Python Thread related

1.Thread.join([timeout])

Wait until the thread terminates. This blocks the calling thread until the thread whose join() method is called terminates – either normally or through an unhandled exception – or until the optional timeout occurs.

等待进程结束。也就是说，其屏蔽调用线程，直到此线程方法终止（要么正常执行完毕，或者未处理的异常，或者时间超时）

下面通过例子来说明：

没有设定timeout情况，Main 线程启动，work1 和work2 线程执行，完毕退出，Main线程执行终止

import os
import threading
import time
import logging
import random

def work1():
    count=0
    while count<=5:
        threadname= threading.currentThread()
        wait_time=random.randrange(1,4)
        print("%s,count =%s wait for =%s s,time %s "%(threadname,count,wait_time,time.ctime()[-13:]))
        time.sleep(wait_time)
        count +=1
     
def work2():
    i=0
    while i<=5:
        threadname= threading.currentThread()
        wait_time=random.randrange(1,4)
        print("%s,i     =%s wait for =%s s,time %s "%(threadname,i,wait_time,time.ctime()[-13:]))
        time.sleep(wait_time)
        i +=1

if __name__ =="__main__":
    mainthread= threading.currentThread()
    print '%s main thread is waiting for exit'% mainthread
    test1=threading.Thread(name='work1',target=work1)
    test2=threading.Thread(name='work2',target=work2)
    test1.start()
    test2.start()
    test1.join()
    test2.join()    
    print 'main thread finish'

2个线程设定超时时间work1 5s,work2 4s，9s之后调用线程结束而不等待超时的线程：

import os
import threading
import time
import logging
import random

def work1():
    count=0
    while count<=5:
        threadname= threading.currentThread()
        wait_time=random.randrange(1,4)
        print("%s,count =%s wait for =%s s,time %s "%(threadname,count,wait_time,time.ctime()[-13:]))
        time.sleep(wait_time)
        count +=1
     
def work2():
    i=0
    while i<=5:
        threadname= threading.currentThread()
        wait_time=random.randrange(1,4)
        print("%s,i     =%s wait for =%s s,time %s "%(threadname,i,wait_time,time.ctime()[-13:]))
        time.sleep(wait_time)
        i +=1

if __name__ =="__main__":
    mainthread= threading.currentThread()
    print '%s main thread is waiting for exit'% mainthread
    test1=threading.Thread(name='work1',target=work1)
    test2=threading.Thread(name='work2',target=work2)
    test1.start()
    test2.start()
    test1.join(4)
    test2.join(5)    
    print 'main thread finish

 2.Producer and comsumer

import Queue
import threading
import random

#writelock =threading.Lock()
class Producer(threading.Thread):
    def __init__(self,q,con,name):
        super(Producer,self).__init__()
        self.q = q
        self.con = con
        self.name = name
        print "produce" +self.name+"started"
    def run(self):
        while 1:
            #global writelock      
            self.con.acquire()#acquire the lock   
            if self.q.full():#if queue is full
               #with writelock:#output info
               print "queue is full, producer wait"
               self.con.wait()#wait for resource
            else:
                value = random.ranint(0,10)
                #with writelock:
                print self.name+"put value"+self.name+":"+str(value)+"into queue"
            self.q.put((self.name+":"+str(value)))#put to queue
            self.con.notify()#inform consumer
        self.con.release()#release the lock
        
class Consumer(threading.Thread):
    def __init__(self,q,con,name):
        super(Consumer,self).__init__()
        self.q = q
        self.con = con
        self.name = name
        print "consume" +self.name+"started
"
    def run(self):
        while 1:
            #global writelock
            self.con.acquire()
            if self.q.empty():#if empty
                #with writelock:
                print "queue is empty,consumer wait"
                self.con.wait()#wait the resource ready
            else:
                value = self.q.get()#get one element from queue
                #with writelock:
                print self.name +"get value"+ value+"from queue"
                self.q.notify()#inform producer
            self.con.release()#release the lock


if __name__ == "__main__":
    print "start to run
"
    q = Queue.Queue(10)
    con = threading.Condition()
    p = Producer(q,con,"p1")
    p.start()
    p1 = Producer(q,con,"p2")
    p1.start()
    c1 = Consumer(q,con,"c1")
    c1.start()


        

        
    

3.Queue

programming python 4th 205页

Queue 提供标准的队列数据结构，实现python对象的先进先出，其可包含基本类型（string，list，dictionary......），类实例，任何可调用函数或绑定的方法等。但是Queue不像正常的list，因为其自动被线程获取和释放锁操作。

#coding:utf-8"
import logging,threading,time
import Queue

def fibo_task(cond):
    with cond:
        while shared_queue.empty():
            logger.info("[%s]- waiting for element in queue......" % threading.current_thread().name)
            cond.wait()
        else:
            value =shared_queue.get()
            a,b=0,1
            for item in range(value):
                a,b=b,a+b
                fibo_dict[value] = a
        shared_queue.task_done()
        time.sleep(2)
        logger.debug("[%s] fibo of key[%d] with result[%d]" % (threading.current_thread().name,value,fibo_dict[value]))
                     
def queue_task(cond):
    logging.debug('starting  list data to queue......')
    with cond:
        for data in impit_list:
            shared_queue.put(data)
        #[shared_queue.put(data) for data in  impit_list]
        cond.notifyAll()


if __name__ == "__main__":
    logger =logging.getLogger()
    logger.setLevel(logging.DEBUG)
    formatter =logging.Formatter('%(asctime)s =%(message)s')
    
    ch=logging.StreamHandler()
    ch.setLevel(logging.DEBUG)
    ch.setFormatter(formatter)
    logger.addHandler(ch)
    fibo_dict={}
    shared_queue =Queue.Queue()
    impit_list =[3,10,5,7]
    queue_cond=threading.Condition()
    print "main thread starting......"
    threads =[threading.Thread(target=fibo_task,args=(queue_cond,)) for i in range(4)]
    #for thread in threads:
        #thread.setDaemon(True)
        #print 'daemon is %d' % thread.isDaemon()
    
    [thread.start() for thread in threads]
    
    prod = threading.Thread(name='queue_task_thread',target=queue_task,args=(queue_cond,))
    prod.setDaemon(True)
    prod.start()
   
    [thread.join() for thread in threads]    
    print "main thread done"