feat(events): DLQ support for EventBus target

packages/@aws-cdk/aws-events-targets/README.md

@@ -28,7 +28,7 @@ Currently supported are:
 * Put a record to a Kinesis stream
 * [Log an event into a LogGroup](#log-an-event-into-a-loggroup)
 * Put a record to a Kinesis Data Firehose stream
-* Put an event on an EventBridge bus
+* [Put an event on an EventBridge bus](#put-an-event-on-an-eventbridge-bus)
 
 See the README of the `@aws-cdk/aws-events` library for more information on
 EventBridge.
@@ -266,3 +266,23 @@ rule.addTarget(
  } ),
 )
 ```
+
+## Put an event on an EventBridge bus
+
+Use the `EventBus` target to route event to a different EventBus.
+
+The code snippet below creates the scheduled event rule that route events to an imported event bus.
+
+```ts
+const rule = new events.Rule(this, 'Rule', {
+ schedule: events.Schedule.expression('rate(1 minute)'),
+});
+
+rule.addTarget(new targets.EventBus(
+ events.EventBus.fromEventBusArn(
+ this,
+ 'External',
+ `arn:aws:events:eu-west-1:999999999999:event-bus/test-bus`,
+ ),
+));
+```

packages/@aws-cdk/aws-events-targets/lib/event-bus.ts

@@ -1,9 +1,12 @@
 import * as events from '@aws-cdk/aws-events';
 import * as iam from '@aws-cdk/aws-iam';
-import { singletonEventRole } from './util';
+import * as sqs from '@aws-cdk/aws-sqs';
+import { singletonEventRole, addToDeadLetterQueueResourcePolicy } from './util';
 
 /**
  * Configuration properties of an Event Bus event
+ *
+ * Cannot extend TargetBaseProps. Retry policy is not supported for Event bus targets.
  */
 export interface EventBusProps {
  /**
@@ -12,25 +15,39 @@ export interface EventBusProps {
  * @default a new role is created.
  */
  readonly role?: iam.IRole;
+
+ /**
+ * The SQS queue to be used as deadLetterQueue.
+ * Check out the [considerations for using a dead-letter queue](https://docs.aws.amazon.com/eventbridge/latest/userguide/rule-dlq.html#dlq-considerations).
+ *
+ * The events not successfully delivered are automatically retried for a specified period of time,
+ * depending on the retry policy of the target.
+ * If an event is not delivered before all retry attempts are exhausted, it will be sent to the dead letter queue.
+ *
+ * @default - no dead-letter queue
+ */
+ readonly deadLetterQueue?: sqs.IQueue;
 }
 
 /**
  * Notify an existing Event Bus of an event
  */
 export class EventBus implements events.IRuleTarget {
- private readonly role?: iam.IRole;
-
- constructor(private readonly eventBus: events.IEventBus, props: EventBusProps = {}) {
- this.role = props.role;
- }
+ constructor(private readonly eventBus: events.IEventBus, private readonly props: EventBusProps = {}) { }
 
  bind(rule: events.IRule, _id?: string): events.RuleTargetConfig {
- if (this.role) {
- this.role.addToPrincipalPolicy(this.putEventStatement());
+ if (this.props.role) {
+ this.props.role.addToPrincipalPolicy(this.putEventStatement());
  }
- const role = this.role ?? singletonEventRole(rule, [this.putEventStatement()]);
+ const role = this.props.role ?? singletonEventRole(rule, [this.putEventStatement()]);
+
+ if (this.props.deadLetterQueue) {
+ addToDeadLetterQueueResourcePolicy(rule, this.props.deadLetterQueue);
+ }
+
  return {
  arn: this.eventBus.eventBusArn,
+ deadLetterConfig: this.props.deadLetterQueue ? { arn: this.props.deadLetterQueue?.queueArn } : undefined,
  role,
  };
  }

packages/@aws-cdk/aws-events-targets/test/event-bus/event-rule-target.test.ts

@@ -1,6 +1,7 @@
 import '@aws-cdk/assert-internal/jest';
 import * as events from '@aws-cdk/aws-events';
 import * as iam from '@aws-cdk/aws-iam';
+import * as sqs from '@aws-cdk/aws-sqs';
 import { Stack } from '@aws-cdk/core';
 import * as targets from '../../lib';
 
@@ -90,4 +91,79 @@ test('with supplied role', () => {
  Ref: 'Role1ABCC5F0',
  }],
  });
-});
+});
+
+test('with a Dead Letter Queue specified', () => {
+ const stack = new Stack();
+ const rule = new events.Rule(stack, 'Rule', {
+ schedule: events.Schedule.expression('rate(1 min)'),
+ });
+ const queue = new sqs.Queue(stack, 'Queue');
+
+ rule.addTarget(new targets.EventBus(
+ events.EventBus.fromEventBusArn(
+ stack,
+ 'External',
+ 'arn:aws:events:us-east-1:123456789012:default',
+ ),
+ { deadLetterQueue: queue },
+ ));
+
+ expect(stack).toHaveResource('AWS::Events::Rule', {
+ Targets: [{
+ Arn: 'arn:aws:events:us-east-1:123456789012:default',
+ Id: 'Target0',
+ RoleArn: {
+ 'Fn::GetAtt': [
+ 'RuleEventsRoleC51A4248',
+ 'Arn',
+ ],
+ },
+ DeadLetterConfig: {
+ Arn: {
+ 'Fn::GetAtt': [
+ 'Queue4A7E3555',
+ 'Arn',
+ ],
+ },
+ },
+ }],
+ });
+
+ expect(stack).toHaveResource('AWS::SQS::QueuePolicy', {
+ PolicyDocument: {
+ Statement: [
+ {
+ Action: 'sqs:SendMessage',
+ Condition: {
+ ArnEquals: {
+ 'aws:SourceArn': {
+ 'Fn::GetAtt': [
+ 'Rule4C995B7F',
+ 'Arn',
+ ],
+ },
+ },
+ },
+ Effect: 'Allow',
+ Principal: {
+ Service: 'events.amazonaws.com',
+ },
+ Resource: {
+ 'Fn::GetAtt': [
+ 'Queue4A7E3555',
+ 'Arn',
+ ],
+ },
+ Sid: 'AllowEventRuleRule',
+ },
+ ],
+ Version: '2012-10-17',
+ },
+ Queues: [
+ {
+ Ref: 'Queue4A7E3555',
+ },
+ ],
+ });
+});

packages/@aws-cdk/aws-events-targets/test/event-bus/integ.event-bus.expected.json

@@ -19,6 +19,14 @@
  ]
  ]
  },
+ "DeadLetterConfig": {
+ "Arn": {
+ "Fn::GetAtt": [
+ "Queue4A7E3555",
+ "Arn"
+ ]
+ }
+ },
  "Id": "Target0",
  "RoleArn": {
  "Fn::GetAtt": [
@@ -78,6 +86,50 @@
  }
  ]
  }
+ },
+ "Queue4A7E3555": {
+ "Type": "AWS::SQS::Queue",
+ "UpdateReplacePolicy": "Delete",
+ "DeletionPolicy": "Delete"
+ },
+ "QueuePolicy25439813": {
+ "Type": "AWS::SQS::QueuePolicy",
+ "Properties": {
+ "PolicyDocument": {
+ "Statement": [
+ {
+ "Action": "sqs:SendMessage",
+ "Condition": {
+ "ArnEquals": {
+ "aws:SourceArn": {
+ "Fn::GetAtt": [
+ "Rule4C995B7F",
+ "Arn"
+ ]
+ }
+ }
+ },
+ "Effect": "Allow",
+ "Principal": {
+ "Service": "events.amazonaws.com"
+ },
+ "Resource": {
+ "Fn::GetAtt": [
+ "Queue4A7E3555",
+ "Arn"
+ ]
+ },
+ "Sid": "AllowEventRuleeventsourcestackRuleFCA41174"
+ }
+ ],
+ "Version": "2012-10-17"
+ },
+ "Queues": [
+ {
+ "Ref": "Queue4A7E3555"
+ }
+ ]
+ }
  }
  }
-}
+}

packages/@aws-cdk/aws-events-targets/test/event-bus/integ.event-bus.ts

@@ -1,5 +1,6 @@
 /// !cdk-integ pragma:ignore-assets
 import * as events from '@aws-cdk/aws-events';
+import * as sqs from '@aws-cdk/aws-sqs';
 import * as cdk from '@aws-cdk/core';
 import * as targets from '../../lib';
 
@@ -12,12 +13,18 @@ class EventSourceStack extends cdk.Stack {
  const rule = new events.Rule(this, 'Rule', {
  schedule: events.Schedule.expression('rate(1 minute)'),
  });
+
+ const queue = new sqs.Queue(this, 'Queue');
+
  rule.addTarget(new targets.EventBus(
  events.EventBus.fromEventBusArn(
  this,
  'External',
  `arn:aws:events:${this.region}:999999999999:event-bus/test-bus`,
  ),
+ {
+ deadLetterQueue: queue,
+ },
  ));
  }
 }