[Yandex Cloud documentation](../../../index.md) > [Yandex API Gateway](../../index.md) > [Step-by-step guides](../index.md) > Creating a trigger > Creating a trigger for Cloud Logging

# Creating a trigger for Cloud Logging that sends messages to WebSocket connections

Create a [trigger for Cloud Logging](../../concepts/trigger/cloud-logging-trigger.md) to send messages to [WebSocket connections](../../concepts/extensions/websocket.md) when you add entries to a [log group](../../../logging/concepts/log-group.md).

## Getting started {#before-you-begin}

To create a trigger, you will need:

* API gateway. Messages will be sent to WebSocket connections accessing the API gateway at the path specified in the trigger settings. If you do not have an API gateway, [create one](../api-gw-create.md).

    {% note info %}

    The trigger does not call the API gateway when sending messages to WebSocket connections.

    {% endnote %}

* [Service account](../../../iam/concepts/users/service-accounts.md) with the `api-gateway.websocketBroadcaster` role. If you do not have a service account, [create one](../../../iam/operations/sa/create.md).

* Log group whose new entries will set off the trigger. If you do not have a log group, [create one](../../../logging/operations/create-group.md).

## Creating a trigger {#trigger-create}

{% note info %}

The trigger is initiated within five minutes after it is created.

{% endnote %}

{% list tabs group=instructions %}

- Management console {#console}

    1. In the [management console](https://console.yandex.cloud), select the folder where you want to create a trigger.

    1. Navigate to **API Gateway**.

    1. In the left-hand panel, select ![image](../../../_assets/console-icons/gear-play.svg) **Triggers**.

    1. Click **Create trigger**.

    1. Under **Basic settings**:

        * Enter a name and description for the trigger.
        * In the **Type** field, select `Cloud Logging`.
        * In the **Launched resource** field, select `API gateway`.

    1. Under **Cloud Logging settings**, specify:

        * Log group.
        * Optionally, types of resources, e.g., `serverless.function` in Cloud Functions.
        * Optionally, IDs of your resources or Yandex Cloud resources, e.g., functions in Cloud Functions.
        * Optionally, log streams.
        * Optionally, logging levels.
        
        A trigger fires when the specified log group receives entries that comply with all of the optional settings. If the optional setting is not specified, the trigger fires for any value.

    1. Under **Batch message settings**, specify:

        * Batch size. The values may range from 1 to 1,000. The default value is 1.
        * Maximum wait time. The values may range from 1 to 60 seconds. The default value is 1 second.

       The trigger groups messages within the specified wait time period and sends them to WebSocket connections. The number of messages cannot exceed the specified batch size.

    1. Under **API gateway settings**:
       * In the **API gateway** field, select the API gateway.
       * In the **Path** field, specify the path in the OpenAPI specification. Messages will be sent through WebSocket connections established using this path.
       * In the **Service account** field, select the [service account](../../../iam/concepts/users/service-accounts.md) to send messages to WebSocket connections.

    1. Click **Create trigger**.

- CLI {#cli}

    If you do not have the Yandex Cloud CLI yet, [install and initialize it](../../../cli/quickstart.md#install).

    The folder used by default is the one specified when [creating](../../../cli/operations/profile/profile-create.md) the CLI profile. To change the default folder, use the `yc config set folder-id <folder_ID>` command. You can also specify a different folder for any command using `--folder-name` or `--folder-id`. If you access a resource by its name, the search will be limited to the default folder. If you access a resource by its ID, the search will be global, i.e., through all folders based on access permissions.

  To create a trigger that sends messages to WebSocket connections, run this command:

    ```bash
    yc serverless trigger create logging \
      --name <trigger_name> \
      --log-group-name <log_group_name> \
      --batch-size 1 \
      --batch-cutoff 1s \
      --resource-ids <resource_ID> \
      --resource-types <resource_type> \
      --stream-names <logging_stream> \
      --log-levels <logging_level> \
      --gateway-id <API_gateway_ID> \
      --gateway-websocket-broadcast-path <path> \
      --gateway-websocket-broadcast-service-account-id <service_account_ID>
    ```

    Where:

    * `--name`: Trigger name.
    * `--log-group-name`: Name of the log group whose new log entries will invoke the container.

    * `--batch-size`: Message batch size. This is an optional parameter. The values may range from 1 to 10. The default value is 1.
    * `--batch-cutoff`: Maximum wait time. This is an optional parameter. The values may range from 0 to 20 seconds. The default value is 10 seconds. The trigger groups messages for a period not exceeding `batch-cutoff` and sends them to WebSocket connections. The number of messages cannot exceed `batch-size`.

    * `--resource-ids`: IDs of your resources or Yandex Cloud resources, e.g., functions in Cloud Functions. This is an optional setting.
    * `--resource-types`: Types of resources, e.g., `serverless.function` in Cloud Functions. This is an optional setting.
    * `--stream-names`: Log streams. This is an optional setting.
    * `--log-levels`: Logging levels. This is an optional setting.
      A trigger fires when the specified log group receives entries that comply with all of the following settings: `resource-ids`, `resource-types`, `stream-names`, and `log-levels`. If the setting is not specified, the trigger fires for any value.

    * `--gateway-id`: API gateway ID.
    * `--gateway-websocket-broadcast-path`: Path in the OpenAPI specification. Messages will be sent through WebSocket connections established using this path.
    * `--gateway-websocket-broadcast-account-id`: Service account ID with permissions to send messages to WebSocket connections.

    Result:

    ```text
    id: a1s5msktijh2********
    folder_id: b1gmit33hgh2********
    created_at: "2023-08-04T15:19:15.353909857Z"
    name: logging-trigger
    rule:
      logging:
        log_group_id: e23bidnftlh2********
        resource_type:
          - serverless.functions
        resource_id:
          - d4e1gpsgam78********
        stream_name:
          - test
        levels:
          - INFO
        batch_settings:
          size: "1"
          cutoff: 1s
        gateway_websocket_broadcast:
          gateway_id: d4eofc7n0mh2********
          path: /
          service_account_id: aje3932acdh2********
    status: ACTIVE
    ```

- API {#api}

  To create a trigger for Cloud Logging, use the [create](../../triggers/api-ref/Trigger/create.md) REST API method for the [Trigger](../../triggers/api-ref/Trigger/index.md) resource or the [TriggerService/Create](../../triggers/api-ref/grpc/Trigger/create.md) gRPC API call.

{% endlist %}

## Checking the result {#check-result}

Check that the trigger operates correctly. Do it by viewing the [API gateway logs](../api-gw-logs.md) that present information about its incoming requests.

## See also {#see-also}

* [Trigger for Cloud Logging that invokes a Cloud Functions function](../../../functions/operations/trigger/cloud-logging-trigger-create.md)
* [Trigger for Cloud Logging that invokes a Serverless Containers container](../../../serverless-containers/operations/cloud-logging-trigger-create.md)