[rabbitmq-discuss] A question about RabbitMQ "Presence Exchange" Plugin

[Marek Majkowski]

2012/2/8 Liuzhuofu <liuzhuofu at huawei.com>:
>     When I use RabbitMQ "Presence Exchange" Plugin, I found when a client
> (name:"Client_1") bind to the x-presence exchange, the queue
> (name:"monitor_queue") with "" route key can get a "bind" msg, but if I
> didn't subscribe the queue("Client_1") with a process, when the "client_1"
> coredown, the "monitor_queue" can not get a "unbind" msg. If I subcribe the
> queue("client_1"), when "client_1" coredown or exit, the monitor_queue can
> got a "unbind" msg.
>
>     My question is: I have bind the queue("client_1") to the
> exchange("monitor"), why can not got the "unbind" msg when queue("client_1")
> not be subscribed, but can got the "unbind" msg when queue("client_1") be
> subscribed.

Take a look at the readme:
https://github.com/tonyg/presence-exchange#readme

"bindings made with the empty string "" as their binding
key, which receive presence messages, but do not
produce them; and bindings made with any other binding key,
which produce presence messages but do not receive them."

Marek