最近在项目中遇到这一需求：
我需要一个函数工作，比如远程连接一个端口，远程读取文件等，但是我给的时间有限，比如，4秒钟如果你还没有读取完成或者连接成功，我就不等了，很可能对方已经宕机或者拒绝了。这样可以批量做一些事情而不需要一直等，浪费时间。
结合我的需求，我想到这种办法：
1、在主进程执行，调用一个进程执行函数，然后主进程sleep，等时间到了，就kill 执行函数的进程。
测试一个例子：
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import time
import threading
def p(i):
print i
class task(threading.Thread):
def __init__(self,fun,i):
threading.Thread.__init__(self)
self.fun = fun
self.i = i
self.thread_stop = False
def run(self):
while not self.thread_stop:
self.fun(self.i)
def stop(self):
self.thread_stop = True
def test():
thread1 = task(p,2)
thread1.start()
time.sleep(4)
thread1.stop()
return
if __name__ == '__main__':
test()
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经过测试只定了4秒钟。
经过我的一番折腾，想到了join函数，这个函数式用来等待一个线程结束的，如果这个函数没有结束的话，那么，就会阻塞当前运行的程序。关键是，这个参数有一个可选参数：join([timeout]): 阻塞当前上下文环境的线程，直到调用此方法的线程终止或到达指定的timeout（可选参数）。
不多说了贴下面代码大家看下：
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#!/usr/bin/env python
#-*-coding:utf-8-*-
'''''
author:cogbee
time:2014-6-13
function:readme
'''
import pdb
import time
import threading
import os
#pdb.set_trace()
class task(threading.Thread):
def __init__(self,ip):
threading.Thread.__init__(self)
self.ip = ip
self.thread_stop = False
def run(self):
while not self.thread_stop:
#//添加你要做的事情，如果成功了就设置一下<span style="font-family: Arial, Helvetica, sans-serif;">self.thread_stop变量。</span>
[python] view plaincopy在CODE上查看代码片派生到我的代码片
if file != '':
self.thread_stop = True
def stop(self):
self.thread_stop = True
def test(eachline):
global file
list = []
for ip in eachline:
thread1 = task(ip)
thread1.start()
thread1.join(3)
if thread1.isAlive():
thread1.stop()
continue
#将可以读取的都存起来
if file != '':
list.append(ip)
print list
if __name__ == '__main__':
eachline = ['1.1.1.1','222.73.5.54']
test(eachline)
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下面给大家分享我写的一段杀死线程的代码。
由于python线程没有提供abort方法，分享下面一段代码杀死线程：
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import threading
import inspect
import ctypes
def _async_raise(tid, exctype):
"""raises the exception, performs cleanup if needed"""
if not inspect.isclass(exctype):
raise TypeError("Only types can be raised (not instances)")
res = ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, ctypes.py_object(exctype))
if res == 0:
raise ValueError("invalid thread id")
elif res != 1:
# """if it returns a number greater than one, you're in trouble,
# and you should call it again with exc=NULL to revert the effect"""
ctypes.pythonapi.PyThreadState_SetAsyncExc(tid, 0)
raise SystemError("PyThreadState_SetAsyncExc failed")
class Thread(threading.Thread):
def _get_my_tid(self):
"""determines this (self's) thread id"""
if not self.isAlive():
raise threading.ThreadError("the thread is not active")
# do we have it cached?
if hasattr(self, "_thread_id"):
return self._thread_id
# no, look for it in the _active dict
for tid, tobj in threading._active.items():
if tobj is self:
self._thread_id = tid
return tid
raise AssertionError("could not determine the thread's id")
def raise_exc(self, exctype):
"""raises the given exception type in the context of this thread"""
_async_raise(self._get_my_tid(), exctype)
def terminate(self):
"""raises SystemExit in the context of the given thread, which should
cause the thread to exit silently (unless caught)"""
self.raise_exc(SystemExit)
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使用例子：
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>>> import time
>>> from thread2 import Thread
>>>
>>> def f():
... try:
... while True:
... time.sleep(0.1)
... finally:
... print "outta here"
...
>>> t = Thread(target = f)
>>> t.start()
>>> t.isAlive()
True
>>> t.terminate()
>>> t.join()
outta here
>>> t.isAlive()
False
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试了一下，很不错，只是在要kill的线程中如果有time.sleep()时，好像工作不正常，没有找出真正的原因是什么。已经是很强大了。哈哈。