memcached启动脚本（class练习）

说明：使用类的方式编写程序启动脚本（memcached)

 import time
 import os
 from subprocess import Popen,PIPE

 class Process(object):
     'mamcached rc scripts'
     def __init__(self,name,program,args,workdir):
         self.name = name
         self.program = program
         self.args = args
         self.workdir = workdir
         self._init()

     def _init(self):
         '''/var/tmp/memcached'''
         if not os.path.exists(self.workdir):
             os.mkdir(self.workdir)
             os.chdir(self.workdir)

     def _pidfile(self):
         '''/var/tmp/memcached/memcached.pid'''
         return os.path.join(self.workdir,'%s.pid' % self.name)

     def _writepid(self):
         if self.pid:
             with open(self._pidfile(),'w') as fd:
                 fd.write(str(self.pid))

     def _getpid(self):
         p = Popen(['pidof','memcached'],stdout=PIPE)
         pid = p.stdout.read().strip('\n')
         if pid:
             return int(pid)
         return None

     def start(self):
         cmd = self.program + ' ' + self.args
         p = Popen(cmd,stdout=PIPE,shell=True)
         self.pid = p.pid
         self._writepid()
         print('%s start Successful ' % self.name)

     def stop(self):
         result = self._getpid()
         if result:
             os.kill(result,15)
             if os.path.exists(self._pidfile()):
                 os.remove(self._pidfile())
             print('The %s are stoped !' % self.name)

     def restart(self):
         self.stop()
         time.sleep(1)
         self.start()

     def status(self):
         pid = self._getpid()
         if pid:
             print('The %s is running , The pid is %s' % (self.name,pid))
         else:
             print('The %s is not running!' % self.name)

     def help(self):
         print('Usage: %s {start|restart|status|stop}' % __file__ )

 def main():
     name = 'memcached'
     program = '/usr/bin/memcached'
     args = '-u nobody -p 11211 -c 1024 -m 64 '
     wd = '/var/tmp/memcached'
     pm = Process(name,program,args,wd)
     try:
         cmd = sys.argv[1]
     except IndexError as e:
         sys.exit('Option Error')
     if cmd == 'start':
         pm.start()
     elif cmd == 'stop':
         pm.stop()
     elif cmd == 'restart':
         pm.restart()
     elif cmd == 'status':
         pm.status()
     else:
         pm.help()

 if __name__ == '__main__':
     main()