如何在Python中捕获SIGINT？

Question

我正在开发一个启动多个进程和数据库连接的python脚本.我偶尔想用Ctrl+ C信号杀死脚本,我想做一些清理工作.

在Perl我会这样做:

$SIG{'INT'} = 'exit_gracefully';

sub exit_gracefully {
    print "Caught ^C \n";
    exit (0);
}

我如何在Python中模拟这个？

Answer 1

signal.signal像这样注册您的处理程序:

#!/usr/bin/env python
import signal
import sys
def signal_handler(sig, frame):
        print('You pressed Ctrl+C!')
        sys.exit(0)
signal.signal(signal.SIGINT, signal_handler)
print('Press Ctrl+C')
signal.pause()

代码改编自此处.

signal可以在此处找到更多文档.

Answer 2

您可以将其视为异常(KeyboardInterrupt),就像任何其他异常一样.创建一个新文件并使用以下内容从shell运行它以查看我的意思:

import time, sys

x = 1
while True:
    try:
        print x
        time.sleep(.3)
        x += 1
    except KeyboardInterrupt:
        print "Bye"
        sys.exit()

Answer 3

作为上下文管理器:

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:

with GracefulInterruptHandler() as h:
    for i in xrange(1000):
        print "..."
        time.sleep(1)
        if h.interrupted:
            print "interrupted!"
            time.sleep(2)
            break

嵌套处理程序:

with GracefulInterruptHandler() as h1:
    while True:
        print "(1)..."
        time.sleep(1)
        with GracefulInterruptHandler() as h2:
            while True:
                print "\t(2)..."
                time.sleep(1)
                if h2.interrupted:
                    print "\t(2) interrupted!"
                    time.sleep(2)
                    break
        if h1.interrupted:
            print "(1) interrupted!"
            time.sleep(2)
            break

从这里:https://gist.github.com/2907502

Answer 4

您可以通过捕获异常来处理CTRL+ .您可以在异常处理程序中实现任何清理代码.CKeyboardInterrupt

Answer 5

从Python的文档:

import signal
import time

def handler(signum, frame):
    print 'Here you go'

signal.signal(signal.SIGINT, handler)

time.sleep(10) # Press Ctrl+c here

Answer 6

又一个片段

简称main为主要功能,并exit_gracefully为CTRL+ c处理器

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        pass
    finally:
        exit_gracefully()

Answer 7

我调整了@udi的代码来支持多个信号(没什么特别的):

class GracefulInterruptHandler(object):
    def __init__(self, signals=(signal.SIGINT, signal.SIGTERM)):
        self.signals = signals
        self.original_handlers = {}

    def __enter__(self):
        self.interrupted = False
        self.released = False

        for sig in self.signals:
            self.original_handlers[sig] = signal.getsignal(sig)
            signal.signal(sig, self.handler)

        return self

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

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

    def release(self):
        if self.released:
            return False

        for sig in self.signals:
            signal.signal(sig, self.original_handlers[sig])

        self.released = True
        return True

此代码支持键盘中断调用(SIGINT)和SIGTERM(kill <process>)

Answer 8

与Matt J的回答相反，我使用了一个简单的对象。这使我有可能将此处理程序解析为需要停止安全的所有线程。

class SIGINT_handler():
    def __init__(self):
        self.SIGINT = False

    def signal_handler(self, signal, frame):
        print('You pressed Ctrl+C!')
        self.SIGINT = True


handler = SIGINT_handler()
signal.signal(signal.SIGINT, handler.signal_handler)

别处

while True:
    # task
    if handler.SIGINT:
        break

Answer 9

如果您想确保您的清理过程完成，我会通过使用SIG_IGN来添加Matt J 的答案，以便进一步忽略这将防止您的清理被中断。SIGINT

import signal
import sys

def signal_handler(signum, frame):
    signal.signal(signum, signal.SIG_IGN) # ignore additional signals
    cleanup() # give your process a chance to clean up
    sys.exit(0)

signal.signal(signal.SIGINT, signal_handler) # register the signal with the signal handler first
do_stuff()