Create a workflow by using Terraform

Create a workflow by using Terraform

This quickstart shows you how to create, deploy, and execute your first workflow using Terraform. Terraform is an infrastructure-as-code tool that enables you to predictably create, change, and improve your cloud infrastructure by using code. Learn how to use Terraform to provision infrastructure on Google Cloud.

In this quickstart, the sample workflow sends a request to a public API and then returns the API's response.

You will complete the following:

1. Enable the Workflows API using Terraform.
2. Create a service account for the workflow using Terraform.
3. Define and deploy a workflow using Terraform.
4. Execute the workflow using the Google Cloud CLI.

Before you begin

Security constraints defined by your organization might prevent you from completing the following steps. For troubleshooting information, see Develop applications in a constrained Google Cloud environment.

Note that Cloud Shell has Terraform already integrated. If you need to install Terraform, see the HashiCorp Terraform documentation.

1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.
2. Install the Google Cloud CLI.

3. To initialize the gcloud CLI, run the following command:

   gcloud init

4. Create or select a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   • Create a Google Cloud project:

     gcloud projects create PROJECT_ID

     Replace PROJECT_ID with a name for the Google Cloud project you are creating.

   • Select the Google Cloud project that you created:

     gcloud config set project PROJECT_ID

     Replace PROJECT_ID with your Google Cloud project name.

5. Make sure that billing is enabled for your Google Cloud project.

6. Enable the Cloud Resource Manager and Identity and Access Management (IAM) APIs:

   gcloud services enable cloudresourcemanager.googleapis.com iam.googleapis.com

7. Install the Google Cloud CLI.

8. To initialize the gcloud CLI, run the following command:

   gcloud init

9. Create or select a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   • Create a Google Cloud project:

     gcloud projects create PROJECT_ID

     Replace PROJECT_ID with a name for the Google Cloud project you are creating.

   • Select the Google Cloud project that you created:

     gcloud config set project PROJECT_ID

     Replace PROJECT_ID with your Google Cloud project name.

10. Make sure that billing is enabled for your Google Cloud project.

11. Enable the Cloud Resource Manager and Identity and Access Management (IAM) APIs:

    gcloud services enable cloudresourcemanager.googleapis.com iam.googleapis.com

Create a Terraform configuration file

Create a Terraform configuration file called main.tf and include the Google provider for Terraform resources used in this quickstart.

Note that you can use interpolation for substitutions such as reference variables, attributes of resources, and call functions.

1. Create a directory:

   mkdir terraform

2. Go to the terraform directory:

   cd terraform

3. Add a new file, main.tf, to the directory:

   nano main.tf

4. Add the following resources to the main.tf file:

   1. Assign the ID of the project:

      provider "google" {
      project = "PROJECT_ID"
      }

      Replace PROJECT_ID with your project's ID.

   2. Enable the Workflows API:

      # Enable Workflows API
      resource "google_project_service" "default" {
        service            = "workflows.googleapis.com"
        disable_on_destroy = false
      }

   3. Create a service account for the workflow:

      # Create a dedicated service account
      resource "google_service_account" "default" {
        account_id   = "sample-workflows-sa"
        display_name = "Sample Workflows Service Account"
      }

   4. Define the workflow using the google_workflows_workflow resource:

      Important: When you define workflows in Terraform, variables must be escaped with $${...} and not ${...}.
      # Create a workflow
      resource "google_workflows_workflow" "default" {
        name            = "sample-workflow"
        region          = "us-central1"
        description     = "A sample workflow"
        service_account = google_service_account.default.id
        labels = {
          env = "test"
        }
        user_env_vars = {
          url = "https://timeapi.io/api/Time/current/zone?timeZone=Europe/Amsterdam"
        }
        source_contents = <<-EOF
        # This is a sample workflow that you can replace with your source code
        #
        # The workflow does the following:
        # - Retrieves the current date from a public API and stores the
        #   response in `currentDate`
        # - Retrieves a list of Wikipedia articles from a public API related
        #   to the day of the week stored in `currentDate`
        # - Returns the list of articles in the workflow output
        #
        # Note that when you define workflows in Terraform, variables must be
        # escaped with two dollar signs ($$) and not a single sign ($)
      
        - getCurrentDate:
            call: http.get
            args:
                url: $${sys.get_env("url")}
            result: currentDate
        - readWikipedia:
            call: http.get
            args:
                url: https://en.wikipedia.org/w/api.php
                query:
                    action: opensearch
                    search: $${currentDate.body.dayOfWeek}
            result: wikiResult
        - returnOutput:
            return: $${wikiResult.body[1]}
      EOF
      
        depends_on = [google_project_service.default]
      }

      The following arguments are used in the sample workflow:

      • name: the name of your workflow.
      • region: the location of your workflow.
      • description: a description of your workflow.
      • service_account: the email address or unique ID of the service account associated with the latest workflow version. This service account represents the identity of the workflow and determines what permissions the workflow has. If you don't specify a service account during the workflow's creation, the workflow uses the default Compute Engine service account for its identity. For more information, see Grant a workflow permission to access Google Cloud resources.
      • labels: a list of key-value label pairs to assign to this workflow that helps you organize your Google Cloud instances. For more information, see What are labels?
      • user_env_vars: user-defined environment variables associated with this workflow revision. For more information, see Use environment variables.
      • source_contents: the Workflows code to execute. For the file size limit, see Resource limits.

      Other optional arguments include the following:

      • crypto_key_name: the resource ID for a Cloud Key Management Service key in the following format:

        projects/PROJECT_NAME/locations/LOCATION/keyRings/KEY_RING/cryptoKeys/KEY_NAME

        For more information, see Use customer-managed encryption keys.

      • call_log_level: the level of logging to apply to calls and call responses during executions of this workflow. Possible values are:

        • CALL_LOG_LEVEL_UNSPECIFIED
        • LOG_ALL_CALLS
        • LOG_ERRORS_ONLY
        • LOG_NONE

        For more information, see Call logging.

      • project: the ID of the project in which the resource belongs. If it is not provided, the provider project is used.

      • name_prefix: creates a unique name beginning with the specified prefix. If this and name are unspecified, a random value is chosen for the name.

Create and execute the workflow

Deploy your Terraform resources to create the workflow and then execute the workflow.

1. Initialize Terraform in the directory:

   terraform init

2. Check that the changes you propose with Terraform match the expected plan:

   terraform plan

   You can ignore the note regarding not using the -out option.

3. Create the workflow:

   terraform apply

4. At the Enter a value prompt, type yes to proceed with the creation of resources.

5. Confirm that a workflow is created:

   gcloud workflows list --location us-central1

   The output should be similar to the following:

   NAME                                                                    STATE   REVISION_ID  UPDATE_TIME
   projects/project-name/locations/us-central1/workflows/sample-workflow   ACTIVE  000001-f9a   2024-02-24T13:38:58.353765906Z

6. Optionally, you can execute the workflow:

   gcloud workflows execute sample-workflow

Clean up

To avoid incurring charges to your Google Cloud account for the resources used on this page, delete the Google Cloud project with the resources.

1. Delete all the resources you created with Terraform:

   terraform destroy

2. Delete the workflow you created:

   gcloud workflows delete sample-workflow

   When asked if you want to continue, enter y.
3. Alternatively, you can delete your Google Cloud project to avoid incurring charges. Deleting your Google Cloud project stops billing for all the resources used within that project.
   Caution: Deleting a project has the following effects:
   • Everything in the project is deleted. If you used an existing project for the tasks in this document, when you delete it, you also delete any other work you've done in the project.
   • Custom project IDs are lost. When you created this project, you might have created a custom project ID that you want to use in the future. To preserve the URLs that use the project ID, such as an appspot.com URL, delete selected resources inside the project instead of deleting the whole project.

   Delete a Google Cloud project:

   gcloud projects delete PROJECT_ID

What's next

• Control the order of execution in a workflow.

• Update an existing workflow.

• Explore sample workflows.

• Learn more about the Workflows syntax.