AWS Lambda Powertools for Java is an open-source library to help discover and incorporate serverless best practices early and quickly. It is a suite of utilities for AWS Lambda Functions that makes tracing with AWS X-Ray, structured logging, and creating custom metrics asynchronously easier.

Logging

• Captures key fields from Lambda context, cold start, and structures logging output as JSON.
• Log Lambda event when instructed, disabled by default, can be enabled explicitly via annotation param.
• Appends additional keys to structured log at any point in time.

Tracing

• Powertools tracing is an opinionated thin wrapper for AWS X-Ray Java SDK and provides functionality to reduce the overhead of performing common tracing tasks.
• Captures cold start as annotation, and responses as well as full exceptions as metadata.
• Helper methods to improve the developer experience of creating new X-Ray subsegments.
• Better developer experience when developing with multiple threads.
• Auto patch supported modules by AWS X-Ray.

Metrics

• Aggregates up to 100 metrics using a single CloudWatch EMF object (large JSON blob).
• Validates against common metric definitions mistakes (metric unit, values, max dimensions, max metrics, etc).
• Metrics are created asynchronously by the CloudWatch service, no custom stacks needed.
• Context manager to create a one-off metric with a different dimension.

Extra utilities

• Idempotency – allows safe retries for your function
• Parameters – retrieves values from Parameter Store or Secrets Manager
• SQS large message handling – handles SQS messages with payloads in S3
• SQS batch processing – handles partial failures when processing SQS batches
• Validation – JSON schema validation for payloads
• Serialization utilities – manipulates JSON data in your functions