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Posted to users@qpid.apache.org by Pavel Moravec <pm...@redhat.com> on 2012/01/03 11:03:09 UTC

QMF raising event when defaut binding is created?

Hi all,
I realized that currently QMF does not raise an event when a default binding is created (by "default binding" I mean a binding of type "{exchange:'', queue:<queuename>, key:<queuename>}" that is created automatically when a queue is created).

To check that behavior, let subscribe to "qmf.default.topic/agent.ind.event.org_apache_qpid_broker.bind.#" and create a queue - no message will be send to the subscription. Any other binding crated is notified by sending a message to the subscription.

My question is: is that a inconsistency that shall be fixed or a desired behavior?

The answer might not be so plain as the '' exchange and the "default bindings" are rather hacks to allow sending messages to queues directly. So while technically the defualt bindings are a real bindings, logically they are not.

Does somebody (plan to) benefit either by raising QMF event when a default binding is created or not raising so?

Kind regards,
Pavel



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Re: QMF raising event when defaut binding is created?

Posted by Ted Ross <tr...@redhat.com>.
Pavel,

The creation of the default binding is a side-effect of creating a queue 
(as is the deletion of the binding when the queue is deleted).  The 
event is not raised because it is implied as always occurring after the 
creation of a queue.

-Ted

On 01/03/2012 05:03 AM, Pavel Moravec wrote:
> Hi all,
> I realized that currently QMF does not raise an event when a default binding is created (by "default binding" I mean a binding of type "{exchange:'', queue:<queuename>, key:<queuename>}" that is created automatically when a queue is created).
>
> To check that behavior, let subscribe to "qmf.default.topic/agent.ind.event.org_apache_qpid_broker.bind.#" and create a queue - no message will be send to the subscription. Any other binding crated is notified by sending a message to the subscription.
>
> My question is: is that a inconsistency that shall be fixed or a desired behavior?
>
> The answer might not be so plain as the '' exchange and the "default bindings" are rather hacks to allow sending messages to queues directly. So while technically the defualt bindings are a real bindings, logically they are not.
>
> Does somebody (plan to) benefit either by raising QMF event when a default binding is created or not raising so?
>
> Kind regards,
> Pavel
>
>
>
> ---------------------------------------------------------------------
> Apache Qpid - AMQP Messaging Implementation
> Project:      http://qpid.apache.org
> Use/Interact: mailto:users-subscribe@qpid.apache.org
>


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Re: QMF raising event when defaut binding is created?

Posted by Fraser Adams <fr...@blueyonder.co.uk>.
Hi Pavel,
I'm no expert on AMQP, but my suspicion is that this relates to the fact 
that the default binding (which is to the default direct exchange) isn't 
a "true" binding - as far as I'm aware it is illegal for users to bind 
or unbind to the default direct exchange (it's very definitely impossble 
to do this via QMF as the address key is <exname>/<qname>/<key> and it 
doesnt work with a blank <exname>).

So as a guess because that is essentially a "hardcoded" binding that 
can't be unbound etc. I suspect that's why bind events don't get generated.

Someone who knows more about the AMQP spec might be able to give a 
better answer though..

Frase



On 03/01/12 10:03, Pavel Moravec wrote:
> Hi all,
> I realized that currently QMF does not raise an event when a default binding is created (by "default binding" I mean a binding of type "{exchange:'', queue:<queuename>, key:<queuename>}" that is created automatically when a queue is created).
>
> To check that behavior, let subscribe to "qmf.default.topic/agent.ind.event.org_apache_qpid_broker.bind.#" and create a queue - no message will be send to the subscription. Any other binding crated is notified by sending a message to the subscription.
>
> My question is: is that a inconsistency that shall be fixed or a desired behavior?
>
> The answer might not be so plain as the '' exchange and the "default bindings" are rather hacks to allow sending messages to queues directly. So while technically the defualt bindings are a real bindings, logically they are not.
>
> Does somebody (plan to) benefit either by raising QMF event when a default binding is created or not raising so?
>
> Kind regards,
> Pavel
>
>
>
> ---------------------------------------------------------------------
> Apache Qpid - AMQP Messaging Implementation
> Project:      http://qpid.apache.org
> Use/Interact: mailto:users-subscribe@qpid.apache.org
>


---------------------------------------------------------------------
Apache Qpid - AMQP Messaging Implementation
Project:      http://qpid.apache.org
Use/Interact: mailto:users-subscribe@qpid.apache.org