Why didn't my threads exit correctly ?
MRAB
python at mrabarnett.plus.com
Thu Oct 3 14:25:46 EDT 2013
On 03/10/2013 18:37, 李洛 wrote:
> Hi list,
> I write an example script using threading as follow.
> It look like hang when the list l_ip is empty. And any suggestion with
> debug over the threading in Python ?
>
> 1 #!/usr/bin/env python
> 2 # -*- coding: utf-8 -*-
> 3 import re
> 4 import os
> 5 import threading
> 6 from Queue import Queue
> 7 from time import sleep
> 8
> 9 l_ip = []
> 10 l_result = []
> 11 result = re.compile(r"[1-3] received")
> 12
> 13 class ping(threading.Thread):
> 14 """ """
> 15 def __init__(self, l_ip, l_result):
> 16 threading.Thread.__init__(self)
> 17 self.l_ip = l_ip
> 18 #self.l_result = l_result
> 19
> 20 def run(self):
> 21 """ """
> 22 while True:
> 23 try:
> 24 ip = self.l_ip.pop()
> 25 except IndexError as e:
> 26 print e
> 27 break
> 28 ping_out = os.popen(''.join(['ping -q -c3 ',ip]), 'r')
> 29 print 'Ping ip:%s' % ip
> 30 while True:
> 31 line = ping_out.readline()
> 32 if not line: break
> 33 if result.findall(line):
> 34 l_result.append(ip)
> 35 break
> 36
> 37 queue = Queue()
> 38
> 39 for i in range(1,110):
> 40 l_ip.append(''.join(['192.168.1.', str(i)]))
> 41 for i in xrange(10):
> 42 t = ping(l_ip, l_result)
> 43 t.start()
> 44 queue.put(t)
> 45 queue.join()
> 46 print "Result will go here."
> 47 for i in l_result:
> 48 print 'IP %s is OK' % i
>
queue.join() will block until the queue is empty, which is never is!
You're putting the workers in the queue, whereas the normal way of
doing it is to put them into a list, the inputs into a queue, and the
outputs into another queue. The workers then 'get' from the input
queue, do some processing, and 'put' to the output queue.
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