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I am trying to build a sort of asynchronous server by using RabbitMQ along with JAVA. I have two exchanges Original_Exch and Dead_Exch, and one queue in each. Both the exchanges are declared DLX (dead letter exchange of each other's queue).

Now come to the problem, I am publishing a message to Original_Exch in the form of a json string which contains email Info ( such as To,Subject, Message body, attachment, etc ). After consuming this message from the queue bind to Original_exch, I am sending email to the specified email address. In case email is not sent successfully I am transferring this message to Dead_Exch and after 2 seconds ( using TTL for that ) the message is again being transferred to Original_Exch.

Let's assume a scenario in which a particular message is moving from one exchange to another due to continuous failure. In that case I want to make sure that if it has been transferred to Original_Exch 10 times, it should be dropped ( deleted ) from queue permanently and should not be transferred to Dead_Exch.

There are so many answers for almost similar kind of questions but none of them are satisfactory ( from a learner point of view ).

Thanks..........

Haridesh Yadav
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Messages which have been dead-letterred have a x-death header with details about which queue(s) it went through and how many times. See an article about dead-letter exchanges on RabbitMQ website.

So you can use this header to do what you want. I see two solutions:

  • In your consumer, when a mail could not be delivered, look at the x-death header and decide if you want to dead-letter it (Basic.Nack with requeue set to false) or drop it (Basic.Ack).
  • Use a header exchange type for Dead_Exch and configure the binding to match on x-death.

Because header exchanges only do exact match on the header value, the first solution is more flexible and less error-prone.

Jean-Sébastien Pédron
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