[英]How to exit a multithreaded program?
I was just messing around with threading in python, wrote this basic IM thingy [code at bottom]我只是在搞乱 python 中的线程,写了这个基本的 IM thingy [底部代码]
I noticed that when I kill the program with Cc it doesn't exit, it just hangs forever.我注意到当我用 Cc 杀死程序时它不会退出,它只是永远挂起。
I'm just guessing it's waiting for each thread to finish what they are doing, but since it's an endless loop that will never happen.我只是猜测它正在等待每个线程完成他们正在做的事情,但因为这是一个永远不会发生的无限循环。
So I guess I need to kill each thread manually, or end the loop when the killsignal comes in.所以我想我需要手动杀死每个线程,或者在killsignal进来时结束循环。
How would I do that?我该怎么做?
#!/usr/bin/env python
import threading
import socket
class Listen(threading.Thread):
def run(self):
conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
conn.bind(('', 2727))
conn.listen(1)
while True:
channel, details = conn.accept()
print str(details)+": "+channel.recv(250)
channel.send("got it")
channel.close()
class Shout(threading.Thread):
def run(self):
while True:
try:
address = raw_input("who u talking to? ")
conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
conn.connect((address, 2727))
break
except:
print "can't connect to "+ str(address)
while True:
conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
conn.connect((address, 2727))
conn.send(raw_input())
conn.close()
listen = Listen().start()
shout = Shout().start()
I see several causes of the misbehavior in your code.我在您的代码中看到了导致不当行为的几个原因。
Beside all these things, here is my try for a solution.除了所有这些之外,这是我尝试的解决方案。 Still there is much that can be improved.仍然有很多可以改进的地方。 You should consider the answer from Mark Tolonen too, since the SocketServer class is surely provided to ease several things in handling this kind of stuff.您也应该考虑 Mark Tolonen 的回答,因为肯定提供了 SocketServer class 来简化处理此类事情的几件事。 But you should keep on studying the basics too.但是你也应该继续学习基础知识。
#!/usr/bin/env python
import threading
import socket
import time
import errno
class StoppableThread(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.stop_event = threading.Event()
def stop(self):
if self.isAlive() == True:
# set event to signal thread to terminate
self.stop_event.set()
# block calling thread until thread really has terminated
self.join()
class Accept(StoppableThread):
def __init__(self, port):
StoppableThread.__init__(self)
self.port = port
self.threads = []
def run(self):
# handle connection acception
conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
conn.bind(('', self.port ))
conn.listen(5)
# set socket timeout to ~10ms
conn.settimeout(0.01)
while self.stop_event.is_set() == False:
try:
csock, caddr = conn.accept()
# spawn a new thread to handle the client connection
listen_thread = Listen(csock, caddr)
self.threads.append(listen_thread)
listen_thread.start()
except socket.timeout:
# socket operation timeout
# clear all terminated threads from thread list
for thread in self.threads:
if thread.isAlive() == False:
self.threads.remove(thread)
self.stop_threads()
def stop_threads(self):
# stop all running threads
for listen_thread in self.threads:
if listen_thread.isAlive() == True:
listen_thread.stop()
self.threads = []
class Listen(StoppableThread):
def __init__(self, csock, caddr):
StoppableThread.__init__(self)
self.csock = csock
self.caddr = caddr
self.csock.setblocking(False)
def run(self):
while self.stop_event.is_set() == False:
try:
recv_data = self.csock.recv(250)
if len(recv_data) > 0:
print str(self.caddr)+": " + recv_data
self.csock.send("got it")
else:
# connection was closed by foreign host
self.stop_event.set()
except socket.error as (sock_errno, sock_errstr):
if (sock_errno == errno.EWOULDBLOCK):
# socket would block - sleep sometime
time.sleep(0.1)
else:
# unexpected / unhandled error - terminate thread
self.stop_event.set()
channel.close()
class Shout(StoppableThread):
def __init__(self, sport):
StoppableThread.__init__(self)
self.sport = sport
def run(self):
while self.stop_event.is_set() == False:
try:
address = raw_input("who u talking to? ")
conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
conn.connect((address, self.sport))
break
except socket.error:
# handle connection problems
print "can't connect to "+ str(address)
except:
# exit thread in case of an unexpected error
self.stop_event.set()
while self.stop_event.is_set() == False:
try:
# chat loop: send messages to remote host
print "what to send? :",
msg = raw_input()
# beware: send() function may block indefinitly here and it might not send all bytes as expected !!
conn.send(msg)
except:
# exit thread in case of an unexpected error
self.stop_event.set()
# close socket before thread terminates
conn.close()
def main():
do_exit = False
server_port = 2727
# start server socket thread
accept = Accept(server_port)
accept.start()
# start transmitting client socket thread
shout = Shout(server_port)
shout.start()
while do_exit == False:
try:
# sleep some time
time.sleep(0.1)
except KeyboardInterrupt:
# Ctrl+C was hit - exit program
do_exit = True
# stop all running threads
shout.stop()
accept.stop()
# exit main program after all threads were terminated gracefully
if __name__ == "__main__":
main()
Look at the Python library source for SocketServer.py, in particular the implementation of server_forever() to see how a server implements a quit.查看 SocketServer.py 的 Python 库源代码,特别是 server_forever() 的实现,以了解服务器如何实现退出。 It uses select() to poll the server socket for new connections and tests a quit flag.它使用 select() 来轮询服务器套接字以获取新连接并测试退出标志。 Here's a hack on your source to use SocketServer, and I added a quit flag to Shout().这是使用 SocketServer 的源代码的 hack,我在 Shout() 中添加了退出标志。 It will run the Shout and Listen threads for 5 seconds and then stop them.它将运行 Shout 和 Listen 线程 5 秒钟,然后停止它们。
import socket
import SocketServer
import threading
import time
class Handler(SocketServer.StreamRequestHandler):
def handle(self):
print str(self.client_address) + ": " + self.request.recv(250)
self.request.send("got it\n")
class Listen(threading.Thread):
def run(self):
self.server = SocketServer.TCPServer(('',2727),Handler)
self.server.serve_forever()
def stop(self):
self.server.shutdown()
class Shout(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
self.quit = False
def run(self):
while not self.quit:
conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
conn.connect(('localhost', 2727))
conn.send('sending\n')
print conn.recv(100)
conn.close()
def stop(self):
self.quit = True
listen = Listen()
listen.start()
shout = Shout()
shout.start()
time.sleep(5)
shout.stop()
listen.stop()
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