add 'template' services

src/risotto/dispatcher.py

@@ -60,7 +60,7 @@ class CallDispatcher:
                 mandatories = list(config.value.mandatory())
                 if mandatories:
                     mand = [mand.split('.')[-1] for mand in mandatories]
-                    raise ValueError(_(f'missing parameters in response: {mand}'))
+                    raise ValueError(_(f'missing parameters in response: {mand} in message "{risotto_context.message}"'))
                 try:
                     config.value.dict()
                 except Exception as err:
@@ -238,6 +238,10 @@ class Dispatcher(register.RegisterDispatcher, CallDispatcher, PublishDispatcher)
         # return the config
         return config
 
+    def get_service(self,
+                    name: str):
+        return self.injected_self[name]
+
 
 dispatcher = Dispatcher()
 register.dispatcher = dispatcher