Move "treat_as_gen" detection into `_invoke()`

tractor/_actor.py

@@ -46,6 +46,19 @@ async def _invoke(
 ):
     """Invoke local func and return results over provided channel.
     """
+    sig = inspect.signature(func)
+    treat_as_gen = False
+    if 'chan' in sig.parameters:
+        assert 'cid' in sig.parameters, \
+            f"{func} must accept a `cid` (caller id) kwarg"
+        kwargs['chan'] = chan
+        kwargs['cid'] = cid
+        # TODO: eventually we want to be more stringent
+        # about what is considered a far-end async-generator.
+        # Right now both actual async gens and any async
+        # function which declares a `chan` kwarg in its
+        # signature will be treated as one.
+        treat_as_gen = True
     try:
         is_async_partial = False
         is_async_gen_partial = False
@@ -183,11 +196,13 @@ class Actor:
         log.debug(f"{uid} successfully connected back to us")
         return event, self._peers[uid][-1]
 
-    def load_namespaces(self) -> None:
-        # We load namespaces after fork since this actor may
-        # be spawned on a different machine from the original nursery
-        # and we need to try and load the local module code (if it
-        # exists)
+    def load_modules(self) -> None:
+        """Load allowed RPC modules locally (after fork).
+
+        Since this actor may be spawned on a different machine from
+        the original nursery we need to try and load the local module
+        code (if it exists).
+        """
         for path in self.rpc_module_paths:
             self._mods[path] = importlib.import_module(path)
 
@@ -261,6 +276,8 @@ class Actor:
                 await chan.aclose()
 
     async def _push_result(self, actorid, cid: str, msg: dict) -> None:
+        """Push an RPC result to the local consumer's queue.
+        """
         assert actorid, f"`actorid` can't be {actorid}"
         q = self.get_waitq(actorid, cid)
         log.debug(f"Delivering {msg} from {actorid} to caller {cid}")
@@ -288,9 +305,9 @@ class Actor:
     async def _process_messages(
         self, chan: Channel, treat_as_gen: bool = False
     ) -> None:
-        """Process messages async-RPC style.
+        """Process messages for the channel async-RPC style.
 
-        Process rpc requests and deliver retrieved responses from channels.
+        Receive multiplexed RPC requests and deliver responses over ``chan``.
         """
         # TODO: once https://github.com/python-trio/trio/issues/467 gets
         # worked out we'll likely want to use that!
@@ -336,23 +353,9 @@ class Actor:
                     func = getattr(self._mods[ns], funcname)
 
                 # spin up a task for the requested function
-                sig = inspect.signature(func)
-                treat_as_gen = False
-                if 'chan' in sig.parameters:
-                    assert 'cid' in sig.parameters, \
-                        f"{func} must accept a `cid` (caller id) kwarg"
-                    kwargs['chan'] = chan
-                    kwargs['cid'] = cid
-                    # TODO: eventually we want to be more stringent
-                    # about what is considered a far-end async-generator.
-                    # Right now both actual async gens and any async
-                    # function which declares a `chan` kwarg in its
-                    # signature will be treated as one.
-                    treat_as_gen = True
-
                 log.debug(f"Spawning task for {func}")
                 cs = await self._root_nursery.start(
-                    _invoke, self, cid, chan, func, kwargs, treat_as_gen,
+                    _invoke, self, cid, chan, func, kwargs,
                     name=funcname
                 )
                 # never allow cancelling cancel requests (results in
@@ -421,7 +424,7 @@ class Actor:
                 self._root_nursery = nursery
 
                 # load allowed RPC module
-                self.load_namespaces()
+                self.load_modules()
 
                 # Startup up channel server
                 host, port = accept_addr