On 10 March 2013 09:42, Fraser Adams <[email protected]> wrote: > >> Yeah - from an AMQP 1.0 point of view one might consider Queues and >> Exchanges both as types of "Nodes" (the 1.0 transport for the Java >> Broker actually allows you to publish directly to Queues and subscribe >> to Exchanges)... how to present this and the 0.x view as a single >> coherent model will be "interesting" (are bindings links from >> exchanges to queues I wonder) > > As per previous post I'm *really* interested in this going forward as I > suspect are many people. Publishing to a queue seems fairly "normal" given > that the default direct exchange provided a mechanism to use a producer > address that just looked like a queue, but subscribing to an exchange seems > weirder. In the latter case clearly a topic address made it look like this > was happening, but a temporary queue was always put in place *actually* > subscribing to exchanges seems more unusual as one would normally expect > some sort of "elastic" buffering to decouple producers and consumers. I > guess that with Qpid there's the concept of prefetching messages so I guess > that this gives the necessary buffering (unless synchronous behaviour has > been specified). > > I'd really like to understand more about how this is currently working in > AMQP 1.0/Proton do you have some example Addresses that are being used - I'm > particularly interested in how an existing AddressString containing a > headers exchange and bindings to that might work.
So, what the Java Broker does under the covers is actually to create a temporary subscription queue. One could actually implement subscriptions to exchanges such that published messages are not acknowledged until they have been flowed to all recipients... but that would have been a bigger piece of work. Ultimately I want to just add "topic" nodes rather than abusing exchanges for this purpose (I had a 10 line patch that did this that is probably still sitting around somewhere). The primary implementation difference is that messages at the head of a "topic" get silently dropped if there are no subscriptions that have not yet passed that message. > >> >> -- Rob (going seriously off-topic) >> >> > Perhaps, but it's probably a good topic to start, the AMQP 1.0 work has been > quietly going on in dev land and I think this is probably a good time to > start sharing the love a bit on the user list. > +1. We definitely need to talk more about AMQP 1.0 on this list as well as better explaining what things are AMQP 1.0 and what things are "Qpid". -- Rob > > Frase > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [email protected] > For additional commands, e-mail: [email protected] > --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
