What is the most efficient way to achieve the following goal: main process is collecting and distributing events (even loop run_forever) to subprocessess. These subprocesses stay alive and collect signals from outer world or consume signals and perform cpu-bound operations. So far, I came up with something like this:
import os
import time
import signal
import asyncio
from asyncio import PriorityQueue
from multiprocessing import Process, Pipe
class Event(object):
__slots__ = ['type','priority','payload','timestamp']
def __init__(self, _type = None, _priority = None, _payload = None):
self.type, self.priority, self.payload, self.timestamp = _type, _priority, _payload, time.time()
def __str__(self):
return "%s(%s,%s,%s)" % (self.__class__.__name__, self.type, self.priority, self.payload)
def __lt__(self, other):
return (self.priority, self.timestamp) > (other.priority, other.timestamp)
class EventQueue(PriorityQueue):
def _put(self, event):
super()._put( (event.priority, event) )
@asyncio.coroutine
def consumeAnyEvent(eq, acon_write_p = None): ## more args with write_conn pipes
while True:
priority, event = yield from eq.get()
print("consumed",event)
if event.type == 'sig_a':
acon_write_p.send(event)
if event.type == 'sig_b':
pass
if event.type == 'sig_c':
pass
## and so on - broadcast events to relevant sub-processes
yield from asyncio.sleep(0)
@asyncio.coroutine
def produceSignalA(eq,read_p):
while True:
yield from asyncio.sleep(0)
row = read_p.recv()
if row:
yield from eq.put( Event( 'sig_a', payload = row ) )
class someSource(object):
"""db, http, file watch or other io"""
def fetch(self):
pass
def someSlowMethod(a=None):
"""cpu-bound operations"""
pass
def signalAPublisher(pipe):
read_p, write_p = pipe
read_p.close()
s = someSource()
while True:
result = s.fetch()
if result:
write_p.send(result)
def signalAConsumer(pipe):
read_p, write_p = pipe
while True:
inp = read_p.recv()
if inp:
result = someSlowMethod(inp)
write_p.send(result)
def main():
## main process is responsible for handling events:
## colllecting from all signal publisher subprocessses
## and broadcasting to all interested consumer subprocesses
eventQueue = EventQueue()
apub_read_p, apub_write_p = Pipe()
acon_read_p, acon_write_p = Pipe()
## more pipes for Signal B, ... Signal Z
signalAPublisher_p = Process(target=signalAPublisher, args=((apub_read_p, apub_write_p),))
signalAConsumer_p = Process(target=signalAPublisher, args=((acon_read_p, acon_write_p),))
signalAPublisher_p.start()
signalAConsumer_p.start()
## and so on for Signal B, Signal C, ... Signal Z
loop = asyncio.get_event_loop()
try:
tasks = asyncio.gather(
loop.create_task(produceSignalA(eventQueue,apub_read_p)),
loop.create_task(consumeAnyEvent(eventQueue,acon_write_p))
)
loop.run_forever()
except KeyboardInterrupt:
print("Caught keyboard interrupt. Canceling tasks...")
tasks.cancel()
finally:
loop.close()
os.kill(signalAPublisher_p.pid, signal.SIGTERM)
os.kill(signalAConsumer_p.pid, signal.SIGTERM)
## kill for Signal B, ... Signal Z
if __name__ == '__main__':
main()
However I have a feeling that the above is not efficient / elegant enough and i'm missing something. Any ideas, suggestions?
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