如何中断/停止/结束悬挂多线程的Python程序

Question

我有一个实现线程像这样的Python程序：

class Mythread(threading.Thread): 
     def __init__(self, name, q): 
      threading.Thread.__init__(self) 
      self.name = name 
      self.q = q 

     def run(self): 
      print "Starting %s..." % (self.name) 
      while True: 
       ## Get data from queue 
       data = self.q.get() 
       ## do_some_processing with data ### 
       process_data(data) 
       ## Mark Queue item as done 
       self.q.task_done() 
      print "Exiting %s..." % (self.name) 


    def call_threaded_program(): 
     ##Setup the threads. Define threads,queue,locks 
     threads = []  
     q = Queue.Queue() 
     thread_count = n #some number 
     data_list = [] #some data list containing data 

     ##Create Threads 
     for thread_id in range(1, thread_count+1): 
      thread_name = "Thread-" + str(thread_id) 
      thread = Mythread(thread_name,q) 
      thread.daemon = True 
      thread.start() 

     ##Fill data in Queue 
     for data_item in data_list: 
      q.put(data_item) 

     try: 
      ##Wait for queue to be exhausted and then exit main program 
      q.join() 
     except (KeyboardInterrupt, SystemExit) as e: 
      print "Interrupt Issued. Exiting Program with error state: %s"%(str(e)) 
      exit(1) 

的call_threaded_program（）是从不同的程序调用。

我的代码在正常情况下工作。但是，如果在其中一个线程中发生错误/异常，程序就会卡住（因为队列连接无限阻塞）。我能够退出该计划的唯一方法是关闭终端本身。

线程退出时终止此程序的最佳方法是什么？有没有干净的（其实我会采取任何方式）这样做？我知道这个问题已经被无数次地问过了，但我仍然无法找到令人信服的答案。我真的很感激任何帮助。

编辑： 我试着删除队列中的连接和使用的全球出口标志为Is there any way to kill a Thread in Python? 建议。然而，现在的行为就是这么奇怪，我无法理解到底是怎么回事。

import threading 
    import Queue 
    import time 

    exit_flag = False 

    class Mythread (threading.Thread): 
     def __init__(self,name,q): 
      threading.Thread.__init__(self) 
      self.name = name 
      self.q = q 

     def run(self): 
      try:  
       # Start Thread 
       print "Starting %s...."%(self.name) 
       # Do Some Processing 
       while not exit_flag: 
        data = self.q.get() 
        print "%s processing %s"%(self.name,str(data)) 
        self.q.task_done() 
       # Exit thread 
       print "Exiting %s..."%(self.name) 
      except Exception as e: 
       print "Exiting %s due to Error: %s"%(self.name,str(e)) 


    def main(): 
     global exit_flag 

     ##Setup the threads. Define threads,queue,locks 
     threads = []  
     q = Queue.Queue() 
     thread_count = 20 
     data_list = range(1,50) 

     ##Create Threads 
     for thread_id in range(1,thread_count+1): 
      thread_name = "Thread-" + str(thread_id) 
      thread = Mythread(thread_name,q) 
      thread.daemon = True 
      threads.append(thread) 
      thread.start() 

     ##Fill data in Queue 
     for data_item in data_list: 
      q.put(data_item) 


     try: 
      ##Wait for queue to be exhausted and then exit main program 
      while not q.empty(): 
      pass 

      # Stop the threads 
      exit_flag = True 

      # Wait for threads to finish 
      print "Waiting for threads to finish..." 
      while threading.activeCount() > 1: 
      print "Active Threads:",threading.activeCount() 
      time.sleep(1) 
      pass 

      print "Finished Successfully" 
     except (KeyboardInterrupt, SystemExit) as e: 
      print "Interrupt Issued. Exiting Program with error state: %s"%(str(e)) 


    if __name__ == '__main__': 
     main() 

程序的输出是如下：

#Threads get started correctly 
    #The output also is getting processed but then towards the end, All i see are 
    Active Threads: 16 
    Active Threads: 16 
    Active Threads: 16... 

然后程序只是挂起或保持上打印活动线程。但是，由于退出标志设置为True，所以线程的运行方法未被执行。所以我不知道如何保持这些线程或发生了什么。

编辑： 我发现了这个问题。在上面的代码中，线程的get方法被阻塞，因此无法退出。用超时的get方法取而代之。我对刚才的run方法，我改良下面

def run(self): 
      try: 
        #Start Thread 
        printing "Starting %s..."%(self.name) 
        #Do Some processing 
        while not exit_flag: 
          try: 
           data = self.q.get(True,self.timeout) 
           print "%s processing %s"%(self.name,str(data)) 
           self.q.task_done() 
          except: 
           print "Queue Empty or Timeout Occurred. Try Again for %s"%(self.name) 


        # Exit thread 
        print "Exiting %s..."%(self.name) 
      except Exception as e: 
       print "Exiting %s due to Error: %s"%(self.name,str(e)) 

Answer 1

我在C.做到了一次基本上我有这样开始了其他的人，并让他们的轨道，即主要工序中的代码。存储PID并等待返回码。如果您在某个流程中出现错误，代码将会显示，然后您可以停止其他所有流程。希望这有助于

编辑：

对不起，我可以在我的答案，你是使用线程都忘记了。但我认为它仍然适用。您可以打包或修改线程以获取返回值，也可以使用多线程池库。

how to get the return value from a thread in python?

Python thread exit code

Answer 2

如果要强制所有线程退出时，进程退出，你在创建线程之前，可以设置线程的“守护进程”标志设置为True。

http://docs.python.org/2/library/threading.html#threading.Thread.daemon