Send a custom event to EventBridge - Amazon Step Functions
Create the State Machine and Provision ResourcesStart a New ExecutionExample State Machine CodeIAM Example
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Send a custom event to EventBridge

This sample project demonstrates how to use Step Functions to send a custom event to an event bus that matches a rule with multiple targets (Amazon EventBridge, Amazon Lambda, Amazon Simple Notification Service, Amazon Simple Queue Service). This sample project creates the following:

  • Amazon EventBridge

  • An Amazon SNS topic

  • An Amazon SQS queue

  • A Lambda function

  • Related Amazon Identity and Access Management (IAM) roles

For more information about Step Functions and Step Functions service integrations, see the following:

Note

This sample project may incur charges.

For new Amazon users, a free usage tier is available. On this tier, services are free below a certain level of usage. For more information about Amazon costs and the Free Tier, see EventBridge Pricing.

Create the State Machine and Provision Resources

  1. Open the Step Functions console and choose Create a state machine.

  2. Choose Run a sample project, and then choose Send a custom event to EventBridge.

    The state machine Code and Visual Workflow are displayed.

    Training model workflow.

  3. Choose Next.

    The Deploy resources page is displayed, listing the resources that will be created. For this sample project, the resources include:

    • An Amazon Step Functions state machine

    • An EventBridge event bus

    • An EventBridge rule

    • An Amazon SNS topic

    • An Amazon SQS queue

    • A Lambda Function

    • Related IAM roles

  4. Choose Deploy Resources.

    Note

    It can take up to 25 minutes for these resources and related IAM permissions to be created. While the Deploy resources page is displayed, you can open the Stack ID link to see which resources are being provisioned.

Start a New Execution

  1. Open the Step Functions console.

  2. On the State machines page, choose the EventBridgeStateMachine state machine that was created by the sample project, and then choose Start execution.

  3. On the New execution page, enter an execution name (optional), and then choose Start Execution.

  4. (Optional) To identify your execution, you can specify a name for it in the Name box. By default, Step Functions generates a unique execution name automatically.

    Note

    Step Functions allows you to create state machine, execution, and activity names that contain non-ASCII characters. These non-ASCII names don't work with Amazon CloudWatch. To ensure that you can track CloudWatch metrics, choose a name that uses only ASCII characters.

  5. (Optional) Go to the newly created state machine on the Step Functions Dashboard, and then choose New execution.

  6. When an execution is complete, you can select states on the Visual workflow and browse the Input and Output under Step details.

Example State Machine Code

The state machine in this sample project integrates with EventBridge by sending a custom event to an EventBridge event bus. The event sent to the event bus matches an EventBridge rule that triggers a Lambda function that sends messages to an Amazon SNS topic and an Amazon SQS queue.

Browse through this example state machine to see how Step Functions manages EventBridge.

For more information about how Amazon Step Functions can control other Amazon services, see Using Amazon Step Functions with other services.

{
  "Comment": "An example of the Amazon States Language for sending a custom event to Amazon EventBridge",
  "StartAt": "Send a custom event",
  "States": {
    "Send a custom event": {
      "Resource": "arn:<PARTITION>:states:::events:putEvents",
      "Type": "Task",
      "Parameters": {
        "Entries": [{
          "Detail": {
            "Message": "Hello from Step Functions!"
          },
          "DetailType": "MessageFromStepFunctions",
          "EventBusName": "<EVENT_BUS_NAME>",
          "Source": "my.statemachine"
        }]
      },
      "End": true
    }
  }
}

For information about how to configure IAM when using Step Functions with other Amazon services, see IAM Policies for integrated services.

IAM Example

These example Amazon Identity and Access Management (IAM) policies generated by the sample project include the least privilege necessary to execute the state machine and related resources. We recommend that you include only those permissions that are necessary in your IAM policies. 

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": [
                "events:PutEvents"
            ],
            "Resource": [
                "arn:aws:events:us-east-1:1234567890:event-bus/stepfunctions-sampleproject-eventbus"
            ],
            "Effect": "Allow"
        }
    ]
}

For information about how to configure IAM when using Step Functions with other Amazon services, see IAM Policies for integrated services.