RabbitMQ: Move a message to DLX when there are no queues in the original exchange

Question

I'm wondering whether it is possible to configure RabbitMQ to move a message to a DLX after it's been sitting in another (topic) exchange for a period of time without being delivered to any queue and consumed?

All examples I've seen require that a queue exist, because the DLX mapping must be declared on the queue. But what if there is no queue?

In my case, clients declare auto-delete queues that go away when the client closes the connection. This causes a problem for the publisher on the topic exchange, which is never notified that the message isn't likely to be consumed in the time allotted.

FWIW, I'm using RabbitMQ from C#.

[UPDATE]

I found an article that seems to suggest I need to set up something called an alternate exchange in addition to a DLX, because DLX only receives messages that have already been routed. I'm currently trying to understand how it's supposed to work.

Further suggestions are appreciated!

Answer 1

Take a look at alternate exchange docs article

When declaring main exchange, you can provide the name of alternate exchange as parameter.

• Create the alternate exhange and make it of type fanout .
• Create a single durable queue bound to that alternate exchange.

Now all unrouted messages should end up in that queue.