I am attempting to host two versions of the same WCF service on the same server. The two service assemblies in question have the same version number, and differ only in content. However, they are located at two different physical locations pointed at by two separate (but identically named) virtual directories in two separate IIS sites. Each site is bound to a distinct host name, and the app I am currently testing with is configured to send requests to the correct host (I am overriding domain name resolution using the hosts file.) Furthermore, each site under which this service is hosted uses a separate (but identically configured) application pool.
I thought all of these measures would be sufficient to eliminate any possible confusion on the part of IIS as to which assembly I am trying to execute when I send a request to a particular endpoint URL. However, requests to the second site continue to be handled by the version of the assembly pointed to by the first site. My Visual Studio debug session is attached to every w3wp.exe instance currently running, which eliminates the possibility that I am debugging the wrong app pool. When I pull up the source code files for each version of the service, the breakpoints in both files indicate that symbols have been loaded and that they will be hit (although this changed after I shut down IIS and deleted the temporary ASP.Net files for the service.)
To make matters stranger, I am successfully running and debugging two versions of the same web app using the same scheme, and everything is working correctly. The only difference seems to be that one pair of virtual directories are hosting web apps and the other pair of virtual directories are hosting WCF services.
When I look at the modules panel, it indicates that the version of the assembly being loaded is coming from the temporary ASP.NET folder.
Can anyone explain why IIS is loading the wrong version of the assembly in question? Does it have something to do with the caching going on in the Temporary ASP.Net folder?
Just to confirm that the correct endpoint is getting hit, I shut down the first site and tried the request again. The exception I received made it clear that the endpoint for the second site was not being hit.
Now I just need to figure out why the endpoint element in the project's web.config is being ignored in favor of the endpoint defined in the machine.config.