quotas

https://cloud.google.com/pubsub/quotas

Subscription types for the subscriber side:

For a pull subscription, your subscriber client initiates requests to a Pub/Sub server to retrieve messages using the REST Pull API , RPC PullRequest API , the REST StreamingPullRequest API , or the RPC StreamingPullRequest API . Most subscriber clients do not make these requests directly and instead rely on the Google Cloud-provided high-level client library that performs streaming pull requests internally and delivers messages asynchronously.

Push subscription

Here is a brief description of the workflow that references Figure 3:

1. The Pub/Sub server sends each message as an HTTPS request to the subscriber client at a pre-configured endpoint. This request is shown as a PushRequest in the image.
2. The endpoint acknowledges the message by returning an HTTP success status code. A non-success response indicates that the message must be re-sent. This response is shown as a PushResponse in the image.
3. Pub/Sub dynamically adjusts the rate of push requests based on the rate at which it receives success responses.

https://cloud.google.com/pubsub/docs/subscriber

Subscription snippets https://cloud.google.com/pubsub/docs/create-subscription

Publisher snippets https://cloud.google.com/pubsub/docs/publisher

cli snippets