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Lambda Asynchronous Invocations & DLQ

  • S3, SNS, CloudWatch Events
  • The events are placed in an Event Queue
  • Lambda attempts to retry on errors
    • 3 tries in total
    • 1 minute wait after 1st, then 2 minutes wait
  • Make sure the processing is idempotent (in case of retries)
  • If the function is retried, you will see duplicate logs entries in CloudWatch Logs
  • Can define a DLQ (dead letter queue) - SNS or SQS - for failed processing (need correct IAM permissions)
  • Asynchronous invocations allow you to speed up the processing if you don't need to wait for the result (ex: you need 1000 files processed)

Services invocated asynchronously

  • Amazon Simple Storage Service (S3)
  • Amazon Simple Notification Service (SNS)
  • Amazon CloudWatch Events / EventBridge
  • AWS CodeCommit (CodeCommit Trigger: new branch, new tag, new push)
  • AWs CodePipeline (invoke a Lambda function during the pipeline, Lambda must callback)
  • other
  • Amazon CloudWatch Logs (log processing)
  • Amazon Simple Email Service
  • AWS CloudFormation
  • AWS Config
  • AWS IoT
  • AWS IoT Events