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('
')
        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()