Python:如何在其中一个线程因错误而中断后添加新线程

Question

我正在尝试创建线程循环，到目前为止代码很好。但是当线程由于某些异常而退出时，我遇到了问题。

现在我正在尝试弄清楚如何在一个线程因异常而退出后启动其他线程。我确实浏览了一下，但我没有找到任何适用于这个复杂代码的示例。任何帮助都会很棒！

如果线程已停止且队列不为空，则重新启动已停止的线程并继续执行列表的其余部分。

这是我的代码：

some_list = [1,2,3,4,5,6,7,8]
exitFlag = 0
class threads():
@staticmethod
def process_data(threadName, q,queueLock):
workQueue = q
while not exitFlag:
queueLock.acquire()
if not workQueue.empty():
data = q.get()
queueLock.release()
print "%s processing %s" % (threadName, data)
else:
queueLock.release()
sleep(1)
def run_threads(self):
threadList = ["Thread-1", "Thread-2", "Thread-3"]
nameList = some_list
queueLock = threading.Lock()
workQueue = Queue.Queue(1000000)
threads = []
threadID = 1
# Create new threads
for tName in threadList:
thread = myThread(threadID, tName, workQueue,queueLock)
thread.start()
threads.append(thread)
threadID += 1
# Fill the queue
queueLock.acquire()
for word in nameList:
workQueue.put(word)
queueLock.release()
# Wait for queue to empty
while not workQueue.empty():
pass
# Notify threads it's time to exit
global exitFlag
exitFlag = 1
# Wait for all threads to complete
for t in threads:
t.join()
print "Exiting Main Thread"

class myThread (threading.Thread,threads):
def __init__(self, threadID, name, q,queueLock):
self.thread = threading.Thread(target=self.run)
threading.Thread.__init__(self,target=self.run)
self.threadID = threadID
self.queueLock = queueLock
self.name = name
self.q = q
def run(self):
print "Starting " + self.name
threads.process_data(self.name, self.q,self.queueLock)
print "Exiting " + self.name
threads().run_threads()

Answer 1

这样的事情应该可以工作：

...
# Wait for queue to empty
while not workQueue.empty():
for (i, t) in enumerate(threads):
if not t.is_alive():
print("Recreating thread " + t.name)
thread = myThread(threadID, threadList[i], workQueue,queueLock)
thread.start()
threads[i] = thread
threadID += 1
...

我建议将线程启动代码放入某个方法中，因为它现在将被复制且难以维护。

这里的问题是您可能会"丢失"由致命线程从队列中弹出的数据。