I am trying to build an application in Windows Azure that requires notifications - so I am using Http Polling, but I got a problem. I need to get to the very same instance of my web role so I can maintain the polling. I found a solution with web farm request rewriting(adding extra proxy role), but I don't like the solution.
Soo my question: Is there a way to do stateless polling and if there is someone that implemented this - can you give me a hint or link?
You just need the poll request to thunk through to some sort of shared 'stateful' layer. Probably the best candidate would be to use the Windows Azure caching service. http://www.windowsazure.com/en-us/home/tour/caching/ you could also just use storage and choosing between the two will largely be determined by how busy your app is; i.e. whether it is cheaper to pay a fixed cost for some cache space with no per request charge or pay almost nothing for your storage space but pay a per request charge.
By taking this approach it does not matter if susequent polling requests end up routed to a different instance. To me this is best practice regardless; I've seen some fugly bugs pop up when people assume session affinity when making AJAX calls back into an Azure web role.
