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社区首页 >问答首页 >如何在Python中实现看门狗定时器?

如何在Python中实现看门狗定时器?
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Stack Overflow用户
提问于 2013-04-22 21:46:18
回答 3查看 17.1K关注 0票数 11

我想用Python实现一个简单的看门狗定时器,有两个用例:

  • Watchdog可确保函数的执行时间不超过x x确保特定的常规执行函数确实至少每隔y

执行一次

我该怎么做?

EN

回答 3

Stack Overflow用户

回答已采纳

发布于 2013-04-22 21:46:38

刚刚发布了我自己的解决方案:

from threading import Timer

class Watchdog(Exception):
    def __init__(self, timeout, userHandler=None):  # timeout in seconds
        self.timeout = timeout
        self.handler = userHandler if userHandler is not None else self.defaultHandler
        self.timer = Timer(self.timeout, self.handler)
        self.timer.start()

    def reset(self):
        self.timer.cancel()
        self.timer = Timer(self.timeout, self.handler)
        self.timer.start()

    def stop(self):
        self.timer.cancel()

    def defaultHandler(self):
        raise self

用法如果您想确保函数在x秒内完成:

watchdog = Watchdog(x)
try:
  # do something that might take too long
except Watchdog:
  # handle watchdog error
watchdog.stop()

用法如果您定期执行某项操作,并希望确保至少每隔y秒执行一次:

import sys

def myHandler():
  print "Whoa! Watchdog expired. Holy heavens!"
  sys.exit()

watchdog = Watchdog(y, myHandler)

def doSomethingRegularly():
  # make sure you do not return in here or call watchdog.reset() before returning
  watchdog.reset()
票数 12
EN

Stack Overflow用户

发布于 2016-06-06 15:50:28

signal.alarm()为您的程序设置一个超时,您可以在主循环中调用它,并将其设置为您准备容忍的两个时间中较大的一个:

import signal
while True:
    signal.alarm(10)
    infloop()
票数 2
EN

Stack Overflow用户

发布于 2020-04-08 16:08:07

这是我在我的应用程序中使用的wdt,没有使用类。它没有办法阻止它:

from threading import Event, Thread

def wdt(time, callback):
    # a reset flag
    reset_e = Event()
    # a function to reset the wdt
    def reset(): reset_e.set()
    # the function to run in a differen thread
    def checker():
        # check if reset flag is set.
        # wait for specified time to give chance to reset.
        while reset_e.wait(time):
            # it was set in time. clear and wait again
            reset_e.clear()
        # time run out.
        callback()
    # the event is not set by default. Set it
    reset()
    # create and start the wdt
    t = Thread(target=checker)
    t.start()
    # return the resetter
    return reset


# The callback to run if wdt is not reset
def bark():
    print('woof')       

# Test
import time
reset = wdt(1.0, bark)
time.sleep(0.9)
reset()
time.sleep(2.0)
票数 0
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页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/16148735

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