Question

我有一个需要很长时间才能完成的程序。我想要它能够捕获SIGINT（ctrl-c）并调用self.save_work()方法。

目前，我的signal_hander()无效程序到达self时未定义signal_handler()。

如何进行设置，以便在self.save_work之后调用SIGINT？

#!/usr/bin/env python
import signal 

def signal_handler(signal, frame):    
    self.save_work()   # Does not work
    exit(1)
signal.signal(signal.SIGINT, signal_handler)

class Main(object):
    def do_stuff(self):
        ...
    def save_work(self):
        ...
    def __init__(self):
        self.do_stuff()
        self.save_work()

if __name__=='__main__':
    Main()

Answer 1

如果您只想捕获ctr + c，那么您可以捕获KeyboardInterrupt异常：

class Main(object):
    def do_stuff(self):
        ...
    def save_work(self):
        ...
    def __init__(self):
        try:
            self.do_stuff()
        except KeyboardInterrupt:
            pass # Or print helpful info
        self.save_work()

并不是说我认为这毕竟是一个很好的设计。看起来你需要使用函数而不是构造函数。

Answer 2

通常，“工作”涉及某种大循环。要驯服你的循环，并防止它在未知步骤中破坏，你可以使用以下上下文管理器：

import signal

class GracefulInterruptHandler(object):

    def __init__(self, sig=signal.SIGINT):
        self.sig = sig

    def __enter__(self):

        self.interrupted = False
        self.released = False

        self.original_handler = signal.getsignal(self.sig)

        def handler(signum, frame):
            self.release()
            self.interrupted = True

        signal.signal(self.sig, handler)

        return self

    def __exit__(self, type, value, tb):
        self.release()

    def release(self):

        if self.released:
            return False

        signal.signal(self.sig, self.original_handler)

        self.released = True

        return True

使用：

import time

/// do stuff:
with GracefulInterruptHandler() as h:
    for i in xrange(1000):
        print "..."
        time.sleep(1)
        if h.interrupted:
            print "interrupted!"
            time.sleep(5)
            break

save_work()

从这里开始：https://gist.github.com/2907502

Answer 3

import signal

def signal_handler(signal, frame):    
   #do some stuff

def main():
   #do some more stuff


if __name__=='__main__':
    signal.signal(signal.SIGINT, signal_handler)
    main()

在SIGINT之后保存工作

3 个答案: