Trigger for Data Streams that sends messages to WebSocket connections

A trigger for Data Streams sends messages to WebSocket connections when data is sent to a stream.

A trigger for Data Streams requires service accounts to manage the stream and send messages to WebSocket connections. You can use the same service account for both operations.

For more information about creating a trigger for Data Streams, see Creating a trigger for Data Streams that sends messages to WebSocket connections.

Message batchingMessage batching

The batching settings allow sending several messages to WebSocket connections at a time. They set a top limit on a message batch size and its accumulation time. For example, if the message batch size is 3, WebSocket connections can receive batches containing from 1 to 3 messages.

Roles required for the proper operation of a trigger for Data StreamsRoles required for the proper operation of a trigger for Data Streams

• To create a trigger, you need a permission for the service account under which the trigger runs the operation. This permission comes with the iam.serviceAccounts.user and editor roles or higher.
• For the trigger to fire, service accounts need the following roles:
  • api-gateway.websocketBroadcaster for the folder containing the API gateway.
  • yds.admin for the stream that invokes the trigger when data is sent to it.

Format of the message from the trigger for Data StreamsFormat of the message from the trigger for Data Streams

The trigger for Data Streams accepts and sends messages in JSON format only.

After the trigger fires, it will send a message with the messages array to WebSocket connections:

{
   "messages":[
      {
         "key1":"value1"
      },
      {
         "key2":"value2"
      }
   ]
}

See alsoSee also

• Trigger for Data Streams that runs a Serverless Containers container
• Trigger for Data Streams that runs a Cloud Functions function