Create a task timer with Lambda and Amazon SNS - AWS Step Functions
Step 1: Create the state machine and provision resourcesStep 2: Run the state machine

Create a task timer with Lambda and Amazon SNS

This sample project creates a task timer. It implements an AWS Step Functions state machine that implements a Wait state, and uses an AWS Lambda function that sends an Amazon Simple Notification Service (Amazon SNS) notification. A Wait workflow state state is a state type that waits for a trigger to perform a single unit of work.

Note

This sample project implements an AWS Lambda function to send an Amazon Simple Notification Service (Amazon SNS) notification. You can also send an Amazon SNS notification directly from the Amazon States Language. See Integrating other services with Step Functions.

This sample project creates the state machine, a Lambda function, and an Amazon SNS topic, and configures the related AWS Identity and Access Management (IAM) permissions. For more information about the resources that are created with the Task Timer sample project, see the following:

For more information about how AWS Step Functions can control other AWS services, see Integrating other services with Step Functions.

Step 1: Create the state machine and provision resources

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

  2. Type Task Timer in the search box, and then choose Task Timer from the search results that are returned.

  3. Choose Next to continue.

  4. Step Functions lists the AWS services used in the sample project you selected. It also shows a workflow graph for the sample project. Deploy this project to your AWS account or use it as a starting point for building your own projects. Based on how you want to proceed, choose Run a demo or Build on it.

    This sample project deploys the following resources:

    • a Lambda function that sends an Amazon SNS notification.

    • An AWS Step Functions state machine

    • Related AWS Identity and Access Management (IAM) roles

    The following image shows the workflow graph for the Task Timer sample project:

    Workflow graph of the Task Timer sample project.

  5. Choose Use template to continue with your selection.

  6. Do one of the following:

    • If you selected Build on it, Step Functions creates the workflow prototype, but does not deploy the resources in the workflow definition, so you can continue building out your workflow prototype.

      In Workflow Studio'sDesign mode, you can can additional states into your workflow protoype. Or, you can switch to the Code mode to use the integrated code editor to edit the Amazon States Language (ASL) definition of your state machine from the Step Functions console.

      Important

      You may need to update the placeholder Amazon Resource Name (ARN) for the resources used in the sample project before you can run your workflow.

    • If you selected Run a demo, Step Functions creates a read-only project which uses an AWS CloudFormation template to deploy the AWS resources in that template to your AWS account. You can view the state machine definition by choosing the Code mode.

      Choose Deploy and run to deploy the project and create the resources.

      Note that deploying can take up to 10 minutes for resources and IAM permissions to be created. While your resources are being deployed, you can open the AWS CloudFormation Stack ID link to see which resources are being provisioned.

      After all the resources have been created, you should see the project on the State machines page in the console.

      Important

      Standard charges may apply for each service used in the CloudFormation template.

Step 2: Run the state machine

After all the resources are provisioned and deployed, the Start execution dialog box is displayed with example input similar to the following.

{
    "jobName": "my-job",{
  "topic": "arn:aws:sns:us-east-2:123456789012:StepFunctionsSample-TaskTimercc68840e-c3d3-42a8-911e-821b7ce248e5-SNSTopic-44UjcFxzhACT",
  "message": "HelloWorld",
  "timer_seconds": 10
}

  • In the Start execution dialog box, do the following:

    1. (Optional) To identify your execution, you can specify a name, or use the default generated execution name .

      Note

      Step Functions accepts names for state machines, executions, activities, and labels that contain non-ASCII characters. Because names with non-ASCII characters will not work with Amazon CloudWatch, we recommend using only ASCII charcters so you can track metrics in CloudWatch.

    2. (Optional) In the Input box, enter input values in JSON format to run your workflow.

      If you chose to Run a demo, you need not provide any execution input.

      Note

      If the demo project you deployed contains prepopulated execution input data, use that input to run the state machine.

    3. Choose Start execution.

    4. The Step Functions console directs you to a page that's titled with your execution ID. This page is known as the Execution Details page. On this page, you can review the execution results as the execution progresses or after it's complete.

      To review the execution results, choose individual states on the Graph view, and then choose the individual tabs on the Step details pane to view each state's details including input, output, and definition respectively. For details about the execution information you can view on the Execution Details page, see Execution Details page – Interface overview.

    For example, the following image shows the output of the selected step Wait for Timestamp. The output of this step is passed as input to the Send SNS Message step.

    Execution output of the Wait for Timestamp step selected in the Graph view.