python 检测键盘按键，随时停止程序

不是我原创的，但是原文我已经找不到在哪了。侵删。

很好用的函数。Linux ubuntu下可用。可能不适用于win10环境和多进程（非终端环境）环境。多进程的按键停止方法见：https://blog.csdn.net/qxqxqzzz/article/details/105642875

import sys
import tty
import termios
import signal
import time

def readchar():
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    try:
        tty.setraw(sys.stdin.fileno())
        ch = sys.stdin.read(1)
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
    return ch

def readkey(getchar_fn=None):
    getchar = getchar_fn or readchar
    c1 = getchar()
    if ord(c1) != 0x1b:
        return c1
    c2 = getchar()
    if ord(c2) != 0x5b:
        return c1
    c3 = getchar()
    return chr(0x10 + ord(c3) - 65)

def set_timeout(num, callback):
    def wrap(func):
        def handle(signum, frame):  # 收到信号 SIGALRM 后的回调函数，第一个参数是信号的数字，第二个参数是the interrupted stack frame.
            raise RuntimeError

        def to_do(*args, **kwargs):
            try:
                signal.signal(signal.SIGALRM, handle)  # 设置信号和回调函数
                signal.alarm(num)  # 设置 num 秒的闹钟
                print('press e to stop this program...')
                r = func(*args, **kwargs)
                print('Detected Key pressed.\n')
                signal.alarm(0)  # 关闭闹钟
                return r
            except RuntimeError as e:
                callback()

        return to_do

    return wrap


def after_timeout():  # 超时后的处理函数
    print("No key pressed!\n")

@set_timeout(2, after_timeout)  # 限时 2 秒超时
def press_pause():
    key = readkey()
    return key



if __name__ == '__main__':
    while True:
        # 检测按键，停止训练，保存当前模型和最佳模型
        key = press_pause()
        if key != None:
            print(key+'\n')
            if key == 'e':
                print('exit')
                break
        time.sleep(1)