如何正确处理SIGINT以关闭文件/连接

Daedalus Mythos 发表于 Dev

达达拉斯神话

我想在脚本中实现正确的SIGINT处理，该脚本将打开多个文件和一个数据库连接。如果脚本是CTRL + C或其他方式中断，则应将其关闭。

以前，我使用KeyboardInterrupt异常捕获CTRL + C，在那儿我检查是否定义了文件/连接，如果如此，则关闭它们，然后退出。

这是否真的是pythonic的方式，还是建议使用信号处理程序？例如

import signal, sys, time

def handler(signum, frame):
    print("..kthxbye")
    sys.exit(1)

def main():
    signal.signal(signal.SIGINT, handler)
    i = 0
    while True:
        print(i)
        i += 1
        time.sleep(1)

if __name__ == "__main__":
    main()

这对我来说似乎比较干净，但是我不知道如何将文件名或数据库连接传递给处理程序。

Pasztorpisti

我宁愿KeyboardInterrupt在主线程上捕获异常。KeyboardInterrupt是SIGINTpython默认处理程序的结果。与直接KeyboardInterrupt捕获时相比，异常的异常处理程序是一个更安全/友好的上下文SIGINT。

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        cleanup()

编辑：这是如何在两种方法之间共享变量（状态）：

程序：

import sys, time

class SharedState:
    def __init__(self):
        self.var0 = 42
        self.var1 = 'string'

# method 1
shared_variable = 'woof woof'

# method 2: avoiding global declarations in functions
shared_state = SharedState()

def main():
    # In order to write a global variable you need a global
    # declaration otherwise the assignment would create a
    # local variable

    global shared_variable
    shared_variable = 5

    shared_state.var0 = 10

    time.sleep(10)

def cleanup():
    print shared_variable
    print shared_state.var0
    sys.exit(1)

if __name__ == '__main__':
    try:
        main()
    except KeyboardInterrupt:
        cleanup()

面向对象（我的偏爱）：

import sys, time

# method 3: object oriented programming
class Program:
    def __init__(self):
        self.var0 = 42
        self.var1 = 'string'

    def main(self):
        self.var0 = 5
        self.var1 = 'woof woof'
        time.sleep(10)

    def cleanup(self):
        # both main and cleanup can access the member
        # variables of this class
        print self.var0
        print self.var1
        sys.exit(1)

    def execute(self):
        try:
            self.main()
        except KeyboardInterrupt:
            self.cleanup()

if __name__ == '__main__':
    Program().execute()