Cleanup Session after each request.

It's good practice to cleanup the SQL session after each
request so that the next request gets a fresh one.

It's an application decision whether one wants a
just-in-case ROLLBACK or COMMIT. There are two ideas behind
it, really. I have decided for ROLLBACK. The idea is "if
you forget to commit your changes yourself, there's
something broken. Maybe you got an exception?".

mediagoblin/app.py

@@ -184,6 +184,14 @@ class MediaGoblinApp(object):
         for m in self.meddleware[::-1]:
             m.process_response(request, response)
 
+        # Reset the sql session, so that the next request
+        # gets a fresh session
+        try:
+            self.db.reset_after_request()
+        except TypeError:
+            # We're still on mongo
+            pass
+
         return response(environ, start_response)
 
 

mediagoblin/db/sql/open.py

@@ -36,6 +36,7 @@ class DatabaseMaster(object):
         Session.flush()
 
     def reset_after_request(self):
+        Session.rollback()
         Session.remove()