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tractor/tractor/_ipc.py

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Python

# tractor: structured concurrent "actors".
# Copyright 2018-eternity Tyler Goodlet.
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
"""
Inter-process comms abstractions
"""
from __future__ import annotations
import platform
import struct
import typing
from collections.abc import AsyncGenerator, AsyncIterator
from typing import (
Any, Tuple, Optional,
Type, Protocol, TypeVar,
)
from tricycle import BufferedReceiveStream
import msgpack
import trio
from async_generator import asynccontextmanager
from .log import get_logger
from ._exceptions import TransportClosed
log = get_logger(__name__)
_is_windows = platform.system() == 'Windows'
log = get_logger(__name__)
def get_stream_addrs(stream: trio.SocketStream) -> Tuple:
# should both be IP sockets
lsockname = stream.socket.getsockname()
rsockname = stream.socket.getpeername()
return (
tuple(lsockname[:2]),
tuple(rsockname[:2]),
)
MsgType = TypeVar("MsgType")
# TODO: consider using a generic def and indexing with our eventual
# msg definition/types?
# - https://docs.python.org/3/library/typing.html#typing.Protocol
# - https://jcristharif.com/msgspec/usage.html#structs
class MsgTransport(Protocol[MsgType]):
stream: trio.SocketStream
drained: list[MsgType]
def __init__(self, stream: trio.SocketStream) -> None:
...
# XXX: should this instead be called `.sendall()`?
async def send(self, msg: MsgType) -> None:
...
async def recv(self) -> MsgType:
...
def __aiter__(self) -> MsgType:
...
def connected(self) -> bool:
...
# defining this sync otherwise it causes a mypy error because it
# can't figure out it's a generator i guess?..?
def drain(self) -> AsyncIterator[dict]:
...
@property
def laddr(self) -> Tuple[str, int]:
...
@property
def raddr(self) -> Tuple[str, int]:
...
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
self._laddr, self._raddr = get_stream_addrs(stream)
# create read loop instance
self._agen = self._iter_packets()
self._send_lock = trio.StrictFIFOLock()
# public i guess?
self.drained: list[dict] = []
async def _iter_packets(self) -> AsyncGenerator[dict, None]:
'''
Yield packets from the underlying stream.
'''
unpacker = msgpack.Unpacker(
raw=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.transport(f"received {data}") # type: ignore
if data == b'':
raise TransportClosed(
f'transport {self} was already closed prior to read'
)
unpacker.feed(data)
for packet in unpacker:
yield packet
@property
def laddr(self) -> Tuple[Any, ...]:
return self._laddr
@property
def raddr(self) -> Tuple[Any, ...]:
return self._raddr
async def send(self, msg: Any) -> None:
async with self._send_lock:
return await self.stream.send_all(
msgpack.dumps(msg, use_bin_type=True)
)
async def recv(self) -> Any:
return await self._agen.asend(None)
async def drain(self) -> AsyncIterator[dict]:
'''
Drain the stream's remaining messages sent from
the far end until the connection is closed by
the peer.
'''
try:
async for msg in self._iter_packets():
self.drained.append(msg)
except TransportClosed:
for msg in self.drained:
yield msg
def __aiter__(self):
return self._agen
def connected(self) -> bool:
return self.stream.socket.fileno() != -1
class MsgspecTCPStream(MsgpackTCPStream):
'''
A ``trio.SocketStream`` delivering ``msgpack`` formatted data
using ``msgspec``.
'''
def __init__(
self,
stream: trio.SocketStream,
prefix_size: int = 4,
) -> None:
import msgspec
super().__init__(stream)
self.recv_stream = BufferedReceiveStream(transport_stream=stream)
self.prefix_size = prefix_size
# TODO: struct aware messaging coders
self.encode = msgspec.msgpack.Encoder().encode
self.decode = msgspec.msgpack.Decoder().decode # dict[str, Any])
async def _iter_packets(self) -> AsyncGenerator[dict, None]:
'''Yield packets from the underlying stream.
'''
import msgspec # noqa
last_decode_failed: bool = False
while True:
try:
header = await self.recv_stream.receive_exactly(4)
except (
ValueError,
# not sure entirely why we need this but without it we
# seem to be getting racy failures here on
# arbiter/registry name subs..
trio.BrokenResourceError,
):
raise TransportClosed(
f'transport {self} was already closed prior ro read'
)
if header == b'':
raise TransportClosed(
f'transport {self} was already closed prior ro read'
)
size, = struct.unpack("<I", header)
log.transport(f'received header {size}') # type: ignore
msg_bytes = await self.recv_stream.receive_exactly(size)
log.transport(f"received {msg_bytes}") # type: ignore
try:
yield self.decode(msg_bytes)
except (
msgspec.DecodeError,
UnicodeDecodeError,
):
if not last_decode_failed:
# ignore decoding errors for now and assume they have to
# do with a channel drop - hope that receiving from the
# channel will raise an expected error and bubble up.
log.error('`msgspec` failed to decode!?')
last_decode_failed = True
else:
raise
async def send(self, msg: Any) -> None:
async with self._send_lock:
bytes_data: bytes = self.encode(msg)
# supposedly the fastest says,
# https://stackoverflow.com/a/54027962
size: bytes = struct.pack("<I", len(bytes_data))
return await self.stream.send_all(size + bytes_data)
def get_msg_transport(
key: Tuple[str, str],
) -> Type[MsgTransport]:
return {
('msgpack', 'tcp'): MsgpackTCPStream,
('msgspec', 'tcp'): MsgspecTCPStream,
}[key]
class Channel:
'''
An inter-process channel for communication between (remote) actors.
Wraps a ``MsgStream``: transport + encoding IPC connection.
Currently we only support ``trio.SocketStream`` for transport
(aka TCP).
'''
def __init__(
self,
destaddr: Optional[Tuple[str, int]],
msg_transport_type_key: Tuple[str, str] = ('msgpack', 'tcp'),
# TODO: optional reconnection support?
# auto_reconnect: bool = False,
# on_reconnect: typing.Callable[..., typing.Awaitable] = None,
) -> None:
# self._recon_seq = on_reconnect
# self._autorecon = auto_reconnect
# TODO: maybe expose this through the nursery api?
try:
# if installed load the msgspec transport since it's faster
import msgspec # noqa
msg_transport_type_key = ('msgspec', 'tcp')
except ImportError:
pass
self._destaddr = destaddr
self._transport_key = msg_transport_type_key
# Either created in ``.connect()`` or passed in by
# user in ``.from_stream()``.
self._stream: Optional[trio.SocketStream] = None
self.msgstream: Optional[MsgTransport] = None
# set after handshake - always uid of far end
self.uid: Optional[Tuple[str, str]] = None
self._agen = self._aiter_recv()
self._exc: Optional[Exception] = None # set if far end actor errors
self._closed: bool = False
# flag set on ``Portal.cancel_actor()`` indicating
# remote (peer) cancellation of the far end actor runtime.
self._cancel_called: bool = False # set on ``Portal.cancel_actor()``
@classmethod
def from_stream(
cls,
stream: trio.SocketStream,
**kwargs,
) -> Channel:
src, dst = get_stream_addrs(stream)
chan = Channel(destaddr=dst, **kwargs)
# set immediately here from provided instance
chan._stream = stream
chan.set_msg_transport(stream)
return chan
def set_msg_transport(
self,
stream: trio.SocketStream,
type_key: Optional[Tuple[str, str]] = None,
) -> MsgTransport:
type_key = type_key or self._transport_key
self.msgstream = get_msg_transport(type_key)(stream)
return self.msgstream
def __repr__(self) -> str:
if self.msgstream:
return repr(
self.msgstream.stream.socket._sock).replace( # type: ignore
"socket.socket", "Channel")
return object.__repr__(self)
@property
def laddr(self) -> Optional[Tuple[str, int]]:
return self.msgstream.laddr if self.msgstream else None
@property
def raddr(self) -> Optional[Tuple[str, int]]:
return self.msgstream.raddr if self.msgstream else None
async def connect(
self,
destaddr: Tuple[Any, ...] = None,
**kwargs
) -> MsgTransport:
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
)
msgstream = self.set_msg_transport(stream)
log.transport(
f'Opened channel[{type(msgstream)}]: {self.laddr} -> {self.raddr}'
)
return msgstream
async def send(self, item: Any) -> None:
log.transport(f"send `{item}`") # type: ignore
assert self.msgstream
await self.msgstream.send(item)
async def recv(self) -> Any:
assert self.msgstream
return await self.msgstream.recv()
# 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.transport(
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()
return self
async def __aexit__(self, *args):
await self.aclose(*args)
def __aiter__(self):
return self._agen
# async def _reconnect(self) -> None:
# """Handle connection failures by polling until a reconnect can be
# established.
# """
# down = False
# while True:
# try:
# with trio.move_on_after(3) as cancel_scope:
# await self.connect()
# cancelled = cancel_scope.cancelled_caught
# if cancelled:
# log.transport(
# "Reconnect timed out after 3 seconds, retrying...")
# continue
# else:
# log.transport("Stream connection re-established!")
# # TODO: run any reconnection sequence
# # on_recon = self._recon_seq
# # if on_recon:
# # await on_recon(self)
# break
# except (OSError, ConnectionRefusedError):
# if not down:
# down = True
# log.transport(
# f"Connection to {self.raddr} went down, waiting"
# " for re-establishment")
# await trio.sleep(1)
async def _aiter_recv(
self
) -> AsyncGenerator[Any, None]:
'''
Async iterate items from underlying stream.
'''
assert self.msgstream
while True:
try:
async for item in self.msgstream:
yield item
# sent = yield item
# if sent is not None:
# # optimization, passing None through all the
# # time is pointless
# await self.msgstream.send(sent)
except trio.BrokenResourceError:
# if not self._autorecon:
raise
await self.aclose()
# if self._autorecon: # attempt reconnect
# await self._reconnect()
# continue
def connected(self) -> bool:
return self.msgstream.connected() if self.msgstream else False
@asynccontextmanager
async def _connect_chan(
host: str, port: int
) -> typing.AsyncGenerator[Channel, None]:
'''
Create and connect a channel with disconnect on context manager
teardown.
'''
chan = Channel((host, port))
await chan.connect()
yield chan
await chan.aclose()