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

Written by
Updated at May 13, 2025

Create a trigger for Cloud Logging to send messages to WebSocket connections when you add entries to a log group.

Getting started

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.

    Note

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

  • Service account with the api-gateway.websocketBroadcaster role. If you do not have a service account, create one.

  • A log group that activates the trigger when entries are added there. If you do not have a log group, create one.

Creating a trigger

Note

The trigger is initiated within 5 minutes of being created.

  1. In the management console, select the folder where you want to create a trigger.

  2. Open API Gateway.

  3. In the left-hand panel, select Triggers.

  4. Click Create trigger.

  5. 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.

  6. Under Cloud Logging settings, specify:

    • Log group.
    • (Optional) Resource types, such as serverless.function for Cloud Functions functions.
    • (Optional) IDs of Yandex Cloud or your resources, such as Cloud Functions functions.
    • (Optional) Log streams.
    • (Optional) Logging levels.

    A trigger fires when records that match all the optional settings are added to the specified log group. If an optional setting is not specified, the trigger fires for any value of the setting.

  7. 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 for a period not exceeding the specified wait time and sends them to WebSocket connections. The number of messages cannot exceed the specified batch size.

  8. 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 to send messages to WebSocket connections.

  9. Click Create trigger.

If you do not have the Yandex Cloud (CLI) command line interface yet, install and initialize it.

The folder specified when creating the CLI profile is used by default. To change the default folder, use the yc config set folder-id <folder_ID> command. You can specify a different folder using the --folder-name or --folder-id parameter.

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

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 that will invoke a container when entries are added to it.
  • --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 Yandex Cloud or your resources, such as Cloud Functions functions. This is an optional parameter.
  • --resource-types: Resource types, such as serverless.function for Cloud Functions functions. This is an optional parameter.
  • --stream-names: Log streams. This is an optional parameter.
  • --log-levels: Logging levels. This is an optional parameter.
    The trigger fires when the specified log group receives records that match all of the following parameters: resource-ids, resource-types, stream-names, and log-levels. If a parameter is not specified, the trigger fires for any value of the parameter.
  • --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:

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

To create a trigger for Cloud Logging, use the create REST API method for the Trigger resource or the TriggerService/Create gRPC API call.

Checking the result

Check that the trigger operates correctly. Do it by viewing the API gateway logs that present information about its incoming requests.

See also

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