Power Tools for AWS Lambda

Introduction

• Power Tools for AWS Lambda is a set of utilities and features that help developers build and operate serverless applications on AWS Lambda.
• It was launched in 2020 and started with core utilities around observability, such as structured logging, custom metrics, and distributed tracing.
• Over time, Power Tools expanded to include more features like batch processing, input/output validation, idempotency, and more.
• Power Tools is an open-source project maintained by AWS and contributions are welcome from the community.

Structured Logging

• Traditional logging in Lambda involves using a logging library and emitting strings to standard output/error.
• This can make it challenging to parse and query logs, especially at scale.
• Power Tools Logger provides a structured logging solution that emits JSON objects, allowing for easy querying and filtering in CloudWatch Logs.
• The logger supports features like setting a service name, adding contextual information, and generating correlation IDs.
• Power Tools Logger is also extensible, allowing users to customize the log format to their needs.
• A common practice is to use "wide logging", where a single log entry contains all relevant information about a request, instead of multiple scattered logs.

Event Handler

• When building serverless APIs backed by Lambda, there are many common concerns to address, such as routing, input/output serialization, validation, and observability.
• Power Tools Event Handler provides a layer of abstraction to handle these concerns, allowing developers to focus on their business logic.
• It supports features like routing, input validation, open API specification generation, middleware, and more.
• The Event Handler is designed to be provider-agnostic, so you can easily switch between different entry points (e.g., API Gateway, ALB, Function URLs) without changing your application code.

Idempotency

• Idempotency is the ability to perform an operation multiple times without changing the result.
• This is important for use cases like financial transactions, where you don't want to charge a user twice.
• Power Tools Idempotency utility provides a way to make your Lambda functions idempotent by tracking the state of previous executions and returning the cached result if the same input is received.
• It supports different persistence layers (e.g., DynamoDB, Redis) and allows you to configure the idempotency based on specific fields in the input payload.

Batch Processing

• When your Lambda function is triggered by event sources like SQS, Kinesis, or DynamoDB streams, it receives a batch of records to process.
• Power Tools Batch Processing utility helps you handle partial failures, where some records in the batch fail to process while others succeed.
• It provides a simple API to process the batch, and automatically handles retrying failed records while marking successful ones as processed.
• The Batch Processing utility is designed to be trigger-agnostic, so you can easily switch between different event sources without changing your application code.

Roadmap and Community

• Power Tools for AWS Lambda is actively maintained by AWS, and the roadmap is driven by customer feedback and demand.
• The roadmap for upcoming versions is published and can be found online.
• Customers are encouraged to provide feedback, open issues, and contribute to the project on GitHub.