, memory, and disk storage with the function. They also share environment variables, in addition to permissions, using the same AWS Identity and Access Management (IAM) role as the function.

For more details on resources, security, and performance with extensions, see the companion blog post “Introducing AWS Lambda extensions”.

For example extensions and wrapper scripts to help you build your own extensions, see the GitHub repository.

Showing extensions in action

The demo shows how external extensions integrate deeply with functions and the Lambda runtime. The demo creates an example Lambda function with a single extension using either the AWS CLI, or AWS SAM.

The example shows how an external extension can start before the runtime, run during the Lambda function invocation, and shut down after the runtime shuts down.

To set up the example, visit the GitHub repo, and follow the instructions in the README.md file.

The example Lambda function uses the custom provided.al2 runtime based on Amazon Linux 2. Using the custom runtime helps illustrate in more detail how the Lambda service, Runtime API, and the function communicate. The extension is delivered using a Lambda layer.

The runtime, function, and extension, log their status events to Amazon CloudWatch Logs. The extension initializes as a separate process and waits to receive the function invocation event from the Extensions API. It then sleeps for 5 seconds before calling the API again to register to receive the next event. The extension sleep simulates the processing of a parallel process. This could, for example, collect telemetry data to send to an external observability service.

When the Lambda function is invoked, the extension, runtime and function perform the following steps. I walk through the steps using the log output.

1. The Lambda service adds the configured extension Lambda layer. It then searches the /opt/extensions folder, and finds an extension called extension1.sh. The extension executable launches before the runtime initializes. It registers with the Extensions API to receive INVOKE and SHUTDOWN events using the following API call.

curl -sS -LD "$HEADERS" -XPOST "http://${AWS_LAMBDA_RUNTIME_API}/2020-01-01/extension/register" --header "Lambda-Extension-Name: ${LAMBDA_EXTENSION_NAME}" -d "{ \"events\": [\"INVOKE\", \"SHUTDOWN\"]}" > $TMPFILE
Extension discovery, registration, and start

Extension discovery, registration, and start

2. The Lambda custom provided.al2 runtime initializes from the bootstrap file.

Runtime initialization

Runtime initialization

3. The runtime calls the Runtime API to get the next event using the following API call. The HTTP request is blocked until the event is received.

curl -sS -LD "$HEADERS" -X GET "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/next" > $TMPFILE &

The extension calls the Extensions API and waits for the next event. The HTTP request is again blocked until one is received.

curl -sS -L -XGET "http://${AWS_LAMBDA_RUNTIME_API}/2020-01-01/extension/event/next" --header "Lambda-Extension-Identifier: ${EXTENSION_ID}" > $TMPFILE &
Runtime and extension call APIs to get the next event

Runtime and extension call APIs to get the next event

4. The Lambda service receives an invocation event. It sends the event payload to the runtime using the Runtime API. It sends an event to the extension informing it about the invocation, using the Extensions API.

Runtime and extension receive event

Runtime and extension receive event

5. The runtime invokes the function handler. The function receives the event payload.

Runtime invokes handler

Runtime invokes handler

6. The function runs the handler code. The Lambda runtime receives back the function response and sends it back to the Runtime API with the following API call.

curl -sS -X POST "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/$REQUEST_ID/response" -d "$RESPONSE" > $TMPFILE
Runtime receives function response and sends to Runtime API

Runtime receives function response and sends to Runtime API

7. The Lambda runtime then waits for the next invocation event (warm start).

Runtime waits for next event

Runtime waits for next event

8. The extension continues processing for 5 seconds, simulating the processing of a companion process. The extension finishes, and uses the Extensions API to register again to wait for the next event.

Extension processing

Extension processing

9. The function invocation report is logged.

Function invocation report

Function invocation report

10. When Lambda is about to shut down the execution environment, it sends the Runtime API a shut down event.

Lambda runtime shut down event

Lambda runtime shut down event

11. Lambda then sends a shut down event to the extensions. The extension finishes processing and then shuts down after the runtime.

Lambda extension shut down event

Lambda extension shut down event

The demo shows the steps the runtime, function, and extensions take during the Lambda lifecycle.

An external extension registers and starts before the runtime. When Lambda receives an invocation event, it sends it to the runtime. It then sends an event to the extension informing it about the invocation. The runtime invokes the function handler, and the extension does its own processing of the event. The extension continues processing after the function invocation completes. When Lambda is about to shut down the execution environment, it sends a shut down event to the runtime. It then sends one to the extension, so it can finish processing.

To see a sequence diagram of this flow, see the Extensions API documentation.

Pricing

Extensions share the same billing model as Lambda functions. When using Lambda functions with extensions, you pay for requests served and the combined compute time used to run your code and all extensions, in 100 ms increments. To learn more about the billing for extensions, visit the Lambda FAQs page.

Conclusion

Lambda extensions enable you to extend Lambda’s execution environment to more easily integrate with your favorite tools for monitoring, observability, security, and governance.

Extensions can run additional code; before, during, and after a function invocation. There are extensions available today from AWS Lambda Ready Partners. These cover use-cases such as application performance monitoring, secrets management, configuration management, and vulnerability detection. Extensions make it easier to use your existing tools with your serverless applications. For more information on the available extensions, see the companion post “Introducing Lambda Extensions – In preview“.

You can also build your own extensions to integrate your own tooling using the new Extensions API. For example extensions and wrapper scripts, see the GitHub repository.

Extensions are now available in preview in the following Regions: us-east-1, us-east-2, us-west-1, us-west-2, ca-central-1, eu-west-1, eu-west-2, eu-west-3, eu-central-1, eu-north-1, eu-south-1, sa-east-1, me-south-1, ap-northeast-1, ap-northeast-2, ap-northeast-3, ap-southeast-1, ap-southeast-2, ap-south-1, and ap-east-1.

For more serverless learning resources, visit https://serverlessland.com.

Introducing AWS Lambda Extensions – In preview

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/introducing-aws-lambda-extensions-in-preview/

AWS Lambda is announcing a preview of Lambda Extensions, a new way to easily integrate Lambda with your favorite monitoring, observability, security, and governance tools. In this post I explain how Lambda extensions work, how you can begin using them, and the extensions from AWS Lambda Ready Partners that are available today.

Extensions help solve a common request from customers to make it easier to integrate their existing tools with Lambda. Previously, customers told us that integrating Lambda with their preferred tools required additional operational and configuration tasks. In addition, tools such as log agents, which are long-running processes, could not easily run on Lambda.

Extensions are a new way for tools to integrate deeply into the Lambda environment. There is no complex installation or configuration, and this simplified experience makes it easier for you to use your preferred tools across your application portfolio today. You can use extensions for use-cases such as:

  • capturing diagnostic information before, during, and after function invocation
  • automatically instrumenting your code without needing code changes
  • fetching configuration settings or secrets before the function invocation
  • detecting and alerting on function activity through hardened security agents, which can run as separate processes from the function

You can use extensions from AWS, AWS Lambda Ready Partners, and open source projects. There are extensions available today for AppDynamics, Check Point, Datadog, Dynatrace, Epsagon, HashiCorp, Lumigo, New Relic, Thundra, Splunk SignalFX, AWS AppConfig, and Amazon CloudWatch Lambda Insights.

You can learn how to build your own extensions, in the companion post “Building Extensions for AWS Lambda – In preview“.

Overview

Lambda Extensions is designed to be the easiest way to plug in the tools you use today without complex installation or configuration management. You deploy extensions as Lambda layers, with the AWS Management Console and AWS Command Line Interface (AWS CLI). You can also use infrastructure as code tools such as AWS CloudFormation, the AWS Serverless Application Model (AWS SAM), Serverless Framework, and Terraform. You can use Stackery to automate the integration of extensions from Epsagon, New Relic, Lumigo, and Thundra.

There are two components to the Lambda Extensions capability: the Extensions API and extensions themselves. Extensions are built using the new Lambda Extensions API which provides a way for tools to get greater control during function initialization, invocation, and shut down. This API builds on the existing Lambda Runtime API, which enables you to bring custom runtimes to Lambda.

AWS Lambda execution environment with the Extensions API

AWS Lambda execution environment with the Extensions API

Most customers will use extensions without needing to know about the capabilities of the Extensions API that enables them. You can just consume capabilities of an extension by configuring the options in your Lambda functions. Developers who build extensions use the Extensions API to register for function and execution environment lifecycle events.

Extensions can run in either of two modes – internal and external.

  • Internal extensions run as part of the runtime process, in-process with your code. They allow you to modify the startup of the runtime process using language-specific environment variables and wrapper scripts. Internal extensions enable use cases such as automatically instrumenting code.
  • External extensions allow you to run separate processes from the runtime but still within the same execution environment as the Lambda function. External extensions can start before the runtime process, and can continue after the runtime shuts down. External extensions enable use cases such as fetching secrets before the invocation, or sending telemetry to a custom destination outside of the function invocation. These extensions run as companion processes to Lambda functions.

For more information on the Extensions API and the changes to the Lambda lifecycle, see “Building Extensions for AWS Lambda – In preview

AWS Lambda Ready Partners extensions available at launch

Today, you can use extensions with the following AWS and AWS Lambda Ready Partner’s tools, and there are more to come:

  • AppDynamics provides end-to-end transaction tracing for AWS Lambda. With the AppDynamics extension, it is no longer mandatory for developers to include the AppDynamics tracer as a dependency in their function code, making tracing transactions across hybrid architectures even simpler.
  • The Datadog extension brings comprehensive, real-time visibility to your serverless applications. Combined with Datadog’s existing AWS integration, you get metrics, traces, and logs to help you monitor, detect, and resolve issues at any scale. The Datadog extension makes it easier than ever to get telemetry from your serverless workloads.
  • The Dynatrace extension makes it even easier to bring AWS Lambda metrics and traces into the Dynatrace platform for intelligent observability and automatic root cause detection. Get comprehensive, end-to-end observability with the flip of a switch and no code changes.
  • Epsagon helps you monitor, troubleshoot, and lower the cost for your Lambda functions. Epsagon’s extension reduces the overhead of sending traces to the Epsagon service, with minimal performance impact to your function.
  • HashiCorp Vault allows you to secure, store, and tightly control access to your application’s secrets and sensitive data. With the Vault extension, you can now authenticate and securely retrieve dynamic secrets before your Lambda function invokes.
  • Lumigo provides a monitoring and observability platform for serverless and microservices applications. The Lumigo extension enables the new Lumigo Lambda Profiler to see a breakdown of function resources, including CPU, memory, and network metrics. Receive actionable insights to reduce Lambda runtime duration and cost, fix bottlenecks, and increase efficiency.
  • Check Point CloudGuard provides full lifecycle security for serverless applications. The CloudGuard extension enables Function Self Protection data aggregation as an out-of-process extension, providing detection and alerting on application layer attacks.
  • New Relic provides a unified observability experience for your entire software stack. The New Relic extension uses a simpler companion process to report function telemetry data. This also requires fewer AWS permissions to add New Relic to your application.
  • Thundra provides an application debugging, observability and security platform for serverless, container and virtual machine (VM) workloads. The Thundra extension adds asynchronous telemetry reporting functionality to the Thundra agents, getting rid of network latency.
  • Splunk offers an enterprise-grade cloud monitoring solution for real-time full-stack visibility at scale. The Splunk extension provides a simplified runtime-independent interface to collect high-resolution observability data with minimal overhead. Monitor, manage, and optimize the performance and cost of your serverless applications with Splunk Observability solutions.
  • AWS AppConfig helps you manage, store, and safely deploy application configurations to your hosts at runtime. The AWS AppConfig extension integrates Lambda and AWS AppConfig seamlessly. Lambda functions have simple access to external configuration settings quickly and easily. Developers can now dynamically change their Lambda function’s configuration safely using robust validation features.
  • Amazon CloudWatch Lambda Insights enables you to efficiently monitor, troubleshoot, and optimize Lambda functions. The Lambda Insights extension simplifies the collection, visualization, and investigation of detailed compute performance metrics, errors, and logs. You can more easily isolate and correlate performance problems to optimize your Lambda environments.

You can also build and use your own extensions to integrate your organization’s tooling. For instance, the Cloud Foundations team at Square has built their own extension. They say:

The Cloud Foundations team at Square works to make the cloud accessible and secure. We partnered with the Security Infrastructure team, who builds infrastructure to secure Square’s sensitive data, to enable serverless applications at Square,​ and ​provide mTLS identities to Lambda​.

Since beginning work on Lambda, we have focused on creating a streamlined developer experience. Teams adopting Lambda need to learn a lot about AWS, and we see extensions as a way to abstract away common use cases. For our initial exploration, we wanted to make accessing secrets easy, as with our current tools each Lambda function usually pulls 3-5 secrets.

The extension we built and open source fetches secrets on cold starts, before the Lambda function is invoked. Each function includes a configuration file that specifies which secrets to pull. We knew this configuration was key, as Lambda functions should only be doing work they need to do. The secrets are cached in the local /tmp directory, which the function reads when it needs the secret data. This makes Lambda functions not only faster, but reduces the amount of code for accessing secrets.

Showing extensions in action with AWS AppConfig

This demo shows an example of using the AWS AppConfig with a Lambda function. AWS AppConfig is a capability of AWS Systems Manager to create, manage, and quickly deploy application configurations. It lets you dynamically deploy external configuration without having to redeploy your applications. As AWS AppConfig has robust validation features, all configuration changes can be tested safely before rolling out to your applications.

AWS AppConfig has an available extension which gives Lambda functions access to external configuration settings quickly and easily. The extension runs a separate local process to retrieve and cache configuration data from the AWS AppConfig service. The function code can then fetch configuration data faster using a local call rather than over the network.

To set up the example, visit the GitHub repo and follow the instructions in the README.md file.

The example creates an AWS AppConfig application, environment, and configuration profile. It stores a loglevel value, initially set to normal.

AWS AppConfig application, environment, and configuration profile

AWS AppConfig application, environment, and configuration profile

An AWS AppConfig deployment runs to roll out the initial configuration.

AWS AppConfig deployment

AWS AppConfig deployment

The example contains two Lambda functions that include the AWS AppConfig extension. For a list of the layers that have the AppConfig extension, see the blog post “AWS AppConfig Lambda Extension”.

As extensions share the same permissions as Lambda functions, the functions have execution roles that allow access to retrieve the AWS AppConfig configuration.

Lambda function add layer

Lambda function add layer

The functions use the extension to retrieve the loglevel value from AWS AppConfig, returning the value as a response. In a production application, this value could be used within function code to determine what level of information to send to CloudWatch Logs. For example, to troubleshoot an application issue, you can change the loglevel value centrally. Subsequent function invocations for both functions use the updated value.

Both Lambda functions are configured with an environment variable that specifies which AWS AppConfig configuration profile and value to use.

Lambda environment variable specifying AWS AppConfig profile

Lambda environment variable specifying AWS AppConfig profile

The functions also return whether the invocation is a cold start.

Running the functions with a test payload returns the loglevel value normal. The first invocation is a cold start.

{
  "event": {
    "hello": "world"
  },
  "ColdStart": true,
  "LogLevel": "normal"
}

Subsequent invocations return the same value with ColdStart set to false.

{
  "event": {
    "hello": "world"
  },
  "ColdStart": false,
  "LogLevel": "normal"
}

Create a new AWS Config hosted configuration profile version setting the loglevel value to verbose. Run a new AWS AppConfig deployment to update the value. The extension for both functions retrieves the new value. The function configuration itself is not changed.

Running another test invocation for both functions returns the updated value still without a cold start.

{
  "event": {
    "hello": "world"
  },
  "ColdStart": false,
  "LogLevel": "verbose"
}

AWS AppConfig has worked seamlessly with Lambda to update a dynamic external configuration setting for multiple Lambda functions without having to redeploy the function configuration.

The only function configuration required is to add the layer which contains the AWS AppConfig extension.

Pricing

Extensions share the same billing model as Lambda functions. When using Lambda functions with extensions, you pay for requests served and the combined compute time used to run your code and all extensions, in 100 ms increments. To learn more about the billing for extensions, visit the Lambda FAQs page.

Resources, security, and performance with extensions

Extensions run in the same execution environment as the function code. Therefore, they share resources with the function, such as CPU, memory, disk storage, and environment variables. They also share permissions, using the same AWS Identity and Access Management (IAM) role as the function.

You can configure up to 10 extensions per function, using up to five layers at a time. Multiple extensions can be included in a single layer.

The size of the extensions counts towards the deployment package limit. This cannot exceed the unzipped deployment package size limit of 250 MB.

External extensions are initialized before the runtime is started so can increase the delay before the function is invoked. Today, the function invocation response is returned after all extensions have completed. An extension that takes time to complete can increase the delay before the function response is returned. If an extension performs compute-intensive operations, function execution duration may increase. To measure the additional time the extension runs after the function invocation, use the new PostRuntimeExtensionsDuration CloudWatch metric to measure the extra time the extension takes after the function execution. To understand the impact of a specific extension, you can use the Duration and MaxMemoryUsed CloudWatch metrics, and run different versions of your function with and without the extension. Adding more memory to a function also proportionally increases CPU and network throughput.

The function and all extensions must complete within the function’s configured timeout setting which applies to the entire invoke phase.

Conclusion

Lambda extensions enable you to extend the Lambda service to more easily integrate with your favorite tools for monitoring, observability, security, and governance.

Today, you can install a number of available extensions from AWS Lambda Ready Partners. These cover use-cases such as application performance monitoring, secrets management, configuration management, and vulnerability detection. Extensions make it easier to use your existing tools with your serverless applications.

You can also build extensions to integrate your own tooling using the new Extensions API. For more information, see the companion post “Building Extensions for AWS Lambda – In preview“.

Extensions are now available in preview in the following Regions: us-east-1, us-east-2, us-west-1, us-west-2, ca-central-1, eu-west-1, eu-west-2, eu-west-3, eu-central-1, eu-north-1, eu-south-1, sa-east-1, me-south-1, ap-northeast-1, ap-northeast-2, ap-northeast-3, ap-southeast-1, ap-southeast-2, ap-south-1, and ap-east-1.

For more serverless learning resources, visit https://serverlessland.com.

Introducing IAM and Lambda authorizers for Amazon API Gateway HTTP APIs

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/introducing-iam-and-lambda-authorizers-for-amazon-api-gateway-http-apis/

Amazon API Gateway HTTP APIs enable you to create RESTful APIs with lower latency and lower cost than API Gateway REST APIs.

The API Gateway team is continuing work to improve and migrate popular REST API features to HTTP APIs. We are adding two of the most requested features, AWS Identity and Access Management (IAM) authorizers and AWS Lambda authorizers.

HTTP APIs already support JWT authorizers as a part of OpenID Connect (OIDC) and OAuth 2.0 frameworks. For more information, see “Simple HTTP API with JWT Authorizer.”

IAM authorization

AWS IAM roles and policies offer flexible, robust, and fully managed access controls, without writing any code. You can use IAM roles and policies to control who can create and manage your APIs, in addition to who can invoke them. IAM authorization for HTTP API routes is the best choice for internal or private APIs called by other AWS services like AWS Lambda.

IAM authorization for HTTP API APIs is similar to that for REST APIs. IAM access is determined by identity policies, which are attached to IAM users, groups, or roles. These policies define what identity can access which HTTP APIs routes. See “AWS Services That Work with IAM.”

Lambda authorization

A Lambda authorizer is a Lambda function which API Gateway calls for an authorization check when a client makes a request to an HTTP API route. You can use Lambda authorizers to implement custom authorization schemes to comply with your security requirements.

New authorizer features

HTTP API Lambda authorizers have some new features compared to REST APIs. There is a new payload and response format, including a simple Boolean authorization option.

New payload versions and response format

Lambda authorizers for HTTP APIs introduce a new payload format, version 2.0. If you need compatibility to use the same Lambda authorizers for both REST and HTTP APIs, you can continue to use version 1.0.

The payload format version also determines the request format and response structure that you must send to and return from your Lambda authorizer function. The version 2.0 payload context now allows non-string values. With version 1.0, your Lambda authorizer must return an IAM policy that allows or denies access to your API route. This is the same existing functionality as REST APIs. You can use standard IAM policy syntax in the policy. For examples of IAM policies, see “Control access for invoking an API.”

If you choose the new 2.0 format version when configuring the authorizer, you can now return either a Boolean value, or an IAM policy. The Boolean value enables simple responses from the authorizer without having to construct an IAM policy, and is in the format:

{
  "isAuthorized": true/false,
  "context": {
    "exampleKey": "exampleValue"
  }
}

The context object is optional. You can pass context properties on to Lambda integrations or access logs by using $context.authorizer.property. To learn more, see “Customizing HTTP API access logs.”

Caching authorizer responses

You can enable caching for a Lambda authorizer for up to one hour. To enable caching, your authorizer must have at least one identity source. API Gateway calls the Lambda authorizer function only when all of the specified identity sources are present. API Gateway uses the identity sources as the cache key. If a client specifies the same identity source parameters within the cache TTL, API Gateway uses the cached authorizer result. The Lambda authorizer function is not invoked.

Caching is enabled at the API Gateway level per authorizer. It is important to understand the effect of caching, particularly with simple responses and multiple routes. When using a simple response, the authorizer fully allows or denies all API requests that match the cached identity source values.

For example, you have two different routes using the same Lambda authorizer with a simple response. Both routes have different access requirements. The first route allows access to GET /list-users with an Authorization header with the value SecretTokenUsers. The second route denies access using the same header to GET /list-admins.

The Lambda authorizer has a single identity source, $request.header.Authorization, with the following code:

$request.header.Authorization.
exports.handler = async(event, context) => {
    let response = {
        "isAuthorized": false,
        "context": {
            "AuthInfo": "defaultdeny"
        }
    };
    if ((event.routeKey === "GET /list-users") && (event.headers.Authorization === "SecretTokenUsers")) {
        response = {
            "isAuthorized": true,
            "context": {
                "AuthInfo": "true-users"
            }
        };
    }
    if ((event.routeKey === "GET /list-admins") && (event.headers.authorization === "SecretTokenUsers")) {
        response = {
            "isAuthorized": false,
            "context": {
                "AuthInfo": "false-admins",
            }
        };
    }
    return response;
};

As both routes share the same identity source parameter, a cache result from successfully accessing /list-users with the Authorization header could allow access to /list-admins which is not intended. To cache responses differently per route, add $context.routeKey as an additional identity source. This creates a cache key that is unique for each route.

If more granular permissions are required, disable simple responses and return an IAM policy instead.

Testing Lambda authorizers

You have an existing Lambda function behind an HTTP API and want to add a Lambda authorizer using the new Boolean simple response. Create a new Lambda authorizer function with the following code.

exports.handler = async(event, context) => {
    let response = {
        "isAuthorized": false,
        "context": {
            "AuthInfo": "defaultdeny"
        }
    };
    if (event.headers.Authorization === "secretToken") {
        response = {
            "isAuthorized": true,
            "context": {
                "AuthInfo": "Customer1"
            }
        };
    }
    return response;
};

The authorizer returns true if a header called Authorization has the value secretToken.

To create an authorizer, browse to the API Gateway console. Navigate to your HTTP API, choose Authorization under Develop, select the Attach authorizers to routes tab, and choose Create and attach an authorizer.

Create and attach HTTP API authorizer

Create and attach HTTP API authorizer

Create the Lambda authorizer, pointing to your Lambda authorizer function. Select Payload format version 2.0 with a Simple response.

Create Lambda simple authorizer settings

Create Lambda simple authorizer settings

Enable caching and add two identity sources, $request.header.Authorization and $context.routeKey, to ensure that your cache key is unique when adding multiple routes.

Add caching and identity sources to Lambda authorizer

Add caching and identity sources to Lambda authorizer

Choose Create and attach. The route is now using a Lambda authorizer.

HTTP API route includes Lambda authorizer

HTTP API route includes Lambda authorizer

The following examples to test the API authentication use Postman but you can use any HTTP client.

Send a GET request to the HTTP APIs URL without specifying any authorization header.

Postman unauthorized GET request

Postman unauthorized GET request

API Gateway returns a 401 Unauthorized response, as expected. The required $request.header.Authorization identity source is not provided, so the Lambda authorizer is not called.

Enter a valid Authorization header key, but an invalid value.

Postman Forbidden GET request

Postman Forbidden GET request

API Gateway returns a 403 Forbidden response as the request is now passed to the Lambda authorizer, which has evaluated the value, and returned "isAuthorized": false.

Supply a valid Authorization header key and value.

Postman successful authorized GET request

Postman successful authorized GET request

API Gateway authorizes the request using the Lambda authorizer and sends the request to the Lambda function integration which returns a successful 200 response.

For more Lambda authorizer code examples see “Custom Authorizer Blueprints for AWS Lambda.”

AWS CloudFormation support

Lambda authorizers for HTTP APIs are configured as AWS::ApiGatewayV2::Authorizer CloudFormation resources. Today, they are imported into AWS Serverless Application Model (AWS SAM) applications as native CloudFormation resources.

LambdaAuthorizer:
    Type: 'AWS::ApiGatewayV2::Authorizer'
    Properties:
    Name: LambdaAuthorizer
    ApiId: !Ref HttpApi
    AuthorizerType: REQUEST
    AuthorizerUri: arn:aws:apigateway:{region}:lambda:path/2015-03-31/functions/arn:aws:lambda: {region}:{account id}:function:{Function name}/invocations
    IdentitySource:
        - $request.header.Authorization
    AuthorizerPayloadFormatVersion: 2.0

Conclusion

IAM and Lambda authorizers are two of the most requested features for Amazon API Gateway HTTP APIs. You can now use IAM authorization in a similar way to API Gateway REST APIs. Lambda authorizers for HTTP APIs offer the option of a simpler Boolean response with the new version 2.0 payload and response format. You configure identity sources to specify the location of data that’s required to authorize a request, which are also used as the cache key.

These authorizers are generally available in all AWS Regions where API Gateway is available. To learn more about options for protecting your APIs, you can read the documentation. For more information about Amazon API Gateway, visit the product page.

For the latest blogs, videos, and training for AWS Serverless, see https://serverlessland.com/.

Using AWS Lambda IAM condition keys for VPC settings

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/using-aws-lambda-iam-condition-keys-for-vpc-settings/

You can now control the Amazon Virtual Private Cloud (VPC) settings for your AWS Lambda functions using AWS Identity and Access Management (IAM) condition keys. IAM condition keys enable you to further refine the conditions under which an IAM policy statement applies. You can use the new condition keys in IAM policies when granting permissions to create and update functions.

The three new condition keys for VPC settings are lambda:VpcIds, lambda:SubnetIds, and lambda:SecurityGroupIds. The keys allow you to ensure that users can only deploy functions connected to one or more allowed VPCs, subnets, and security groups. If users try to create or update a function with VPC settings that are not allowed, Lambda rejects the operation.

Understanding Lambda and VPCs

All of the Lambda compute infrastructure runs inside VPCs owned by the Lambda service. Lambda functions can only be invoked by calling the Lambda API. There is no direct network access to the execution environment where your functions run.

Non-VPC connected Lambda functions

When your Lambda function is not configured to connect to your own VPCs, the function can access anything available on the public internet. This includes other AWS services, HTTPS endpoints for APIs, or services and endpoints outside AWS. The function cannot directly connect to your private resources inside of your VPC.

VPC connected Lambda functions

You can configure a Lambda function to connect to private subnets in a VPC in your account. When a Lambda function is configured to use a VPC, the Lambda function still runs inside the AWS Lambda service VPC. The function then sends all network traffic through your VPC and abides by your VPC’s network controls. You can use these controls to define where your functions can connect using security groups and network ACLs. Function egress traffic comes from your own network address space, and you have network visibility using VPC flow logs.

You can restrict access to network locations, including the public internet. A Lambda function connected to a VPC has no internet access by default. To give your function access to the internet, you can route outbound traffic to a network address translation (NAT) gateway in a public subnet.

When you configure your Lambda function to connect to your own VPC, it uses a shared elastic network interface (ENI) managed by AWS Hyperplane. The connection creates a VPC-to-VPC NAT and does a cross-account attachment, which allows network access from your Lambda functions to your private resources.

AWS Lambda service VPC with VPC-to-VPT NAT to customer VPC

AWS Lambda service VPC with VPC-to-VPT NAT to customer VPC

The Hyperplane ENI is a managed network interface resource that the Lambda service controls and sits in your VPC inside of your account. Multiple execution environments share the ENI to securely access resources inside of a VPC in your account. You still do not have direct network access to the execution environment.

When are ENIs created?

The network interface creation happens when your Lambda function is created or its VPC settings are updated. When a function is invoked, the execution environment uses the pre-created network interface and quickly establishes a network tunnel to it. This reduces the latency that was previously associated with creating and attaching a network interface during a cold start.

How many ENIs are required?

Because the network interfaces are shared across execution environments, typically only a handful of network interfaces are required per function. Every unique security group:subnet combination across functions in your account requires a distinct network interface. If multiple functions in the same account use the same security group:subnet pairing, it reuses the same network interface. This way, a single application with multiple functions but the same network and security configuration can benefit from the existing interface configuration.

Your function scaling is no longer directly tied to the number of network interfaces. Hyperplane ENIs can scale to support large numbers of concurrent function executions.

If your functions are not active for a long period of time, Lambda reclaims its network interfaces, and the function becomes idle and inactive. You must invoke an idle function to reactivate it. The first invocation fails and the function enters a pending state again until the network interface is available.

Using the new Lambda condition keys for VPC settings

With the new VPC condition key settings, you can specify one or more required VPC, subnets, and security groups. The lambda:VpcIds value is inferred from the subnet and security groups the CreateFunction API caller provides.

The condition syntax is in the format "Condition":{"{condition-operator}":{"{condition-key}":"{condition-value}"}}. You can use condition operators with multiple keys and values to construct policy documents.

I have a private VPC configured with the following four subnets:

Private VPC subnets

Private VPC subnets

I have a MySQL database instance running in my private VPC. The instance is running in us-east-1b in subnet subnet-046c0d0c487b0515b with a failover in us-east-1c in subnet subnet-091e180fa55fb8e83. I have an associated security group sg-0a56588b3406ee3d3 allowing access to the database. As this is a private subnet, I don’t allow internet access.

I want to ensure that any Lambda functions I create with my account must only connect to my private VPC.

  1. I create the following IAM policy document, which I attach to my account. It uses a Deny condition key with a ForAllValues:StringNotEquals condition operator to specify a required VpcId.
  2. {
        "Version": "2012-10-17",
        "Statement": [
    		{
    			"Sid": "Stmt159186333251",
    			"Action": ["lambda:CreateFunction","lambda:UpdateFunctionConfiguration"],
    			"Effect": "Deny",
    			"Resource": "*",
    			"Condition": {"ForAllValues:StringNotEquals": {"lambda:VpcIds":["vpc-0eebf3d0fe63a2db1"]}}
    		}
        ]
    }
    
  3. I attempt to create a Lambda function that does not connect to my VPC by excluding --vpc-config in the API call.
  4. aws lambda create-function --function-name MyVPCLambda1 \
      --runtime python3.7 --handler helloworld.handler --zip-file fileb://vpccondition.zip \
      --region us-east-1 --role arn:aws:iam::123456789012:role/VPCConditionLambdaRole
    
  5. I receive an AccessDeniedException error with an explicit deny:
  6. Lambda function creation AccessDeniedException

    Lambda function creation AccessDeniedException

  7. I attempt to create the Lambda function again and include any one of the subnets in my VPC, along with the security group. I must include both the SubnetIds and SecurityGroupId values with the --vpc-config.
aws lambda create-function --function-name MyVPCLambda1 \
  --vpc-config "SubnetIds=['subnet-019c87c9b67742a8f'],SecurityGroupIds=['sg-0a56588b3406ee3d3']" \
  --runtime python3.7 --handler helloworld.handler --zip-file fileb://vpccondition.zip \
  --region us-east-1 --role arn:aws:iam::123456789012:role/VPCConditionLambdaRole

The function is created successfully.

Successfully create Lambda function connected to VPC

Successfully create Lambda function connected to VPC

I also want to ensure that any Lambda functions created in my account must have the following in the configuration:

  • My private VPC
  • Both subnets containing my database instances
  • The security group including the MySQL database instance
  1. I amend my account IAM policy document to include restrictions for SubnetIds and SecurityGroupIds. I do not need to specify VpcIds as this is inferred.
  2. {
        "Version": "2012-10-17",
        "Statement": [
    		{
    			"Sid": "Stmt159186333252",
    			"Action": ["lambda:CreateFunction","lambda:UpdateFunctionConfiguration"],
    			"Effect": "Deny",
    			"Resource": "*",
    			"Condition": {"ForAllValues:StringNotEquals": {"lambda:SubnetIds": ["subnet-046c0d0c487b0515b","subnet-091e180fa55fb8e83"]}}
    		},
    		{
    			"Sid": "Stmt159186333253",
    			"Action": ["lambda:CreateFunction","lambda:UpdateFunctionConfiguration"],
    			"Effect": "Deny",
    			"Resource": "*",
    			"Condition": {"ForAllValues:StringNotEquals": {"lambda:SecurityGroupIds": ["sg-0a56588b3406ee3d3"]}}
    		}
        ]
    }
    
  3. I try to create another Lambda function, using --vpc-config values with a subnet in my VPC that’s not in the allowed permission list, along with the security group.
  4. aws lambda create-function --function-name MyVPCLambda2 \
      --vpc-config "SubnetIds=['subnet-019c87c9b67742a8f'],SecurityGroupIds=['sg-0a56588b3406ee3d3']" \
      --runtime python3.7 --handler helloworld.handler --zip-file fileb://vpccondition.zip \
      --region us-east-1 --role arn:aws:iam::123456789012:role/VPCConditionLambdaRole
    

    I receive an AccessDeniedException error.

  5. I retry, specifying both valid and allowed SubnetIds and SecurityGroupIds:
aws lambda create-function --function-name MyVPCLambda2 \
  --vpc-config "SubnetIds=['subnet-046c0d0c487b0515b','subnet-091e180fa55fb8e83'],SecurityGroupIds=['sg-0a56588b3406ee3d3']" \
  --runtime python3.7 --handler helloworld.handler --zip-file fileb://vpccondition.zip \
  --region us-east-1 --role arn:aws:iam::123456789012:role/VPCConditionLambdaRole

The function creation is successful.

Successfully create Lambda function connected to specific subnets and security groups

Successfully create Lambda function connected to specific subnets and security groups

With these settings, I can ensure that I can only create Lambda functions with the allowed VPC network security settings.

Updating Lambda functions

When updating Lambda function configuration, you do not need to specify the VPC settings if they already exist. Lambda checks the existing VPC settings before making the authorization call to IAM.

The following command to add more memory to the Lambda function, without specifying the VPC configuration, is successful as the configuration already exists.

aws lambda update-function-configuration --function-name MyVPCLambda2 --memory-size 512

Lambda layer condition keys

Lambda also has another existing condition key – lambda:Layer.

Lambda layers allow you to share code and content between multiple Lambda functions, or even multiple applications.

The lambda:Layer condition key allows you to enforce that a function must include a particular layer, or allowed group of layers. You can also prevent using layers. You can limit using layers to only those from your accounts, preventing layers published by accounts that are not yours.

Conclusion

You can now control the VPC settings for your Lambda functions using IAM condition keys.

The new VPC setting condition keys are available in all AWS Regions where Lambda is available. To learn more about the new condition keys and view policy examples, see “Using IAM condition keys for VPC settings” and  “Resource and Conditions for Lambda actions” in the Lambda Developer Guide.  To learn more about using IAM condition keys, see “IAM JSON Policy Elements: Condition” in the IAM User Guide.

Building well-architected serverless applications: Controlling serverless API access – part 3

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/building-well-architected-serverless-applications-controlling-serverless-api-access-part-3/

This series of blog posts uses the AWS Well-Architected Tool with the Serverless Lens to help customers build and operate applications using best practices. In each post, I address the nine serverless-specific questions identified by the Serverless Lens along with the recommended best practices. See the Introduction post for a table of contents and explanation of the example application.

Security question SEC1: How do you control access to your serverless API?

This post continues part 2 of this security question. Previously, I cover Amazon Cognito user and identity pools, JSON web tokens (JWT), API keys and usage plans.

Best practice: Scope access based on identity’s metadata

Authenticated users should be separated into logical groups, roles, or tiers. Separation can also be based on custom authentication token attributes included within Security Assertion Markup Language (SAML) or JSON Web Tokens (JWT). Consider using the user’s identity metadata to enable fine-grain control access to resources and actions.

Scoping access based on authentication metadata allows you to provide limited and fine-grained capabilities and access to consumers based on their roles and intent.

Review levels of access, identity metadata, and separate consumers into logical groups/tiers

With JWT or SAML, ensure you have the right level of information available within the token claims to help you develop authorization logic. Use custom private claims along with a unique namespace for non-public information. Private claims are to share custom information specifically with your application client. Unique namespaces are to avoid name collision for custom claims. For more information, see the AWS Partner Network blog post “Understanding JWT Public, Private and Reserved Claims”.

With Amazon Cognito, you can use custom attributes or the Pre Token Generation Lambda Trigger feature. This AWS Lambda trigger allows you to customize a JWT token claim before the token is generated.

To illustrate using Amazon Cognito groups, I use the example from this blog post. The example uses Amplify CLI to create a web application for managing group membership. API Gateway handles authentication using an Amazon Cognito user pool as part of an administrator API. Two Amazon Cognito user pool groups are created using amplify auth update, one for admin, and one for editors.

  1. I navigate to the deployed web application and create two users, an administrator called someadminuser and an editor user called awesomeeditor.
  2. Show Amazon Cognito user creation

    Show Amazon Cognito user creation

  3. I navigate to the Amazon Cognito user pool console, choose Users and groups under General settings, and can see that both users are created.
  4. View Amazon Cognito users created

    View Amazon Cognito users created

  5. I choose the Groups tab and see that there are two user pool groups set up as part of amplify auth update.
  6. I add the someadminuser to the admin group.
  7. View Amazon Cognito user added to group and IAM role

    View Amazon Cognito user added to group and IAM role

  8. There is an AWS Identity and Access Management (IAM) role associated with the administrator group. This IAM role has an associated identity policy that grants permission to access an S3 bucket for some future application functionality.
  9. {
        "Version": "2012-10-17",
        "Statement": [
            {
                "Action": [
                    "s3:PutObject",
                    "s3:GetObject",
                    "s3:ListBucket",
                    "s3:DeleteObject"
                ],
                "Resource": [
                    "arn:aws:s3:::mystoragebucket194021-dev/*"
                ],
                "Effect": "Allow"
            }
        ]
    }
    
  10. I log on to the web application using both the someadminuser and awesomeeditor accounts and compare the two JWT accessToken Amazon Cognito has generated.

The someadminuser has a cognito:groups claim within the token showing membership of the user pool group admin.

View JWT with group membership

View JWT with group membership

This token with its group claim can be used in a number of ways to authorize access.

Within this example frontend application, the token is used against an API Gateway resource using an Amazon Cognito authorizer.

An Amazon Cognito authorizer is an alternative to using IAM or Lambda authorizers to control access to your API Gateway method. The client first signs in to the user pool, and receives a token. The client then calls the API method with the token which is typically in the request’s Authorization header. The API call only succeeds if a valid is supplied. Without the correct token, the client isn’t authorized to make the call.

In this example, the Amazon Cognito authorizer authorizes access at the API method. Next, the event payload passed to the Lambda function contains the token. The function reads the token information. If the group membership claim includes admin, it adds the awesomeeditor user to the Amazon Cognito user pool group editors.

  1. To see how this is configured, I navigate to the API Gateway console and select the AdminQueries API.
  2. I view the /{proxy+}/ANY resource.
  3. I see that the Integration Request is set to LAMBDA_PROXY. which calls the AdminQueries Lambda function.
  4. View API Gateway Lambda proxy path

    View API Gateway Lambda proxy path

  5. I view the Method Request.
  6. View API Gateway Method Request using Amazon Cognito authorization

    View API Gateway Method Request using Amazon Cognito authorization

  7. Authorization is set to an Amazon Cognito user pool authorizer with an OAuth scope of aws.cognito.signin.user.admin. This scope grants access to Amazon Cognito user pool API operations that require access tokens, such as AdminAddUserToGroup.
  8. I navigate to the Authorizers menu item, and can see the configured Amazon Cognito authorizer.
  9. In the Amazon Cognito user pool details, the Token Source is set to Authorization. This is the name of the header sent to the Amazon Cognito user pool for authorization.
  10. View Amazon Cognito authorizer settings

    View Amazon Cognito authorizer settings

  11. I navigate to the AWS Lambda console, select the AdminQueries function which amplify add auth added, and choose the Permissions tab. I select the Execution role and view its Permissions policies.
  12. I see that the function execution role allows write permission to the Amazon Cognito user pool resource. This allows the function to amend the user pool group membership.
  13. View Lambda execution role permissions including Amazon Cognito write

    View Lambda execution role permissions including Amazon Cognito write

  14. I navigate back to the AWS Lambda console, and view the configuration for the AdminQueries function. There is an environment variable set for GROUP=admin.
Lambda function environment variables

Lambda function environment variables

The Lambda function code checks if the authorizer.claims token includes the GROUP environment variable value of admin. If not, the function returns err.statusCode = 403 and an error message. Here is the relevant section of code within the function.

// Only perform tasks if the user is in a specific group
const allowedGroup = process.env.GROUP;
…..
  // Fail if group enforcement is being used
  if (req.apiGateway.event.requestContext.authorizer.claims['cognito:groups']) {
    const groups = req.apiGateway.event.requestContext.authorizer.claims['cognito:groups'].split(',');
    if (!(allowedGroup && groups.indexOf(allowedGroup) > -1)) {
      const err = new Error(`User does not have permissions to perform administrative tasks`);
      err.statusCode = 403;
      next(err);
    }
  } else {
    const err = new Error(`User does not have permissions to perform administrative tasks`);
    err.statusCode = 403;
    next(err);
  }

This example shows using a JWT to perform authorization within a Lambda function.

If the authorization is successful, the function continues and adds the awesomeeditor user to the editors group.

To show this flow in action:

  1. I log on to the web application using the awesomeeditor account, which is not a member of the admin group. I choose the Add to Group button.
  2. Sign in as editor

    Sign in as editor

  3. Using the browser developer tools I see that the API request has failed, returning the 403 error code from the Lambda function.
  4. Shows 403 access denied

    Shows 403 access denied

  5. I log on to the web application using the someadminuser account and choose the Add to Group button.
  6. Sign in as admin

    Sign in as admin

  7. Using the browser developer tools I see that the API request is now successful as the user is a member of the admin group.
  8. API successful call as admin

    API successful call as admin

  9. I navigate back to the Amazon Cognito user pool console, and view Users and groups. The awesomeeditor user is now a member of the editors group.
User now member of editors group

User now member of editors group

The Lambda function has added the awesomeeditor account to the editors group.

Implement authorization logic based on authentication metadata

Another way to separate users for authorization is using Amazon Cognito to define a resource server with custom scopes.

A resource server is a server for access-protected resources. It handles authenticated requests from an app that has an access token. This API can be hosted in Amazon API Gateway or outside of AWS. A scope is a level of access that an app can request to a resource. For example, if you have a resource server for airline flight details, it might define two scopes. One scope for all customers with read access to view the flight details, and one for airline employees with write access to add new flights. When the app makes an API call to request access and passes an access token, the token has one or more embedded scopes.

JWT with scope

JWT with scope

This allows you to provide different access levels to API resources for different application clients based on the custom scopes. It is another mechanism for separating users during authentication.

For authorizing based on token claims, use an API Gateway Lambda authorizer.

For more information, see “Using Amazon Cognito User Pool Scopes with Amazon API Gateway”.

With AWS AppSync, use GraphQL resolvers. AWS Amplify can also generate fine-grained authorization logic via GraphQL transformers (directives). You can annotate your GraphQL schema to a specific data type, data field, and specific GraphQL operation you want to allow access. These can include JWT groups or custom claims. For more information, see “GraphQL API Security with AWS AppSync and Amplify”, and the AWS AppSync documentation for Authorization Use Cases, and fine-grained access control.

Improvement plan summary:

  1. Review levels of access, identity metadata and separate consumers into logical groups/tiers.
  2. Implement authorization logic based on authentication metadata

Conclusion

Controlling serverless application API access using authentication and authorization mechanisms can help protect against unauthorized access and prevent unnecessary use of resources. In part 1, I cover the different mechanisms for authorization available for API Gateway and AWS AppSync. I explain the different approaches for public or private endpoints and show how to use IAM to control access to internal or private API consumers.

In part 2, I cover using Amplify CLI to add a GraphQL API with an Amazon Cognito user pool handling authentication. I explain how to view JSON Web Token (JWT) claims, and how to use Amazon Cognito identity pools to grant temporary access to AWS services. I also show how to use API keys and API Gateway usage plans for rate limiting and throttling requests.

In this post, I cover separating authenticated users into logical groups. I first show how to use Amazon Cognito user pool groups to separate users with an Amazon Cognito authorizer to control access to an API Gateway method. I also show how JWTs can be passed to a Lambda function to perform authorization within a function. I then explain how to also separate users using custom scopes by defining an Amazon Cognito resource server.

In an upcoming post, I will cover the second security question from the Well-Architected Serverless Lens about managing serverless security boundaries.

Building well-architected serverless applications: Controlling serverless API access – part 2

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/building-well-architected-serverless-applications-controlling-serverless-api-access-part-2/

This series of blog posts uses the AWS Well-Architected Tool with the Serverless Lens to help customers build and operate applications using best practices. In each post, I address the nine serverless-specific questions identified by the Serverless Lens along with the recommended best practices. See the Introduction post for a table of contents and explanation of the example application.

Security question SEC1: How do you control access to your serverless API?

This post continues part 1 of this security question. Previously, I cover the different mechanisms for authentication and authorization available for Amazon API Gateway and AWS AppSync. I explain the different approaches for public or private endpoints and show how to use AWS Identity and Access Management (IAM) to control access to internal or private API consumers.

Required practice: Use appropriate endpoint type and mechanisms to secure access to your API

I continue to show how to implement security mechanisms appropriate for your API endpoint.

Using AWS Amplify CLI to add a GraphQL API

After adding authentication in part 1, I use the AWS Amplify CLI to add a GraphQL AWS AppSync API with the following command:

amplify add api

When prompted, I specify an Amazon Cognito user pool for authorization.

Amplify add Amazon Cognito user pool for authorization

Amplify add Amazon Cognito user pool for authorization

To deploy the AWS AppSync API configuration to the AWS Cloud, I enter:

amplify push

Once the deployment is complete, I view the GraphQL API from within the AWS AppSync console and navigate to Settings. I see the AWS AppSync API uses the authorization configuration added during the part 1 amplify add auth. This uses the Amazon Cognito user pool to store the user sign-up information.

View AWS AppSync authorization settings with Amazon Cognito

View AWS AppSync authorization settings with Amazon Cognito

For a more detailed walkthrough using Amplify CLI to add an AWS AppSync API for the serverless airline, see the build video.

Viewing JWT tokens

When I create a new account from the serverless airline web frontend, Amazon Cognito creates a user within the user pool. It handles the 3-stage sign-up process for new users. This includes account creation, confirmation, and user sign-in.

Serverless airline Amazon Cognito based sign-in process

Serverless airline Amazon Cognito based sign-in process

Once the account is created, I browse to the Amazon Cognito console and choose Manage User Pools. I navigate to Users and groups under General settings and view my user account.

View User Account

View User Account

When I sign in to the serverless airline web app, I authenticate with Amazon Cognito, and the client receives user pool tokens. The client then calls the AWS AppSync API, which authorizes access using the tokens, connects to data sources, and resolves the queries.

Amazon Cognito tokens used by AWS AppSync

Amazon Cognito tokens used by AWS AppSync

During the sign-in process, I can use the browser developer tools to view the three JWT tokens Amazon Cognito generates and returns to the client. These are the accesstoken, idToken, and refreshToken.

View tokens with browser developer tools

View tokens with browser developer tools

I copy the .idToken value and use the decoder at https://jwt.io/ to view the contents.

JSON web token decoded

JSON web token decoded

The decoded token contains claims about my identity. Claims are pieces of information asserted about my identity. In this example, these include my Amazon Cognito username, email address, and other sign-up fields specified in the user pool. The client can use this identity information inside the application.

The ID token expires one hour after I authenticate. The client uses the Amazon Cognito issued refreshToken to retrieve new ID and access tokens. By default, the refresh token expires after 30 days, but can be set to any value between 1 and 3650 days. When using the mobile SDKs for iOS and Android, retrieving new ID and access tokens is done automatically with a valid refresh token.

For more information, see “Using Tokens with User Pools”.

Accessing AWS services

An Amazon Cognito user pool is a managed user directory to provide access for a user to an application. Amazon Cognito has a feature called identity pools (federated identities), which allow you to create unique identities for your users. These can be from user pools, or other external identity providers.

These unique identities are used to get temporary AWS credentials to directly access other AWS services, or external services via API Gateway. The Amplify client libraries automatically expire, rotate, and refresh the temporary credentials.

Identity pools have identities that are either authenticated or unauthenticated. Unauthenticated identities typically belong to guest users. Authenticated identities belong to authenticated users who have received a token by a login provider, such as a user pool. The Amazon Cognito issued user pool tokens are exchanged for AWS access credentials from an identity pool.

JWT-tokens-from-Amazon-Cognito-user-pool-exchanged-for-AWS-credentials-from-Amazon-Cognito-identity-pool

JWT-tokens-from-Amazon-Cognito-user-pool-exchanged-for-AWS-credentials-from-Amazon-Cognito-identity-pool

API keys

For public content and unauthenticated access, both Amazon API Gateway and AWS AppSync provide API keys that can be used to track usage. API keys should not be used as a primary authorization method for production applications. Instead, use these for rate limiting and throttling. Unauthenticated APIs require stricter throttling than authenticated APIs.

API Gateway usage plans specify who can access API stages and methods, and also how much and how fast they can access them. API keys are then associated with the usage plans to identify API clients and meter access for each key. Throttling and quota limits are enforced on individual keys.

Throttling limits determine how many requests per second are allowed for a usage plan. This is useful to prevent a client from overwhelming a downstream resource. There are two API Gateway values to control this, the throttle rate and throttle burst, which use the token bucket algorithm. The algorithm is based on an analogy of filling and emptying a bucket of tokens representing the number of available requests that can be processed. The bucket in the algorithm has a fixed size based on the throttle burst and is filled at the token rate. Each API request removes a token from the bucket. The throttle rate then determines how many requests are allowed per second. The throttle burst determines how many concurrent requests are allowed and is shared across all APIs per Region in an account.

Token bucket algorithm

Token bucket algorithm

Quota limits allow you to set a maximum number of requests for an API key within a fixed time period. When billing for usage, this also allows you to enforce a limit when a client pays by monthly volume.

API keys are passed using the x-api-key header. API Gateway rejects requests without them.

For example, within the serverless airline, the loyalty service uses an AWS Lambda function to fetch loyalty points and next tier progress via an API Gateway REST API /loyalty/{customerId}/get resource.

I can use this API to simulate the effect of usage plans with API keys.

  1. I navigate to the airline-loyalty API /loyalty/{customerId}/get resource in API Gateway console.
  2. I change the API Key Required value to be true.
  3. Setting API Key Required on API Gateway method

    Setting API Key Required on API Gateway method

  4. I choose Deploy API from the Actions menu.
  5. I create a usage plan in the Usage Plans section of the API Gateway Console.
  6. I choose Create and enter a name for the usage plan.
  7. I select Enable throttling and set the rate to one request per second and the burst to two requests. These are artificially low numbers to simulate the effect.
  8. I select Enable quota and set the limit to 10 requests per day.
  9. Create API Gateway usage plan

    Create API Gateway usage plan

  10. I click Next.
  11. I associate an API Stage by choosing Add API Stage, and selecting the airline Loyalty API and Prod Stage.
  12. Associate usage plan to API Gateway stage

    Associate usage plan to API Gateway stage

  13. I click Next, and choose Create API Key and add to Usage Plan
  14. Create API key and add to usage plan.

    Create API key and add to usage plan.

  15. I name the API Key and ensure it is set to Auto Generate.
  16. Name API Key

  17. I choose Save then Done to associate the API key with the usage plan.
API key associated with usage plan

API key associated with usage plan

I test the API authentication, in addition to the throttles and limits using Postman.

I issue a GET request against the API Gateway URL using a customerId from the airline Airline-LoyaltyData Amazon DynamoDB table. I don’t specify any authorization or API key.

Postman unauthenticated GET request

Postman unauthenticated GET request

I receive a Missing Authentication Token reply, which I expect as the API uses IAM authentication and I haven’t authenticated.

I then configure authentication details within the Authorization tab, using an AWS Signature. I enter my AWS user account’s AccessKey and SecretKey, which has an associated IAM identity policy to access the API.

Postman authenticated GET request without access key

Postman authenticated GET request without access key

I receive a Forbidden reply. I have successfully authenticated, but the API Gateway method rejects the request as it requires an API key, which I have not provided.

I retrieve and copy my previously created API key from the API Gateway console API Keys section, and display it by choosing Show.

Retrieve API key.

Retrieve API key.

I then configure an x-api-key header in the Postman Headers section and paste the API key value.

Having authenticated and specifying the required API key, I receive a response from the API with the loyalty points value.

Postman successful authenticated GET request with access key

Postman successful authenticated GET request with access key

I then call the API with a number of quick successive requests.

When I exceed the throttle rate limit of one request per second, and the throttle burst limit of two requests, I receive:

{"message": "Too Many Requests"}

When I then exceed the quota of 10 requests per day, I receive:

{"message": "Limit Exceeded"}

I view the API key usage within the API Gateway console Usage Plan section.

I select the usage plan, choose the API Keys section, then choose Usage. I see how many requests I have made.

View API key usage

View API key usage

If necessary, I can also grant a temporary rate extension for this key.

For more information on using API Keys for unauthenticated access for AWS AppSync, see the documentation.

API Gateway also has support for AWS Web Application Firewall (AWS WAF) which helps protect web applications and APIs from attacks. It is another mechanism to apply rate-based rules to prevent public API consumers exceeding a configurable request threshold. AWS WAF rules are evaluated before other access control features, such as resource policies, IAM policies, Lambda authorizers, and Amazon Cognito authorizers. For more information, see “Using AWS WAF with Amazon API Gateway”.

AWS AppSync APIs have built-in DDoS protection to protect all GraphQL API endpoints from attacks.

Improvement plan summary:

  1. Determine your API consumer and choose an API endpoint type.
  2. Implement security mechanisms appropriate to your API endpoint

Conclusion

Controlling serverless application API access using authentication and authorization mechanisms can help protect against unauthorized access and prevent unnecessary use of resources.

In this post, I cover using Amplify CLI to add a GraphQL API with an Amazon Cognito user pool handling authentication. I explain how to view JSON Web Token (JWT) claims, and how to use identity pools to grant temporary access to AWS services. I also show how to use API keys and API Gateway usage plans for rate limiting and throttling requests.

This well-architected question will be continued where I look at segregating authenticated users into logical groups. I will first show how to use Amazon Cognito user pool groups to separate users with an Amazon Cognito authorizer to control access to an API Gateway method. I will also show how to pass JWTs to a Lambda function to perform authorization within a function. I will then explain how to also segregate users using custom scopes by defining an Amazon Cognito resource server.

Building well-architected serverless applications: Controlling serverless API access – part 1

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/building-well-architected-serverless-applications-controlling-serverless-api-access-part-1/

This series of blog posts uses the AWS Well-Architected Tool with the Serverless Lens to help customers build and operate applications using best practices. In each post, I address the nine serverless-specific questions identified by the Serverless Lens along with the recommended best practices. See the Introduction post for a table of contents and explanation of the example application.

Security question SEC1: How do you control access to your serverless API?

Use authentication and authorization mechanisms to prevent unauthorized access, and enforce quota for public resources. By controlling access to your API, you can help protect against unauthorized access and prevent unnecessary use of resources.

AWS has a number of services to provide API endpoints including Amazon API Gateway and AWS AppSync.

Use Amazon API Gateway for RESTful and WebSocket APIs. Here is an example serverless web application architecture using API Gateway.

Example serverless application architecture using API Gateway

Example serverless application architecture using API Gateway

Use AWS AppSync for managed GraphQL APIs.

AWS AppSync overview diagram

AWS AppSync overview diagram

The serverless airline example in this series uses AWS AppSync to provide the frontend, user-facing public API. The application also uses API Gateway to provide backend, internal, private REST APIs for the loyalty and payment services.

Good practice: Use an authentication and an authorization mechanism

Authentication and authorization are mechanisms for controlling and managing access to a resource. In this well-architected question, that is a serverless API. Authentication is verifying who a client or user is. Authorization is deciding whether they have the permission to access a resource. By enforcing authorization, you can prevent unauthorized access to your workload from non-authenticated users.

Integrate with an identity provider that can validate your API consumer’s identity. An identity provider is a system that provides user authentication as a service. The identity provider may use the XML-based Security Assertion Markup Language (SAML), or JSON Web Tokens (JWT) for authentication. It may also federate with other identity management systems. JWT is an open standard that defines a way for securely transmitting information between parties as a JSON object. JWT uses frameworks such as OAuth 2.0 for authorization and OpenID Connect (OIDC), which builds on OAuth2, and adds authentication.

Only authorize access to consumers that have successfully authenticated. Use an identity provider rather than API keys as a primary authorization method. API keys are more suited to rate limiting and throttling.

Evaluate authorization mechanisms

Use AWS Identity and Access Management (IAM) for authorizing access to internal or private API consumers, or other AWS Managed Services like AWS Lambda.

For public, user facing web applications, API Gateway accepts JWT authorizers for authenticating consumers. You can use either Amazon Cognito or OpenID Connect (OIDC).

App client authenticates and gets tokens

App client authenticates and gets tokens

For custom authorization needs, you can use Lambda authorizers.

A Lambda authorizer (previously called a custom authorizer) is an AWS Lambda function which API Gateway calls for an authorization check when a client makes a request to an API method. This means you do not have to write custom authorization logic in a function behind an API. The Lambda authorizer function can validate a bearer token such as JWT, OAuth, or SAML, or request parameters and grant access. Lambda authorizers can be used when using an identity provider other than Amazon Cognito or AWS IAM, or when you require additional authorization customization.

Lambda authorizers

Lambda authorizers

For more information, see the AWS Hero blog post, “The Complete Guide to Custom Authorizers with AWS Lambda and API Gateway”.

The AWS documentation also has a useful section on “Understanding Lambda Authorizers Auth Workflow with Amazon API Gateway”.

Enforce authorization for non-public resources within your API

Within API Gateway, you can enable native authorization for users authenticated using Amazon Cognito or AWS IAM. For authorizing users authenticated by other identity providers, use Lambda authorizers.

For example, within the serverless airline, the loyalty service uses a Lambda function to fetch loyalty points and next tier progress. AWS AppSync acts as the client using an HTTP resolver, via an API Gateway REST API /loyalty/{customerId}/get resource, to invoke the function.

To ensure only AWS AppSync is authorized to invoke the API, IAM authorization is set within the API Gateway method request.

Viewing API Gateway IAM authorization

Viewing API Gateway IAM authorization

The serverless airline uses the AWS Serverless Application Model (AWS SAM) to deploy the backend infrastructure as code. This makes it easier to know which IAM role has access to the API. One of the benefits of using infrastructure as code is visibility into all deployed application resources, including IAM roles.

The loyalty service AWS SAM template contains the AppsyncLoyaltyRestApiIamRole.

AppsyncLoyaltyRestApiIamRole:
Type: AWS::IAM::Role
Properties:
AssumeRolePolicyDocument:
Version: 2012-10-17
Statement:
- Effect: Allow
  AppsyncLoyaltyRestApiIamRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service: appsync.amazonaws.com
            Action: sts:AssumeRole
      Path: /
      Policies:
        - PolicyName: LoyaltyApiInvoke
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action:
                  - execute-api:Invoke
                # arn:aws:execute-api:region:account-id:api-id/stage/METHOD_HTTP_VERB/Resource-path
                Resource: !Sub arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${LoyaltyApi}/*/*/*

The IAM role specifies that appsync.amazonaws.com can perform an execute-api:Invoke on the specific API Gateway resource arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${LoyaltyApi}/*/*/*

Within AWS AppSync, you can enable native authorization for users authenticating using Amazon Cognito or AWS IAM. You can also use any external identity provider compliant with OpenID Connect (OIDC).

Improvement plan summary:

  1. Evaluate authorization mechanisms.
  2. Enforce authorization for non-public resources within your API

Required practice: Use appropriate endpoint type and mechanisms to secure access to your API

APIs may have public or private endpoints. Consider public endpoints to serve consumers where they may not be part of your network perimeter. Consider private endpoints to serve consumers within your network perimeter where you may not want to expose the API publicly. Public and private endpoints may have different levels of security.

Determine your API consumer and choose an API endpoint type

For providing public content, use Amazon API Gateway or AWS AppSync public endpoints.

For providing content with restricted access, use Amazon API Gateway with authorization to specific resources, methods, and actions you want to restrict. For example, the serverless airline application uses AWS IAM to restrict access to the private loyalty API so only AWS AppSync can call it.

With AWS AppSync providing a GraphQL API, restrict access to specific data types, data fields, queries, mutations, or subscriptions.

You can create API Gateway private REST APIs that you can only access from your AWS Virtual Private Cloud(VPC) by using an interface VPC endpoint.

API Gateway private endpoints

API Gateway private endpoints

For more information, see “Choose an endpoint type to set up for an API Gateway API”.

Implement security mechanisms appropriate to your API endpoint

With Amazon API Gateway and AWS AppSync, for both public and private endpoints, there are a number of mechanisms for access control.

For providing content with restricted access, API Gateway REST APIs support native authorization using AWS IAM, Amazon Cognito user pools, and Lambda authorizers. Amazon Cognito user pools is a feature that provides a managed user directory for authentication. For more detailed information, see the AWS Hero blog post, “Picking the correct authorization mechanism in Amazon API Gateway“.

You can also use resource policies to restrict content to a specific VPC, VPC endpoint, a data center, or a specific AWS Account.

API Gateway resource policies are different from IAM identity policies. IAM identity policies are attached to IAM users, groups, or roles. These policies define what that identity can do on which resources. For example, in the serverless airline, the IAM role AppsyncLoyaltyRestApiIamRole specifies that appsync.amazonaws.com can perform an execute-api:Invoke on the specific API Gateway resource arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${LoyaltyApi}/*/*/*

Resource policies are attached to resources such as an Amazon S3 bucket, or an API Gateway resource or method. The policies define what identities can access the resource.

IAM access is determined by a combination of identity policies and resource policies.

For more information on the differences, see “Identity-Based Policies and Resource-Based Policies”. To see which services support resource-based policies, see “AWS Services That Work with IAM”.

API Gateway HTTP APIs support JWT authorizers as a part of OpenID Connect (OIDC) and OAuth 2.0 frameworks.

API Gateway WebSocket APIs support AWS IAM and Lambda authorizers.

With AWS AppSync public endpoints, you can enable authorization with the following:

  • AWS IAM
  • Amazon Cognito User pools for email and password functionality
  • Social providers (Facebook, Google+, and Login with Amazon)
  • Enterprise federation with SAML

Within the serverless airline, AWS Amplify Console hosts the public user facing site. Amplify Console provides a git-based workflow for building, deploying, and hosting serverless web applications. Amplify Console manages the hosting of the frontend assets for single page app (SPA) frameworks in addition to static websites, along with an optional serverless backend. Frontend assets are stored in S3 and the Amazon CloudFront global edge network distributes the web app globally.

The AWS Amplify CLI toolchain allows you to add backend resources using AWS CloudFormation.

Using Amplify CLI to add authentication

For the serverless airline, I use the Amplify CLI to add authentication using Amazon Cognito with the following command:

amplify add auth

When prompted, I specify the authentication parameters I require.

Amplify add auth

Amplify add auth

Amplify CLI creates a local CloudFormation template. Use the following command to deploy the updated authentication configuration to the cloud:

amplify push

Once the deployment is complete, I view the deployed authentication nested stack resources from within the CloudFormation Console. I see the Amazon Cognito user pool.

View Amplify authentication CloudFormation nested stack resources

View Amplify authentication CloudFormation nested stack resources

For a more detailed walkthrough using Amplify CLI to add authentication for the serverless airline, see the build video.

For more information on Amplify CLI and authentication, see “Authentication with Amplify”.

Conclusion

To help protect against unauthorized access and prevent unnecessary use of serverless API resources, control access using authentication and authorization mechanisms.

In this post, I cover the different mechanisms for authorization available for API Gateway and AWS AppSync. I explain the different approaches for public or private endpoints and show how to use IAM to control access to internal or private API consumers. I walk through how to use the Amplify CLI to create an Amazon Cognito user pool.

This well-architected question will be continued in a future post where I continue using the Amplify CLI to add a GraphQL API. I will explain how to view JSON Web Tokens (JWT) claims, and how to use Cognito identity pools to grant temporary access to AWS services. I will also show how to use API keys and API Gateway usage plans for rate limiting and throttling requests.

Building well-architected serverless applications: Approaching application lifecycle management – part 3

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/building-well-architected-serverless-applications-approaching-application-lifecycle-management-part-3/

This series of blog posts uses the AWS Well-Architected Tool with the Serverless Lens to help customers build and operate applications using best practices. In each post, I address the nine serverless-specific questions identified by the Serverless Lens along with the recommended best practices. See the Introduction post for a table of contents and explanation of the example application.

Question OPS2: How do you approach application lifecycle management?

This post continues part 2 of this Operational Excellence question where I look at deploying to multiple stages using temporary environments, and rollout deployments. In part 1, I cover using infrastructure as code with version control to deploy applications in a repeatable manner.

Good practice: Use configuration management

Use environment variables and configuration management systems to make and track configuration changes. These systems reduce errors caused by manual processes, reduce the level of effort to deploy changes, and help isolate configuration from business logic.

Environment variables are suited for infrequently changing configuration options such as logging levels, and database connection strings. Configuration management systems are for dynamic configuration that might change frequently or contain sensitive data such as secrets.

Environment variables

The serverless airline example used in this series uses AWS Amplify Console environment variables to store application-wide settings.

For example, the Stripe payment keys for all branches, and names for individual branches, are visible within the Amplify Console in the Environment variables section.

AWS Amplify environment variables

AWS Amplify environment variables

AWS Lambda environment variables are set up as part of the function configuration stored using the AWS Serverless Application Model (AWS SAM).

For example, the airline booking ReserveBooking AWS SAM template sets global environment variables including the LOG_LEVEL with the following code.

Globals:
    Function:
        Environment:
            Variables:
                LOG_LEVEL: INFO

This is visible in the AWS Lambda console within the function configuration.

AWS Lambda environment variables in console

AWS Lambda environment variables in console

See the AWS Documentation for more information on using AWS Lambda environment variables and also how to store sensitive data. Amazon API Gateway can also pass stage-specific metadata to Lambda functions.

Dynamic configuration

Dynamic configuration is also stored in configuration management systems to specify external values and is unique to each environment. This configuration may include values such as an Amazon Simple Notification Service (Amazon SNS) topic, Lambda function name, or external API credentials. AWS System Manager Parameter Store, AWS Secrets Manager, and AWS AppConfig have native integrations with AWS CloudFormation to store dynamic configuration. For more information, see the examples for referencing dynamic configuration from within AWS CloudFormation.

For the serverless airline application, dynamic configuration is stored in AWS Systems Manager Parameter Store. During CloudFormation stack deployment, a number of parameters are stored in Systems Manager. For example, in the booking service AWS SAM template, the booking SNS topic ARN is stored.

BookingTopicParameter:
    Type: "AWS::SSM::Parameter"
    Properties:
        Name: !Sub /${Stage}/service/booking/messaging/bookingTopic
        Description: Booking SNS Topic ARN
        Type: String
        Value: !Ref BookingTopic

View the stored SNS topic value by navigating to the Parameter Store console, and search for BookingTopic.

Finding Systems Manager Parameter Store values

Finding Systems Manager Parameter Store values

Select the Parameter name and see the Amazon SNS ARN.

Viewing SNS topic value

Viewing SNS topic value

The loyalty service then references this value within another stack.

When the Amplify Console Makefile deploys the loyalty service, it retrieves this value for the booking service from Parameter Store, and references it as a parameter-override. The deployment is also parametrized with the $${AWS_BRANCH} environment variable if there are multiple environments within the same AWS account and Region.

sam deploy \
	--parameter-overrides \
	BookingSNSTopic=/$${AWS_BRANCH}/service/booking/messaging/bookingTopic

Environment variables and configuration management systems help with managing application configuration.

Improvement plan summary

  1. Use environment variables for configuration options that change infrequently such as logging levels, and database connection strings.
  2. Use a configuration management system for dynamic configuration that might change frequently or contain sensitive data such as secrets.

Best practice: Use CI/CD including automated testing across separate accounts

Continuous integration/delivery/deployment is one of the cornerstones of cloud application development and a vital part of a DevOps initiative.

Explanation of CI/CD stages

Explanation of CI/CD stages

Building CI/CD pipelines increases software delivery quality and feedback time for detecting and resolving errors. I cover how to deploy multiple stages in isolated environments and accounts, which helps with creating separate testing CI/CD pipelines in part 2. As the serverless airline example is using AWS Amplify Console, this comes with a built-in CI/CD pipeline.

Automate the build, deployment, testing, and rollback of the workload using KPI and operational alerts. This eases troubleshooting, enables faster remediation and feedback time, and enables automatic and manual rollback/roll-forward should an alert trigger.

I cover metrics, KPIs, and operational alerts in this series in the Application Health part 1, and part 2 posts. I cover rollout deployments with traffic shifting based on metrics in this question’s part 2.

CI/CD pipelines should include integration, and end-to-end tests. I cover local unit testing for Lambda and API Gateway in part 2.

Add an optional testing stage to Amplify Console to catch regressions before pushing code to production. Use the test step to run any test commands at build time using any testing framework of your choice. Amplify Console has deeper integration with the Cypress test suite that allows you to generate a UI report for your tests. Here is an example to set up end-to-end tests with Cypress.

Cypress testing example

Cypress testing example

There are a number of AWS and third-party solutions to host code and create CI/CD pipelines for serverless applications.

AWS Code Suite

AWS Code Suite

For more information on how to use the AWS Code* services together, see the detailed Quick Start deployment guide Serverless CI/CD for the Enterprise on AWS.

All these AWS services have a number of integrations with third-party products so you can integrate your serverless applications with your existing tools. For example, CodeBuild can build from GitHub and Atlassian Bitbucket repositories. CodeDeploy integrates with a number of developer tools and configuration management systems. CodePipeline has a number of pre-built integrations to use existing tools for your serverless applications. For more information specifically on using CircleCI for serverless applications, see Simplifying Serverless CI/CD with CircleCI and the AWS Serverless Application Model.

Improvement plan summary

  1. Use a continuous integration/continuous deployment (CI/CD) pipeline solution that deploys multiple stages in isolated environments/accounts.
  2. Automate testing including but not limited to unit, integration, and end-to-end tests.
  3. Favor rollout deployments over all-at-once deployments for more resilience, and gradually learn what metrics best determine your workload’s health to appropriately alert on.
  4. Use a deployment system that supports traffic shifting as part of your pipeline, and rollback/roll-forward traffic to previous versions if an alert is triggered.

Good practice: Review function runtime deprecation policy

Lambda functions created using AWS provided runtimes follow official long-term support deprecation policies. Third-party provided runtime deprecation policy may differ from official long-term support. Review your runtime deprecation policy and have a mechanism to report on runtimes that, if deprecated, may affect your workload to operate as intended.

Review the AWS Lambda runtime policy support page to understand the deprecation schedule for your runtime.

AWS Health provides ongoing visibility into the state of your AWS resources, services, and accounts. Use the AWS Personal Health Dashboard for a personalized view and automate custom notifications to communication channels other than your AWS Account email.

Use AWS Config to report on AWS Lambda function runtimes that might be near their deprecation. Run compliance and operational checks with AWS Config for Lambda functions.

If you are unable to migrate to newer runtimes within the deprecation schedule, use AWS Lambda custom runtimes as an interim solution.

Improvement plan summary

  1. Identify and report runtimes that might deprecate and their support policy.

Conclusion

Introducing application lifecycle management improves the development, deployment, and management of serverless applications. In part 1, I cover using infrastructure as code with version control to deploy applications in a repeatable manner. This reduces errors caused by manual processes and gives you more confidence your application works as expected. In part 2, I cover prototyping new features using temporary environments, and rollout deployments to gradually shift traffic to new application code.

In this post I cover configuration management, CI/CD for serverless applications, and managing function runtime deprecation.

In an upcoming post, I will cover the first Security question from the Well-Architected Serverless Lens – Controlling access to serverless APIs.

Building well-architected serverless applications: Approaching application lifecycle management – part 2

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/building-well-architected-serverless-applications-approaching-application-lifecycle-management-part-2/

This series of blog posts uses the AWS Well-Architected Tool with the Serverless Lens to help customers build and operate applications using best practices. In each post, I address the nine serverless-specific questions identified by the Serverless Lens along with the recommended best practices. See the Introduction post for a table of contents and explanation of the example application.

Question OPS2: How do you approach application lifecycle management?

This post continues part 1 of this Operational Excellence question. Previously, I covered using infrastructure as code with version control to deploy applications in a repeatable manner.

Good practice: Prototype new features using temporary environments

Storing application configuration as infrastructure as code allows deployment of multiple, repeatable, isolated versions of an application.

Create multiple temporary environments for new features you may need to prototype, and tear them down as you complete them. Temporary environments enable fine grained feature isolation and higher fidelity development when interacting with managed services. This allows you to gain confidence your workload integrates and operates as intended.

These environments can also be in separate accounts which help isolate limits, access to data, and resiliency. For best practices on multi-account deployments, see the AWS Partner Network blog post: Best Practices Guide for Multi-Account AWS Deployments.

There are a number of ways to deploy separate environments for an application. To make the deployment simpler, it is good practice to separate dynamic configuration from your infrastructure logic.

For an application managed via the AWS Serverless Application Model (AWS SAM), use an AWS SAM CLI parameter to specify a new stack-name which deploys a new copy of the application as a separate stack.

For example, there is an existing AWS SAM application with a stack-name of app-test. To deploy a new copy, specify a new stack-name of app-newtest with the following command line:

sam deploy --stack-name app-newtest

This deploys a whole new copy of the application in the same account as a separate stack.

For the serverless airline example used in this series, deploy a whole new copy of the application following the deployment instructions, either into the same AWS account, or a completely different account. This is useful when each developer in a team has a sandbox environment. In this example, you only need to configure payment provider credentials as environment variables and seed the database with possible flights as these are currently manual post installation tasks.

However, maintaining an entirely separate codebase copy of an application becomes difficult to manage and reconcile over time.

As the airline application code is stored in a fork in a GitHub account, use git branches for separate environments. In typical development teams, developers may deploy a main branch to production, have a dev branch as staging, and create feature branches when working on new functionality. This allows safe prototyping in sandbox environments without affecting the main codebase, and use git as a mechanism to merge code and resolve conflicts. Changes are automatically pushed to production once they are merged into the main (or production) branch.

Git branching flow

Git branching flow

As the airline example is using AWS Amplify Console, there are a few different options to create a new environment linked to a feature branch.

You can create a whole new Amplify Console app deployment, either in a separate Region, or in a separate AWS account, which then connects to a feature branch by following the deployment instructions. Create a new branch called new-feature in GitHub and in the Amplify Console, select Connect App, and navigate to the repository and the new-feature branch. Configure the payment provider credentials as environment variables.

Deploy new application pointing to feature branch

You can also connect the existing Amplify Console deployment to a git branch, deploying the new-feature branch into the same AWS account and Region.

Amplify Environments

Amplify Environments

In the Amplify Console, navigate to the existing app, select Connect Branch, and choose the new-feature branch. Create a new Backend environment to deploy the full stack. If the feature branch is only frontend code changes, you can choose to use the same backend components.

Connect Amplify Console to feature branch

Connect Amplify Console to feature branch

Amplify Console then deploys a new stack in addition to the develop branch based on the code in the feature-branch.

New feature branch deploying within existing deployment.

New feature branch deploying within existing deployment.

You do not need to add the payment provider environment variables as these are stored per application, per Region, for all branches.

Amplify environment variables for All Branches.

Amplify environment variables for All Branches.

Using git and branching with Amplify Console, you have automatic deployments when any changes are pushed to the GitHub repository. If there are any issues with a particular deployment, you can revert the changes in git which will kick off a redeploy to a known good version. Once you are happy with the feature, you can merge the changes into the production branch which will again kick off another deployment.

As it is simple to set up multiple test environments, make sure to practice good application hygiene, as well as cost management, by identifying and deleting any temporary environments that are no longer required. It may be helpful to include the stack owner’s contact details via CloudFormation tags. Use Amazon CloudWatch scheduled tasks to notify and tag temporary environments for deletion, and provide a mechanism to delay its deletion if needed.

Prototyping locally

With AWS SAM or a third-party framework, you can run API Gateway, and invoke Lambda function code locally for faster development iteration. Local debugging and testing can help for quick confirmation that function code is working, and is also useful for some unit tests. Local testing cannot duplicate the full functionality of the cloud. It is suited to testing services with custom logic, such as Lambda, rather than trying to duplicate all cloud managed services such as Amazon SNS, or Amazon S3 locally. Don’t try to bring the cloud to the test, rather bring the testing to the cloud.

Here is an example of executing a function locally.

I use AWS SAM CLI to invoke the Airline-GetLoyalty Lambda function locally to test some functionality. AWS SAM CLI uses Docker to simulate the Lambda runtime. As the function only reads from DynamoDB, I use stubbed data, or can set up DynamoDB Local.

1. I pass a JSON event to the function to simulate the event from API Gateway, as well as passing in environment variables as JSON. Create sample events using sam local generate-event.

2. I run sam build GetFunc to build the function dependencies, in this case NodeJS.

$ sam build GetFunc
Building resource 'GetFunc'
Running NodejsNpmBuilder:NpmPack
Running NodejsNpmBuilder:CopyNpmrc
Running NodejsNpmBuilder:CopySource
Running NodejsNpmBuilder:NpmInstall
Running NodejsNpmBuilder:CleanUpNpmrc

Build Succeeded

3. I run sam local invoke passing in the event payload and environment variables. This spins up a Docker container, executes the function, and returns the result.

$ sam local invoke --event src/get/event.json --env-vars local-env-vars.json GetFunc
Invoking index.handler (nodejs10.x)

Fetching lambci/lambda:nodejs10.x Docker container image......
Mounting /home/ec2-user/environment/samples/aws-serverless-airline-booking/src/backend/loyalty/.aws-sam/build/GetFunc as /var/task:ro,delegated inside runtime container
START RequestId: 7be7e9a5-9f2f-1520-fbd1-a013485105d3 Version: $LATEST
END RequestId: 7be7e9a5-9f2f-1520-fbd1-a013485105d3
REPORT RequestId: 7be7e9a5-9f2f-1520-fbd1-a013485105d3 Init Duration: 249.89 ms Duration: 76.40 ms Billed Duration: 100 ms Memory Size: 512 MB Max Memory Used: 54 MB

{"statusCode": 200,"body": "{\"points\":0,\"level\":\"bronze\",\"remainingPoints\":50000}"}

For more information on using AWS SAM to run API Gateway, and invoke Lambda functions locally, see the AWS Documentation. For third-part framework solutions, see Invoking AWS Lambda functions locally with Serverless framework and Develop locally against cloud services with Stackery.

Improvement plan summary:

  1. Use a serverless framework to deploy temporary environments named after a feature.
  2. Implement a process to identify temporary environments that may not have been deleted over an extended period of time
  3. Prototype application code locally and test integrations directly with managed services

Good practice: Use a rollout deployment mechanism

Use a rollout deployment for production workloads as opposed to all-at-once mechanisms. Rollout deployments reduce the risk of a failed deployment by gradually deploying application changes to a limited set of customers. Use all-at-once deployments to deploy the entire application. This is best suited for non-production systems.

AWS Lambda versions and aliases

For production Lambda functions, it is best to deploy a new function version for every deployment. Versions can represent the stable version or reflect particular features. Create Lambda aliases which are pointers to particular function versions. Invoke Lambda functions using the aliases, with a specific alias for the stable production version. If an alias is not specified, the latest application code deployment is invoked which may not reflect a stable version or a desired feature. Use the new feature alias version for testing without affecting users of the stable production version.

AWS Lambda function versions and aliases

AWS Lambda function versions and aliases

See AWS Documentation to manage Lambda function versions and aliases using the AWS Management Console, or Lambda API.

Alias routing

Use Lambda alias’ routing configuration to introduce traffic shifting to send a small percentage of traffic to a second function alias or version for a rolling deployment. This is commonly called a canary release.

For example, configure Lambda alias named stable to point to function version 2. A new function version 3 is deployed with alias new-feature. Use the new-feature alias to test the new deployment without impacting production traffic to the stable version.

During production rollout, use alias routing. For example, 90% of invocations route to the stable version while 10% route to alias new-feature pointing to version 3. If the 10% is successful, deployment can continue until all traffic is migrated to version 3, and the stable alias is then pointed to version 3.

AWS Lambda alias routing

AWS Lambda alias routing

AWS SAM supports gradual Lambda deployments with a feature called Safe Lambda deployments using AWS CodeDeploy. This creates new versions of a Lambda function, and automatically creates aliases pointing to the new version. Customer traffic gradually shifts to the new version or rolls back automatically if any specified CloudWatch alarms trigger. AWS SAM supports canary, linear, and all-at-once deployments preference types.

Pre-traffic and post-traffic Lambda functions can also verify if the newly deployed code is working as expected.

In the airline example, create a safe deployment for the ReserveBooking Lambda function by adding the example AWS SAM template code specified in the instructions. This migrates 10 percent of traffic every 10 minutes with CloudWatch alarms to check for any function errors. You could also alarm on latency, or any custom metric.

During the Amplify Console build phase, the safe deployment is initiated. Navigate to the CodeDeploy console and see the deployment in progress.

AWS CodeDeploy deployment in progress

AWS CodeDeploy deployment in progress

Selecting the deployment, you can see the Traffic shifting progress and the Deployment details.

AWS CodeDeploy traffic shifting in progress.

AWS CodeDeploy traffic shifting in progress.

Within Deployment details, select the DeploymentGroup, and view the CloudWatch Alarms CodeDeploy is using to test the rollout.

Amazon CloudWatch Alarms AWS CodeDeploy is using to test the rollout

Amazon CloudWatch Alarms AWS CodeDeploy is using to test the rollout

Within Deployment details, select the Application, select the Revisions tab, and select the latest Revision location and view the CurrentVersion and TargetVersion for this deployment.

View deployment versions

View deployment versions

View Deployment status and see the traffic has now shifted to the new version. The Amplify Console build also continues.

Traffic shifting complete

Traffic shifting complete

View the Lambda function versions and aliases in the Lambda console, selecting Qualifiers.

Viewing Lambda function version and aliases

Viewing Lambda function version and aliases

Amazon API Gateway also supports canary release deployments at the API layer.

A rollout deployment provides traffic shifting, A/B testing, and the ability to roll back to any version at any point in time. AWS SAM makes it simple to add safe deployments to serverless applications.

Improvement plan summary

  1. For production systems, use a linear deployment strategy to gradually rollout changes to customers.
  2. For high volume production systems, use a canary deployment strategy when you want to limit changes to a fixed percentage of customers for an extended period of time.

Conclusion

Introducing application lifecycle management improves the development, deployment, and management of serverless applications. In this post I cover a number of methods to prototype new features using temporary environments. I show how to use rollout deployments to gradually shift traffic to new application code.

This well-architected question will continue in an upcoming post where I look at configuration management, CI/CD for serverless applications, and managing function runtime deprecation.

Building well-architected serverless applications: Approaching application lifecycle management – part 1

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/building-well-architected-serverless-applications-approaching-application-lifecycle-management-part-1/

This series of blog posts uses the AWS Well-Architected Tool with the Serverless Lens to help customers build and operate applications using best practices. In each post, I address the nine serverless-specific questions identified by the Serverless Lens along with the recommended best practices. See the Introduction post for a table of contents and explanation of the example application.

Question OPS2: How do you approach application lifecycle management?

Adopt lifecycle management approaches that improve the flow of changes to production with higher fidelity, fast feedback on quality, and quick bug fixing. These practices help you rapidly identify, remediate, and limit changes that impact customer experience. By having an approach to application lifecycle management, you can reduce errors caused by manual process and increase the levels of control to gain confidence your workload operates as intended.

Required practice: Use infrastructure as code and stages isolated in separate environments

Infrastructure as code is a process of provisioning and managing cloud resources by storing application configuration in a template file. Using infrastructure as code helps to deploy applications in a repeatable manner, reducing errors caused by manual processes such as creating resources in the AWS Management Console.

Storing code in a version control system enables tracking and auditing of changes and releases over time. This is used to roll back changes safely to a known working state if there is an issue with an application deployment.

Infrastructure as code

For AWS Cloud development the built-in choice for infrastructure as code is AWS CloudFormation. The template file, written in JSON or YAML, contains a description of the resources an application needs. CloudFormation automates the deployment and ongoing updates of the resources by creating CloudFormation stacks.

CloudFormation code example creating infrastructure

CloudFormation code example creating infrastructure

There are a number of higher-level tools and frameworks that abstract and then generate CloudFormation. A serverless specific framework helps model the infrastructure necessary for serverless workloads, providing either declarative or imperative mechanisms to define event sources for functions. It wires permissions between resources automatically, adds resource configuration, code packaging, and any infrastructure necessary for a serverless application to run.

The AWS Serverless Application Model (AWS SAM) is an AWS open-source framework optimized for serverless applications. The AWS Cloud Development Kit allows you to provision cloud resources using familiar programming languages such as TypeScript, JavaScript, Python, Java, and C#/.Net. There are also third-party solutions for creating serverless cloud resources such as the Serverless Framework.

The AWS Amplify Console provides a git-based workflow for building, deploying, and hosting serverless applications including both the frontend and backend. The AWS Amplify CLI toolchain enables you to add backend resources using CloudFormation.

For a large number of resources, consider breaking common functionality such as monitoring, alarms, or dashboards into separate infrastructure as code templates. With CloudFormation, use nested stacks to help deploy them as part of your serverless application stack. When using AWS SAM, import these nested stacks as nested applications from the AWS Serverless Application Repository.

AWS CloudFormation nested stacks

AWS CloudFormation nested stacks

Here is an example AWS SAM template using nested stacks. There are two AWS::Serverless::Application nested resources, api.template.yaml and database.template.yaml. For more information on nested stacks, see the AWS Partner Network blog post: CloudFormation Nested Stacks Primer.

Version control

The serverless airline example application used in this series uses Amplify Console to provide part of the backend resources, including authentication using Amazon Cognito, and a GraphQL API using AWS AppSync.

The airline application code is stored in GitHub as a version control system. Fork, or copy, the application to your GitHub account. Configure Amplify Console to connect to the GitHub fork.

When pushing code changes to a fork, Amplify Console automatically deploys these backend resources along with the rest of the application. It hosts the application at the Production branch URL, and you can also configure a custom domain name if needed.

AWS Amplify Console App details

AWS Amplify Console App details

The Amplify Console configuration to create the API and Authentication backend resources is found in the backend-config.json file. The resources are provisioned during the Amplify Console build phase.

To view the deployed resources, within the Amplify Console, navigate to the awsserverlessairline application. Select Backend environments and then select an environment, in this example sampledev.

Select the API and Authentication tabs to view the created backend resources.

AWS Amplify Console deployed backend resources

AWS Amplify Console deployed backend resources

Using multiple tools

Applications can use multiple tools and frameworks even within a single project to manage the infrastructure as code. Within the airline application, AWS SAM is also used to provision the rest of the serverless infrastructure using nested stacks. During the Amplify Console build process, the Makefile contains the AWS SAM build instructions for each application service.

For example, the AWS SAM build instructions to deploy the booking service are as follows:

deploy.booking: ##=> Deploy booking service using SAM
	$(info [*] Packaging and deploying Booking service...)
	cd src/backend/booking && \
		sam build && \
		sam package \
			--s3-bucket $${DEPLOYMENT_BUCKET_NAME} \
			--output-template-file packaged.yaml && \
		sam deploy \
			--template-file packaged.yaml \
			--stack-name $${STACK_NAME}-booking-$${AWS_BRANCH} \
			--capabilities CAPABILITY_IAM \
			--parameter-overrides \
	BookingTable=/$${AWS_BRANCH}/service/amplify/storage/table/booking \
	FlightTable=/$${AWS_BRANCH}/service/amplify/storage/table/flight \
	CollectPaymentFunction=/$${AWS_BRANCH}/service/payment/function/collect \
	RefundPaymentFunction=/$${AWS_BRANCH}/service/payment/function/refund \
	AppsyncApiId=/$${AWS_BRANCH}/service/amplify/api/id \
	Stage=$${AWS_BRANCH}

Each service has its own AWS SAM template.yml file. The files contain the resources for each of the booking, catalog, log-processing, loyalty, and payment services. This means that the services can be managed independently within the application as separate stacks. In larger applications, these services may be managed by separate teams, or be in separate repositories, environments or AWS accounts. It may make sense to split out some common functionality such as alarms, or dashboards into separate infrastructure as code templates.

AWS SAM can also use IAM roles to assume temporary credentials and deploy a serverless application to separate AWS accounts.

For more information on managing serverless code, see Best practices for organizing larger serverless applications.

View the deployed resources in the AWS CloudFormation Console. Select Stacks from the left-side navigation bar, and select the View nested toggle.

Viewing CloudFormation nested stacks

Viewing CloudFormation nested stacks

The serverless airline application is a more complex example application comprising multiple services composed of multiple CloudFormation stacks. Some stacks are managed via Amplify Console and others via AWS SAM. Using infrastructure as code is not only for large and complex applications. As a best practice, we suggest using SAM or another framework for even simple, small serverless applications with a single stack. For a getting started tutorial, see the example Deploying a Hello World Application.

Improvement plan summary:

  1. Use a serverless framework to help you execute functions locally, build and package application code. Separate packaging from deployment, deploy to isolated stages in separate environments, and support secrets via configuration management systems.
  2. For a large number of resources, consider breaking common functionalities such as alarms into separate infrastructure as code templates.

Conclusion

Introducing application lifecycle management improves the development, deployment, and management of serverless applications. In this post I cover using infrastructure as code with version control to deploy applications in a repeatable manner. This reduces errors caused by manual processes and gives you more confidence your application works as expected.

This well-architected question will continue in an upcoming post where I look further at deploying to multiple stages using temporary environments, and rollout deployments.

Building well-architected serverless applications: Understanding application health – part 2

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/building-well-architected-serverless-applications-understanding-application-health-part-2/

This series of blog posts uses the AWS Well-Architected Tool with the Serverless Lens to help customers build and operate applications using best practices. In each post, I address the nine serverless-specific questions identified by the Serverless Lens along with the recommended best practices. See the Introduction post for a table of contents and explaining the example application.

Question OPS1: How do you evaluate your serverless application’s health?

This post continues part 1 of this Operational Excellence question. Previously, I covered using Amazon CloudWatch out-of-the-box standard metrics and alerts, and structured and centralized logging with the Embedded Metrics Format.

Best practice: Use application, business, and operations metrics

Identifying key performance indicators (KPIs), including business, customer, and operations outcomes, in additional to application metrics, helps to show a higher-level view of how the application and business is performing.

Business KPIs measure your application performance against business goals. For example, if fewer flight reservations are flowing through the system, the business would like to know.

Customer experience KPIs highlight the overall effectiveness of how customers use the application over time. Examples are perceived latency, time to find a booking, make a payment, etc.

Operational metrics help to see how operationally stable the application is over time. Examples are continuous integration/delivery/deployment feedback time, mean-time-between-failure/recovery, number of on-call pages and time to resolution, etc.

Custom Metrics

Embedded Metrics Format can also emit custom metrics to help understand your workload health’s impact on business.

The airline booking service uses AWS Step Functions, AWS Lambda, Amazon SNS, and Amazon DynamoDB.

In the confirm booking module function handler, I add a new namespace and dimension to associate this set of logs with this application and service.

metrics.set_namespace("ServerlessAirlineEMF")
metrics.put_dimensions({"service":"confirm_booking"})

Within the try statement within the try/except block, I emit a metric for a successful booking:

metrics.put_metric("BookingSuccessful", 1, "Count")

And within the except statement within the try/except block, I emit a metric for a failed booking:

metrics.put_metric("BookingFailed", 1, "Count")

Once I make a booking, within the CloudWatch console, I navigate to Logs | Log groups and select the Airline-ConfirmBooking-develop group. I select a log stream and find the custom metric as part of the structured log entry.

structured-log-entry

Custom metric structured log entry

I can also create a custom metric graph. Within the CloudWatch console, I navigate to Metrics. I see the ServerlessAirlineEMF Custom Namespace is available.

custom-namespace

Custom metric namespace

I select the Namespace and the available metric.

available-namespace

Available metric

I select a Line graph, add a name, and see the successful booking now plotted on the graph.

custom-metric-plotted

Plotted CloudWatch metric

I can also visualize and analyze this metric using CloudWatch Insights.

Once a booking is made, within the CloudWatch console, I navigate to Logs | Insights. I select the /aws/lambda/Airline-ConfirmBooking-develop log group. I choose Run query which shows a list of discovered fields on the right of the console.

I can search for discovered booking related fields.

cloudwatch-insights-discovered-fieldsI then enter the following in the query pane to search the logs and plot the sum of BookingReference and choose Run Query:

fields @timestamp, @message
| stats sum(@BookingReference)

cloudwatch-insights-displayed-bookingreference

CloudWatch Insights query

There are a number of other component metrics that are important to measure. Track interactions between upstream and downstream components such as message queue length, integration latency, and throttling.

Improvement plan summary:

  1. Identify user journeys and metrics from each customer transaction.
  2. Create custom metrics asynchronously instead of synchronously for improved performance, cost, and reliability outcomes.
  3. Emit business metrics from within your workload to measure application performance against business goals.
  4. Create and analyze component metrics to measure interactions with upstream and downstream components.
  5. Create and analyze operational metrics to assess the health of your continuous delivery pipeline and operational processes.

Good practice: Use distributed tracing and code is instrumented with additional context

Logging provides information on the individual point in time events the application generates. Tracing provides a wider continuous view of an application. Tracing helps to follow a user journey or transaction through the application.

AWS X-Ray is an example of a distributed tracing solution, there are a number of third-party options as well. X-Ray collects data about the requests that your application serves and also builds a service graph, which shows all the components of an application. This provides visibility to understand how upstream/downstream services may affect workload health.

For the most comprehensive view, enable X-Ray across as many services as possible and include X-Ray tracing instrumentation in code. This is the list of AWS Services integrated with X-Ray.

X-Ray receives data from services as segments. Segments for a common request are then grouped into traces. Segments can be further broken down into more granular subsegments. Custom data key-value pairs are added to segments and subsegments with annotations and metadata. Traces can also be grouped which helps with filter expressions.

AWS Lambda instruments incoming requests for all supported languages. Lambda application code can be further instrumented to emit information about its status, correlation identifiers, and business outcomes to determine transaction flows across your workload.

X-Ray tracing for a Lambda function is enabled in the Lambda Console. Select a Lambda function. I select the Airline-ReserveBooking-develop function. In the Configuration pane, I select to enable X-Ray Active tracing.

x-ray-enable

X-Ray tracing enabled

X-Ray can also be enabled via CloudFormation with the following code:

TracingConfig:
  Mode: Active

Lambda IAM permissions to write to X-Ray are added automatically when active tracing is enabled via the console. When using CloudFormation, Allow the Actions xray:PutTraceSegments and xray:PutTelemetryRecords

It is important to understand what invocations X-Ray does trace. X-Ray applies a sampling algorithm. If an upstream service, such as API Gateway with X-Ray tracing enabled, has already sampled a request, the Lambda function request is also sampled. Without an upstream request, X-Ray traces data for the first Lambda invocation each second, and then 5% of additional invocations.

For the airline application, X-Ray tracing is initiated within the shared library with the code:

from aws_xray_sdk.core import models, patch_all, xray_recorder

Segments, subsegments, annotations, and metadata are added to functions with the following example code:

segment = xray_recorder.begin_segment('segment_name')
# Start a subsegment
subsegment = xray_recorder.begin_subsegment('subsegment_name')
# Add metadata and annotations
segment.put_metadata('key', dict, 'namespace')
subsegment.put_annotation('key', 'value')
# Close the subsegment and segment
xray_recorder.end_subsegment()
xray_recorder.end_segment()

For example, within the collect payment module, an annotation is added for a successful payment with:

tracer.put_annotation("PaymentStatus", "SUCCESS")

CloudWatch ServiceLens

Once a booking is made and payment is successful, the tracing is available in the X-Ray console.

I explore how Amazon CloudWatch ServiceLens connects metrics, logs and the X-Ray tracing. Within the CloudWatch console, I navigate to ServiceLens | Service Map.

I can visualize all application resources and dependencies where X-Ray is enabled. I can trace performance or availability issues. If there was an issue connecting to SNS for example, this would be shown.

I select the Airline-CollectPayment-develop node and can view the out-of-the-box standard Lambda metrics.

I can select View Logs to jump to the CloudWatch Logs Insights console.

cloudwatch-insights-service-map-view

CloudWatch Insights Service map

I select View dashboard to see the function metrics, node map, and function details.

cloudwatch-insights-service-map-dashboard

CloudWatch Insights Service Map dashboard

I select View traces and can filter by the custom metric PaymentStatus. I select SUCCESS and chose Add to filter. I then select a trace.

cloudwatch-insights-service-map-select-trace

CloudWatch Insights Filtered traces

I see the full trace details, which show the full application transaction of a payment collection.

cloudwatch-insights-service-map-view-trace

Segments timeline

Selecting the Lambda handler subsegment – ## lambda_handler, I can view the trace Annotations and Metadata, which include the business transaction details such as Customer and PaymentStatus.

cloudwatch-insights-service-map-view-trace-annotations

X-Ray annotations

Trace groups are another feature of X-Ray and ServiceLens. Trace groups use filter expressions such as Annotation.PaymentStatus = "FAILED" which are used to view traces that match the particular group. Service graphs can also be viewed, and CloudWatch alarms created based on the group.

CloudWatch ServiceLens provides powerful capabilities to understand application performance bottlenecks and issues, helping determine how users are impacted.

Improvement plan summary:

  1. Identify common business context and system data that are commonly present across multiple transactions.
  2. Instrument SDKs and requests to upstream/downstream services to understand the flow of a transaction across system components.

Recent announcements

There have been a number of recent announcements for X-Ray and CloudWatch to improve how to evaluate serverless application health.

Conclusion

Evaluating application health helps you identify which services should be optimized to improve your customer’s experience. In part 1, I cover out-of-the-box standard metrics and alerts, as well as structured and centralized logging. In this post, I explore custom metrics and distributed tracing and show how to use ServiceLens to view logs, metrics, and traces together.

In an upcoming post, I will cover the next Operational Excellence question from the Well-Architected Serverless Lens – Approaching application lifecycle management.

Building well-architected serverless applications: Understanding application health – part 1

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/building-well-architected-serverless-applications-understanding-application-health-part-1/

This series of blog posts uses the AWS Well-Architected Tool with the Serverless Lens to help customers build and operate applications using best practices. In each post, I address the nine serverless-specific questions identified by the Serverless Lens along with the recommended best practices. See the Introduction post for a table of contents and explaining the example application.

Question OPS1: How do you evaluate your serverless application’s health?

Evaluating your metrics, distributed tracing, and logging gives you insight into business and operational events, and helps you understand which services should be optimized to improve your customer’s experience. By understanding the health of your Serverless Application, you will know whether it is functioning as expected, and can proactively react to any signals that indicate it is becoming unhealthy.

Required practice: Understand, analyze, and alert on metrics provided out of the box

It is important to understand metrics for every AWS service used in your application so you can decide how to measure its behavior. AWS services provide a number of out-of-the-box standard metrics to help monitor the operational health of your application.

As these metrics are generated automatically, it is a simple way to start monitoring your application and can also be augmented with custom metrics.

The first stage is to identify which services the application uses. The airline booking component uses AWS Step Functions, AWS Lambda, Amazon SNS, and Amazon DynamoDB.

When I make a booking, as shown in the Introduction post, AWS services emit metrics to Amazon CloudWatch. These are processed asynchronously without impacting the application’s performance.

There are two default CloudWatch dashboards to visualize key metrics quickly: per service and cross service.

Per service

To view the per service metrics dashboard, I open the CloudWatch console.

per-service-metrics-dashboardI select a service where Overview is shown, such as Lambda. Now I can view the metrics for all Lambda functions in the account.

per-service-metrics-lambdaCross service

To see an overview of key metrics across all AWS services, open the CloudWatch console and choose View cross service dashboard.

cross-service-metrics-dashboardI see a list of all services with one or two key metrics displayed. This provides a good overview of all services your application uses.

Alerting

The next stage is to identify the key metrics for comparison and set up alerts for under- and over-performing services. Here are some recommended metrics to alarm on for a number of AWS services.

Alerts can be configured manually or via infrastructure as code tools such as the AWS Serverless Application Model, AWS CloudFormation, or third-party tools.

To configure a manual alert for Lambda function errors using CloudWatch Alarms:

  1. I open the CloudWatch console and select Alarms and select Create Alarm.
  2. I choose Select Metric and from AWS Namespaces, select Lambda, Across All Functions and select Errors and select Select metric.add-metric-to-alert
  3. I change the Statistic to Sum and the Period to 1 minute.metric-values
  4. Under Conditions, I select a Static threshold Greater than 1 and select Next.

Alarms can also be created using anomaly detection rather than static values if there is a discernible pattern or trend. Anomaly detection looks at past metric data and uses machine learning to create a model of expected values. Alerts can then be configured if they fall outside this band of “normal” values. I use a Static threshold for this alarm.

  1. For the notification, I set the trigger to alarm to an existing SNS topic with my email address, then choose Next.metric-notification
  2. I enter a descriptive alarm name such as serverlessairline-lambda-prod-errors > 1, select Next, and choose Create alarm.

I have now manually set up an alarm.

Use CloudWatch composite alarms to combine multiple alarms to reduce noise and focus on critical issues. For example, a single alarm could trigger if there are both Lambda function errors as well as high Lambda concurrent executions.

It is simpler and more scalable to include alerting within infrastructure as code. Here is an example of alerting programmatically using CloudFormation.

I view the out of the box standard metrics and in this example, manually create an alarm for Lambda function errors.

Improvement plan summary:

  1. Understand what metrics and dimensions each managed service used provides.
  2. Configure alerts on relevant metrics for when services are unhealthy.

Good practice: Use structured and centralized logging

Central logging provides a single place to search and analyze logs. Structured logging means selecting a consistent log format and content structure to simplify querying across multiple components.

To identify a business transaction across components, such as a particular flight booking, log operational information from upstream and downstream services. Add information such as customer_id along with business outcomes such as order=accepted or order=confirmed. Make sure you are not logging any sensitive or personal identifying data in any logs.

Use JSON as your logging output format. Log multiple fields in a single object or dictionary rather than many one line messages for simpler searching.

Here is an example of a structured logging format.

The airline booking component, which is written in Python, currently uses a shared library with a separate log processing stack.

Embedded Metrics Format is a simpler mechanism to replace the shared library and use structured logging. CloudWatch Embedded Metrics adds environmental metadata such as Lambda Function version and also automatically extracts custom metrics so you can visualize and alarm on them. There are open-source client libraries available for Node.js and Python.

I then add embedded metrics to the individual confirm booking module with the following steps:

  1. I install the aws-embedded-metrics library using the instructions.
  2. In the function init code, I import the module and create a metric_scope with the following code

from aws_embedded_metrics import metric_scope
@metric_scope

  1. In the function handler, I log the generated bookingReference with the following code.

metrics.set_property("BookingReference", ret["bookingReference"])

In this example I also log the entire incoming event details.

metrics.set_property("event", event)

It is best practice to only log what is required to avoid unnecessary costs. Ensure the event does not have any sensitive or personal identifying data which is available to anyone who has access to the logs.

To avoid the duplicate logging in this example airline application which adds cost, I remove the existing shared library logger.*() lines.

When I make a booking, the CloudWatch log message is in structured JSON format. It contains the properties I set event, BookingReference, as well as function metadata.

I can then search for all log activity related to a specific booking across multiple functions with booking_id. I can track customer activity across multiple bookings using customer_id.

Logging is often created as a shared library resource which all functions reference. Another option is using Lambda Layers, which lets functions import additional code such as external libraries. Multiple functions can share this code.

Improvement plan summary:

  1. Log request identifiers from downstream services, component name, component runtime information, unique correlation identifiers, and information that helps identify a business transaction.
  2. Use JSON as the logging output. Prefer logging entire objects/dictionaries rather than many one line messages. Mask or remove sensitive data when logging.
  3. Minimize logging debugging information to a minimum as they can incur both costs and increase noise to signal ratio

Conclusion

Evaluating serverless application health helps understand which services should be optimized to improve your customer’s experience. I cover out of the box metrics and alerts, as well as structured and centralized logging.

This well-architected question will be continued in an upcoming post where I look at custom metrics and distributed tracing.

Building well-architected serverless applications: Introduction

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/building-well-architected-serverless-applications-introduction/

Customers building production applications in the cloud are looking to build and operate their applications following best practices. Best practices are useful throughout the software development lifecycle and help to answer the question “am I well-architected?”

Serverless technologies provide a solid foundation for building well-architected applications with a goal to reduce and minimize the impact of issues that can happen. What does it mean to be “well architected”?

In 2015, AWS released the AWS Well-Architected Framework.  It’s a structured way to compare applications against AWS architectural best practices with advice on how to improve. This formalized framework publicly documents the approach our solutions architects use when conducting architectural reviews. The Well-Architected Framework can be used by customers and partners to evaluate applications. It’s currently based on five pillars:

  • Operational Excellence
  • Security
  • Reliability
  • Performance Efficiency
  • Cost Optimization

In 2017, AWS extended the framework’s general advice to be more application domain specific with the concept of a “lens”. A lens adds additional questions for specific technology areas, which focus on what is different from the generic advice. Today, there are three technology domain lenses:

In 2018, AWS added the AWS Well-Architected Tool within the AWS Management Console. The tool allows you to define a Workload and answer a number of questions based on each of the five pillars. Each question has context to explain what the question means and why it is important, and then provides a number of best practices.

well-architected-tool-questionThe tool is used to assess risks, and find opportunities for improvement for workloads. It can also provide a broader view across multiple applications for a central team. Each question has a number of best practices to follow, categorized as high or medium risk. This can help you decide where to focus.

Serverless Lens

In February, we added functionality to apply lenses to the Well-Architected Tool. The first one is the Serverless Lens. This includes nine questions, each with additional best practice recommendations to follow.

serverless-lens-in-consoleApplying best practices to production applications may need some more time and effort. The Well-Architected Tool and Serverless Lens are available to help and are not intended to only be a one-time check.

We suggest at a minimum reading the whitepapers and being familiar with the questions before the design phase. It’s a good idea to check throughout the application lifecycle; halfway (or sooner), close to launch, and post-launch for each iteration. Although it is never too late to add best practices to your applications, starting early helps reduce the remediation process as well as making it part of the full application lifecycle journey.

The following posts are a multi-part series addressing each of the questions within the Serverless Lens of the Well-Architected Tool.

Series Episodes: Building well-architected serverless applications

  1. Introduction
  2. Operational Excellence: Understanding serverless application health
    1. Out of the box metrics and alerts; structured and centralized logging
    2. Custom metrics and distributed tracing (upcoming)
  3. Operational Excellence – Understanding serverless application health (upcoming)
  4. Operational Excellence – Approaching application lifecycle management (upcoming)
  5. Security – Controlling access to serverless APIs (upcoming)
  6. Security – Managing serverless security boundaries (upcoming)
  7. Security – Implementing application security (upcoming)
  8. Reliability – Regulating inbound request rates (upcoming)
  9. Reliability – Building resiliency into serverless applications (upcoming)
  10. Performance Efficiency – Optimizing your Serverless Application Performance (upcoming)
  11. Cost Optimization – Optimizing your Serverless Application Costs (upcoming)

Example application

For this series, I am looking at an example application, AWS Serverless Airline Booking. This is a complete web application for a fictional airline booking service built using serverless technologies that provide Flight Search, Payment, Booking, and Loyalty Point features.

I show how to use the Well-Architected Tool with the Serverless Lens to help apply serverless best practices to the application.

airline-mobile-exampleThis web application is the theme of Season 2 of Build on Serverless, which is a video series on Twitch.tv, and presented at AWS re:Invent 2019.

You can view this application directly on GitHub or deploy into an AWS account using the Getting Started instructions. This is not required to follow this Building Well-Architected Serverless Applications series but allows you to explore the code.

The application architecture consists of a frontend web application, which interacts with a number of backend microservices to provide the airline booking functionality.

airline-architectureThere are four backend services that make up the application:

Service Description
Catalog Provides flight search
Booking Provides new and list bookings. Business workflow implemented in Python.
Payment Provides payment authorization, collection, and refund workflows using Stripe. Business workflow implemented in Python
Loyalty Provides loyalty points for customers including tiers. Implemented in TypeScript.

Once the application is deployed, I can create a booking by searching for flights.

Once I select an available flight, I enter payment details using a test Stripe credit card.

The application authorizes the payment, confirms, and stores the booking and then updates the loyalty points.

Next steps

Building serverless applications using best practices can give you more confidence in the architecture and operations of your workloads.

Using the Well-Architected Tool and Serverless Lens can give you more visibility into your applications. They can help pinpoint and rank areas to improve. Well-Architected works best when integrated into your application lifecycle processes.

Continue learning in the next post, which dives into the first Well-Architected Serverless Lens question: Operational Excellence – Understanding Serverless Application Health – part1.

Introducing Amazon EventBridge schema registry and discovery – In preview

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/introducing-amazon-eventbridge-schema-registry-and-discovery-in-preview/

Today, AWS announces the preview of Amazon EventBridge schema registry and discovery. These are new developer tool features, which allow you to automatically find events and their structure, or schema, and store them in a shared central location. This makes it faster and easier to build event-driven applications. You can access the registry and generate code bindings for schemas directly in popular Integrated Development Environments (IDEs), including JetBrains IntelliJ and PyCharm, Microsoft Visual Studio Code, as well as through the Amazon EventBridge console and APIs.

What is a schema?

A schema represents the structure of an event, and commonly includes information such as the title and type of each piece of data. For example, in a review on a product website, a schema might include fields for the reviewer’s name, user id, and review description, and that the name is a text string, and the user id is an integer. The event schema is important for developers as it shows what data is contained in the event, and allows them to write code based on that data.

Event-driven architectures

Developers embracing event-driven architectures may use an event bus such as Amazon EventBridge. EventBridge allows application decoupling without needing to write point-to-point integrations between services. This decoupling increases developer independence, as they simply subscribe to the events they’re interested in, reducing dependencies on other teams to write integrations.

However, decoupling introduces a new set of challenges. Finding events and their schema is a manual process. Developers must coordinate with the team responsible for publishing an event, or look through documentation to find its schema, and then manually create an object for the event in order to use it in their code.

EventBridge schema registry solves these problems by introducing two capabilities, a schema registry and schema discovery.

Schema registry

A schema registry stores a collection of schemas. You can use schema registry to search for, find, and track different schemas used and generated by your applications. Schemas for all AWS sources supported in EventBridge are automatically visible in your schema registry. SaaS partner and custom schemas can be generated and added to the registry using the schema discovery feature.

Schema discovery

Schema discovery automates the process of finding schemas and adding them to your registry. When schema discovery is enabled for an EventBridge event bus, the schema of each event sent to the bus is automatically added to the registry. If the schema of an event changes, schema discovery automatically creates a new version in the registry. Once a schema is added to the registry, you can generate a code binding for the schema, either in the EventBridge console or directly in your IDE.

Generally, you only enable schema discovery in your development environments (AWS Free Tier includes 5 million ingested events). Schemas of any new events you create are automatically added to your registry to use when developing your application. If you need to audit all of the events going through your event bus, you can enable discovery on your production event bus, and pay $0.10 per million events ingested for any usage outside of the Free Tier.

Code bindings

Once a schema is added to the registry, you can download a code binding. This allows you to represent the event as a strongly typed object in your code, and take advantage of IDE features such as validation and auto-complete. Code bindings are available for Java, Python, or TypeScript programming languages. You can download bindings from the AWS Management Console, or directly from your IDE with the AWS Toolkit plugin for IntelliJ and VS Code.

If you use the AWS Serverless Application Model (SAM), you can now use the interactive sam init command to generate a serverless application with a schema as a trigger. This automatically adds a class file for the schema to your code, and generates a handler function that serializes the trigger event into an object. This makes it quicker to build serverless event-driven applications.

Event Schemas

Viewing the schema registry

You can view the schema registry in the Amazon EventBridge console and download code bindings.

  1. Choose Go to schema registry and then choose Schemas in the left-side navigation bar. You can view and search for built-in AWS schemas, as well as your discovered and custom schemas within the registry.
  2. For example, searching for a schema for AWS Step Functions, there is an existing schema for: aws.states.StepFunctionsExecutionStatusChange. The schema details as well as the JSON representation are visible.
  3. json schema

  4. To Download code bindings to use in your IDE, select a language option, download the .zip file, and manually import the schema into your IDE.

Automatically discovering schemas

Schema registry’s discovery capabilities allow you to generate schemas for your own events. EventBridge can ingest events from a number of SaaS vendors including, for example MongoDB.

In this example, I use an online shop, which stores product reviews in a MongoDB database. A MongoDB trigger is configured to send all new database entries to the EventBridge MongoDB partner event bus. A Lambda function is then triggered for all new events and calls Amazon Comprehend to do sentiment analysis on the new reviews. Any negative reviews generate a service desk ticket for further investigation.

  1. I have previously set up MongoDB Atlas to connect as a SaaS partner to EventBridge. I have configured a stitch trigger to send events to EventBridge for any updates to the database.
  2. To discover the schema, in the EventBridge console, I navigate to Events and Partner event sources.
  3. I select the MongoDB event source and choose Associate with event bus.
  4. I choose Associate.
  5. I Navigate to Event buses and choose the MongoDB Custom event bus and choose Start discovery. An event bus-managed rule is created automatically.
  6. custom event busses

  7. I write a new product review, creating a new database record, which triggers a new event on the event bus. You can simulate this using the AWS CLI. Replace the EventBusName with your partner event bus.
  8. aws events put-events --entries '[[{"Source": "mystore","DetailType": "Review Created","EventBusName":"aws.partner/mongodb.com/stitch.trigger/5ddf5c9476ff0ff8b0916763","Detail": "{\"star_rating\": 5,  \"description\": \"The size and length fit me well and the design is fun. I felt very secure wearing this tshirt. \",  \"helpful_count\": 34,  \"unhelpful_count\": 1,  \"pros\": [\"lightweight\",\"fits well\"  ],  \"cons\": [],  \"customer\": {\"name\": \"Julian Wood\",\"email\": \"[email protected]\",\"phone\": \"+1 604 123 1234\"  },  \"product\": {\"product_id\": 788032119674292922,\"title\": \"Encrypt Everything Tshirt\",\"sku\": \"encrypt-everything-tshirt\",\"inventory_id\": 23190823132,\"size\": \"medium\",\"taxable\": true,\"image_url\": \"https://img.mystore.test/encrypt-tshirt.jpg\",\"weight\": 200.0}}"}]'

  9. I navigate to Schema registry and schemas, choose Discovered schema registry, and can see the discovered schema from the new review event.
  10. Choosing the schema name, I can view the generated schema. Here is an excerpt

Schema discovery has automatically discovered the MongoDB schema from events passing through the event bus and added it to the registry.

Downloading code bindings directly into an IDE

Schema code bindings can be downloaded directly from the AWS Management Console as well as within an IDE, for example JetBrains IntelliJ.

  1. I have IntelliJ installed.
  2. I launch IntelliJ, navigate to File | Settings, and choose Plugins.
  3. On the Marketplace tab, in Search plugins, I enter AWS. When AWS Toolkit by Amazon Web Services is displayed, I select it and choose Install. Minimum version 1.9 is required.
  4. AWSToolkit

  5. I accept the third-party Plugins Privacy Note and choose Restart IDE.
  6. Once the IDE has restarted, I navigate to AWS Explorer at the bottom-left of the IDE to view available schemas.
  7. I choose Configure AWS connection.
  8. Configure AWS Connection

  9. I choose Credentials, my local AWS account profiles are automatically loaded from the AWS credentials file.
  10. I choose Schemas\discovered-schemas, right-click and then choose View Schema to see the schema.
  11. View Schema

  12. I can then use the code binding in a project, I navigate to File | New Project.
  13. A number of languages and frameworks are available to build an application. I want to build a serverless application and so choose AWS and AWS Serverless Application, which builds an AWS Serverless Application Model application project. I choose Next.
  14. Create SAM App

  15. I enter a Project name and file location, choosing java8 as the Runtime.
  16. I choose AWS SAM EventBridge App from Scratch (for any Event trigger from a Schema Registry) for Gradle.
  17. I select Credentials and Region
  18. Under Event Schema, I browse the available schema. At the end of the list, I find the discovered MongoDB schema. I select it and choose Finish.

SAM Peoject

Once the project is created, I can see the event schema imported into the SAM project.

I navigate to and open mongodb-app\HelloWorldFunction\src\main\java\helloworld\App.java to see the Lambda handler created with the event schema details. I can also use full IDE auto-complete with the schema.

Code Completion

I can then add the Amazon Comprehend sentiment analysis code using the schema into the Lambda function.
The SAM template.yaml in the project root directory specifies the Lambda function triggered by an EventBridge event (previously called CloudWatchEvent) using the discovered MongoDB schema.
I change the EventBusName to the correct partner event bus.

Resources:
  HelloWorldFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: HelloWorldFunction
      Handler: helloworld.App::handleRequest
      Runtime: java8
      Environment: 
        Variables:
          PARAM1: VALUE
      Events:
        HelloWorld:
          Type: CloudWatchEvent 
          Properties:
            EventBusName:
                - aws.partner/mongodb.com/stitch.trigger/5ddf5c9476ff0ff8b0916763
            Pattern:
              source:
                - aws.partner/mongodb.com.test/stitch.trigger/5ddf5c9476ff0ff8b0916
              detail-type:
                - MongoDB Database Trigger for my_store.reviews

I can then deploy the SAM application.
I navigate to File | Deploy SAM Application .I choose Create Stack and enter a name. Select an S3 bucket and choose Deploy.

Deploy SAM

The SAM application is deployed. I can also automate the process using SAM CLI. Version 0.35.0 includes the schema features in the new interactive sam init command. This uses an AWS Quick Start Template to generate a handler function and add a class file for the schema to my code.

Pricing

Usage of the schema registry is free.

Schema discovery includes a free tier of 5M ingested events per month. In use cases where discovery is used in your development environment, your usage should stay within the free tier.

For additional usage outside of the free tier:

  • $0.10 per million events ingested for discovery.

All ingested events are measured in 8 KB chunks.

Availability

The EventBridge schema registry preview is available in the US East (Ohio), US West (Oregon), US East (Northern Virginia) Asia Pacific (Tokyo) Region, and Europe (Ireland) Regions. For details on EventBridge availability, please see the AWS Region table (https://aws.amazon.com/about-aws/global-infrastructure/regional-product-services/).

Conclusion

Amazon EventBridge schema registry and discovery helps developers take advantage of new schema capabilities to build exciting event-driven applications. All AWS sources supported in EventBridge are visible in your schema registry. SaaS partner and custom schemas can be added automatically using schema discovery. Code bindings, which allow you to represent the event as an object in your code, can be downloaded from the console or directly within IDEs.

Happy coding with event schemas!

Introducing AWS Lambda Destinations

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/introducing-aws-lambda-destinations/

Today we’re announcing AWS Lambda Destinations for asynchronous invocations. This is a feature that provides visibility into Lambda function invocations and routes the execution results to AWS services, simplifying event-driven applications and reducing code complexity.

Asynchronous invocations

When a function is invoked asynchronously, Lambda sends the event to an internal queue. A separate process reads events from the queue and executes your Lambda function. When the event is added to the queue, Lambda previously only returned a 2xx status code to confirm that the queue has received this event. There was no additional information to confirm whether the event had been processed successfully.

A common event-driven microservices architectural pattern is to use a queue or message bus for communication. This helps with resilience and scalability. Lambda asynchronous invocations can put an event or message on Amazon Simple Notification Service (SNS), Amazon Simple Queue Service (SQS), or Amazon EventBridge for further processing. Previously, you needed to write the SQS/SNS/EventBridge handling code within your Lambda function and manage retries and failures yourself.

With Destinations, you can route asynchronous function results as an execution record to a destination resource without writing additional code. An execution record contains details about the request and response in JSON format including version, timestamp, request context, request payload, response context, and response payload. For each execution status such as Success or Failure you can choose one of four destinations: another Lambda function, SNS, SQS, or EventBridge. Lambda can also be configured to route different execution results to different destinations.

Asynchronous Function Execution Result

Success

When a function is invoked successfully, Lambda routes the record to the destination resource for every successful invocation. You can use this to monitor the health of your serverless applications via execution status or build workflows based on the invocation result.

You no longer need to chain long-running Lambda functions together synchronously. Previously you needed to complete the entire workflow within the Lambda 15-minute function timeout, pay for idle time, and wait for a response. Destinations allows you to return a Success response to the calling function and then handle the remaining chaining functions asynchronously.

Failure

Alongside today’s announcement of Maximum Event Age and Maximum Retry Attempt for asynchronous invocations, Destinations gives you the ability to handle the Failure of function invocations along with their Success. When a function invocation fails, such as when retries are exhausted or the event age has been exceeded (hitting its TTL), Destinations routes the record to the destination resource for every failed invocation for further investigation or processing.

Dead Letter Queues (DLQ) have been available since 2016 and are a great way to handle asynchronous failure situations. Destinations provide more useful capabilities by passing additional function execution information, including code exception stack traces, to more destination services.

Destinations and DLQs can be used together and at the same time although Destinations should be considered a more preferred solution. If you already have DLQs set up, existing functionality does not change and Destinations does not replace existing DLQ configurations. If both Destinations and DLQ are used for Failure notifications, function invoke errors are sent to both DLQ and Destinations targets.

How to configure Destinations

Adding Destinations is a straightforward process. This walkthrough uses the AWS Management Console but you can also use the AWS CLI, AWS SAM, AWS CloudFormation, or language-specific SDKs for Lambda.

  1. Open the Lambda console Functions page. Choose an existing Lambda function, or create a new one. In this example, I create a new Lambda function. Choose Create Function.
  2. Enter a Function name, select Node.js 12.x for Runtime, and Choose or create an execution role. Ensure that your Lambda function execution role includes access to the destination resource.
    Basic information
  3. Choose Create function.
  4. Within the Function code pane, paste the following Lambda function code. The code generates a function execution result of either Success or Failure depending on a JSON input ("Success": true or "Success": false).
    // Lambda Destinations tester, Success returns a json blob, Failure throws an error
    
    exports.handler = function(event, context, callback) {
        var event_received_at = new Date().toISOString();
        console.log('Event received at: ' + event_received_at);
        console.log('Received event:', JSON.stringify(event, null, 2));
    
        if (event.Success) {
            console.log("Success");
            context.callbackWaitsForEmptyEventLoop = false;
            callback(null);
        } else {
            console.log("Failure");
            context.callbackWaitsForEmptyEventLoop = false;
            callback(new Error("Failure from event, Success = false, I am failing!"), 'Destination Function Error Thrown');
        }
    };
    
  5. Choose Save.
  6. To configure Destinations, within the Designer pane, choose Add destination.
    Designer pane
  7. Select the Source as Asynchronous invocation. Select the Condition as On failure or On success, depending on your use case. In this example, I select On Success.
  8. Enter the Amazon Resource Name (ARN) for the Destination SQS queue, SNS topic, Lambda function, or EventBridge event bus. In this example, I use the ARN of an SNS topic I have already configured.
    Add destination
  9. Choose Save. The Destination is added to SNS for On Success.
    Designer
  10. Add another Destination for Failure to Lambda. Within the Designer pane, choose Add destination.
    Add destination
  11. Select the Source as Asynchronous invocation, the Condition as On failure and Enter a Destination Lambda function ARN, then choose Save.
    Enter a Destination Lambda function ARN, and choose Save
  12. The Destination is added to Lambda for On Failure.
    7. The Destination has been added to Lambda for On Failure.

Success testing

To test invoking the asynchronous Lambda function to generate a Success result, use the AWS CLI:

aws lambda invoke --function-name event-destinations --invocation-type Event --payload '{ "Success": true }' response.json

The Lambda function is invoked successfully with a response "StatusCode": 202.

And an SNS notification email is received, showing the invocation details with "condition":"Success" and the requestPayload.

{
	"version": "1.0",
	"timestamp": "2019-11-24T23:08:25.651Z",
	"requestContext": {
		"requestId": "c2a6f2ae-7dbb-4d22-8782-d0485c9877e2",
		"functionArn": "arn:aws:lambda:sa-east-1:123456789123:function:event-destinations:$LATEST",
		"condition": "Success",
		"approximateInvokeCount": 1
	},
	"requestPayload": {
		"Success": true
	},
	"responseContext": {
		"statusCode": 200,
		"executedVersion": "$LATEST"
	},
	"responsePayload": null
}

Failure testing

The Lambda function can be set to Failure by throwing an exception within the code. To test invoking the asynchronous Lambda function to generate a Failure result, use the AWS CLI:

aws lambda invoke --function-name event-destinations --invocation-type Event --payload '{ "Success": false }' response.json

The Lambda function is executed and reports a successful invoke on the Lambda processing queue. If Lambda is not able to add the event to the queue, the error message appears in the command output.

However, due to the exception error within the code, the function invocation will fail. Destinations then routes the invoke failure to the configured destination Lambda function. You can see the failed function invocation information in the Amazon CloudWatch Logs for the Destination function including "condition": "RetriesExhausted", along with the requestPayload, errorMessage, and stackTrace.

2019-11-24T21:52:47.855Z	d123456-c0dd-4871-a123-a356cb1b3ba6	EVENT
{
    "version": "1.0",
    "timestamp": "2019-11-24T21:52:47.333Z",
    "requestContext": {
        "requestId": "8ea123e4-1db7-4aca-ad10-d9ca1234c1fd",
        "functionArn": "arn:aws:lambda:sa-east-1:123456678912:function:event-destinations:$LATEST",
        "condition": "RetriesExhausted",
        "approximateInvokeCount": 3
    },
    "requestPayload": {
        "Success": false
    },
    "responseContext": {
        "statusCode": 200,
        "executedVersion": "$LATEST",
        "functionError": "Handled"
    },
    "responsePayload": {
        "errorMessage": "Failure from event, Success = false, I am failing!",
        "errorType": "Error",
        "stackTrace": [ "exports.handler (/var/task/index.js:18:18)" ]
    }
}

Destination-specific JSON format

  • For SNS/SQS, the JSON object is passed as the Message to the destination.
  • For Lambda, the JSON is passed as the payload to the function. The destination function cannot be the same as the source function. For example, if LambdaA has a Destination configuration attached for Success, LambdaA is not a valid destination ARN. This prevents recursive functions.
  • For EventBridge, the JSON is passed as the Detail in the PutEvents call. The source is lambda, and detail type is either Lambda Function Invocation Result - Success or Lambda Function Invocation Result – Failure. The resource fields contain the function and destination ARNs.

AWS CloudFormation configuration

Destinations CloudFormation configuration is created via the following YAML.

Resources: 
  EventInvokeConfig:
    Type: AWS::Lambda::EventInvokeConfig
    Properties:
        FunctionName: “YourLambdaFunctionWithEventInvokeConfig”
        Qualifier: "$LATEST"
        MaximumEventAgeInSeconds: 600
        MaximumRetryAttempts: 0
        DestinationConfig:
            OnSuccess:
                Destination: “arn:aws:sns:us-east-1:123456789012:YourSNSTopicOnSuccess”
            OnFailure:
                Destination: “arn:aws:lambda:us-east-1:123456789012:function:YourLambdaFunctionOnFailure”

Conclusion

AWS Lambda Destinations gives you more visibility and control of function execution results. This helps you build better event-driven applications, reducing code, and using Lambda’s native failure handling controls.

There are no additional costs for enabling Lambda Destinations. However, calls made to destination target services may be charged.

To learn more, see Lambda Destinations in the AWS Lambda Developer Guide.

Python 3.8 runtime now available in AWS Lambda

Post Syndicated from Julian Wood original https://aws.amazon.com/blogs/compute/python-3-8-runtime-now-available-in-aws-lambda/

You can now develop your AWS Lambda functions using the Python 3.8 runtime. Start using this runtime today by specifying a runtime parameter value of python3.8 when creating or updating Lambda functions.

New Python runtime features

Python 3.8 is a stable release and brings several new features, including assignment expressions, positional-only arguments, and vectorcall.

Assignment expressions

Assignment expressions provide a way to assign values to variables within expressions using the new notation NAME := expr. This is informally known as the “walrus operator,” as it looks like the eyes and tusks of a walrus on its side.

Before:

>>> walrus = True
print(walrus)
True

After:

>>> print(walrus := True)
True

Previously, assignment was only available in statement form. With Python 3.8, it is available in list comprehensions and other expression contexts.

For examples, usage, and limitations, see PEP-572.

Positional-only arguments

Positional-only parameters give more control to library authors by introducing a new function parameter syntax `/` to indicate that some function parameters must be specified positionally and cannot be used as keyword arguments.

When describing APIs, they can be used to better express the intended usage and allow the API to evolve in a safe, backward-compatible way. They also make the Python language more consistent with existing documentation and the behavior of various “builtin” and standard library functions.

For a full specification, including syntax and examples, see PEP-570 and PEP-457.

f-strings support

An f-string is a formatted string literal to enclose variables, and even expressions, inside curly braces. An F-string is evaluated at runtime and included in the string, recognized by the leading f:

>>> city = "London"
>>> f"Living in {city} is amazing"
'Living in London is amazing'

Python 3.8 adds the ability to use assignment expressions inside f-strings which are evaluated from left-to-right.

>>> import math
>>> radius = 3.8

>>> f"With a diameter of {( diameter := 2 * radius)}, the circumference is {math.pi * diameter:.2f}"
' With a diameter of 7.6 the circumference is 23.88'

Vectorcall

Vectorcall is a new protocol and calling convention based on the “fastcall” convention, which was previously used internally by CPython. The new features can be used by any user-defined extension class. Vectorcall generalizes the calling convention used internally for Python and builtin functions so that all calls can benefit from better performance. It is designed to remove the overhead of temporary object creation and multiple indirections.

For additional information on vectorcall, see PEP-590.

Amazon Linux 2

Python 3.8, like Node.js 10 and 12, and Java 11, is based on an Amazon Linux 2 execution environment. Amazon Linux 2 provides a secure, stable, and high-performance execution environment to develop and run cloud and enterprise applications.

Next steps

Get started building with Python 3.8 today by specifying a runtime parameter value of python3.8 when creating or updating your Lambda functions.

Enjoy, go build with Python 3.8!