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Move ipc types into separate module

asyncgen_closing_fix
Tyler Goodlet 2018-05-30 12:36:23 -04:00
parent 183c14ba79
commit 968c385c35
1 changed files with 136 additions and 0 deletions

136
piker/ipc.py 100644
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"""
Inter-process comms abstractions
"""
from typing import Coroutine
import msgpack
import trio
from .log import get_logger
log = get_logger('broker.core')
class StreamQueue:
"""Stream wrapped as a queue that delivers ``msgpack`` serialized objects.
"""
def __init__(self, stream):
self.stream = stream
self.peer = stream.socket.getpeername()
self._agen = self._iter_packets()
async def _iter_packets(self):
"""Yield packets from the underlying stream.
"""
unpacker = msgpack.Unpacker(raw=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")
return
if data == b'':
log.debug("Stream connection was closed")
return
unpacker.feed(data)
for packet in unpacker:
yield packet
async def put(self, data):
return await self.stream.send_all(
msgpack.dumps(data, use_bin_type=True))
async def get(self):
return await self._agen.asend(None)
async def __aiter__(self):
return self._agen
class Client:
"""The most basic client.
Use this to talk to any micro-service daemon or other client(s) over a
TCP socket managed by ``trio``.
"""
def __init__(
self, sockaddr: tuple,
on_reconnect: Coroutine,
auto_reconnect: bool = True,
):
self.sockaddr = sockaddr
self._recon_seq = on_reconnect
self._autorecon = auto_reconnect
self.squeue = None
async def connect(self, sockaddr: tuple = None, **kwargs):
sockaddr = sockaddr or self.sockaddr
stream = await trio.open_tcp_stream(*sockaddr, **kwargs)
self.squeue = StreamQueue(stream)
return stream
async def send(self, item):
await self.squeue.put(item)
async def recv(self):
try:
return await self.squeue.get()
except trio.BrokenStreamError as err:
if self._autorecon:
await self._reconnect()
return await self.recv()
async def aclose(self, *args):
await self.squeue.stream.aclose()
async def __aenter__(self):
await self.connect(self.sockaddr)
return self
async def __aexit__(self, *args):
await self.aclose(*args)
async def _reconnect(self):
"""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.warn(
"Reconnect timed out after 3 seconds, retrying...")
continue
else:
log.warn("Stream connection re-established!")
# run any reconnection sequence
await self._recon_seq(self)
break
except (OSError, ConnectionRefusedError):
if not down:
down = True
log.warn(
f"Connection to {self.sockaddr} went down, waiting"
" for re-establishment")
await trio.sleep(1)
async def aiter_recv(self):
"""Async iterate items from underlying stream.
"""
while True:
try:
async for item in self.squeue:
yield item
except trio.BrokenStreamError as err:
if not self._autorecon:
raise
if self._autorecon: # attempt reconnect
await self._reconnect()
continue
else:
return