[rabbitmq-discuss] Broadcasting and STOMP (was Re: python stomp examples)

Thu Sep 11 16:35:58 BST 2008

Hi again,

  Thanks for all the info the last couple of days.  I think I've now
got my head around the basics, and I've also got my alpha application
working with broadcast, so cheers to that.

> It's not perfect. It will *usually* be a fairish round-robin, cycling
> through consumers in a regular cycle. If anything happens, though, such
> as the addition or removal of a consumer, or the rejection of an
> individual message, or TCP flow-control kicking in, the order of
> consumers can be shuffled. Usually the shuffling will be minor, but it
> can in general be arbitrary.
Good to know.

>> Thanks for this link, although maybe I should have looked harder for
>> the spec myself.  Instead I fruitlessly searched about the rabbitmq
>> site for 'fanout' and 'topic'.
>
> We're working on improving the website and the wiki.
I hadn't meant this comment as a criticism of the website or wiki,
rather I was indicting myself for being lazy and not seeking out the
protocol specification myself from the very beginning.

That said, I think it would also be useful to add to the STOMP wiki
page an additional note on broadcast SEND.  In particular I found that
in order to send a message to a broadcast exchange it needs look
something like:
---------------------------------
SEND
destination:x.mytopic
exchange:amq.topic

my message
\x00
--------------------------------

However my initial newb intuition was that it should look more like:
---------------------------------
SEND
destination:
exchange:amq.topic
routing_key:x.mytopic

my message
\x00
--------------------------------

The ruby examples cleared this up but not before I experienced a bit
of confusion on the subject.

Thanks again!

Cheers,
  Joe

>
>> Hmm.  From the AMQP spec it looks like I can create a 'durable'
>> exchange, which means that there shouldn't be any obstacle to creating
>> a hybrid producer client, right?  I am working primarily with python,
>> so I'm thinking I can use stomper+py-amqplib or python-qpid
>> (http://barryp.org/software/py-amqplib/) then just use amqp module to
>> add the exchange and do all my message passing with STOMP.
>
> Absolutely. That sounds right to me.
>
> Regards,
>  Tony
> --
>  [][][] Tony Garnock-Jones     | Mob: +44 (0)7905 974 211
>   [][] LShift Ltd             | Tel: +44 (0)20 7729 7060
>  []  [] http://www.lshift.net/ | Email: tonyg at lshift.net
>