[aws-events] Add support for Rule Dead Letter Queue

[DaWyz]

Amazon EventBridge recently added support for dead letter queues.

Use Case

It makes event-driven applications more resilient and durable by storing your events in queues when the events can't be delivered, or the target is unavailable. See the documentation for more information.

Proposed Solution

Following the CloudFormation documentation, it is possible to pass the deadLetterConfig at the rule level and at the target level. I suspect it makes more sense to set it at the target level so we can target different DLQs for targets on the same rule if needed.

A target would have the possibility to pass a Queue as a property. That would be straight forward. Also, we would need to attach a policy to the queue to allow the rule to SendMessage to the queue.

See below a usage example.

import * as logs from "@aws-cdk/aws-logs";
import * as sqs from "@aws-cdk/aws-sqs";
import * as events from "@aws-cdk/aws-events";
import * as targets from "@aws-cdk/aws-events-targets";

const logGroup = new logs.LogGroup(this, 'MyLogGroup', {
  logGroupName: 'MyLogGroup',
});

const rule = new events.Rule(this, 'rule', {
  eventPattern: {
    source: ["aws.ec2"],
  },
});

const myDeadLetterQueue = new sqs.Queue(this, 'Queue');

rule.addTarget(new targets.CloudWatchLogGroup(logGroup, {
  deadLetterQueue: myDeadLetterQueue
}));

Others

I'm happy to have a go at it.

• 👋 I may be able to implement this feature request
• ⚠️ This feature might incur a breaking change

---

This is a 🚀 Feature Request

[DaWyz]

Added a Draft Pull Request for an idea of the implementation. It's only for the Lambda function. I guess we could move the code to the util file if needed, then add the property/call to the function in each targets (or create a BaseTarget class ?). Happy to only work on one of the targets on this pull request.

[github-actions]

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