如何在Python中捕获SIGINT？

Question

我正在开发一个python脚本，它启动几个进程和数据库连接。我时不时地想用一个Ctrl+C信号来终止脚本，我想做一些清理工作。

在Perl中，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

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

从这里开始：https://gist.github.com/2907502

Answer 2

你可以把它当作一个例外（键盘中断），就像其他的一样。创建一个新文件并从shell运行它，其中包含以下内容，以了解我的意思：

import time, sys

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