An order-processing platform issues 'PlaceOrder' instructions that must be processed exactly once, can never be duplicated, and require dead-letter handling for any message the worker cannot process. Which Azure messaging service fits these command-style requirements?
- AUse Azure Event Grid topics with CloudEvents schema and webhook handlers.
- BUse Azure Service Bus queues for the PlaceOrder workflow with peek-lock receivers. Correct
- CUse Azure Event Hubs with multiple partitions and consumer groups.
- DUse Azure Storage Queues with 7-day retention and visibility timeout.
Why A is wrong: Event Grid is optimised for discrete events with at-least-once push semantics and explicitly does not provide duplicate detection or transactional guarantees that PlaceOrder commands require.
Why B is correct: Correct. The architecture guide defines commands as high-value messages that must be delivered at least once and processed at most once, with dead-letter handling for poison messages.
Why C is wrong: Event Hubs is a log-based streaming service tuned for high-volume telemetry and has no dead-letter queue or duplicate-detection facility for individual command processing.
Why D is wrong: Storage Queues lack dead-letter queues, duplicate detection, and transactions, so they cannot satisfy the strict command-processing requirements stated.