python使用Ctrl+C中断threading多线程死循环及setDaemon守护进程

川长思鸟来 2022-06-15 08:42 253阅读 0赞

threading多线程，没有提供线程退出的方法。  
如果在死循环多线程，则即使CTRL+C也没有任何效果：  
例如：

#coding=utf8
    import threading
    import time
    
    def showperson(name):
        while True:
           time.sleep(1)
           print 'show person :%s'%name
    
    print '%s thread start!'%(time.ctime())
    
    list=[]
    for i in range(3):
      t =threading.Thread(target=showperson,args=("person-%d"%i,))
      list.append(t)
      t.start()
    
    for threadinglist in list:
        threadinglist.join()
    
    print '%s thread end!'%(time.ctime())

输出：

[root@myrpc zrd]# python threadkill.py 
    Fri May 26 22:38:37 2017 thread start!
    show person :person-0
    show person :person-1
    show person :person-2
    ^C^Cshow person :person-0
    show person :person-1
    show person :person-2
    ^C^C^C^Cshow person :person-0
    show person :person-1
    show person :person-2
    ^C^C^C^Cshow person :person-0
    show person :person-1
    show person :person-2
    ^C^C^C^C^Cshow person :person-1
    show person :person-0
    show person :person-2
    ^C^C^C^C^Cshow person :person-1
    show person :person-0
    show person :person-2
    show person :person-1

最后只有kill进程才能退出：

# ps -ef | grep python
    root       1781   1635  0 May25 pts/1    00:00:00 python
    root       1824   1635  0 May25 pts/1    00:00:00 python
    root       5479   5451  0 22:04 pts/2    00:00:00 python
    root       5576   5550  0 22:38 pts/3    00:00:00 python threadkill.py
    root       5600   5580  0 22:38 pts/4    00:00:00 grep python
    
    kill -9 1781 1824 5479 5576

那怎么样才能退出呢，可以设置守护进程setDaemon  
并且不能使用join将进程挂起，否则也无法退出，但是并不能使用join，则会重复上面的问题，  
这里使用while空循环  
修改如下：

#coding=utf8
    import threading
    import time
    
    def showperson(name):
        while True:
           time.sleep(1)
           print 'show person :%s'%name
    
    print '%s thread start!'%(time.ctime())
    
    list=[]
    for i in range(3):
      t =threading.Thread(target=showperson,args=("person-%d"%i,))
      list.append(t)
      t.setDaemon(True)
      t.start()
    
    while True:
        pass
    
    print '%s thread end!'%(time.ctime())

输出：

# python threadkill.py 
    Fri May 26 22:47:17 2017 thread start!
    show person :person-0
    show person :person-1
    show person :person-2
    ^CTraceback (most recent call last):
      File "threadkill.py", line 19, in <module>
        while True:
    KeyboardInterrupt

使用CTRL+C退出了程序，但是抛出一个异常  
解决方法  
1.设置异常处理，抛出一个提示程序退出

#coding=utf8
    import threading
    import time
    
    def showperson(name):
        while True:
           time.sleep(1)
           print 'show person :%s'%name
    
    print '%s thread start!'%(time.ctime())
    
    try:
       list=[]
       for i in range(3):
           t =threading.Thread(target=showperson,args=("person-%d"%i,))
           list.append(t)
           t.setDaemon(True)
           t.start()
    
       while True:
           pass
    except KeyboardInterrupt,e:
        print "you stop the threading"
    
    print '%s thread end!'%(time.ctime())

输出：

# python threadkill.py 
    Fri May 26 23:01:00 2017 thread start!
    show person :person-0
    show person :person-1
    show person :person-2
    ^Xshow person :person-0
    show person :person-1
    show person :person-2
    ^X^X^X^Xshow person :person-0
    show person :person-1
    show person :person-2
    ^A^A^Ashow person :person-0
    show person :person-1
    show person :person-2
    ^Cyou stop the threading
    Fri May 26 23:01:15 2017 thread end!

CTRL+c的时候才退出

2.编写quit退出，使用signal信号传递

#coding=utf8
    import threading
    import time
    import sys
    import signal
    
    def showperson(name):
        while True:
           time.sleep(1)
           print 'show person :%s'%name
    
    print '%s thread start!'%(time.ctime())
    
    def quit(signal_num,frame):
        print "you stop the threading"
        sys.exit()
    
    try:
       signal.signal(signal.SIGINT, quit)
       signal.signal(signal.SIGTERM, quit)
    
       list=[]
       for i in range(3):
           t =threading.Thread(target=showperson,args=("person-%d"%i,))
           list.append(t)
           t.setDaemon(True)
           t.start()
    
       while True:
           pass
    except Exception,e:
        print e
    
    print '%s thread end!'%(time.ctime())

结果：

Fri May 26 23:10:43 2017 thread start!
    show person :person-0
    show person :person-1
    show person :person-2
    show person :person-0
    show person :person-1
    show person :person-2
    ^Cyou stop the threading

但是这个退出，不会进行后面的步骤，而之前的异常捕获处理后会进行后续步骤