Google Cloud Pub/Sub Messaging Service

Google Pub/Sub

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.

Intro to Google Pub/Sub

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 Quick Facts

  1. Global Availability: Google Pub/Sub offers a global service footprint, available in all current and future GCP regions, ensuring that messages are ingested, processed, and delivered with minimal latency.
  2. High Throughput: Google Pub/Sub is designed to provide high throughput and low-latency messaging, supporting up to millions of messages per second, depending on the size of messages and network conditions.
  3. Retention Period: Google Pub/Sub retains unacknowledged messages for seven days, giving ample time for subscribers to process each message and ensuring that no message is missed due to short-term processing failures.
  4. Integration Capabilities: Google Pub/Sub can natively integrate with numerous Google Cloud services, such as Google Cloud Storage, Google BigQuery, and Google Cloud Functions, facilitating seamless data workflows and processing.
  5. Reliability: Boasting an SLA of 99.95% availability, Google Pub/Sub ensures that applications can count on its infrastructure to reliably deliver messages across a wide range of use cases and scenarios.

Key Features of Google Pub/Sub

  • Global Scale: Google Pub/Sub is designed to automatically provide the resources required by applications, scaling up and down as demand changes, with no pre-provisioning required.
  • Real-time Analytics: Integration with data streaming tools like Google Dataflow enables real-time analytics on the data passing through the system.
  • End-to-End Encryption: Messages are encrypted both in transit and at rest. The service automatically manages cryptographic keys on your behalf using the same technology that Google uses for its own production services.
  • Durable Message Storage: Unacknowledged messages are retained for seven days, ensuring that subscription applications have ample time to process each message.
  • Multi-language SDKs: Google Pub/Sub provides client libraries in multiple languages, including Java, Python, Node.js, and more.

How Google Pub/Sub Works

Google Pub/Sub relies on two main concepts: topics and subscriptions.

  1. Topics: A named resource to which messages are sent by publishers.
  2. Subscriptions: Each subscription is associated with a single topic, and contains the stream of messages associated with that topic. Different subscribers can receive messages at different times, allowing for complex processing architectures.

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.

Alternatives to Google Pub/Sub

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.

Getting Started with Google Pub/Sub


  • A Google Cloud account and a project set up on the Google Cloud Console.
  • The Google Cloud SDK installed on your machine.


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.

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