[rabbitmq-discuss] Plugin Hooks / Callbacks

[Matthew Sackman]

Hi Andy,

On Wed, Feb 10, 2010 at 03:44:26PM -0800, Arco wrote:
> Now my question is - how to invoke the plugin from RabbitMQ?  I'd like
> the plugin to be called whenever a message enters an exchange, and
> also whenever a message leaves a queue.

Yes, that kind of thing is high on our todo list. The simple fact is
that it's very very hard to do this kind of thing without hurting
performance, and it's also very hard to add enough hooks everywhere to
satisfy everyone.

> Does RabbitMQ have hooks to register plugin callbacks like this, or do
> I have to modify the RabbitMQ source directly??

Because of the difficulty of working out the "right" way to do it, we
haven't done it yet ;) As a result, you'd have to alter the RabbitMQ
source directly.

Personally, I think the best way to do this is to use the dbg module.
With enough care in the match specs and some careful book keeping, I
think this is by far the easiest and most flexible way to insert such
hooks dynamically into the system.

Matthew