Working with AWS Step Functions using the AWS Toolkit - AWS Cloud9
PrerequisitesCreate and publish a state machineRun a state machine in AWS ToolkitDownload a state machine definition file and visualize its workflow

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Working with AWS Step Functions using the AWS Toolkit

The AWS Toolkit provides support for AWS Step Functions. Step Functions allow you to create state machines that define workflows for AWS Lambda functions and other AWS services that support business-critical application.

You can use the AWS Toolkit to do the following with Step Functions:

  • Create and publish a state machine, which is a workflow made up of individual steps.

  • Download a file that defines a state machine workflow.

  • Run a state machine workflow with input you've entered or selected.

Prerequisites

Step Functions can run code and access AWS resources (such as invoking a Lambda function). To maintain security, you must grant Step Functions access to those resources by using an IAM role.

With AWS Toolkit, you can take advantage of automatically generated IAM roles that are valid for the AWS Region in which you create the state machine. To create your own IAM role for a state machine, see How AWS Step Functions Works with IAM in the AWS Step Functions Developer Guide.

Create and publish a state machine

When you create a state machine with AWS Toolkit, you choose a starter template that defines a workflow for a business case. You can then edit or replace that template to suit your specific needs. For more information on defining a state machine in a file that represents its structure, see Amazon States Language in the AWS Step Functions Developer Guide.

  1. In the AWS Explorer pane, open the context (right-click) menu for Step Functions, and then choose Create a new Step Function state machine.

  2. In the command panel, choose a starter template for your state machine's workflow.

  3. Next, choose a format for the Amazon States Language (ASL) file that defines your state machine.

    An editor opens to display the ASL file that defines the state machine's workflow.

    Note

    For information on editing the ASL file to customize your workflow, see State Machine Structure.

  4. In the ASL file, choose Publish to Step Functions to add your state machine to the AWS Cloud.

    Note

    You can also choose Render graph in the ASL file to display a visual representation of the state machine's workflow.

    Diagram that shows how to choose Publish to Step Functions

  5. In the command panel, choose an AWS Region to host your step function.

  6. Next, you can choose to create a new step function or update an existing one.

    Quick Create

    This option allows you to create a new step function from the ASL file using the step-functions/latest/dg/concepts-standard-vs-express.html. You're asked to specify the following:

    • An IAM role that allows your step function to run code and access AWS resources. (You can choose an automatically generated IAM role that's valid for the AWS Region in which you create the state machine.)

    • A name for your new function.

    You can check that your state machine was successfully created and obtain its ARN in the AWS Toolkit output tab.

    Quick Update

    If a state machine already exists in the AWS Region, you can choose one to update with the current ASL file.

    You can check that your state machine was successfully updated and obtain its ARN in the AWS Toolkit output tab.

    After you create a state machine, it appears under Step Functions in the AWS Explorer pane. If it doesn't immediately appear, choose the Toolkit menu, Refresh Explorer.

Run a state machine in AWS Toolkit

You can use AWS Toolkit to run remote state machines. The running state machine receives JSON text as input and passes that input to the first state in the workflow. Individual states receive JSON as input and usually pass JSON as output to the next state. For more information, see Input and Output Processing in Step Functions.

  1. In the AWS Explorer pane, choose Step Functions. Then open the context (right-click) menu for a specific state machine and choose Start Execution.

  2. In the Start Execution pane, add the JSON-formatted input for state machine's workflow by either entering the text directly in the field below or uploading a file from your local device.

  3. Choose Execute

    The AWS Toolkit output tab displays a confirmation that the workflow has started and the ARN of the process ID. You can use that process ID to check in the AWS Step Functions console whether the workflow ran successfully. You can also see the timestamps for when your workflow started and ended.

Download a state machine definition file and visualize its workflow

To download a state machine means you download a file containing JSON text that represents the structure of that state machine. You can then edit this file to create a new state machine or update an existing one. For more information, see Amazon States Language in the AWS Step Functions Developer Guide.

  1. In the AWS Explorer pane, choose Step Functions. Then open the context (right-click) menu for a specific state machine and choose Download Definition.

    Note

    The context menu also offers the options to Copy Name and Copy ARN.

  2. In the Save dialog box, select the folder in your environment where you store downloaded state machine file, and then choose Save.

    The JSON-formatted file that defines your state machine's workflow is displayed in an editor.

  3. To display a visual representation of the workflow, choose Render graph.

    A window displays a flowchart, which shows the sequence of states in your state machine's workflow.

    Visual representation of the state machine's workflow