tasks: improve logging on failed tasks

rhodecode/lib/celerylib/loader.py

@@ -276,7 +276,11 b' class RequestContextTask(Task):'
             raise Exception(
                 'Unable to fetch required data from request: {}. \n'
                 'This task is required to be executed from context of '
-                'request in a webapp'.format(repr(req)))
+                'request in a webapp. Task: {}'.format(
+                    repr(req),
+                    self
+                )
+            )
 
         if req:
             # we hook into kwargs since it is the only way to pass our data to