Re: GSoC project: fedmsg for the Debian infrastructure
On Thu, Apr 25, 2013 at 07:20:09PM +0200, Jonas Smedegaard wrote:
> Quoting Simon Chopin (2013-04-25 18:07:29)
> > Quoting Daniel Pocock (2013-04-25 17:34:03)
> > > ZeroMQ is a very lightweight solution - it is brokerless (like
> > > multicast) so won't necessarily support the requirement for durable
> > > subscriptions (keeping messages queued up for clients that are
> > > disconnected)
> > > http://www.zeromq.org/topics:requirements-for-reliability
> >
> > As I mentionned in my original email (granted, without expanding much
> > on it), I plan to implement a mechanism to solve this very problem by
> > keeping the messages sent on the emitter side and resending them on
> > demand.
>
> Hmm - so essentially you will follow a standard for low-level transport
> of messages, but invent something custom for the slightly higher level
> QoS handling. Sounds odd to me.
>
> > > Some things that are worth looking at:
> > >
> > > - do we want to use an AMQP broker? In theory, this is an open
> > > standard like SMTP: the clients and brokers are interchangeable
> >
> > This solution has been already examined by the Fedora folks, and
> > rejected by lack of scalability WRT the broker. This sort of question
> > is actually why I think it is a good idea to use fedmsg because its
> > authors have needs that are quite similar to ours, and virtually the
> > same use cases.
>
> Fair enough.
>
> Could you perhaps point to the relevant prior discussions - I am curious
> what they found bad about AMQP, and also curious if they had considered
> MQTT which seems the perfect fit for this (simpler than AMQP, yet
> includes simple QoS and simple authentication not in 0MQ).
Indeed. Both MQTT [1] and PZQ [2] seem interesting, which is hard or me to say
given my unabashed bias towards WSO2.
If we are wed to fedmsg and fedmsg is wed to ZeroMQ, then I'd be interested in
leveragingone of MQTT or PZQ for QoS.
[1] http://mqtt.org/
[2] https://github.com/mkoppanen/pzq/wiki/An-Introduction-To-PZQ
--
Luca Filipozzi
http://www.crowdrise.com/SupportDebian
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