IPC primitives improvements

- Rename the `Client` to `Channel`
- Add better `__repr__()`
- use laddr, raddr instead of sockaddr, peer
- don't allow re-entrant `Channel.connect()` calls
- Make `Channel` an async iterable
kivy_mainline_and_py3.8
Tyler Goodlet 2018-06-07 00:19:31 -04:00
parent 485aa76ff6
commit 2f82db33f4
1 changed files with 71 additions and 25 deletions

View File

@ -1,13 +1,13 @@
"""
Inter-process comms abstractions
"""
from typing import Coroutine
from typing import Coroutine, Tuple
import msgpack
import trio
from .log import get_logger
log = get_logger('broker.core')
log = get_logger('ipc')
class StreamQueue:
@ -15,32 +15,43 @@ class StreamQueue:
"""
def __init__(self, stream):
self.stream = stream
self.peer = stream.socket.getpeername()
self._agen = self._iter_packets()
self._laddr = self.stream.socket.getsockname()[:2]
self._raddr = self.stream.socket.getpeername()[:2]
self._send_lock = trio.Lock()
async def _iter_packets(self):
"""Yield packets from the underlying stream.
"""
unpacker = msgpack.Unpacker(raw=False)
unpacker = msgpack.Unpacker(raw=False, use_list=False)
while True:
try:
data = await self.stream.receive_some(2**10)
log.trace(f"Data is {data}")
except trio.BrokenStreamError:
log.error(f"Stream connection {self.peer} broke")
log.error(f"Stream connection {self.raddr} broke")
return
if data == b'':
log.debug("Stream connection was closed")
log.debug(f"Stream connection {self.raddr} was closed")
return
unpacker.feed(data)
for packet in unpacker:
yield packet
@property
def laddr(self):
return self._laddr
@property
def raddr(self):
return self._raddr
async def put(self, data):
return await self.stream.send_all(
msgpack.dumps(data, use_bin_type=True))
async with self._send_lock:
return await self.stream.send_all(
msgpack.dumps(data, use_bin_type=True))
async def get(self):
return await self._agen.asend(None)
@ -49,25 +60,48 @@ class StreamQueue:
return self._agen
class Client:
"""The most basic client.
class Channel:
"""A channel to actors in other processes.
Use this to talk to any micro-service daemon or other client(s) over a
TCP socket managed by ``trio``.
a transport managed by ``trio``.
"""
def __init__(
self, sockaddr: tuple,
on_reconnect: Coroutine,
auto_reconnect: bool = True,
):
self.sockaddr = sockaddr
self,
destaddr: tuple = None,
on_reconnect: Coroutine = None,
auto_reconnect: bool = False,
stream: trio.SocketStream = None, # expected to be active
) -> None:
self._recon_seq = on_reconnect
self._autorecon = auto_reconnect
self.squeue = None
self.squeue = StreamQueue(stream) if stream else None
if self.squeue and destaddr:
raise ValueError(
f"A stream was provided with local addr {self.laddr}"
)
self._destaddr = destaddr or self.squeue.raddr
async def connect(self, sockaddr: tuple = None, **kwargs):
sockaddr = sockaddr or self.sockaddr
stream = await trio.open_tcp_stream(*sockaddr, **kwargs)
def __repr__(self):
if self.squeue:
return repr(
self.squeue.stream.socket._sock).replace(
"socket.socket", "Channel")
return object.__repr__(self)
@property
def laddr(self):
return self.squeue.laddr if self.squeue else (None, None)
@property
def raddr(self):
return self.squeue.raddr if self.squeue else (None, None)
async def connect(self, destaddr: Tuple[str, int] = None, **kwargs):
if self.squeue is not None:
raise RuntimeError("channel is already connected?")
destaddr = destaddr or self._destaddr
stream = await trio.open_tcp_stream(*destaddr, **kwargs)
self.squeue = StreamQueue(stream)
return stream
@ -77,21 +111,25 @@ class Client:
async def recv(self):
try:
return await self.squeue.get()
except trio.BrokenStreamError as err:
except trio.BrokenStreamError:
if self._autorecon:
await self._reconnect()
return await self.recv()
async def aclose(self, *args):
await self.squeue.stream.aclose()
self.squeue = None
async def __aenter__(self):
await self.connect(self.sockaddr)
await self.connect()
return self
async def __aexit__(self, *args):
await self.aclose(*args)
async def __aiter__(self):
return self.aiter_recv()
async def _reconnect(self):
"""Handle connection failures by polling until a reconnect can be
established.
@ -109,13 +147,15 @@ class Client:
else:
log.warn("Stream connection re-established!")
# run any reconnection sequence
await self._recon_seq(self)
on_recon = self._recon_seq
if on_recon:
await on_recon(self)
break
except (OSError, ConnectionRefusedError):
if not down:
down = True
log.warn(
f"Connection to {self.sockaddr} went down, waiting"
f"Connection to {self.raddr} went down, waiting"
" for re-establishment")
await trio.sleep(1)
@ -126,9 +166,15 @@ class Client:
try:
async for item in self.squeue:
yield item
except trio.BrokenStreamError as err:
# sent = yield item
# if sent is not None:
# # optimization, passing None through all the
# # time is pointless
# await self.squeue.put(sent)
except trio.BrokenStreamError:
if not self._autorecon:
raise
self.squeue = None
if self._autorecon: # attempt reconnect
await self._reconnect()
continue