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A company is redesigning its order processing system. They need to ensure that when a customer places an order, the inventory service, payment service, and shipping service all receive the order details. The services should operate independently, and the order details must be delivered to each service exactly once. Which Azure service is most appropriate for reliable, fan-out messaging to multiple independent subscribers?
- AAzure Event Grid
- BAzure Service Bus Topics
- CAzure Queue Storage
- DAzure Event Hubs
Show answer & explanationAnswer & explanation
Correct answer: B. Azure Service Bus Topics
Azure Service Bus Topics enable publish/subscribe messaging, allowing multiple subscribers to receive copies of a message published to the topic. With subscriptions, it ensures reliable, 'exactly once' delivery semantics per subscriber, which is crucial for transactional systems like order processing.
Why the other options are wrong
- A. Azure Event Grid is for event-driven architectures, but Service Bus Topics offer stronger guarantees for message delivery and ordering in complex transactional workflows.
- C. Azure Queue Storage is for point-to-point messaging, not fan-out to multiple independent subscribers.
- D. Azure Event Hubs is for high-throughput data streaming, not for transactional fan-out messaging with 'exactly once' delivery guarantees for individual messages.
Azure Service Bus Topics
A publish/subscribe messaging component within Azure Service Bus that allows producers to send messages to a topic, and multiple subscribers to receive copies of those messages via subscriptions.
- Enables fan-out messaging.
- Supports multiple independent subscribers.
- Provides advanced features like filtering, dead-lettering, and transactional guarantees.
Memory trick: Service Bus Topics are like a newspaper, many subscribers get the same news reliably.