线程捕获KeyboardInterrupter

线程捕获KeyboardInterrupter不能简单用try....except…来捕获。原因在stackover上说的很明白：This is a Python bug. When waiting for a condition in threading.Condition.wait(), KeyboardInterrupt is never sent. 以以下代码为例：

python

import threading
cond = threading.Condition(threading.Lock())
cond.acquire()
cond.wait(None)
print "done"

在wait()返回之前，Keyboardinterrupt的信号是不会发送给运行中的程序的。所以，要想实现捕获KeyboardInterrupt有以下几种方法：

设置信号
在线程中使用timeout

设置信号

示例代码如下

python

import multiprocessing
import time
import signal
import sys


# based on http://stackoverflow.com/a/6191991/1711188
# but instead of calling Pool.join(), we just close and manually poll for processes exiting
# also it assumes we have a finite number of jobs we want to run; if they complete
# it terminates in the normal way


def init_worker():
    signal.signal(signal.SIGINT, signal.SIG_IGN)


def worker(jobid):
    time.sleep(1.1234)
    print("Working on job...", jobid)


def main():
    pool = multiprocessing.Pool(3, init_worker)
    try:
        results = []
        for i in range(23):
            results.append(pool.apply_async(worker, (i,)))


        pool.close()
        while True:
            if all(r.ready() for r in results):
                print("All processes completed")
                return
            time.sleep(1)


    except KeyboardInterrupt:
        print("Caught KeyboardInterrupt, terminating workers")
        pool.terminate()
        pool.join()




if __name__ == "__main__":
    main()

在线程中使用timeout

我初次见于map_async中，用法大抵如下：

python

from multiprocessing.pool import ThreadPool
import time

timeout = 25

with ThreadPool(processes=4) as tp:
    async_result = tp.map_async(time.sleep, [5, 4])

    for i in range(timeout):
        time.sleep(1)

        if async_result.ready():
            if async_result.successful():
                print(async_result.get())
                break
    else:
        print("Task did not complete on time, or with errors")

参考文章

参考如下： https://codecalamity.com/threadpools-explained-in-the-deep-end/https://stackoverflow.com/questions/1408356/keyboard-interrupts-with-pythons-multiprocessing-pool/6191991#6191991

设置信号 ​

在线程中使用timeout ​

参考文章 ​

设置信号

在线程中使用timeout

参考文章