基于 signal模块实现:

signal包负责在Python程序内部处理信号，典型的操作包括预设信号处理函数，暂 停并等待信号，以及定时发出SIGALRM等。要注意，signal包主要是针对UNIX平台(比如Linux, MAC OS)，而Windows内核中由于对信号机制的支持不充分，所以在Windows上的Python不能发挥信号系统的功能。 

# coding:utf8
import time
import signal


# 自定义超时异常
class TimeoutError(Exception):
    def __init__(self, msg):
        super(TimeoutError, self).__init__()
        self.msg = msg


def time_out(interval, callback):
    def decorator(func):
        def handler(signum, frame):
            raise TimeoutError("run func timeout")

        def wrapper(*args, **kwargs):
            try:
                signal.signal(signal.SIGALRM, handler)
                signal.alarm(interval)       # interval秒后向进程发送SIGALRM信号
                result = func(*args, **kwargs)
                signal.alarm(0)              # 函数在规定时间执行完后关闭alarm闹钟
                return result
            except TimeoutError, e:
                callback(e)
        return wrapper
    return decorator


def timeout_callback(e):
    print(e.msg)


@time_out(2, timeout_callback)
def task1():
    print("task1 start")
    time.sleep(3)
    print("task1 end")


@time_out(2, timeout_callback)
def task2():
    print("task2 start")
    time.sleep(1)
    print("task2 end")


if __name__ == "__main__":
    task1()
    task2()

输出: 

 task1 start
 run func timeout
 task2 start
 task2 end

 基于子线程阻塞实现超时:

# coding:utf8
import time
import threading


def callback_func():
    print('超时回调')


def time_out(interval, callback=None):
    def decorator(func):
        def wrapper(*args, **kwargs):
            t =threading.Thread(target=func, args=args, kwargs=kwargs)
            t.setDaemon(True)  # 设置主线程技术子线程立刻结束
            t.start()
            t.join(interval)  # 主线程阻塞等待interval秒
            if t.is_alive() and callback:
                return threading.Timer(0, callback).start()  # 立即执行回调函数
            else:
                return
        return wrapper
    return decorator


@time_out(2, callback_func)
def task3(hh):
    print('**********task3****************')
    for i in range(3):
        time.sleep(1)
        print(i)
        print(hh)


@time_out(2, callback_func)
def task4(hh):
    print('**********task4****************')
    for i in range(3):
        # time.sleep(1)
        print(i)
        print(hh)


if __name__ == '__main__':
    task3('参数')
    task4('参数')

输出:

**********task3****************
0
参数
1
参数
超时回调
**********task4****************
0
参数
1
参数
2
参数

基于协程实现

def callback_func():
    print('callback')


def time_out(interval, callback=None):
    def decorator(func):
        def wrapper(*args, **kwargs):
            ########## 该部分必选在requests之前导入
            import gevent
            from gevent import monkey
            monkey.patch_all()
            ##########
            
            try:
                gevent.with_timeout(interval, func, *args, **kwargs)
            except gevent.timeout.Timeout as e:
                callback() if callback else None

        return wrapper

    return decorator


@time_out(3, callback_func)
def func(a, b):
    import time
    time.sleep(2)
    print(a,b)


func(1, 2)