很多场景为了不阻塞，都需要异步回调机制。这是一个简单的例子。

python的多线程异步常用到queue和threading模块

# @param  Python多线程异步任务队列（实例）
# @author 编程之家 jb51.cc|jb51.cc 

#!/usr/bin/env python
# -*- coding: UTF-8 -*-
 
import logging
import queue
import threading
 
def func_a(a,b):
    return a + b
 
def func_b():
    pass
 
def func_c(a,b,c):
    return a,c
 
# 异步任务队列
_task_queue = queue.Queue()
 
def async_call(function,callback,*args,**kwargs):
    _task_queue.put({
        'function': function,'callback': callback,'args': args,'kwargs': kwargs
    })
 
def _task_queue_consumer():
    """
    异步任务队列消费者
    """
    while True:
        try:
            task = _task_queue.get()
            function = task.get('function')
            callback = task.get('callback')
            args = task.get('args')
            kwargs = task.get('kwargs')
            try:
                if callback:
                    callback(function(*args,**kwargs))
            except Exception as ex:
                if callback:
                    callback(ex)
            finally:
                _task_queue.task_done()
        except Exception as ex:
            logging.warning(ex)
 
def handle_result(result):
    print(type(result),result)
 
if __name__ == '__main__':
    t = threading.Thread(target=_task_queue_consumer)
    t.daemon = True
    t.start()
 
    async_call(func_a,handle_result,1,2)
    async_call(func_b,handle_result)
    async_call(func_c,2,3)
    async_call(func_c,3,4)
 
    _task_queue.join()

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