从角色入口点开始加载DataCache

Question

I want to access my windows Azure Data Cache from my Role Entry StartUp routine. However I keep getting this error:

{"ErrorCode:SubStatus:Server collection cannot be empty."}

However when I do the same from within my Controller class it loads the Data Cache fine and I can go ahead and do things with it.

Is there anything special for the Role Entry class that I have to do to access the Data Cache prior to my application starting?

Or can't I access the Cache in the Role StartUp ?

Cheers

Answer 1

Starting with Azure SDK 1.3, there is a major change - the Full IIS mode. Read this blog post to get full undertanding of full IIS and what is it.

In short - your RoleEntryPoint descendant (where your OnStart method is being executed) lives in whole another AppDomain (and process actually - WaIISHost.exe), while your actual web application just lives in IIS (w3wp.exe). That's why there is no way to do something in OnStart() that would affect your web applicatin or that would be able to directly read your web.config.

If you do read Azure Data Cache in OnStart to do some preload of data for the web application, just do in your Global.asax's Application_Start() event handler.

If you need to read Azure Data Cache in OnStart for reason's specific to the RoleEntryPoint, you have to load the configuration from web.config. Web.config is placed in "./bin/web.config" relative to your AppRoot folder. (there are two copies of your application when you use WebRoles with full IIS - one lives in AppRoot and one lives in SitesRoot).

Hope this helps!

Answer 2

WebRole's OnStart probably does not use your web.config where you probably have specified server names and access keys for your AppFabric DataCache provider.

I would try manually instrumenting the server connection configuration.