Cloud Pub/Sub is Google's managed event streaming service. Because serverless architectures tend to be heavily event-driven, triggering Cloud Functions from Pub/Sub is often a very powerful pattern. When creating a Pub/Sub trigger, developers specify the Pub/Sub topic to be used. Cloud Functions will generate a new push subscription for the specified topic in the form of gcf-<FUNCTION_NAME>-<TOPIC_NAME>. Note that the generated subscription will be automatically deleted upon deletion of the function.
Cloud Pub/Sub triggers deliver the following payload as the event body:
{ "eventId": "27819225098479", "timestamp": "2018-01-27T18:11:24.836Z", "eventType": "providers/cloud.pubsub/eventTypes/topic.publish", "resource": ...
