an asyncio daemon pattern

daemon.py

import asyncio
import queue

ioloop = asyncio.get_event_loop()

def timer(interval=5):
    def wrapper(func):
        async def runner(*args, **kwargs):
            while True:
                asyncio.ensure_future(func(*args, **kwargs))
                await asyncio.sleep(interval)
        return runner
    return wrapper

class ConcurrencyExceededException(Exception):
    pass

def locker(quiet=True, concurrency=1):
    assert concurrency > 0
    locker_queue = queue.Queue(maxsize=concurrency)
    def wrapper(func):
        async def runner(*args, **kwargs):
            try:
                locker_queue.put(object(), block=False)
            except queue.Full:
                if quiet:
                    return 
                else:
                    raise ConcurrencyExceededException()
            try:
                return await func(*args, **kwargs)
            finally:
                locker_queue.get()
        return runner
    return wrapper

@timer(1)
@locker(quiet=False, concurrency=2)
async def test():
    await asyncio.sleep(5)
    print("hey")


ioloop.run_until_complete(test())