AWS Lambda provides built-in mechanisms to handle function failures and automatically retry invocations depending on the type of trigger. These mechanisms help ensure resilience and reliability in event-driven applications by reducing the chances of data loss or missed executions.
Synchronous invocations (e.g., API Gateway): Errors are returned immediately to the caller. No automatic retry.
Asynchronous invocations (e.g., S3, EventBridge): Lambda retries the function twice (for a total of 3 attempts), with delays between attempts.
Stream-based triggers (e.g., DynamoDB Streams, Kinesis): Failed records are retried until they succeed or expire (up to 7 days).
Use Dead Letter Queues (DLQs) to capture failed asynchronous events
Enable Lambda Destinations for success/failure callbacks
Use try/catch blocks and logging in your handler function
Monitor CloudWatch Logs and metrics for error tracking