481 lines
13 KiB
Python
481 lines
13 KiB
Python
# tractor: structured concurrent "actors".
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# Copyright 2018-eternity Tyler Goodlet.
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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"""
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Inter-process comms abstractions
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"""
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from __future__ import annotations
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import platform
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import struct
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import typing
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from collections.abc import (
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AsyncGenerator,
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AsyncIterator,
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)
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from typing import (
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Any,
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runtime_checkable,
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Optional,
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Protocol,
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Type,
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TypeVar,
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)
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from tricycle import BufferedReceiveStream
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import msgspec
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import trio
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from async_generator import asynccontextmanager
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from .log import get_logger
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from ._exceptions import TransportClosed
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log = get_logger(__name__)
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_is_windows = platform.system() == 'Windows'
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log = get_logger(__name__)
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def get_stream_addrs(stream: trio.SocketStream) -> tuple:
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# should both be IP sockets
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lsockname = stream.socket.getsockname()
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rsockname = stream.socket.getpeername()
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return (
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tuple(lsockname[:2]),
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tuple(rsockname[:2]),
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)
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MsgType = TypeVar("MsgType")
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# TODO: consider using a generic def and indexing with our eventual
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# msg definition/types?
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# - https://docs.python.org/3/library/typing.html#typing.Protocol
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# - https://jcristharif.com/msgspec/usage.html#structs
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@runtime_checkable
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class MsgTransport(Protocol[MsgType]):
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stream: trio.SocketStream
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drained: list[MsgType]
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def __init__(self, stream: trio.SocketStream) -> None:
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...
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# XXX: should this instead be called `.sendall()`?
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async def send(self, msg: MsgType) -> None:
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...
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async def recv(self) -> MsgType:
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...
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def __aiter__(self) -> MsgType:
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...
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def connected(self) -> bool:
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...
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# defining this sync otherwise it causes a mypy error because it
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# can't figure out it's a generator i guess?..?
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def drain(self) -> AsyncIterator[dict]:
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...
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@property
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def laddr(self) -> tuple[str, int]:
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...
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@property
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def raddr(self) -> tuple[str, int]:
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...
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# TODO: not sure why we have to inherit here, but it seems to be an
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# issue with ``get_msg_transport()`` returning a ``Type[Protocol]``;
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# probably should make a `mypy` issue?
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class MsgpackTCPStream(MsgTransport):
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'''
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A ``trio.SocketStream`` delivering ``msgpack`` formatted data
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using the ``msgspec`` codec lib.
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'''
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def __init__(
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self,
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stream: trio.SocketStream,
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prefix_size: int = 4,
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) -> None:
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self.stream = stream
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assert self.stream.socket
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# should both be IP sockets
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self._laddr, self._raddr = get_stream_addrs(stream)
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# create read loop instance
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self._agen = self._iter_packets()
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self._send_lock = trio.StrictFIFOLock()
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# public i guess?
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self.drained: list[dict] = []
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self.recv_stream = BufferedReceiveStream(transport_stream=stream)
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self.prefix_size = prefix_size
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# TODO: struct aware messaging coders
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self.encode = msgspec.msgpack.Encoder().encode
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self.decode = msgspec.msgpack.Decoder().decode # dict[str, Any])
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async def _iter_packets(self) -> AsyncGenerator[dict, None]:
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'''Yield packets from the underlying stream.
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'''
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import msgspec # noqa
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decodes_failed: int = 0
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while True:
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try:
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header = await self.recv_stream.receive_exactly(4)
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except (
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ValueError,
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ConnectionResetError,
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# not sure entirely why we need this but without it we
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# seem to be getting racy failures here on
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# arbiter/registry name subs..
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trio.BrokenResourceError,
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):
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raise TransportClosed(
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f'transport {self} was already closed prior ro read'
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)
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if header == b'':
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raise TransportClosed(
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f'transport {self} was already closed prior ro read'
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)
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size, = struct.unpack("<I", header)
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log.transport(f'received header {size}') # type: ignore
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msg_bytes = await self.recv_stream.receive_exactly(size)
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log.transport(f"received {msg_bytes}") # type: ignore
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try:
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yield self.decode(msg_bytes)
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except (
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msgspec.DecodeError,
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UnicodeDecodeError,
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):
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if decodes_failed < 4:
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# ignore decoding errors for now and assume they have to
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# do with a channel drop - hope that receiving from the
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# channel will raise an expected error and bubble up.
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try:
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msg_str: str | bytes = msg_bytes.decode()
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except UnicodeDecodeError:
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msg_str = msg_bytes
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log.error(
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'`msgspec` failed to decode!?\n'
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'dumping bytes:\n'
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f'{msg_str!r}'
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)
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decodes_failed += 1
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else:
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raise
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async def send(self, msg: Any) -> None:
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async with self._send_lock:
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bytes_data: bytes = self.encode(msg)
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# supposedly the fastest says,
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# https://stackoverflow.com/a/54027962
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size: bytes = struct.pack("<I", len(bytes_data))
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return await self.stream.send_all(size + bytes_data)
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@property
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def laddr(self) -> tuple[str, int]:
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return self._laddr
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@property
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def raddr(self) -> tuple[str, int]:
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return self._raddr
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async def recv(self) -> Any:
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return await self._agen.asend(None)
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async def drain(self) -> AsyncIterator[dict]:
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'''
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Drain the stream's remaining messages sent from
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the far end until the connection is closed by
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the peer.
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'''
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try:
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async for msg in self._iter_packets():
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self.drained.append(msg)
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except TransportClosed:
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for msg in self.drained:
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yield msg
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def __aiter__(self):
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return self._agen
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def connected(self) -> bool:
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return self.stream.socket.fileno() != -1
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def get_msg_transport(
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key: tuple[str, str],
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) -> Type[MsgTransport]:
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return {
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('msgpack', 'tcp'): MsgpackTCPStream,
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}[key]
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class Channel:
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'''
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An inter-process channel for communication between (remote) actors.
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Wraps a ``MsgStream``: transport + encoding IPC connection.
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Currently we only support ``trio.SocketStream`` for transport
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(aka TCP) and the ``msgpack`` interchange format via the ``msgspec``
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codec libary.
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'''
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def __init__(
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self,
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destaddr: Optional[tuple[str, int]],
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msg_transport_type_key: tuple[str, str] = ('msgpack', 'tcp'),
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# TODO: optional reconnection support?
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# auto_reconnect: bool = False,
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# on_reconnect: typing.Callable[..., typing.Awaitable] = None,
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) -> None:
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# self._recon_seq = on_reconnect
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# self._autorecon = auto_reconnect
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self._destaddr = destaddr
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self._transport_key = msg_transport_type_key
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# Either created in ``.connect()`` or passed in by
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# user in ``.from_stream()``.
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self._stream: Optional[trio.SocketStream] = None
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self.msgstream: Optional[MsgTransport] = None
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# set after handshake - always uid of far end
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self.uid: Optional[tuple[str, str]] = None
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self._agen = self._aiter_recv()
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self._exc: Optional[Exception] = None # set if far end actor errors
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self._closed: bool = False
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# flag set on ``Portal.cancel_actor()`` indicating
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# remote (peer) cancellation of the far end actor runtime.
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self._cancel_called: bool = False # set on ``Portal.cancel_actor()``
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@classmethod
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def from_stream(
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cls,
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stream: trio.SocketStream,
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**kwargs,
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) -> Channel:
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src, dst = get_stream_addrs(stream)
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chan = Channel(destaddr=dst, **kwargs)
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# set immediately here from provided instance
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chan._stream = stream
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chan.set_msg_transport(stream)
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return chan
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def set_msg_transport(
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self,
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stream: trio.SocketStream,
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type_key: Optional[tuple[str, str]] = None,
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) -> MsgTransport:
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type_key = type_key or self._transport_key
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self.msgstream = get_msg_transport(type_key)(stream)
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return self.msgstream
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def __repr__(self) -> str:
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if self.msgstream:
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return repr(
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self.msgstream.stream.socket._sock).replace( # type: ignore
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"socket.socket", "Channel")
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return object.__repr__(self)
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@property
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def laddr(self) -> Optional[tuple[str, int]]:
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return self.msgstream.laddr if self.msgstream else None
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@property
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def raddr(self) -> Optional[tuple[str, int]]:
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return self.msgstream.raddr if self.msgstream else None
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async def connect(
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self,
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destaddr: tuple[Any, ...] = None,
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**kwargs
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) -> MsgTransport:
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if self.connected():
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raise RuntimeError("channel is already connected?")
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destaddr = destaddr or self._destaddr
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assert isinstance(destaddr, tuple)
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stream = await trio.open_tcp_stream(
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*destaddr,
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**kwargs
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)
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msgstream = self.set_msg_transport(stream)
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log.transport(
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f'Opened channel[{type(msgstream)}]: {self.laddr} -> {self.raddr}'
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)
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return msgstream
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async def send(self, item: Any) -> None:
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log.transport(f"send `{item}`") # type: ignore
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assert self.msgstream
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await self.msgstream.send(item)
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async def recv(self) -> Any:
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assert self.msgstream
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return await self.msgstream.recv()
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# try:
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# return await self.msgstream.recv()
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# except trio.BrokenResourceError:
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# if self._autorecon:
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# await self._reconnect()
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# return await self.recv()
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# raise
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async def aclose(self) -> None:
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log.transport(
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f'Closing channel to {self.uid} '
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f'{self.laddr} -> {self.raddr}'
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)
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assert self.msgstream
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await self.msgstream.stream.aclose()
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self._closed = True
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async def __aenter__(self):
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await self.connect()
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return self
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async def __aexit__(self, *args):
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await self.aclose(*args)
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def __aiter__(self):
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return self._agen
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# async def _reconnect(self) -> None:
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# """Handle connection failures by polling until a reconnect can be
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# established.
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# """
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# down = False
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# while True:
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# try:
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# with trio.move_on_after(3) as cancel_scope:
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# await self.connect()
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# cancelled = cancel_scope.cancelled_caught
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# if cancelled:
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# log.transport(
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# "Reconnect timed out after 3 seconds, retrying...")
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# continue
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# else:
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# log.transport("Stream connection re-established!")
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# # TODO: run any reconnection sequence
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# # on_recon = self._recon_seq
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# # if on_recon:
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# # await on_recon(self)
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# break
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# except (OSError, ConnectionRefusedError):
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# if not down:
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# down = True
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# log.transport(
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# f"Connection to {self.raddr} went down, waiting"
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# " for re-establishment")
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# await trio.sleep(1)
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async def _aiter_recv(
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self
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) -> AsyncGenerator[Any, None]:
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'''
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Async iterate items from underlying stream.
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'''
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assert self.msgstream
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while True:
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try:
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async for item in self.msgstream:
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yield item
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# sent = yield item
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# if sent is not None:
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# # optimization, passing None through all the
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# # time is pointless
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# await self.msgstream.send(sent)
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except trio.BrokenResourceError:
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# if not self._autorecon:
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raise
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await self.aclose()
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# if self._autorecon: # attempt reconnect
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# await self._reconnect()
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# continue
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def connected(self) -> bool:
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return self.msgstream.connected() if self.msgstream else False
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@asynccontextmanager
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async def _connect_chan(
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host: str, port: int
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) -> typing.AsyncGenerator[Channel, None]:
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'''
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Create and connect a channel with disconnect on context manager
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teardown.
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'''
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chan = Channel((host, port))
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await chan.connect()
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yield chan
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await chan.aclose()
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