Publisher
Cloud / Knowledge library
Google Cloud Pub/Sub
Provides global asynchronous messaging with topics and subscriptions
Why learn Google Cloud Pub/Sub?
Teams use Google Cloud Pub/Sub to adopt publish-subscribe messaging without building the complete underlying platform themselves.
The problem it solves
Fans published events out to one or more asynchronous subscribers
Where it came from
Google Cloud Pub/Sub is Google Cloud's offering for publish-subscribe messaging. Its closest catalog counterparts are Azure Service Bus Topics and Amazon SNS; they address the same broad need but are not feature-for-feature identical.
Build your understanding
Work through these exercises in order. Try the task before opening a reference.
- Explain the main responsibility of Google Cloud Pub/Sub.
- Choose a workload that fits Google Cloud Pub/Sub.
- Identify one operational tradeoff of Google Cloud Pub/Sub.
- Compare Google Cloud Pub/Sub with Azure Service Bus Topics.
- Compare Google Cloud Pub/Sub with Amazon SNS.
Documentation and sources
- Google Cloud products at a glance (docs.cloud.google.com)
Connect the ideas
Alternatives
Real World Example
Decoupling Global Inventory Updates
Retailers managing high-volume inventory updates across multiple global warehouses.
The business problem
Direct synchronous API calls between inventory systems and regional storefronts lead to cascading failures when one region experiences high latency or downtime.
How this topic solves it
Google Cloud Pub/Sub provides global asynchronous messaging, allowing inventory systems to publish updates to a topic without needing to know the status of downstream subscribers.
- Create a Pub/Sub topic to serve as the central message bus for inventory events.
- Configure individual subscriptions for each regional storefront application.
- Publish inventory change events from the central warehouse system to the topic.
- Implement logic in regional storefronts to pull and process messages from their respective subscriptions.
- Monitor subscription backlog metrics to ensure regional storefronts are keeping pace with updates.
Shows how inventory updates flow from the source to multiple regional consumers via Pub/Sub.
Global Message Bus
Subscriber
Subscriber
- Inventory System → publishes event → Pub/Sub Topic
- Pub/Sub Topic → delivers message → Storefront A
- Pub/Sub Topic → delivers message → Storefront B
Expected business outcome
Improved system resilience where regional storefronts remain operational even if the central inventory system experiences temporary spikes or maintenance.
Limitations and checks
Pub/Sub is an asynchronous system, meaning there is no guarantee of immediate consistency; check the message delivery latency via monitoring tools to ensure it meets business requirements.