Cloud Pub/Sub operates on the basis of topics and subscriptions. When submitting a message to Cloud Pub/Sub, the message is written to a specific topic. Any number of subscriptions may be attached to a given topic, forming a one-to-many relationship. For each subscription, Cloud Pub/Sub maintains a separate message queue. Each message posted to a given topic will be written to every subscription attached to that topic. As a result, Cloud Pub/Sub follows a publisher-subscriber messaging pattern, where publishers do not maintain any reference to recipients.
The publisher-subscriber messaging pattern has several advantages when working in complex systems. Because the publisher is not concerned with which services receive ...
