使用 python 实现 memcached 的启动服务脚本 rc

#!/usr/bin/python
#coding:utf-8

import sys
import os
from subprocess import Popen, PIPE

class Memcached(object):
    ''' memcached rc script '''
    args = {'USER':'memcached', 'PORT':11211, 'MAXCONN':1024, 'CACHESIZE':64, 'OPTIONS':''}

    def __init__(self, name, program, workdir):
        self.name = name
        self.program = program
        #self.args = args
        self.workdir = workdir

    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 _readConf(self, f):
        with open(f) as fd:
            lines = fd.readlines()
            return dict([i.strip().replace('"', '').split('=') for i in lines])

    def _parseArgs(self):
        conf = self._readConf('/etc/sysconfig/memcached')
        if 'USER' in conf:
            self.args['USER'] = conf['USER']
        if 'PORT' in conf:
            self.args['PORT'] = conf['PORT']
        if 'MAXCONN' in conf:
            self.args['MAXCONN'] = conf['MAXCONN']
        if 'CACHESIZE' in conf:
            self.args['CACHESIZE'] = conf['CACHESIZE']
        options = ['-u', self.args['USER'],
                   '-p', self.args['PORT'],
                   '-m', self.args['CACHESIZE'],
                   '-C', self.args['MAXCONN']]
        os.system('chown %s %s' % (self.args['USER'], self.workdir))
        ''' 这个地方要修改工作目录的权限，用户为memcached，需要有写目录的权限。 '''
        return options

    def start(self):
        pid = self._getPid()
        if pid:
            print '%s is running...' % self.name
            sys.exit()

        self._init()
        cmd = [self.program] + self._parseArgs() + ['-d', '-P', self._pidFile()]
        print cmd
        p = Popen(cmd, stdout = PIPE)
        #self.pid = p.pid
        #self._writePid()
        # 如果程序选项中有-P选项，那么应用程序会自动去写pid文件，不用手动去写，而且要注意pid与手动写入的pid有何区别。
        print '%s start Sucessful' % self.name    

    def _getPid(self):
        p = Popen(['pidof', self.name], stdout=PIPE)
        pid = p.stdout.read().strip()
        return pid

    def stop(self):
        pid = self._getPid()
        if pid:
            os.kill(int(pid), 15)
            if os.path.exists(self._pidFile()):
                os.remove(self._pidFile())
            print '%s is stopped' % self.name

    def restart(self):
        self.stop()
        self.start()

    def status(self):
        pid = self._getPid()
        if pid:
            print '%s is already running' % self.name
        else:
            print '%s is not running' % self.name    

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

def main():
    name = 'memcached'
    prog = '/usr/bin/memcached'
    #args = '-u nobody -p 11211 -c 1024 -m 64'
    wdir = '/var/tmp/memcached'

    rc = Memcached(name, prog, wdir)
    try:
        cmd = sys.argv[1]
    except IndexError, e:
        print "Option error"
        sys.exit()

    if cmd == 'start':
        rc.start()
    elif cmd == 'stop':
        rc.stop()
    elif cmd == 'restart':
        rc.restart()
    elif cmd == 'status':
        rc.status()
    else:
        rc.help()

if __name__ == '__main__':
    main()