Route audit log events to Workflows

An Eventarc trigger declares your interest in a certain event or set of events. You can configure event routing by specifying filters for the trigger, including the event source, and the target workflow.

Events are delivered in the CloudEvents format through an HTTP request. The Workflows service converts the event to a JSON object (following the CloudEvents specification) and passes the event into the workflow execution as a workflow runtime argument. Make sure that the event size does not exceed 512 KB. Events larger than the maximum Workflows arguments size will not trigger workflow executions.

These instructions show you how to configure event routing so that an execution of your workflow is triggered when an audit log is created that matches the trigger's filter criteria. This type of event applies to all event providers. For a list of the audit log events supported by Eventarc, including serviceName and methodName values, see Event types supported by Eventarc.

For more information about capturing events that are triggered when an audit log is created that matches the trigger's filter criteria, see Determine event filters for Cloud Audit Logs.

Prepare to create a trigger

Before creating an Eventarc trigger for a target workflow, complete the following tasks.

Console

  1. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

    Go to project selector

  2. Enable the Eventarc, Eventarc Publishing, Workflows, and Workflow Executions APIs.

    Enable the APIs

  3. If applicable, enable the API related to the events. For example, for Cloud Functions events, enable cloudfunctions.googleapis.com.

  4. If you don't already have one, create a user-managed service account, then grant it the roles and permissions necessary so that Eventarc can manage events for a target workflow.

    1. In the Google Cloud console, go to the Service Accounts page.

      Go to Service Accounts

    2. Select your project.

    3. In the Service account name field, enter a name. The Google Cloud console fills in the Service account ID field based on this name.

      In the Service account description field, enter a description. For example, Service account for event trigger.

    4. Click Create and continue.

    5. To provide appropriate access, in the Select a role list, select the required Identity and Access Management (IAM) roles to grant to your service account. For more information, see Roles and permissions for Workflows targets.

      For additional roles, click Add another role and add each additional role.

    6. Click Continue.

    7. To finish creating the account, click Done.

gcloud

  1. In the Google Cloud console, activate Cloud Shell.

    Activate Cloud Shell

    At the bottom of the Google Cloud console, a Cloud Shell session starts and displays a command-line prompt. Cloud Shell is a shell environment with the Google Cloud CLI already installed and with values already set for your current project. It can take a few seconds for the session to initialize.

  2. Enable the Eventarc, Eventarc Publishing, Workflows, and Workflow Executions APIs:

    gcloud services enable eventarc.googleapis.com \
        eventarcpublishing.googleapis.com \
        workflows.googleapis.com \
        workflowexecutions.googleapis.com
    
  3. If applicable, enable the API related to the direct events. For example, for Cloud Functions events, enable cloudfunctions.googleapis.com.

  4. If you don't already have one, create a user-managed service account, then grant it the roles and permissions necessary so that Eventarc can manage events for a target workflow.

    1. Create the service account:

      gcloud iam service-accounts create SERVICE_ACCOUNT_NAME

      Replace SERVICE_ACCOUNT_NAME with the name of the service account. It must be between 6 and 30 characters, and can contain lowercase alphanumeric characters and dashes. After you create a service account, you cannot change its name.

    2. Grant the required Identity and Access Management (IAM) roles or permissions. For more information, see Roles and permissions for Workflows targets.

Create a trigger

You can create an Eventarc trigger with a deployed workflow as the event receiver by using the Google Cloud CLI (gcloud or Terraform), or through the Google Cloud console.

Console

  1. In the Google Cloud console, go to the Eventarc Triggers page.

    Go to Triggers

  2. Click Create trigger.
  3. Type a Trigger name.

    This is the ID of the trigger and it must start with a letter. It can contain up to 63 lowercase letters, numbers, or hyphens.

  4. For the Trigger type, select Google sources.
  5. Select an Event provider.

    This is the Google service that is the source of events through its audit logs. For example, select BigQuery.

    Note that the event provider name used in the associated Google Cloud documentation might not have a prefix of Cloud or Google Cloud. For example, on the console, Memorystore for Redis is referred to as Google Cloud Memorystore for Redis.

  6. In the Event type list, from the via Cloud Audit Logs events, select an event type.
  7. Select one of the following:
    • Any resource—This is the default and includes dynamically created resources that have identifiers generated at creation time.
    • Specific resource—You must provide the full resource name.
    • Path pattern—You can filter for resources using a path pattern. For example, type projects/_/buckets/eventarc-bucket/objects/random.txt or type projects/_/buckets/**/r*.txt.
  8. To specify the encoding of the event payload, in the Event data content type list, select application/json or application/protobuf.

    Note that an event payload formatted in JSON is larger than one formatted in Protobuf. This might impact reliability depending on your event destination and its limits on event size. For more information, see Known issues.

  9. In the Region list, select a region.

    Cloud Audit Logs triggers for Eventarc are available in specific regions and in the global region, but are not available in dual-region and multi-region locations. To avoid any performance and data residency issues caused by a global trigger, Google recommends that the location match that of the Google Cloud service that is generating events. For more information, see Eventarc locations.

    If you specify the global location, you will receive events from all locations yielding matches for the event filters. For example, by creating a global Eventarc trigger, you can receive events from resources in the EU and US multi-regions.

    Note that there is a known issue with Cloud Audit Logs triggers for Compute Engine that results in events originating from a single region: us-central1. This is regardless of where the virtual machine instance is actually located. When creating your trigger, set the trigger location to either us-central1 or global.

  10. ?
  11. Select the Service account that will invoke your service or workflow.

    Or, you can create a new service account.

    This specifies the Identity and Access Management (IAM) service account email associated with the trigger and to which you previously granted specific roles required by Eventarc.

  12. In the Event destination list, select Workflows.
  13. Select a workflow.

    This is the name of the workflow to pass events to. Events for a workflow execution are transformed and passed to the workflow as runtime arguments.

    For more information, see Create a trigger for Workflows.

  14. Click Create.
  15. After a trigger is created, the event source filters cannot be modified. Instead, create a new trigger and delete the old one. For more information, see Manage triggers.

gcloud

You can create a trigger by running a gcloud eventarc triggers create command along with required and optional flags.

gcloud eventarc triggers create TRIGGER \
    --location=LOCATION \
    --destination-workflow=DESTINATION_WORKFLOW \
    --destination-workflow-location=DESTINATION_WORKFLOW_LOCATION \
    --event-filters="type=google.cloud.audit.log.v1.written" \
    --event-filters="serviceName=SERVICE_NAME" \
    --event-filters="methodName=METHOD_NAME" \
    --event-data-content-type="EVENT_DATA_CONTENT_TYPE" \
    --service-account="MY_SERVICE_ACCOUNT@PROJECT_ID.iam.gserviceaccount.com"

Replace the following:

  • TRIGGER: the ID of the trigger or a fully qualified identifier.
  • LOCATION: the location of the Eventarc trigger. Alternatively, you can set the eventarc/location property; for example, gcloud config set eventarc/location us-central1.

    Eventarc is available in specific locations and in the global location, but it is not available in dual-region and multi-region locations. To avoid any performance and data residency issues caused by a global trigger, we recommend that the location match that of the Google Cloud service that is generating events.

    If you specify the global location, you will receive events from all locations for which the event filters match. For example, by creating a global Eventarc trigger, you can receive events from resources such as Cloud Storage buckets in the EU and US multi-regions.

  • DESTINATION_WORKFLOW: the ID of the deployed workflow that receives the events from the trigger. The workflow can be in any of the Workflows supported locations and does not need to be in the same location as the trigger. However, the workflow must be in the same project as the trigger.
  • DESTINATION_WORKFLOW_LOCATION (optional): the location in which the destination workflow is deployed. If not specified, it is assumed that the workflow is in the same location as the trigger.
  • SERVICE_NAME: the identifier of the Google Cloud service
  • METHOD_NAME: the identifier of the operation
  • EVENT_DATA_CONTENT_TYPE: (optional) the encoding of the event payload. This can be application/json or application/protobuf. The default encoding is application/json.

    Note that an event payload formatted in JSON is larger than one formatted in Protobuf. This might impact reliability depending on your event destination and its limits on event size. For more information, see Known issues.

  • SERVICE_ACCOUNT_NAME: the name of the IAM service account you created to which you granted specific roles required by Workflows.
  • PROJECT_ID: your Google Cloud project ID

Notes:

  • These flags are required:
    • --event-filters="type=google.cloud.audit.log.v1.written"
    • --event-filters="serviceName=VALUE"
    • --event-filters="methodName=VALUE"
  • After a trigger is created, --event-filters="type=google.cloud.audit.log.v1.written" can't be changed. For a different event type, you must create a new trigger.
  • --service-account: The IAM service account email that your Eventarc trigger will use to invoke the workflow executions, and to receive cloud audit logs. We strongly recommend using a service account with the least privileges necessary to access the required resources. To learn more about service accounts, see Create and manage service accounts.
  • For a list of the audit log events supported by Eventarc, including serviceName and methodName values, see Events supported by Eventarc.
  • Each trigger can have multiple event filters, comma delimited in one --event-filters=[ATTRIBUTE=VALUE,...] flag, or you can repeat the flag to add more filters. Only events that match all the filters are sent to the destination. Wildcards and regular expressions are not supported.
  • See Determine event filters for Cloud Audit Logs.
  • Optionally, you can filter events for a specific resource by using the --event-filters="resourceName=VALUE" flag and specifying the complete path to the resource. Omit the flag for dynamically created resources that have identifiers generated at creation time. Or, you can filter events for a set of resources by using the --event-filters-path-pattern="resourceName=VALUE" flag and specifying the resource path pattern.
  • By default, Pub/Sub subscriptions created for Eventarc persist regardless of activity and do not expire. To change the inactivity duration, see Subscription properties.

Example:

gcloud eventarc triggers create helloworld-trigger \
    --location=us-central1 \
    --destination-workflow=my-workflow \
    --destination-workflow-location=europe-west4 \
    --event-filters="type=google.cloud.audit.log.v1.written" \
    --event-filters="serviceName=bigquery.googleapis.com" \
    --event-filters="methodName=jobservice.jobcompleted" \
    --service-account="${SERVICE_ACCOUNT_NAME}@${PROJECT_ID}.iam.gserviceaccount.com"

This creates a trigger called helloworld-trigger for audit logs that are written by bigquery.googleapis.com and for the operation identified as jobservice.jobcompleted.

Terraform

You can create a trigger for a workflow using Terraform. For details, see Trigger a workflow using Eventarc and Terraform.

List a trigger

You can confirm the creation of a trigger by listing Eventarc triggers using the Google Cloud CLI or through the Google Cloud console.

Console

  1. In the Google Cloud console, go to the Eventarc Triggers page.

    Go to Triggers

    This page lists your triggers in all locations, and includes details such as names, regions, event providers, destinations, and more.

  2. To filter your triggers:

    1. Click Filter or the Filter triggers field.
    2. In the Properties list, select an option to filter the triggers by.

    You can select a single property or use the logical operator OR to add more properties.

  3. To sort your triggers, beside any supported column heading, click Sort.

gcloud

Run the following command to list your triggers:

gcloud eventarc triggers list --location=-

This command lists your triggers in all locations, and includes details such as names, types, destinations, and statuses.

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