我正在编写一个python脚本,启动几个进程和数据库连接。有时我想用Ctrl+C信号终止脚本,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);
}

如何在Python中进行类似操作?


当前回答

您可以使用Python内置信号模块中的函数来设置Python中的信号处理程序。特别是信号。Signal (signalnum, handler)函数用于为信号signalnum注册处理函数。

其他回答

另一个片段

将main作为main函数,将exit_elegant作为Ctrl+C处理程序

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

与Matt J的答案相反,我使用了一个简单的对象。这使我有可能将这个处理程序解析到需要安全停止的所有线程。

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)

在其他地方

while True:
    # task
    if handler.SIGINT:
        break

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

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

作为一个上下文管理器:

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

使用方法:

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

嵌套的处理程序:

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

网址:https://gist.github.com/2907502

如果你想确保你的清理过程完成,我将通过使用SIG_IGN添加到Matt J的答案,这样进一步的SIGINT将被忽略,这将防止你的清理被打断。

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()