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Dead letter queue

As explained in Amazon Web Services in Action, Third Edition: An in-depth guide to AWS

A dead-letter queue is a queue that receives messages that exceed a configured number of unsuccessful processing attempts.

A dead-letter queue (DLQ) receives messages that exceed a configured number of unsuccessful processing attempts. It preserves failed work for later inspection or handling. section 16.3.4

In a fault-tolerant web application, the DLQ:

  • Appears beside an SQS queue in the Imagery application’s infrastructure. section 16.3.4
  • Is deployed with S3, DynamoDB, EC2 Auto Scaling groups, an Application Load Balancer, and IAM roles through CloudFormation. section 16.3.4
$ aws cloudformation create-stack --stack-name imagery \
 --template-url https:/ /s3.amazonaws.com/\
 awsinaction-code3/chapter16/template.yaml \
 --capabilities CAPABILITY_IAM

Deploy the surrounding SQS-based application by creating the Imagery CloudFormation stack from the terminal. section 16.3.4

How Amazon Web Services in Action, Third Edition: An in-depth guide to AWS covers it

How deep it goes
Defines the retry-threshold destination but stops short of showing its queue configuration or processing behavior.
Examples
Uses the Imagery application and its CloudFormation deployment as the concrete infrastructure example.
What you can do after
Operate a deployed SQS-based application whose infrastructure includes a dead-letter queue.
How it connects
Connects SQS with CloudFormation, S3, DynamoDB, EC2, Auto Scaling, IAM, and load balancing.

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This explainer was generated by Manning's knowledge graph from the text of Amazon Web Services in Action, Third Edition: An in-depth guide to AWS. The section links point to the parts of the book it draws on.