async function decorator

async_decorator.py

from functools import wraps
from threading import Thread
from queue import Queue


class Async(object):
    __slots__ = ('__result', '__task')

    def __init__(self, func):
        self.__result = Queue()

        @wraps(func)
        def wrapper(*args, **kw):
            r = func(*args, **kw)
            self.__result.put(r)
        self.__task = wrapper

    def __call__(self, *args, **kw):
        thread = Thread(target=self.__task, args=args, kwargs=kw)
        thread.start()
        return Async.Result(self.__result, thread)

    class Result(object):
        def __init__(self, q, t):
            self.__queue = q
            self.__thread = t
        
        def is_done(self):
            return not self.__thread.is_alive()

        def _get_r(self):
            if not self.is_done():
                raise Exception('Not done yet')
            if not hasattr(self, '_result'):
                self._result = self.__queue.get()
            return self._result
        def _set_r(self, v):
            self._result = v

        result = property(_get_r, _set_r)
        del _get_r, _set_r


if __name__ == '__main__':
    import time
    import requests
    
    @Async
    def count(n):
        time.sleep(n)
        return f'sleep {n} done'
    
    @Async
    def http(url):
        r = requests.get(url)
        return r.text
    
    start = time.time()
    
    r1 = count(10)
    r2 = count(5)
    r3 = http('http://www.baidu.com')
    r4 = http('http://b.cn')
    
    for i in range(20):
        print(f'call {i}')
        time.sleep(1)
    
        if r1.is_done():
            print(r1.result)
        if r2.is_done():
            print(r2.result)
        if r3.is_done():
            print(r3.result)
            r3.result = 'r3 done'
        if r4.is_done():
            print(r4.result)
            r4.result = 'r4 done'
    
        if r1.is_done() and r2.is_done() and r3.is_done() and r4.is_done():
            break
    
    end = time.time()
    
    print(end-start)