UDP 保活 python

最近在写公司的项目需要使用UDP 实现一个保活，而且需要用python 写，苦苦查找后，原来已经有大神完成了，就再次保存一下，防止以后忘记。

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""" 心跳客户端,周期性的发送 UDP包 """ import socket, time SERVER_IP = '192.168.0.15'; SERVER_PORT = 43278; BEAT_PERIOD = 5 print 'Sending heartbeat to IP %s , port %d' % (SERVER_IP, SERVER_PORT) print 'press Ctrl-C to stop' while True: hbSocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) hbSocket.sendto('PyHB', (SERVER_IP, SERVER_PORT)) if _ _debug_ _: print 'Time: %s' % time.ctime( ) time.sleep(BEAT_PERIOD)

""" 多线程 heartbeat 服务器""" import socket, threading, time UDP_PORT = 43278; CHECK_PERIOD = 20; CHECK_TIMEOUT = 15 class Heartbeats(dict): """ Manage shared heartbeats dictionary with thread locking """ def _ _init_ _(self): super(Heartbeats, self)._ _init_ _( ) self._lock = threading.Lock( ) def _ _setitem_ _(self, key, value): """ Create or update the dictionary entry for a client """ self._lock.acquire( ) try: super(Heartbeats, self)._ _setitem_ _(key, value) finally: self._lock.release( ) def getSilent(self): """ Return a list of clients with heartbeat older than CHECK_TIMEOUT """ limit = time.time( ) - CHECK_TIMEOUT self._lock.acquire( ) try: silent = [ip for (ip, ipTime) in self.items( ) if ipTime < limit] finally: self._lock.release( ) return silent class Receiver(threading.Thread): """ Receive UDP packets and log them in the heartbeats dictionary """ def _ _init_ _(self, goOnEvent, heartbeats): super(Receiver, self)._ _init_ _( ) self.goOnEvent = goOnEvent self.heartbeats = heartbeats self.recSocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) self.recSocket.settimeout(CHECK_TIMEOUT) self.recSocket.bind(('', UDP_PORT)) def run(self): while self.goOnEvent.isSet( ): try: data, addr = self.recSocket.recvfrom(5) if data == 'PyHB': self.heartbeats[addr[0]] = time.time( ) except socket.timeout: pass def main(num_receivers=3): receiverEvent = threading.Event( ) receiverEvent.set( ) heartbeats = Heartbeats( ) receivers = [ ] for i in range(num_receivers): receiver = Receiver(goOnEvent=receiverEvent, heartbeats=heartbeats) receiver.start( ) receivers.append(receiver) print 'Threaded heartbeat server listening on port %d' % UDP_PORT print 'press Ctrl-C to stop' try: while True: silent = heartbeats.getSilent( ) print 'Silent clients: %s' % silent time.sleep(CHECK_PERIOD) except KeyboardInterrupt: print 'Exiting, please wait...' receiverEvent.clear( ) for receiver in receivers: receiver.join( ) print 'Finished.' if _ _name_ _ == '_ _main_ _': main( )

服务器程序接受ing跟踪“心跳”，她运行的计算机的地址必须和“客户端”程序中的 SERVER_IP一致。服务器必须支持并发，因为来自不同的计算机的心跳可能会同时到达。一个服务器有两种方法支持并发：多线程和异步操作。下面是一个多线程的ThreadbearServer.py，只使用了python标准库中的模块：

import time from twisted.application import internet, service from twisted.internet import protocol from twisted.python import log UDP_PORT = 43278; CHECK_PERIOD = 20; CHECK_TIMEOUT = 15 class Receiver(protocol.DatagramProtocol): """ Receive UDP packets and log them in the "client"s dictionary """ def datagramReceived(self, data, (ip, port)): if data == 'PyHB': self.callback(ip) class DetectorService(internet.TimerService): """ Detect clients not sending heartbeats for too long """ def _ _init_ _(self): internet.TimerService._ _init_ _(self, CHECK_PERIOD, self.detect) self.beats = { } def update(self, ip): self.beats[ip] = time.time( ) def detect(self): """ Log a list of clients with heartbeat older than CHECK_TIMEOUT """ limit = time.time( ) - CHECK_TIMEOUT silent = [ip for (ip, ipTime) in self.beats.items( ) if ipTime < limit] log.msg('Silent clients: %s' % silent) application = service.Application('Heartbeat') # define and link the silent clients' detector service detectorSvc = DetectorService( ) detectorSvc.setServiceParent(application) # create an instance of the Receiver protocol, and give it the callback receiver = Receiver( ) receiver.callback = detectorSvc.update # define and link the UDP server service, passing the receiver in udpServer = internet.UDPServer(UDP_PORT, receiver) udpServer.setServiceParent(application) # each service is started automatically by Twisted at launch time log.msg('Asynchronous heartbeat server listening on port %d\n' 'press Ctrl-C to stop\n' % UDP_PORT)