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Re: Caching strategies in Nova ...


On Mar 23, 2012, at 10:20 AM, Kevin L. Mitchell wrote:

> On Fri, 2012-03-23 at 13:43 +0000, Gabe Westmaas wrote:
>> However, I kind of expect that many users
>> will still poll even if they know they won't get new data until X
>> time. 
> I wish there was some kind of way for us to issue push notifications to
> the client, i.e., have the client register some sort of callback and
> what piece of data / state change they're interested in, then nova would
> call that callback when the condition occurred.  It probably wouldn't
> stop polling, but we could ratchet down rate limits to encourage users
> to use the callback mechanism.

Actually, that is (one) of the things the notifications system was designed to accommodate.   If you use attach a feed generator (like Yagi) to the notification queues, plus a PubSubHubub hub, folks can subscribe to events by event type.  (Other pubsub strategies would work too, like XMPP pubsub) 

> Of course, then there's the problem of, what if the user is behind a
> firewall or some sort of NAT... :/

 PSH pushes to a web callback supplied by the client. Presumably they could run the callback receiver somewhere else, or some thru some proxy. 

> -- 
> Kevin L. Mitchell <kevin.mitchell@xxxxxxxxxxxxx>
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