This question is picking up from the following thread on the (now read-only) OpenRasta Google Group: http://groups.google.com/group/openrasta/browse_thread/thread/67df7a648a9cd843/cf8558b3c632601b?#cf8558b3c632601b
Since that group was made read-only, the guidance is to ask questions here on StackOverflow.
I'm seeing intermittent behaviour whereby StructureMap is returning "No Default Instance defined for PluginFamily" errors when resolving types in OpenRasta. Which type is referred to is inconsistent. Sometimes it is an internal dependency of OpenRasta, sometimes it is one of our own handlers. Sometimes everything works as it should without issue.
The situation is easy to reproduce both locally, using Cassini, and on our test server, Windows 2008 R2 x64 running IIS 7.5. Generally it manifests itself when there is a series of rapid requests against the same OpenRasta service. In our case, we have a web app which is issuing a number of AJAX requests against the service in quick succession. This would appear to suggest that it is somehow timing related. We don't see the issue if we issue single requests at a time.
OpenRasta 2.0.3.0.
StructureMap 2.6.3.
Have you tried updating to the latest asp.net openrasta hosting?
There are also a few issues with the structuremap integration, and some other issues with the auto-registration of handlers in previous versions of OR.
So I'd say try updating the hosting to 2.1, if the problem persists, try making sure your handlers are already registered in SM (instead of letting them be auto-registered), finally try and check in the SM integration code how to make sure the integration uses the correct SM API and uses the context store instead of whatever internal asp.net-specific thing that comes OOB. I'd suggest contacting the owner of the SM integration but we don't have one, it's an oprhaned codebase.
Seb