Cloud Pub/Sub in Google Cloud Platform (GCP) is a messaging service that enables real-time, scalable communication between independent applications. In this overview, we’ll cover the definition, how to use, commands (if applicable), use cases, examples, costs, and pros and cons of Cloud Pub/Sub in GCP.
Definition:
Cloud Pub/Sub is a fully managed, globally available messaging service that facilitates asynchronous, at-least-once delivery of messages between publishers and subscribers. It’s based on the publish-subscribe pattern, which decouples the sender (publisher) and receiver (subscriber) components of an application, enabling them to evolve independently and simplifying the overall system design.
How to use:
1. Create topics: A topic is a named channel where messages are sent. You can create topics using the Cloud Console, `gcloud` command-line tool, or the Cloud Pub/Sub API.
2. Publish messages: Publishers send messages to a specific topic. Messages can be sent using the Cloud Pub/Sub client libraries (available in various languages) or the API.
3. Create subscriptions: Subscribers receive messages by creating a subscription to a topic. Subscriptions can be created using the Cloud Console, `gcloud` command-line tool, or the API.
4. Receive messages: Subscribers receive messages by pulling them from the subscription or using a push endpoint. Messages are delivered at least once, ensuring that no messages are lost due to temporary subscriber unavailability.
Commands:
You can manage Cloud Pub/Sub using the `gcloud` command-line tool:
– To create a topic: `gcloud pubsub topics create TOPIC_NAME`
– To list topics: `gcloud pubsub topics list`
– To create a subscription: `gcloud pubsub subscriptions create SUBSCRIPTION_NAME –topic TOPIC_NAME`
– To list subscriptions: `gcloud pubsub subscriptions list`
– To pull messages from a subscription: `gcloud pubsub subscriptions pull –auto-ack SUBSCRIPTION_NAME`
