当其中一个线程中存在未捕获的异常时，Python 多线程程序不会退出

Question

下面的代码生成 100 个线程并随机生成异常。即使所有线程都完成了执行(而有些线程生成异常(，主程序仍然没有退出。我做错了什么吗？需要修改什么，以便在其中一个线程中发生异常时，主线程仍然退出？

from __future__ import print_function
from threading import Thread
import sys
import random
from queue import Queue

__author__ = 'aanush'
"""
Testing if threading exits the python script gracefully
"""

class NoException(Exception):
pass

class ThreadFail(Thread):
"""
Class which helps us in doing multi-threading which improves performance of the script
"""
def __init__(self, name, counter, queue_):
Thread.__init__(self)
self.queue = queue_
self.threadID = counter
self.name = name
self.counter = counter
def run(self):
while True:
# Expand the tuple from queue and pass it to the target function
some_random_num = self.queue.get()
func_test(some_random_num)
self.queue.task_done()

def func_test(random_num):
if random_num <= 10:
print("Sleep time - {} greater than 10. Not raising exception".format(random_num))
else:
print('sleep time less than 10 : Raising exception')
raise NoException

queue = Queue()
for thread_num in range(100):
worker = ThreadFail('Thread-{}'.format(thread_num), thread_num, queue)
worker.daemon = True
worker.start()
for x in range(1000):
queue.put(random.randrange(1, 15))
queue.join()

Answer 1

您在这里遇到死锁情况。由于异常而终止的线程，不会释放共享资源上的持有锁， 因此，queue被损坏。您需要捕获线程内的异常，并让它们优雅地退出。

def run(self):
while True:
# Expand the tuple from queue and pass it to the target function
some_random_num = self.queue.get()
try:
func_test(some_random_num)
except NoException:
pass
finally:
self.queue.task_done()