The rabbitmq inputs has optional "exchange" and "key" params, but when they do not bind the "queue" to the given "exchange" for the "key" in the "hot bunnies" implementation (note it does it in the "bunny" implementation).
This results in no message being received by the "queue".
Pull request here: https://github.com/logstash/logstash/pull/628
I removed my PR because there was already another one: https://github.com/logstash/logstash/pull/624
merged!