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](https://docs.cloud.google.com/eventarc/docs/cloudevents-json.md.txt)) and passes the event into the workflow execution as a [workflow runtime argument](https://docs.cloud.google.com/workflows/docs/passing-runtime-arguments.md.txt). Make sure that the event size does not exceed the [resource limit](https://docs.cloud.google.com/workflows/quotas.md.txt#resource_limits). Events larger than the maximum Workflows arguments size won't trigger workflow executions. These instructions show you how to configure event routing so that an execution of your workflow is triggered in response to a direct Database Migration event. For more details, see the list of [supported direct events](https://docs.cloud.google.com/eventarc/docs/reference/supported-events.md.txt#directly-from-a-google-cloud-source).
> [!NOTE] > **Note:** If both direct and audit log events are supported for a Google provider, we recommend that you create a trigger that filters for the direct event. Direct events offer a number of advantages over audit log events. For more information, see [Event routes](https://docs.cloud.google.com/eventarc/standard/docs/run/event-routing-options.md.txt). ## 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](https://docs.cloud.google.com/resource-manager/docs/creating-managing-projects.md.txt). > [!NOTE] > **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. [Go to project selector](https://console.cloud.google.com/projectselector2/home/dashboard)
2. Enable the Eventarc, Eventarc Publishing, Workflows, and Workflow Executions APIs. [Enable the APIs](https://console.cloud.google.com/apis/enableflow?apiid=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 Database Migration events, enable the Database Migration API. 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](https://console.cloud.google.com/projectselector/iam-admin/serviceaccounts/create?supportedpurview=project)
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](https://docs.cloud.google.com/eventarc/standard/docs/workflows/roles-permissions.md.txt). 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](https://console.cloud.google.com/?cloudshell=true) At the bottom of the Google Cloud console, a [Cloud Shell](https://docs.cloud.google.com/shell/docs/how-cloud-shell-works.md.txt) 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: ```bash 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 Database Migration events, enable `datamigration.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: ```bash 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](https://docs.cloud.google.com/eventarc/standard/docs/workflows/roles-permissions.md.txt). ## 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. > [!NOTE] > **Note:** Filtering is done through an exact match and does not support wildcards or regular expressions. However, you can use the `--event-filters-path-pattern` flag in the following gcloud CLI command, or define a path pattern through the console. For more information, see [Understand path patterns](https://docs.cloud.google.com/eventarc/docs/path-patterns.md.txt).
### Console 1. In the Google Cloud console, go to the Eventarc **Triggers** page. [Go to Triggers](https://console.cloud.google.com/eventarc/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. In the **Event provider** list, select **Database Migration** . Note that the event provider name used in the associated [Google Cloud documentation](https://docs.cloud.google.com/docs) 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 *Direct* events, select an event type. 7. 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](https://docs.cloud.google.com/eventarc/docs/issues.md.txt). 8. In the **Region** list, select the same region as the Google Cloud service that is generating events. For more information, see [Eventarc locations](https://docs.cloud.google.com/eventarc/docs/locations.md.txt). 9. If applicable to the event provider, click **Add filter** and specify the following: 1. In the **Attribute 1** field, depending on the direct event you chose, select a [resource ID](https://docs.cloud.google.com/apis/design/resource_names) that can act as an event filter. 2. Select an operator: - **Equal** - **Path pattern** For more information, see [Understand path patterns](https://docs.cloud.google.com/eventarc/docs/path-patterns.md.txt). 3. In the **Attribute value 1** field, depending on the operator that you chose, type the exact value or apply a path pattern. 4. If more attribute filters are applicable, click **Add filter** and specify the appropriate values. 10. 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](https://docs.cloud.google.com/eventarc/standard/docs/access-control.md.txt) required by Eventarc. 11. In the **Event destination** list, select **Workflows**. 12. 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](https://docs.cloud.google.com/eventarc/standard/docs/event-providers-targets.md.txt#triggers). 13. Optionally, to add a label, you can click **Add label** . Labels are key-value pairs that help you organize your Google Cloud resources. For more information, see [What are labels?](https://docs.cloud.google.com/resource-manager/docs/labels-overview.md.txt#what-are-labels) 14. Click **Create**. 15. After a trigger is created, the event source filters can't be modified. Instead, create a new trigger and delete the old one. For more information, see [Manage triggers](https://docs.cloud.google.com/eventarc/docs/managing-triggers.md.txt). ### gcloud You can create a trigger by running the `gcloud eventarc triggers create` command along with required and optional flags. ```bash gcloud eventarc triggers create TRIGGER \ --location=LOCATION \ --destination-workflow=DESTINATION_WORKFLOW \ --destination-workflow-location=DESTINATION_WORKFLOW_LOCATION \ --event-filters="type=EVENT_FILTER_TYPE" \ --event-filters="COLLECTION_ID=RESOURCE_ID" \ --event-filters-path-pattern="COLLECTION_ID=PATH_PATTERN" \ --event-data-content-type="EVENT_DATA_CONTENT_TYPE" \ --service-account="SERVICE_ACCOUNT_NAME@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`. To avoid any performance and data residency issues, the location must match the location of the Google Cloud service that is generating events. For more information, see [Eventarc locations](https://docs.cloud.google.com/eventarc/docs/locations.md.txt). - `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](https://docs.cloud.google.com/workflows/docs/locations.md.txt) 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. - `EVENT_FILTER_TYPE`: the identifier of the event. An event is generated when an API call for the method succeeds. For long-running operations, the event is only generated at the end of the operation, and only if the action is performed successfully. For a list of supported event types, see [Google event types supported by Eventarc](https://docs.cloud.google.com/eventarc/docs/reference/supported-events.md.txt#directly-from-a-google-cloud-source). - `COLLECTION_ID` (optional): the [resource](https://docs.cloud.google.com/apis/design/resource_names) component that can act as an event filter, and is one of the following: - `connectionprofile` - `migrationjob` - `RESOURCE_ID`: the identifier of the resource used as the filtering value for the associated collection. For more information, see [Resource ID](https://docs.cloud.google.com/apis/design/resource_names#resource_id). - `PATH_PATTERN`: the [path pattern](https://docs.cloud.google.com/eventarc/docs/path-patterns.md.txt) to apply when filtering for the resource - `EVENT_DATA_CONTENT_TYPE`: (optional) the [encoding of the event payload](https://docs.cloud.google.com/eventarc/standard/docs/overview.md.txt#event-format). 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](https://docs.cloud.google.com/eventarc/docs/issues.md.txt). - `SERVICE_ACCOUNT_NAME`: the name of your user-managed service account. - `PROJECT_ID`: your Google Cloud project ID Notes: - The `--event-filters="type=EVENT_FILTER_TYPE"` flag is required. If no other event filter is set, events for all resources are matched. - `EVENT_FILTER_TYPE` cannot be changed after creation. To change `EVENT_FILTER_TYPE`, create a new trigger and delete the old one. - 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; however, when using the `--event-filters-path-pattern` flag, you can define a resource [path pattern](https://docs.cloud.google.com/eventarc/docs/path-patterns.md.txt). - The `--service-account` flag is used to specify the Identity and Access Management (IAM) service account email associated with the trigger. Example: ``` gcloud eventarc triggers create helloworld-trigger \ --location=us-central1 \ --destination-workflow=my-workflow \ --destination-workflow-location=us-central1 \ --event-filters="type=google.cloud.clouddms.migrationJob.v1.updated" \ --event-filters-path-pattern="migrationjob=my-migrationjob-*" \ --service-account="${SERVICE_ACCOUNT_NAME}@${PROJECT_ID}.iam.gserviceaccount.com" ``` This command creates a trigger called `helloworld-trigger` for the event identified as `google.cloud.clouddms.migrationJob.v1.updated` and matches events for `migrationjob` IDs starting with `my-migrationjob-`.
### Terraform You can create a trigger for a workflow using Terraform. For details, see [Trigger a workflow using Eventarc and Terraform](https://docs.cloud.google.com/eventarc/docs/creating-triggers-terraform.md.txt). > [!NOTE] > **Note:** Although your trigger is created immediately, it can take up to two minutes for a trigger to propagate and filter events. ## 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](https://console.cloud.google.com/eventarc/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: ```bash gcloud eventarc triggers list --location=- ``` This command lists your triggers in all locations, and includes details such as names, types, destinations, and statuses. ## What's next - [Trigger a workflow using Eventarc and Terraform](https://docs.cloud.google.com/eventarc/docs/creating-triggers-terraform.md.txt) - [Learn more about Eventarc](https://docs.cloud.google.com/eventarc/standard/docs/overview.md.txt)