如何中断否则超时的线程？

Question

我需要写一个线程：运行n秒，然后执行 A（并退出）除非它的父级告诉它提前停止，在这种情况下它会执行 B（并退出）我写了一些有效但非常复杂的东西（我相信）。它（错误）使用 aLock()作为标志：import threadingimport timedef countdown(lock):    t = 0    while t < 10:        t += 1        print(t)        try:            lock.release()        except RuntimeError:            # was not told to die (= lock is not set)            pass        else:            # the parent notified to kill by setting the lock            print("child: the lock has been set, means I die before timeout")            return        time.sleep(1)    # executed when timeouting    print("child: I timeouted on my own")    returnlock = threading.Lock()# with timeoutthreading.Thread(target=countdown, args=(lock,)).start()print("parent: sleeping 12 seconds, the thread should timeout in the meantime")time.sleep(12)lock = threading.Lock()# without timeoutthreading.Thread(target=countdown, args=(lock,)).start()print("parent: sleeping 5 seconds, and then setting the flag")time.sleep(5)lock.acquire()print("the counter should exit prematurely while I continue sleeping")time.sleep(5)它工作正常（我不关心时间的细微变化 - 在这种情况下是 6 秒 vs 5 秒，因为主线程和生成的线程共同运行）：1parent: sleeping 12 seconds, the thread should timeout in the meantime2345678910child: I timeouted on my own1parent: sleeping 5 seconds, and then setting the flag2345the counter should exit prematurely while I continue sleeping6child: the lock has been set, means I die before timeout正如我所提到的，这个解决方案对我来说看起来非常复杂。是否有更 Pythonic 的构造可以运行超时线程，可被其父线程中断？

Answer 1

如果额外的线程仅用于倒计时，同时不执行任何其他功能，则该threading.Timer()对象就是为此而创建的。

如果需要，可以使用该.cancel()方法提前取消计时器。更多信息可以在官方文档中找到。

从问题中重写示例（稍作修改）使代码看起来像：

import threading

import time

# with timeout

t = threading.Timer(10.0, lambda: print("I timed out"))

t.start()

print("Parent: Sleeping 12 seconds, the thread should timeout in the meantime")

time.sleep(12)

print("Done sleeping")

# without timeout

t = threading.Timer(10.0, lambda: print("I timed out"))

t.start()

print("Parent: Sleeping 6 seconds, and then cancel timers")

time.sleep(6)

t.cancel()

print("The counter is canceled while I continue sleeping")

time.sleep(6)

print("Done sleeping")