When a channel has no subscribers unhelpful "Dispatcher has no subscribers" is logged. [INT-886]

[spring-operator]

Iwein Fuld opened INT-886 and commented

As a result of this it is tough to debug configuration errors. There are several possible solutions:

• Add a 'client' property on the dispatcher (which should be set to the client channel) so we can log: "Dispatcher for channel 'foo' has no subscribers".
• Add a MessageDispatchingException and catch and wrap that in the channel itself.

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Affects: 2.0 M1

1 votes, 2 watchers

[spring-operator]

Dave Syer commented

Agree. Anything has to be better than what we have - you basically have to debug into the dispatcher to find out what channel it is attached to.

[spring-operator]

Mark Fisher commented

I basically went with Iwein's second suggestion, but rather than adding a MessageDispatchingException, I simply changed the dispatcher code to throw IllegalStateException. The channel (where, obviously, the name is already known) is now responsible for wrapping any non-MessagingException in a MessageDeliveryException.

We could consider adding MessageDispatchingException, but at this point I basically view dispatchers as a component of the channel and, therefore, part of the delivery process. Therefore, throwing a low-level runtime Exception and adding context up at the channel level seems like a good approach here.