GCP - Cloud PubSub
Topics are subscriptions are within a project. Resource names:
//pubsub.googleapis.com/projects/PROJECT_ID/topics/TOPIC//pubsub.googleapis.com/projects/PROJECT_ID/subscriptions/SUBSCRIPTION
Subscription types:
- Pull: the subscriber requests messages from the Pub/Sub server.
- Push: the subscriber creates a endpoint; Pub/Sub server calls the endpoint to "push" a message.
- Export: export messages to a GCP service, e.g. BigQuery, GCS.