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Amazon EventBridge Construct Library

See: Description

Package Description

Amazon EventBridge Construct Library


cfn-resources: Stable

cdk-constructs: Stable

Amazon EventBridge delivers a near real-time stream of system events that describe changes in AWS resources. For example, an AWS CodePipeline emits the State Change event when the pipeline changes its state.


The Rule construct defines an EventBridge rule which monitors an event based on an event pattern and invoke event targets when the pattern is matched against a triggered event. Event targets are objects that implement the IRuleTarget interface.

Normally, you will use one of the source.onXxx(name[, target[, options]]) -> Rule methods on the event source to define an event rule associated with the specific activity. You can targets either via props, or add targets using rule.addTarget.

For example, to define an rule that triggers a CodeBuild project build when a commit is pushed to the "master" branch of a CodeCommit repository:

 // Example automatically generated without compilation. See
 Object onCommitRule = repo.onCommit("OnCommit", Map.of(
         "target", new CodeBuildProject(project),
         "branches", asList("master")));

You can add additional targets, with optional input transformer using eventRule.addTarget(target[, input]). For example, we can add a SNS topic target which formats a human-readable message for the commit.

For example, this adds an SNS topic as a target:

 // Example automatically generated without compilation. See
         .message(events.RuleTargetInput.fromText(String.format("A commit was pushed to the repository %s on branch %s", codecommit.ReferenceEvent.getRepositoryName(), codecommit.ReferenceEvent.getReferenceName())))

Or using an Object:

 // Example automatically generated without compilation. See
                 "DataType", String.format("custom_%s", events.EventField.fromPath("$.detail-type")))))


You can configure a Rule to run on a schedule (cron or rate). Rate must be specified in minutes, hours or days.

The following example runs a task every day at 4am:

 // Example automatically generated without compilation. See
 EcsTask ecsTaskTarget = new EcsTask(new EcsTaskProps().cluster(cluster).taskDefinition(taskDefinition).role(role));
 new Rule(this, "ScheduleRule", new RuleProps()
         .schedule(Schedule.cron(new CronOptions().minute("0").hour("4")))

If you want to specify Fargate platform version, set platformVersion in EcsTask's props like the following example:

 // Example automatically generated without compilation. See
 Object platformVersion = ecs.FargatePlatformVersion.getVERSION1_4();
 Object ecsTaskTarget = EcsTask.Builder.create().cluster(cluster).taskDefinition(taskDefinition).role(role).platformVersion(platformVersion).build();

Event Targets

The @aws-cdk/aws-events-targets module includes classes that implement the IRuleTarget interface for various AWS services.

The following targets are supported:

Cross-account and cross-region targets

It's possible to have the source of the event and a target in separate AWS accounts and regions:

 // Example automatically generated without compilation. See
 App app = new App();
 Stack stack1 = new Stack(app, "Stack1", new StackProps().env(new Environment().account(account1).region("us-west-1")));
 Repository repo = new Repository(stack1, "Repository", new RepositoryProps());
 Stack stack2 = new Stack(app, "Stack2", new StackProps().env(new Environment().account(account2).region("us-east-1")));
 Project project = new Project(stack2, "Project", new ProjectProps());
 repo.onCommit("OnCommit", new OnCommitOptions()
         .target(new CodeBuildProject(project)));

In this situation, the CDK will wire the 2 accounts together:

For more information, see the AWS documentation on cross-account events.


It is possible to archive all or some events sent to an event bus. It is then possible to replay these events.

 // Example automatically generated without compilation. See
 Object stack = new stack();
 Object bus = EventBus.Builder.create(stack, "bus")
 bus.archive("MyArchive", Map.of(
         "archiveName", "MyCustomEventBusArchive",
         "description", "MyCustomerEventBus Archive",
         "eventPattern", Map.of(
                 "account", asList(stack.getAccount())),
         "retention", cdk.Duration.days(365)));

Granting PutEvents to an existing EventBus

To import an existing EventBus into your CDK application, use EventBus.fromEventBusArn, EventBus.fromEventBusAttributes or EventBus.fromEventBusName factory method.

Then, you can use the grantPutEventsTo method to grant event:PutEvents to the eventBus.

 // Example automatically generated without compilation. See
 Object eventBus = EventBus.fromEventBusArn(this, "ImportedEventBus", "arn:aws:events:us-east-1:111111111:event-bus/my-event-bus");
 // now you can just call methods on the eventbus
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