使用python實現memcached的啟動服務指令碼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))
        ``` 這個地方要修改工作目錄的許可權，使用者為memcached，需要有寫目錄的許可權。 ```
        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()
        # 如果程式選項中有-P選項，那麼應用程式會自動去寫pid檔案，不用手動去寫，而且要注意pid與手動寫入的pid有何區別。
        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()