python利用signal自定义函数超时机制

利用signal模块，可以给函数设置一个超时时间（精确到秒），结合装饰器实现：超时时间内函数运行完成正常退出，超时时间内函数未运行完成则抛出Timeout异常。

# coding:utf8
import time
import signal


# 自定义超时异常
class TimeoutError(Exception): pass

# 超过超时时间，调用此函数
def handler(signum, frame):
    raise TimeoutError()

# 函数超时装饰器
def time_out(interval, doc):
    def decorator(func):
        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 as e:
                # 捕获到超时异常，要做的事情
                print("The function failed to run due to timeout, func:<%s>" % doc)
        return wrapper
    return decorator

@time_out(1, "demo.py中task1函数")
def task1():
    print("task1 start")
    time.sleep(1.2)
    print("task1 end")


@time_out(1, "demo.py中task2函数")
def task2():
    print("task2 start")
    time.sleep(0.8)
    print("task2 end")


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


# task1 start
# The function failed to run due to timeout, func:<demo.py中task1函数>
# task2 start
# task2 end