Merge pull request #215 from goodboy/transport_cleaning

Transport cleaning: attempt to define our graceful channel close signal.

setup.py

@@ -38,13 +38,20 @@ setup(
         'tractor.testing',
     ],
     install_requires=[
+
+        # trio related
         'trio>0.8',
-        'msgpack',
         'async_generator',
+        'trio_typing',
+
+        # tooling
         'colorlog',
         'wrapt',
-        'trio_typing',
         'pdbpp',
+
+        # serialization
+        'msgpack',
+
     ],
     tests_require=['pytest'],
     python_requires=">=3.7",

tests/test_cancellation.py

@@ -123,8 +123,15 @@ def test_multierror_fast_nursery(arb_addr, start_method, num_subactors, delay):
 
     assert exc_info.type == tractor.MultiError
     err = exc_info.value
-    assert len(err.exceptions) == num_subactors
-    for exc in err.exceptions:
+    exceptions = err.exceptions
+
+    if len(exceptions) == 2:
+        # sometimes oddly now there's an embedded BrokenResourceError ?
+        exceptions = exceptions[1].exceptions
+
+    assert len(exceptions) == num_subactors
+
+    for exc in exceptions:
         assert isinstance(exc, tractor.RemoteActorError)
         assert exc.type == AssertionError
 

tests/test_debugger.py

@@ -297,15 +297,31 @@ def test_multi_daemon_subactors(spawn, loglevel):
 
     child.expect(r"\(Pdb\+\+\)")
 
+    # there is a race for which subactor will acquire
+    # the root's tty lock first
+
     before = str(child.before.decode())
-    assert "Attaching pdb to actor: ('bp_forever'" in before
+
+    bp_forever_msg = "Attaching pdb to actor: ('bp_forever'"
+    name_error_msg = "NameError"
+
+    if bp_forever_msg in before:
+        next_msg = name_error_msg
+
+    elif name_error_msg in before:
+        next_msg = None
+
+    else:
+        raise ValueError("Neither log msg was found !?")
 
     child.sendline('c')
 
     # first name_error failure
     child.expect(r"\(Pdb\+\+\)")
     before = str(child.before.decode())
-    assert "NameError" in before
+
+    if next_msg:
+        assert next_msg in before
 
     child.sendline('c')
 
@@ -316,9 +332,10 @@ def test_multi_daemon_subactors(spawn, loglevel):
     try:
         child.sendline('c')
         child.expect(pexpect.EOF)
-    except pexpect.exceptions.TIMEOUT:
-        # Failed to exit using continue..?
 
+    except pexpect.exceptions.TIMEOUT:
+
+        # Failed to exit using continue..?
         child.sendline('q')
         child.expect(pexpect.EOF)
 

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
@@ -262,7 +263,7 @@ class Actor:
         self._parent_chan: Optional[Channel] = None
         self._forkserver_info: Optional[
             Tuple[Any, Any, Any, Any, Any]] = None
-        self._actoruid2nursery: Dict[str, 'ActorNursery'] = {}  # type: ignore
+        self._actoruid2nursery: Dict[str, 'ActorNursery'] = {}  # type: ignore  # noqa
 
     async def wait_for_peer(
         self, uid: Tuple[str, str]
@@ -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
 
@@ -578,22 +590,35 @@ class Actor:
                     )
                     await self.cancel_rpc_tasks(chan)
 
-        except trio.ClosedResourceError:
-            log.error(f"{chan} form {chan.uid} broke")
+        except (
+            TransportClosed,
+        ):
+            # channels "breaking" (for TCP streams by EOF or 104
+            # connection-reset) 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.debug(f'channel from {chan.uid} closed abruptly:\n{chan}')
+
         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}")

tractor/_exceptions.py

@@ -38,6 +38,10 @@ class InternalActorError(RemoteActorError):
     """
 
 
+class TransportClosed(trio.ClosedResourceError):
+    "Underlying channel transport was closed prior to use"
+
+
 class NoResult(RuntimeError):
     "No final result is expected for this actor"
 
@@ -63,12 +67,15 @@ def pack_error(exc: BaseException) -> Dict[str, Any]:
 
 
 def unpack_error(
+
     msg: Dict[str, Any],
     chan=None,
     err_type=RemoteActorError
+
 ) -> Exception:
     """Unpack an 'error' message from the wire
     into a local ``RemoteActorError``.
+
     """
     tb_str = msg['error'].get('tb_str', '')
     return err_type(

tractor/_ipc.py

@@ -1,6 +1,7 @@
 """
 Inter-process comms abstractions
 """
+import platform
 import typing
 from typing import Any, Tuple, Optional
 from functools import partial
@@ -10,7 +11,11 @@ import trio
 from async_generator import asynccontextmanager
 
 from .log import get_logger
-log = get_logger('ipc')
+from ._exceptions import TransportClosed
+log = get_logger(__name__)
+
+
+_is_windows = platform.system() == 'Windows'
 
 # :eyeroll:
 try:
@@ -21,10 +26,17 @@ except ImportError:
     Unpacker = partial(msgpack.Unpacker, strict_map_key=False)
 
 
-class MsgpackStream:
-    """A ``trio.SocketStream`` delivering ``msgpack`` formatted data.
-    """
-    def __init__(self, stream: trio.SocketStream) -> None:
+class MsgpackTCPStream:
+    '''A ``trio.SocketStream`` delivering ``msgpack`` formatted data
+    using ``msgpack-python``.
+
+    '''
+    def __init__(
+        self,
+        stream: trio.SocketStream,
+
+    ) -> None:
+
         self.stream = stream
         assert self.stream.socket
         # should both be IP sockets
@@ -35,7 +47,10 @@ class MsgpackStream:
         assert isinstance(rsockname, tuple)
         self._raddr = rsockname[:2]
 
+        # start and seed first entry to read loop
         self._agen = self._iter_packets()
+        # self._agen.asend(None) is None
+
         self._send_lock = trio.StrictFIFOLock()
 
     async def _iter_packets(self) -> typing.AsyncGenerator[dict, None]:
@@ -46,16 +61,39 @@ class MsgpackStream:
             use_list=False,
         )
         while True:
+
             try:
                 data = await self.stream.receive_some(2**10)
+
+            except trio.BrokenResourceError as err:
+                msg = err.args[0]
+
+                # XXX: handle connection-reset-by-peer the same as a EOF.
+                # we're currently remapping this since we allow
+                # a quick connect then drop for root actors when
+                # checking to see if there exists an "arbiter"
+                # on the chosen sockaddr (``_root.py:108`` or thereabouts)
+                if (
+                    # nix
+                    '[Errno 104]' in msg or
+
+                    # on windows it seems there are a variety of errors
+                    # to handle..
+                    _is_windows
+                ):
+                    raise TransportClosed(
+                        f'{self} was broken with {msg}'
+                    )
+
+                else:
+                    raise
+
             log.trace(f"received {data}")  # type: ignore
-            except trio.BrokenResourceError:
-                log.warning(f"Stream connection {self.raddr} broke")
-                return
 
             if data == b'':
-                log.debug(f"Stream connection {self.raddr} was closed")
-                return
+                raise TransportClosed(
+                    f'transport {self} was already closed prior ro read'
+                )
 
             unpacker.feed(data)
             for packet in unpacker:
@@ -96,10 +134,11 @@ class Channel:
         on_reconnect: typing.Callable[..., typing.Awaitable] = None,
         auto_reconnect: bool = False,
         stream: trio.SocketStream = None,  # expected to be active
+
     ) -> None:
         self._recon_seq = on_reconnect
         self._autorecon = auto_reconnect
-        self.msgstream: Optional[MsgpackStream] = MsgpackStream(
+        self.msgstream: Optional[MsgpackTCPStream] = MsgpackTCPStream(
             stream) if stream else None
         if self.msgstream and destaddr:
             raise ValueError(
@@ -112,6 +151,8 @@ class Channel:
         self._exc: Optional[Exception] = None
         self._agen = self._aiter_recv()
 
+        self._closed: bool = False
+
     def __repr__(self) -> str:
         if self.msgstream:
             return repr(
@@ -128,35 +169,49 @@ class Channel:
         return self.msgstream.raddr if self.msgstream else None
 
     async def connect(
-        self, destaddr: Tuple[Any, ...] = None,
+        self,
+        destaddr: Tuple[Any, ...] = None,
         **kwargs
+
     ) -> trio.SocketStream:
+
         if self.connected():
             raise RuntimeError("channel is already connected?")
+
         destaddr = destaddr or self._destaddr
         assert isinstance(destaddr, tuple)
         stream = await trio.open_tcp_stream(*destaddr, **kwargs)
-        self.msgstream = MsgpackStream(stream)
+        self.msgstream = MsgpackTCPStream(stream)
         return stream
 
     async def send(self, item: Any) -> None:
+
         log.trace(f"send `{item}`")  # type: ignore
         assert self.msgstream
+
         await self.msgstream.send(item)
 
     async def recv(self) -> Any:
         assert self.msgstream
+
         try:
             return await self.msgstream.recv()
+
         except trio.BrokenResourceError:
             if self._autorecon:
                 await self._reconnect()
                 return await self.recv()
 
+            raise
+
     async def aclose(self) -> None:
-        log.debug(f"Closing {self}")
+        log.debug(
+            f'Closing channel to {self.uid} '
+            f'{self.laddr} -> {self.raddr}'
+        )
         assert self.msgstream
         await self.msgstream.stream.aclose()
+        self._closed = True
 
     async def __aenter__(self):
         await self.connect()

tractor/_root.py

@@ -105,6 +105,11 @@ async def open_root_actor(
     arbiter_found = False
 
     try:
+        # TODO: this connect-and-bail forces us to have to carefully
+        # rewrap TCP 104-connection-reset errors as EOF so as to avoid
+        # propagating cancel-causing errors to the channel-msg loop
+        # machinery.  Likely it would be better to eventually have
+        # a "discovery" protocol with basic handshake instead.
         async with _connect_chan(host, port):
             arbiter_found = True