Google Cloud Pub/Sub is a real-time messaging service that enables you to send and receive messages between independent applications. Part of the Google Cloud Platform (GCP), it is designed to provide reliable, many-to-many, asynchronous messaging between decoupled systems. Google Pub/Sub can be used to create event-driven architectures, stream analytics, or as a building block for more complex data integration tasks.
Google Cloud Pub/Sub, a key offering of the Google Cloud Platform, was developed leveraging Google’s vast experience in global, real-time data systems. As an asynchronous messaging service, Pub/Sub facilitates real-time communication between decoupled applications through its primary constructs, topics and subscriptions. Topics receive messages from publishers and relay them to all associated subscribers, ensuring reliable, scalable, and timely message delivery across diverse systems and use cases.
Google Pub/Sub relies on two main concepts: topics and subscriptions.
When a message is sent to a topic, it’s delivered to all of the topic’s associated subscriptions. Each message sent to a subscription is sent to the next available subscriber.
There are several other alternatives to Google Pub/Sub that perform similar functions. Below is a chart that compares Google Pub/Sub to its three closest alternatives: AWS SNS, Apache Kafka, and Azure Service Bus.
1: Creating a Topic: Using the Google Cloud Console or the gcloud
CLI, you can create a topic:
gcloud pubsub topics create my-topic-name
2: Creating a Subscription: Once you’ve created a topic, create a subscription to that topic:
gcloud pubsub subscriptions create my-subscription-name --topic my-topic-name
3: Publishing Messages: Using the SDK or CLI, you can publish a message to your topic:
gcloud pubsub topics publish my-topic-name --message "Hello, World!"
4: Receiving Messages: You can pull messages from your subscription using the following command:
gcloud pubsub subscriptions pull --auto-ack my-subscription-name
5: Cleaning Up: Remember to delete your resources after use to avoid incurring unwanted costs:
gcloud pubsub topics delete my-topic-name
gcloud pubsub subscriptions delete my-subscription-name
Google Pub/Sub is a robust and scalable solution for real-time messaging in distributed systems. With a focus on durability, scalability, and security, it provides developers with the tools they need to build responsive and resilient applications in the cloud. The getting started guide above will provide a foundational understanding of how to utilize Google Pub/Sub in your own projects.