如何中斷/停止/結束懸掛多線程的Python程序

我有一個實現線程像這樣的Python程序：如何中斷/停止/結束懸掛多線程的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（）是從不同的程序調用。

我的代碼在正常情況下工作。但是，如果在其中一個線程中發生錯誤/異常，程序就會卡住（因爲隊列連接無限阻塞）。我能夠退出該計劃的唯一方法是關閉終端本身。

線程退出時終止此程序的最佳方法是什麼？有沒有乾淨的（其實我會採取任何方式）這樣做？我知道這個問題已經被無數次地問過了，但我仍然無法找到令人信服的答案。我真的很感激任何幫助。

編輯： 我試着刪除隊列中的連接和使用的全球出口標誌爲Is there any way to kill a Thread in Python? 建議。然而，現在的行爲就是這麼奇怪，我無法理解到底是怎麼回事。

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()

程序的輸出是如下：

#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...

然後程序只是掛起或保持上打印活動線程。但是，由於退出標誌設置爲True，所以線程的運行方法未被執行。所以我不知道如何保持這些線程或發生了什麼。

編輯：我發現了這個問題。在上面的代碼中，線程的get方法被阻塞，因此無法退出。用超時的get方法取而代之。我對剛纔的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))

來源

2013-05-22 NRS