实现可中断的线程

在《从nginx日志读取URL来做性能测试》(http://san-yun.iteye.com/blog/1679215)这篇文章中我实现了一个python多线程来做性能测试，但存在一个问题，线程不可中断,包括两方面：
1. 用户通过kill命令来中断
2. 程序满足某种条件中断（比如测试量大于1000则退出）

下面是我的实现：

# -*- coding: utf-8 -*-
import re
import urllib2
import json
import threading
import Queue
import os
import time
from time import sleep
from threading import Lock
from signal import signal,SIGTERM,SIGINT,SIGQUIT

class Executor:
	def __init__(self,size):	
		self.queue = Queue.Queue()
		self.tasks = []
		self.running = True

		for i  in range(size):
			t = Task(self.queue)
			t.setDaemon(True)
			t.start()
			self.tasks.append(t)

		self._signal()

	def _signal(self):
		signal(SIGTERM,self._exit)
		signal(SIGINT,self._exit)
		signal(SIGQUIT,self._exit)


	def _exit(self,a=None,b=None):
		print 'clean'
		self.cancel()
	
	def cancel(self):
		for task in self.tasks:
		    while not task.cancel():
		        pass

		self.running = False
		self.onCancel()
				
	def submit(self,call):
		self.queue.put(call)	
	
	def join(self):
		#self.queue.join() queue.join()会阻塞,所以不用
		while self.running and not self.queue.empty():
			sleep(0.1)
			if  self.cancelTrigger():
				self.cancel()

	def setCancelTrigger(self,cancelTrigger):
		self.cancelTrigger = cancelTrigger

	def setOnCancel(self,onCancel):
		self.onCancel = onCancel
		

class Task(threading.Thread):

	def __init__(self,queue):
		threading.Thread.__init__(self)
		self.queue = queue
		self.running = True
		self.canceled = False

	def cancel(self):
		self.canceled=True
		return self.isCanceled()

	def isCanceled(self):
		return self.running==False
	
	def run(self):
		while self.running:
			call = self.queue.get()
			call.run()
			self.queue.task_done()
			if self.canceled:
			    self.running = False

客户端使用：

host = "http://7.s.duitang.com"

thread_count = 10 #并发数
max_count=100     #运行次数

total = 0
fail = 0
avg = 0
lock = Lock()

def cancelTrigger():
    return total>=max_count

def onCancel():
    print 'total %s'%total
    print 'fail %s'%fail
    print 'avg %s'%(avg/total)

if __name__ == "__main__":
    f = open("napi","r")
    executor = Executor(thread_count)
    executor.setCancelTrigger(cancelTrigger)
    executor.setOnCancel(onCancel)
    analysis(f.readlines(),executor)
    executor.join()

在实现的时候比较纠结的点：
1. Task如果不是daemon会导致任务永远不会停止，但是如果Task是daemon线程，main线程结束之后daemon就结束了。所以这时需要实现一个join()来阻塞main线程：

  def join(self):  
        #self.queue.join() queue.join()会阻塞,所以不用  
        while self.running and not self.queue.empty():  
            sleep(0.1)  
            if  self.cancelTrigger():  
                self.cancel()  

2. 线程应该可cancel的，之前是直接修改while isrunning的变量，但这样会导致task其实还没有完成的停止下来。所以对于task我引入两个变量来实现安全的停止。

    def cancel(self):  
        for task in self.tasks:  
            while not task.cancel():  
                pass  
  
        self.running = False  
        self.onCancel()  

    def cancel(self):  
        self.canceled=True  
        return self.isCanceled()  

    def run(self):  
        while self.running:  
            call = self.queue.get()  
            call.run()  
            self.queue.task_done()  
            if self.canceled:  
                self.running = False  

3.对于signal专门写了一片文章记录()