Trigger Workflows using Cloud Audit Logs (gcloud CLI)

This quickstart shows you how to execute a workflow using an Eventarc trigger that receives events from BigQuery using Cloud Audit Logs. BigQuery hosts public datasets for you to access and integrate into your applications. The trigger executes the workflow by listening for completed BigQuery jobs and passes the event as runtime arguments to a destination workflow.

You can complete this quickstart using the Google Cloud CLI.

Use Workflows to create and deploy a workflow that extracts and returns the email of the user who ran the query and the query.
Create an Eventarc trigger that connects a BigQuery job to a Workflows event receiver.
Generate an event by running a BigQuery job using the bq command-line tool. This event is passed as a runtime argument to the destination workflow.
View the email of the user who ran the query and the query run.

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.

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.

Install the Google Cloud CLI.

To initialize the gcloud CLI, run the following command:

gcloud init

Create or select a Google Cloud project.

Create a Google Cloud project:
```
gcloud projects create PROJECT_ID
```
Select the Google Cloud project that you created:
```
gcloud config set project PROJECT_ID
```

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

Install the Google Cloud CLI.

To initialize the gcloud CLI, run the following command:

gcloud init

Create or select a Google Cloud project.

Create a Google Cloud project:
```
gcloud projects create PROJECT_ID
```
Select the Google Cloud project that you created:
```
gcloud config set project PROJECT_ID
```

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

Update gcloud components:
```
gcloud components update
```

Enable the Compute Engine, Eventarc, Pub/Sub, and Workflows APIs.

gcloud services enable \
compute.googleapis.com \
eventarc.googleapis.com \
pubsub.googleapis.com \
workflows.googleapis.com \
workflowexecutions.googleapis.com

Set the configuration variables used in this quickstart:

export WORKFLOW_LOCATION=us-central1
export TRIGGER_LOCATION=us-central1
export PROJECT_ID=PROJECT_ID
gcloud config set project ${PROJECT_ID}
gcloud config set workflows/location ${WORKFLOW_LOCATION}
gcloud config set eventarc/location ${TRIGGER_LOCATION}

If you are the project creator, you are granted the basic Owner role (roles/owner). By default, this Identity and Access Management (IAM) role includes the permissions necessary for full access to most Google Cloud resources and you can skip this step.

If you are not the project creator, required permissions must be granted on the project to the appropriate principal. For example, a principal can be a Google Account (for end users) or a service account (for applications and compute workloads). For more information, see the Roles and permissions page for your event destination.
Required permissions

To get the permissions that you need to complete this quickstart, ask your administrator to grant you the following IAM roles on your project:
- Eventarc Admin (roles/eventarc.admin)
- Logs View Accessor (roles/logging.viewAccessor)
- Project IAM Admin (roles/resourcemanager.projectIamAdmin)
- Service Account Admin (roles/iam.serviceAccountAdmin)
- Service Account User (roles/iam.serviceAccountUser)
- Service Usage Admin (roles/serviceusage.serviceUsageAdmin)
- Workflows Admin (roles/workflows.admin)
For more information about granting roles, see Manage access.

You might also be able to get the required permissions through custom roles or other predefined roles.
The Compute Engine default service account is automatically created after enabling or using a Google Cloud service that uses Compute Engine.

For test purposes, you can attach this service account to an Eventarc trigger to represent the identity of the trigger. Note the email format to use when creating a trigger:
```
PROJECT_NUMBER-compute@developer.gserviceaccount.com
```
Replace PROJECT_NUMBER with your Google Cloud project number. You can find your project number on the Dashboard page of the Google Cloud console or by running the following command:
```
gcloud projects describe PROJECT_ID --format='value(projectNumber)'
```
The Compute Engine service account is automatically granted the basic Editor role (roles/editor) on your project. However, if automatic role grants have been disabled, refer to the applicable Roles and permissions instructions on to create a new service account and grant it the required roles.

Caution: We recommend that you use the Compute Engine default service account for test purposes only. For production environments, we strongly recommend creating a new service account and granting it one or more IAM roles that contain the minimum permissions required and follow the principle of least privilege.
Grant the Eventarc Event Receiver role (roles/eventarc.eventReceiver) on the project to the Compute Engine default service account so that the Eventarc trigger can receive events from event providers.
```
gcloud projects add-iam-policy-binding PROJECT_ID \
    --member=serviceAccount:PROJECT_NUMBER-compute@developer.gserviceaccount.com \
    --role=roles/eventarc.eventReceiver
```
Grant the Workflows Invoker role (roles/workflows.invoker) on the project to the Compute Engine default service account so that the account has permission to trigger your workflow execution.
```
gcloud projects add-iam-policy-binding PROJECT_ID \
    --member=serviceAccount:PROJECT_NUMBER-compute@developer.gserviceaccount.com \
    --role=roles/workflows.invoker
```
Grant the Logging Logs Writer role (roles/logging.logWriter) on the project to the Compute Engine default service account so that the workflow can send logs to Cloud Logging.
```
gcloud projects add-iam-policy-binding PROJECT_ID \
    --member=serviceAccount:PROJECT_NUMBER-compute@developer.gserviceaccount.com \
    --role=roles/logging.logWriter
```
If you enabled the Cloud Pub/Sub service agent on or before April 8, 2021, to support authenticated Pub/Sub push requests, grant the Service Account Token Creator role (roles/iam.serviceAccountTokenCreator) to the Google-managed service account. Otherwise, this role is granted by default:
```
gcloud projects add-iam-policy-binding PROJECT_ID \
    --member=serviceAccount:service-PROJECT_NUMBER@gcp-sa-pubsub.iam.gserviceaccount.com \
    --role=roles/iam.serviceAccountTokenCreator
```

Create and deploy a workflow

Create and deploy a workflow that is executed when a BigQuery job completion triggers a workflow with an HTTP request.

Open a terminal or Cloud Shell.
In your home directory, create a new file called myFirstWorkflow.yaml or myFirstWorkflow.json.

Copy and paste the following into the new file and save it:

YAML

main:
  params: [event]
  steps:
      - log_event:
          call: sys.log
          args:
              text: ${event}
              severity: INFO
      - extract_data:
          assign:
          - user: ${event.data.protoPayload.authenticationInfo.principalEmail}
          - query: ${event.data.protoPayload.serviceData.jobCompletedEvent.job.jobConfiguration.query.query}
      - return_data:
              return:
                  user: ${user}
                  query: ${query}

JSON

{
  "main": {
    "params": [
      "event"
    ],
    "steps": [
      {
        "log_event": {
          "call": "sys.log",
          "args": {
            "text": "${event}",
            "severity": "INFO"
          }
        }
      },
      {
        "extract_data": {
          "assign": [
            {
              "user": "${event.data.protoPayload.authenticationInfo.principalEmail}"
            },
            {
              "query": "${event.data.protoPayload.serviceData.jobCompletedEvent.job.jobConfiguration.query.query}"
            }
          ]
        }
      },
      {
        "return_data": {
          "return": {
            "user": "${user}",
            "query": "${query}"
          }
        }
      }
    ]
  }
}

Deploy the workflow:

export MY_WORKFLOW=myFirstWorkflow
gcloud workflows deploy ${MY_WORKFLOW} --source=myFirstWorkflow.yaml

Replace .yaml with .json if you copied the JSON version of the example workflow.

Create an Eventarc trigger

The Eventarc trigger sends events from BigQuery to the Workflows destination.

Create a trigger that filters BigQuery events:

gcloud eventarc triggers create events-cal-trigger \
    --destination-workflow=${MY_WORKFLOW} \
    --destination-workflow-location=${WORKFLOW_LOCATION} \
    --event-filters="type=google.cloud.audit.log.v1.written" \
    --event-filters="serviceName=bigquery.googleapis.com" \
    --event-filters="methodName=jobservice.jobcompleted" \
    --service-account="PROJECT_NUMBER-compute@developer.gserviceaccount.com"

This creates a trigger called events-cal-trigger.

Note that when creating an Eventarc trigger for the first time in a Google Cloud project, there might be a delay in provisioning the Eventarc service agent. This issue can usually be resolved by attempting to create the trigger again. For more information, see Permission denied errors.

To confirm events-cal-trigger was successfully created, run:

gcloud eventarc triggers describe events-cal-trigger --location=${TRIGGER_LOCATION}

The output should be similar to the following listing the time of creation and trigger location:

createTime: '2021-10-14T15:15:43.872360951Z'
[...]
name: projects/PROJECT_ID/locations/us-central1/triggers/events-cal-trigger

Generate and view an event

Run a BigQuery job using the bq command-line tool to generate an event and trigger the workflow. The generated event is passed as a runtime argument of the workflow which returns the user email and query as a result of the workflow execution.

To trigger a workflow, run a BigQuery job that accesses a public dataset and retrieves information from it:
```
bq query --nouse_legacy_sql \
'SELECT
COUNT(*)
FROM
`bigquery-public-data`.samples.shakespeare'
```
The job completion generates an event that is passed as a runtime argument to the workflow which returns the email of the user who ran the query and the query itself.

To verify that a workflow execution was triggered, list the last five executions:

gcloud workflows executions list ${MY_WORKFLOW} --limit=5

The output should be similar to the following, listing a NAME and a STATE equal to SUCCEEDED for each workflow execution.

NAME: projects/218898424763/locations/us-central1/workflows/myFirstWorkflow/executions/a073ad6a-c76b-4437-8d39-2ab3ade289d2
STATE: SUCCEEDED
START_TIME: 2021-11-08T21:59:33.870561996Z
END_TIME: 2021-11-08T21:59:34.150034659Z
NAME: projects/218898424763/locations/us-central1/workflows/myFirstWorkflow/executions/35d7c730-7ba5-4055-afee-c04ed706b179
STATE: SUCCEEDED
START_TIME: 2021-10-14T19:32:39.908739298Z
END_TIME: 2021-10-14T19:32:40.147484015Z

Note that in the output, a073ad6a-c76b-4437-8d39-2ab3ade289d2 from the NAME field is the ID of the workflow execution. Copy your execution ID to use in the next step.

To view the execution status, run the following command:

gcloud workflows executions describe WORKFLOW_EXECUTION_ID --workflow=${MY_WORKFLOW}

Replace WORKFLOW_EXECUTION_ID with the ID of the workflow execution that corresponds to the time at which the BigQuery job completed.

The output should be similar to the following:

argument: [...]
duration: 0.277917625s
endTime: '2021-11-08T21:59:34.150034659Z'
name: projects/218898424763/locations/us-central1/workflows/myFirstWorkflow/executions/a073ad6a-c76b-4437-8d39-2ab3ade289d2
result: '{"query":"SELECT\n  COUNT(*)\nFROM\n  `bigquery-public-data`.samples.shakespeare","user":"USER_EMAIL"}'
startTime: '2021-11-08T21:59:33.870561996Z'
state: SUCCEEDED

Verify that the startTime at which the BigQuery job completed and the START_TIME of the workflow execution correspond to each other.

Congratulations, you have successfully generated a BigQuery event that has triggered a Workflows event receiver using Eventarc.

Clean up

Delete the workflow you created:
```
gcloud workflows delete ${MY_WORKFLOW}
```
When asked if you want to continue, enter y.

Delete the trigger you created:

gcloud eventarc triggers delete events-cal-trigger

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
```

Trigger Workflows using Cloud Audit Logs (gcloud CLI)

Before you begin

Required permissions

Create and deploy a workflow

YAML

JSON

Create an Eventarc trigger

Generate and view an event

Clean up

What's next