python 3.x创建linux/unix守护进程类，python守护进程,如下是python3.x

python 3.x创建linux/unix守护进程类，python守护进程,如下是python3.x

如下是python3.x创建linux/unix守护进程的类，要实现自己的守护进程只需要创建子类，并实现run()方法即可！

"""Generic linux daemon base class for python 3.x."""import sys, os, time, atexit, signalclass daemon:    """A generic daemon class.    Usage: subclass the daemon class and override the run() method."""    def __init__(self, pidfile): self.pidfile = pidfile    def daemonize(self):        """Deamonize class. UNIX double fork mechanism."""        try:             pid = os.fork()             if pid > 0:                # exit first parent                sys.exit(0)         except OSError as err:             sys.stderr.write('fork #1 failed: {0}\n'.format(err))            sys.exit(1)        # decouple from parent environment        os.chdir('/')         os.setsid()         os.umask(0)         # do second fork        try:             pid = os.fork()             if pid > 0:                # exit from second parent                sys.exit(0)         except OSError as err:             sys.stderr.write('fork #2 failed: {0}\n'.format(err))            sys.exit(1)         # redirect standard file descriptors        sys.stdout.flush()        sys.stderr.flush()        si = open(os.devnull, 'r')        so = open(os.devnull, 'a+')        se = open(os.devnull, 'a+')        os.dup2(si.fileno(), sys.stdin.fileno())        os.dup2(so.fileno(), sys.stdout.fileno())        os.dup2(se.fileno(), sys.stderr.fileno())        # write pidfile        atexit.register(self.delpid)        pid = str(os.getpid())        with open(self.pidfile,'w+') as f:            f.write(pid + '\n')    def delpid(self):        os.remove(self.pidfile)    def start(self):        """Start the daemon."""        # Check for a pidfile to see if the daemon already runs        try:            with open(self.pidfile,'r') as pf:                pid = int(pf.read().strip())        except IOError:            pid = None        if pid:            message = "pidfile {0} already exist. " + \                    "Daemon already running?\n"            sys.stderr.write(message.format(self.pidfile))            sys.exit(1)        # Start the daemon        self.daemonize()        self.run()    def stop(self):        """Stop the daemon."""        # Get the pid from the pidfile        try:            with open(self.pidfile,'r') as pf:                pid = int(pf.read().strip())        except IOError:            pid = None        if not pid:            message = "pidfile {0} does not exist. " + \                    "Daemon not running?\n"            sys.stderr.write(message.format(self.pidfile))            return # not an error in a restart        # Try killing the daemon process            try:            while 1:                os.kill(pid, signal.SIGTERM)                time.sleep(0.1)        except OSError as err:            e = str(err.args)            if e.find("No such process") > 0:                if os.path.exists(self.pidfile):                    os.remove(self.pidfile)            else:                print (str(err.args))                sys.exit(1)    def restart(self):        """Restart the daemon."""        self.stop()        self.start()    def run(self):        """You should override this method when you subclass Daemon.        It will be called after the process has been daemonized by         start() or restart()."""