protocols: add broadcast (untested)

This commit is contained in:
Sebastien Bourdeauducq 2016-05-22 17:20:39 -07:00
parent 114b305203
commit 9dd7ea0bcd
1 changed files with 101 additions and 0 deletions

View File

@ -0,0 +1,101 @@
import asyncio
from artiq.protocols import pyon
from artiq.protocols.asyncio_server import AsyncioServer
_init_string = b"ARTIQ broadcast\n"
class Receiver:
def __init__(self, name, notify_cb):
self.name = name
if not isinstance(notify_cb, list):
notify_cb = [notify_cb]
self.notify_cbs = notify_cb
async def connect(self, host, port):
self.reader, self.writer = \
await asyncio.open_connection(host, port, limit=4*1024*1024)
try:
self.writer.write(_init_string)
self.writer.write((self.name + "\n").encode())
self.receive_task = asyncio.ensure_future(self._receive_cr())
except:
self.writer.close()
del self.reader
del self.writer
raise
async def close(self):
try:
self.receive_task.cancel()
try:
await asyncio.wait_for(self.receive_task, None)
except asyncio.CancelledError:
pass
finally:
self.writer.close()
del self.reader
del self.writer
async def _receive_cr(self):
target = None
while True:
line = await self.reader.readline()
if not line:
return
obj = pyon.decode(line.decode())
for notify_cb in self.notify_cbs:
notify_cb(obj)
class Broadcaster(AsyncioServer):
def __init__(self):
AsyncioServer.__init__(self, maxbuf=1024)
self._maxbuf = maxbuf
self._recipients = dict()
async def _handle_connection_cr(self, reader, writer):
try:
line = await reader.readline()
if line != _init_string:
return
line = await reader.readline()
if not line:
return
name = line.decode()[:-1]
queue = asyncio.Queue(self._maxbuf)
if name in self._recipients:
self._recipients[name].add(queue)
else:
self._recipients[name] = {queue}
try:
while True:
line = await queue.get()
writer.write(line)
# raise exception on connection error
await writer.drain()
finally:
self._recipients[name].remove(queue)
if not self._recipients[name]:
del self._recipients[name]
except (ConnectionResetError, ConnectionAbortedError, BrokenPipeError):
# receivers disconnecting are a normal occurence
pass
finally:
writer.close()
def broadcast(self, name, obj):
if name in self._recipients:
line = pyon.encode(obj) + "\n"
line = line.encode()
for recipient in self._recipients[name]:
try:
recipient.put_nowait(line)
except asyncio.QueueFull:
# do not log as logs may be redirected to a Broadcaster
pass