Event Targets for Amazon EventBridge

This library contains integration classes to send Amazon EventBridge to any number of supported AWS Services. Instances of these classes should be passed to the rule.addTarget() method.

Currently supported are:

Event Targets for Amazon EventBridge

See the README of the aws-cdk-lib/aws-events library for more information on EventBridge.

Event retry policy and using dead-letter queues

The Codebuild, CodePipeline, Lambda, StepFunctions, LogGroup, SQSQueue, SNSTopic and ECSTask targets support attaching a dead letter queue and setting retry policies. See the lambda example. Use escape hatches for the other target types.

Invoke a Lambda function

Use the LambdaFunction target to invoke a lambda function.

The code snippet below creates an event rule with a Lambda function as a target triggered for every events from aws.ec2 source. You can optionally attach a dead letter queue.

import aws_cdk.aws_lambda as lambda_


fn = lambda_.Function(self, "MyFunc",
    runtime=lambda_.Runtime.NODEJS_LATEST,
    handler="index.handler",
    code=lambda_.Code.from_inline("exports.handler = handler.toString()")
)

rule = events.Rule(self, "rule",
    event_pattern=events.EventPattern(
        source=["aws.ec2"]
    )
)

queue = sqs.Queue(self, "Queue")

rule.add_target(targets.LambdaFunction(fn,
    dead_letter_queue=queue,  # Optional: add a dead letter queue
    max_event_age=Duration.hours(2),  # Optional: set the maxEventAge retry policy
    retry_attempts=2
))

Log an event into a LogGroup

Use the LogGroup target to log your events in a CloudWatch LogGroup.

For example, the following code snippet creates an event rule with a CloudWatch LogGroup as a target. Every events sent from the aws.ec2 source will be sent to the CloudWatch LogGroup.

import aws_cdk.aws_logs as logs


log_group = logs.LogGroup(self, "MyLogGroup",
    log_group_name="MyLogGroup"
)

rule = events.Rule(self, "rule",
    event_pattern=events.EventPattern(
        source=["aws.ec2"]
    )
)

rule.add_target(targets.CloudWatchLogGroup(log_group))

A rule target input can also be specified to modify the event that is sent to the log group. Unlike other event targets, CloudWatchLogs requires a specific input template format.

import aws_cdk.aws_logs as logs
# log_group: logs.LogGroup
# rule: events.Rule


rule.add_target(targets.CloudWatchLogGroup(log_group,
    log_event=targets.LogGroupTargetInput.from_object(
        timestamp=events.EventField.from_path("$.time"),
        message=events.EventField.from_path("$.detail-type")
    )
))

If you want to use static values to overwrite the message make sure that you provide a string value.

import aws_cdk.aws_logs as logs
# log_group: logs.LogGroup
# rule: events.Rule


rule.add_target(targets.CloudWatchLogGroup(log_group,
    log_event=targets.LogGroupTargetInput.from_object(
        message=JSON.stringify({
            "CustomField": "CustomValue"
        })
    )
))

The cloudwatch log event target will create an AWS custom resource internally which will default to set installLatestAwsSdk to true. This may be problematic for CN partition deployment. To workaround this issue, set installLatestAwsSdk to false.

import aws_cdk.aws_logs as logs
# log_group: logs.LogGroup
# rule: events.Rule


rule.add_target(targets.CloudWatchLogGroup(log_group,
    install_latest_aws_sdk=False
))

Start a CodeBuild build

Use the CodeBuildProject target to trigger a CodeBuild project.

The code snippet below creates a CodeCommit repository that triggers a CodeBuild project on commit to the master branch. You can optionally attach a dead letter queue.

import aws_cdk.aws_codebuild as codebuild
import aws_cdk.aws_codecommit as codecommit


repo = codecommit.Repository(self, "MyRepo",
    repository_name="aws-cdk-codebuild-events"
)

project = codebuild.Project(self, "MyProject",
    source=codebuild.Source.code_commit(repository=repo)
)

dead_letter_queue = sqs.Queue(self, "DeadLetterQueue")

# trigger a build when a commit is pushed to the repo
on_commit_rule = repo.on_commit("OnCommit",
    target=targets.CodeBuildProject(project,
        dead_letter_queue=dead_letter_queue
    ),
    branches=["master"]
)

Start a CodePipeline pipeline

Use the CodePipeline target to trigger a CodePipeline pipeline.

The code snippet below creates a CodePipeline pipeline that is triggered every hour

import aws_cdk.aws_codepipeline as codepipeline


pipeline = codepipeline.Pipeline(self, "Pipeline")

rule = events.Rule(self, "Rule",
    schedule=events.Schedule.expression("rate(1 hour)")
)

rule.add_target(targets.CodePipeline(pipeline))

Start a StepFunctions state machine

Use the SfnStateMachine target to trigger a State Machine.

The code snippet below creates a Simple StateMachine that is triggered every minute with a dummy object as input. You can optionally attach a dead letter queue to the target.

import aws_cdk.aws_iam as iam
import aws_cdk.aws_stepfunctions as sfn


rule = events.Rule(self, "Rule",
    schedule=events.Schedule.rate(Duration.minutes(1))
)

dlq = sqs.Queue(self, "DeadLetterQueue")

role = iam.Role(self, "Role",
    assumed_by=iam.ServicePrincipal("events.amazonaws.com")
)
state_machine = sfn.StateMachine(self, "SM",
    definition=sfn.Wait(self, "Hello", time=sfn.WaitTime.duration(Duration.seconds(10)))
)

rule.add_target(targets.SfnStateMachine(state_machine,
    input=events.RuleTargetInput.from_object({"SomeParam": "SomeValue"}),
    dead_letter_queue=dlq,
    role=role
))

Queue a Batch job

Use the BatchJob target to queue a Batch job.

The code snippet below creates a Simple JobQueue that is triggered every hour with a dummy object as input. You can optionally attach a dead letter queue to the target.

import aws_cdk.aws_ec2 as ec2
import aws_cdk.aws_ecs as ecs
import aws_cdk.aws_batch as batch
from aws_cdk.aws_ecs import ContainerImage

# vpc: ec2.Vpc


compute_environment = batch.FargateComputeEnvironment(self, "ComputeEnv",
    vpc=vpc
)

job_queue = batch.JobQueue(self, "JobQueue",
    priority=1,
    compute_environments=[batch.OrderedComputeEnvironment(
        compute_environment=compute_environment,
        order=1
    )
    ]
)

job_definition = batch.EcsJobDefinition(self, "MyJob",
    container=batch.EcsEc2ContainerDefinition(self, "Container",
        image=ecs.ContainerImage.from_registry("test-repo"),
        memory=cdk.Size.mebibytes(2048),
        cpu=256
    )
)

queue = sqs.Queue(self, "Queue")

rule = events.Rule(self, "Rule",
    schedule=events.Schedule.rate(Duration.hours(1))
)

rule.add_target(targets.BatchJob(job_queue.job_queue_arn, job_queue, job_definition.job_definition_arn, job_definition,
    dead_letter_queue=queue,
    event=events.RuleTargetInput.from_object({"SomeParam": "SomeValue"}),
    retry_attempts=2,
    max_event_age=Duration.hours(2)
))

Invoke an API Gateway REST API

Use the ApiGateway target to trigger a REST API.

The code snippet below creates a Api Gateway REST API that is invoked every hour.

import aws_cdk.aws_apigateway as api
import aws_cdk.aws_lambda as lambda_


rule = events.Rule(self, "Rule",
    schedule=events.Schedule.rate(Duration.minutes(1))
)

fn = lambda_.Function(self, "MyFunc",
    handler="index.handler",
    runtime=lambda_.Runtime.NODEJS_LATEST,
    code=lambda_.Code.from_inline("exports.handler = e => {}")
)

rest_api = api.LambdaRestApi(self, "MyRestAPI", handler=fn)

dlq = sqs.Queue(self, "DeadLetterQueue")

rule.add_target(
    targets.ApiGateway(rest_api,
        path="/*/test",
        method="GET",
        stage="prod",
        path_parameter_values=["path-value"],
        header_parameters={
            "Header1": "header1"
        },
        query_string_parameters={
            "QueryParam1": "query-param-1"
        },
        dead_letter_queue=dlq
    ))

Invoke an API Destination

Use the targets.ApiDestination target to trigger an external API. You need to create an events.Connection and events.ApiDestination as well.

The code snippet below creates an external destination that is invoked every hour.

connection = events.Connection(self, "Connection",
    authorization=events.Authorization.api_key("x-api-key", SecretValue.secrets_manager("ApiSecretName")),
    description="Connection with API Key x-api-key"
)

destination = events.ApiDestination(self, "Destination",
    connection=connection,
    endpoint="https://example.com",
    description="Calling example.com with API key x-api-key"
)

rule = events.Rule(self, "Rule",
    schedule=events.Schedule.rate(Duration.minutes(1)),
    targets=[targets.ApiDestination(destination)]
)

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.

rule = events.Rule(self, "Rule",
    schedule=events.Schedule.expression("rate(1 minute)")
)

rule.add_target(targets.EventBus(
    events.EventBus.from_event_bus_arn(self, "External", "arn:aws:events:eu-west-1:999999999999:event-bus/test-bus")))

Run an ECS Task

Use the EcsTask target to run an ECS Task.

The code snippet below creates a scheduled event rule that will run the task described in taskDefinition every hour.

Tagging Tasks

By default, ECS tasks run from EventBridge targets will not have tags applied to them. You can set the propagateTags field to propagate the tags set on the task definition to the task initialized by the event trigger.

If you want to set tags independent of those applied to the TaskDefinition, you can use the tags array. Both of these fields can be used together or separately to set tags on the triggered task.

import aws_cdk.aws_ecs as ecs

# cluster: ecs.ICluster
# task_definition: ecs.TaskDefinition


rule = events.Rule(self, "Rule",
    schedule=events.Schedule.rate(cdk.Duration.hours(1))
)

rule.add_target(
    targets.EcsTask(
        cluster=cluster,
        task_definition=task_definition,
        propagate_tags=ecs.PropagatedTagSource.TASK_DEFINITION,
        tags=[targets.Tag(
            key="my-tag",
            value="my-tag-value"
        )
        ]
    ))

Launch type for ECS Task

By default, if isEc2Compatible for the taskDefinition is true, the EC2 type is used as the launch type for the task, otherwise the FARGATE type. If you want to override the default launch type, you can set the launchType property.

import aws_cdk.aws_ecs as ecs

# cluster: ecs.ICluster
# task_definition: ecs.TaskDefinition


rule = events.Rule(self, "Rule",
    schedule=events.Schedule.rate(cdk.Duration.hours(1))
)

rule.add_target(targets.EcsTask(
    cluster=cluster,
    task_definition=task_definition,
    launch_type=ecs.LaunchType.FARGATE
))

Assign public IP addresses to tasks

You can set the assignPublicIp flag to assign public IP addresses to tasks. If you want to detach the public IP address from the task, you have to set the flag false. You can specify the flag true only when the launch type is set to FARGATE.

import aws_cdk.aws_ecs as ecs
import aws_cdk.aws_ec2 as ec2

# cluster: ecs.ICluster
# task_definition: ecs.TaskDefinition


rule = events.Rule(self, "Rule",
    schedule=events.Schedule.rate(cdk.Duration.hours(1))
)

rule.add_target(
    targets.EcsTask(
        cluster=cluster,
        task_definition=task_definition,
        assign_public_ip=True,
        subnet_selection=ec2.SubnetSelection(subnet_type=ec2.SubnetType.PUBLIC)
    ))

Enable Amazon ECS Exec for ECS Task

If you use Amazon ECS Exec, you can run commands in or get a shell to a container running on an Amazon EC2 instance or on AWS Fargate.

import aws_cdk.aws_ecs as ecs

# cluster: ecs.ICluster
# task_definition: ecs.TaskDefinition


rule = events.Rule(self, "Rule",
    schedule=events.Schedule.rate(cdk.Duration.hours(1))
)

rule.add_target(targets.EcsTask(
    cluster=cluster,
    task_definition=task_definition,
    task_count=1,
    container_overrides=[targets.ContainerOverride(
        container_name="TheContainer",
        command=["echo", events.EventField.from_path("$.detail.event")]
    )],
    enable_execute_command=True
))