Use mem chan in actor core

tractor/_actor.py

@@ -199,7 +199,9 @@ class Actor:
             Tuple[trio._core._run.CancelScope, typing.Callable, trio.Event]
         ] = {}
         # map {uids -> {callids -> waiter queues}}
-        self._actors2calls: Dict[Tuple[str, str], Dict[str, trio.Queue]] = {}
+        self._cids2qs: Dict[
+            Tuple[Tuple[str, str], str],
+            trio.abc.SendChannel[Any]] = {}
         self._listeners: List[trio.abc.Listener] = []
         self._parent_chan: Optional[Channel] = None
         self._forkserver_info: Optional[Tuple[Any, Any, Any, Any, Any]] = None
@@ -299,37 +301,58 @@ class Actor:
                     log.exception(
                         f"Channel for {chan.uid} was already zonked..")
 
-    async def _push_result(self, actorid, cid: str, msg: dict) -> None:
+    async def _push_result(
+        self,
+        actorid: Tuple[str, str],
+        msg: Dict[str, Any],
+    ) -> 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)
+        cid = msg['cid']
+        send_chan = self._cids2qs[(actorid, cid)]
+        assert send_chan.cid == cid
         log.debug(f"Delivering {msg} from {actorid} to caller {cid}")
+        try:
             # maintain backpressure
-        await q.put(msg)
+            await send_chan.send(msg)
+        except trio.BrokenResourceError:
+            # XXX: local consumer has closed their side
+            # so cancel the far end streaming task
+            log.warning(f"{send_chan} consumer is already closed")
 
-    def get_waitq(
+    def get_memchans(
         self,
         actorid: Tuple[str, str],
         cid: str
-    ) -> trio.Queue:
+    ) -> trio.abc.ReceiveChannel:
         log.debug(f"Getting result queue for {actorid} cid {cid}")
-        cids2qs = self._actors2calls.setdefault(actorid, {})
-        return cids2qs.setdefault(cid, trio.Queue(1000))
+        try:
+            recv_chan = self._cids2qs[(actorid, cid)]
+        except KeyError:
+            send_chan, recv_chan = trio.open_memory_channel(1000)
+            send_chan.cid = cid
+            self._cids2qs[(actorid, cid)] = send_chan
+
+        return recv_chan
 
     async def send_cmd(
-        self, chan: Channel, ns: str, func: str, kwargs: dict
-    ) -> Tuple[str, trio.Queue]:
+        self,
+        chan: Channel,
+        ns: str,
+        func: str,
+        kwargs: dict
+    ) -> Tuple[str, trio.abc.ReceiveChannel]:
         """Send a ``'cmd'`` message to a remote actor and return a
         caller id and a ``trio.Queue`` that can be used to wait for
         responses delivered by the local message processing loop.
         """
         cid = str(uuid.uuid1())
         assert chan.uid
-        q = self.get_waitq(chan.uid, cid)
+        recv_chan = self.get_memchans(chan.uid, cid)
         log.debug(f"Sending cmd to {chan.uid}: {ns}.{func}({kwargs})")
         await chan.send({'cmd': (ns, func, kwargs, self.uid, cid)})
-        return cid, q
+        return cid, recv_chan
 
     async def _process_messages(
         self, chan: Channel,
@@ -364,11 +387,10 @@ class Actor:
                                 f" {chan} from {chan.uid}")
                         break
 
-                    log.debug(f"Received msg {msg} from {chan.uid}")
-                    cid = msg.get('cid')
-                    if cid:
+                    log.trace(f"Received msg {msg} from {chan.uid}")
+                    if msg.get('cid'):
                         # deliver response to local caller/waiter
-                        await self._push_result(chan.uid, cid, msg)
+                        await self._push_result(chan.uid, msg)
                         log.debug(
                             f"Waiting on next msg for {chan} from {chan.uid}")
                         continue