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Quickstart: Workflow

This quickstart showcases how to write applications containing stateful, long-running, reliable workflows using the Workflow API.

Catalyst hosts the workflow execution engine and manages the workflow state, with the external application containing the workflow definition and business logic.

Prerequisites​

Before you proceed, ensure you have the following prereqs installed.

Log in to Catalyst​

Authenticate to Diagrid Catalyst using the following command:

diagrid login

Confirm your organization and user details are correct:

diagrid whoami

Deploy quickstart project​

Create a project and bootstrap the necessary resources to begin developing locally with the Workflow API. This command:

✔️ Creates a new Catalyst project
✔️ Enables managed workflow for the proejct
✔️ Creates an App ID for the application leveraging the Workflow API
✔️ Clones a quickstart application to your machine
✔️ Scaffolds a dev config file to run the quickstart code with the necessary Catalyst connectivity info

diagrid project quickstart --type workflow --language python

Run sample application​

To run the quickstart code locally, you can use the diagrid dev start command. This command:

  • Launches the local quickstart code: Locates the code directory using the value specified for workDir and launches the code using the app command inputs
  • Injects environment variables: Configures the Dapr client to talk to Catalyst using the order-workflow App ID API token
  • Streams application logs: Displays connectivity logs along with real-time app feedback directly in the terminal to make API testing simple

For additional details on the Catalyst local development experience, read Develop Locally with Catalyst APIs.

Install .NET dependencies.

dotnet build

Run the diagrid dev start command:

diagrid dev start

Interact with Catalyst APIs​

With the quickstart application running, it's time to test the Workflow API. Use the curl commands below or take advantage of the REST Client extension using Visual Studio Code with the test.rest file in the root folder of the repo.

Upon successful execution of the three curl commands below, the order-workflow logs should show three requests:

  1. A request to start the workflow execution
  2. A status request
  3. A final request for the completed workflow output

You can also use the Workflow viewer in the Catalyst web console to see the details for your completed workflow instance.

Start workflow​

Open a new terminal and execute the following curl command to start a new workflow instance:

curl -i -X POST http://localhost:5001/workflow/start -H "Content-Type: application/json" -d '{"Name":"Car", "Quantity":2}'

This command will return the instance ID of the workflow that has been started. Save this result as an environment variable for future API calls.

export WORKFLOW_ID=<YOUR_WORKFLOW_INSTANCE_ID>

Get workflow status​

Get the current workflow status using the workflow instance ID:

curl -i -X GET http://localhost:5001/workflow/status/$WORKFLOW_ID

Get workflow output​

Get the final workflow output using the workflow instance ID:

curl -i -X GET http://localhost:5001/workflow/output/$WORKFLOW_ID

Clean up resources​

If you are not going to continue to use this application, you can delete the resources using the following commands:

diagrid appid delete order-workflow

If you want to delete the entire Catalyst project, including the managed infrastructure resources, run the diagrid project delete command.