Accept transport closed error during handshake and msg loop

tractor/_actor.py

@@ -27,6 +27,7 @@ from ._exceptions import (
     unpack_error,
     ModuleNotExposed,
     is_multi_cancelled,
+    TransportClosed,
 )
 from . import _debug
 from ._discovery import get_arbiter
@@ -202,7 +203,7 @@ class Actor:
         enable_modules: List[str] = [],
         uid: str = None,
         loglevel: str = None,
-        arbiter_addr: Optional[Tuple[str, int]] = None,
+        arbiter_addr: Optional[Tuple[str, int]] = (None, None),
         spawn_method: Optional[str] = None
     ) -> None:
         """This constructor is called in the parent actor **before** the spawning
@@ -232,7 +233,7 @@ class Actor:
         # TODO: consider making this a dynamically defined
         # @dataclass once we get py3.7
         self.loglevel = loglevel
-        self._arb_addr = tuple(arbiter_addr) if arbiter_addr is not None else (None, None)
+        self._arb_addr = tuple(arbiter_addr)
 
         # marked by the process spawning backend at startup
         # will be None for the parent most process started manually
@@ -338,7 +339,18 @@ class Actor:
         # send/receive initial handshake response
         try:
             uid = await self._do_handshake(chan)
-        except StopAsyncIteration:
+
+        except (
+            trio.BrokenResourceError,
+            trio.ClosedResourceError,
+            TransportClosed,
+        ):
+            # XXX: This may propagate up from ``Channel._aiter_recv()``
+            # and ``MsgpackStream._inter_packets()`` on a read from the
+            # stream particularly when the runtime is first starting up
+            # inside ``open_root_actor()`` where there is a check for
+            # a bound listener on the "arbiter" addr.  the reset will be
+            # because the handshake was never meant took place.
             log.warning(f"Channel {chan} failed to handshake")
             return
 
@@ -579,22 +591,39 @@ class Actor:
                     )
                     await self.cancel_rpc_tasks(chan)
 
+        except (
+            TransportClosed,
+            trio.BrokenResourceError,
+            trio.ClosedResourceError
+        ):
+            # channels "breaking" is ok since we don't have a teardown
+            # handshake for them (yet) and instead we simply bail out
+            # of the message loop and expect the teardown sequence
+            # to clean up.
+            log.error(f"{chan} form {chan.uid} closed abruptly")
+            # raise
+
         except trio.ClosedResourceError:
             log.error(f"{chan} form {chan.uid} broke")
+
         except (Exception, trio.MultiError) as err:
             # ship any "internal" exception (i.e. one from internal machinery
             # not from an rpc task) to parent
             log.exception("Actor errored:")
             if self._parent_chan:
                 await self._parent_chan.send(pack_error(err))
-            raise
+
             # if this is the `MainProcess` we expect the error broadcasting
             # above to trigger an error at consuming portal "checkpoints"
+            raise
+
         except trio.Cancelled:
             # debugging only
             log.debug(f"Msg loop was cancelled for {chan}")
             raise
+
         finally:
+            # msg debugging for when he machinery is brokey
             log.debug(
                 f"Exiting msg loop for {chan} from {chan.uid} "
                 f"with last msg:\n{msg}")