RabbitMQ: Specify how to populate messaging.destination.name

.chloggen/rabbitmq-destination-name.yaml

@@ -0,0 +1,4 @@
+change_type: breaking
+component: messaging
+note: "RabbitMQ: Specify how to populate `messaging.destination.name`"
+issues: [1529]

docs/messaging/rabbitmq.md

@@ -40,8 +40,26 @@ The Semantic Conventions for [RabbitMQ](https://www.rabbitmq.com/) extend and ov
 
 ## RabbitMQ attributes
 
-In RabbitMQ, the destination is defined by an *exchange* and a *routing key*.
-`messaging.destination.name` MUST be set to the name of the exchange. This will be an empty string if the default exchange is used.
+### Destination name
+
+n RabbitMQ, the destination is defined by an *exchange*, a *routing key* and
+for consumers, a *queue*.
+
+`messaging.destination.name` MUST be set to:
+
+#### Producers
+
+- `{exchange}:{routing key}` when both values are present and non-empty.
+If any has an empty value (e.g., the default exchange is used) it SHOULD be omitted.
+- Otherwise: `amq.default`
+
+#### Consumers
+
+- `{exchange}:{routing key}:{queue}` when all values are present and non-empty.
+If any has an empty value (e.g., the default exchange is used) it SHOULD be omitted.
+
+For cases when `{routing key}` and `{queue}` are equal, only one of them SHOULD
+be used, e.g., `{exchange}:{routing key}`.
 
 <!-- semconv messaging.rabbitmq -->
 <!-- NOTE: THIS TEXT IS AUTOGENERATED. DO NOT EDIT BY HAND. -->