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The notification system is simply 'borrowing' some code from rpc to push notifications. The notifications have a specified JSON message format, documented on the wiki: <a href="http://wiki.openstack.org/NotificationSystem">http://wiki.openstack.org/NotificationSystem</a>
<div>As far as the notification drivers, they are very very simple. </div>
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<div>On Apr 25, 2012, at 2:45 PM, Eric Windisch wrote:</div>
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<div><span style="font-size: 12px;">Sure, but then the contract becomes between the notifier and the client, presumably? I'm not as familiar with the notification system as I should be.</span>
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<div><span style="font-size: 12px;">I haven't written a ZeroMQ notifier yet, figuring that task would be better delayed until the move to openstack-common.</span></div>
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Eric Windisch
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<p style="color: #A0A0A8;">On Wednesday, April 25, 2012 at 3:29 PM, Russell Bryant wrote:</p>
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<div>On 04/25/2012 03:22 PM, Eric Windisch wrote:</div>
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<div>I've heard a few people mention pulling messages off the queue, or</div>
<div>communicating via RPC outside of the project, or outside of Python. In</div>
<div>theory, this sounds nice, but the RPC implementations are strictly</div>
<div>making sure that A can execute calls on target B and that responses get</div>
<div>back to A.</div>
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<div>This has little to do with message queues, other than that message</div>
<div>queues are optionally supported. You shouldn't be peeking behind that</div>
<div>curtain. This is specific to each RPC mechanism and enforcing something</div>
<div>this early might be more problematic than you expect.</div>
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<div>I agree with you that any discussion of other things poking at the rpc</div>
<div>communications is broken and wrong.</div>
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<div>The only case where it does make sense is notifications. In that case,</div>
<div>the fact that it's using rpc is just an implementation detail. If you</div>
<div>enable the rabbit notifier (should probably be renamed at some point),</div>
<div>there is a specific AMQP message exchange where external applications</div>
<div>are to receive notifications from nova.</div>
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<div>This implementation detail means that this can also be used with zeromq</div>
<div>... though I'm not sure that makes sense. There would probably be a</div>
<div>notifier implementation specific to zeromq that could make better use of</div>
<div>that messaging model.</div>
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<div>-- </div>
<div>Russell Bryant</div>
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<div>--</div>
<div><span class="Apple-tab-span" style="white-space: pre; "></span>Monsyne M. Dragon</div>
<div><span class="Apple-tab-span" style="white-space: pre; "></span>OpenStack/Nova </div>
<div><span class="Apple-tab-span" style="white-space: pre; "></span>cell 210-441-0965</div>
<div><span class="Apple-tab-span" style="white-space: pre; "></span>work x 5014190</div>
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