Service Bus

Make your Service Bus message handlers idempotent

Azure Service Bus delivers every message at least once, and duplicates can arrive at the same moment. Here's how to make handling the same message twice harmless, even when two copies race.

How retries really work with the Service Bus trigger

When a Service Bus-triggered function throws, the message is retried immediately, ten times in a row, and then dead-lettered. If you need a delay between attempts, you have to build it.

Changing a message without breaking its consumers

Once other services consume your messages, the message format is a public contract. Additive changes are easy; breaking ones need a plan. Here's how to evolve message contracts safely.

Route messages with Service Bus topic filters

With a topic, every subscription gets every message by default. Filters let each consumer receive only what it needs, without the publisher knowing who's listening.

Don't ignore your dead-letter queue

Every Service Bus queue and subscription has a dead-letter queue. Messages that land there are silently waiting for someone to notice. Here's how to watch it, inspect it and replay it.

The transactional outbox pattern

Saving to the database and publishing a message are two separate operations, and one of them will eventually fail. The outbox pattern makes them succeed or fail together.