nginx tomcat集群配置实现无痛重启服务教程python语言版本

上一次分享的是shell版本的:nginx tomcat集群配置实现无痛重启服务教程

感觉shell语法的怪异实在难以忍受，但java在处理脚本，和shell交互方面的天然弱势导致我最终选择了python来做最代码的各种脚本实现，通过实现无痛重启tomcat的脚本后发现除了调试不方便外，python作为脚本和shell交互简直是神器。

下面是脚本实现：

#encoding=utf8

import re
import os
import commands
import time
import urllib2
from urllib2 import URLError
import socket

tomcat_ps_name="apache-tomcat-6_"
flag=tomcat_ps_name+"\d{4}"
ports=["8080", "8081"]
nginx_path="/usr/local/nginx/"
nginx_vhost_conf_path=nginx_path+"conf/vhost/"
nginx_bin_path=nginx_path+"sbin/nginx"
zuidaima_conf_name="www.zuidaima.com_%s.conf"
tomcat_path="/usr/local/apache-tomcat-_"
zuidaima_conf_name_bak_suffix=".bak"
tomcat_startup_bin_path="/bin/startup.sh"
tomcat_shutdown_bin_path="/bin/shutdown.sh"
ps_grep_tomcat="ps -ef|grep "
zuidaima_domain="http://www.zuidaima.com"
kill_tomcat_pid=ps_grep_tomcat+tomcat_ps_name+"%s|awk '{print $2}'|xargs kill"

#通过conf文件是否是bak来确认正在运行的tomcat端口
def find_running_tomcat_port():
    for _port in ports:
         tomcat_conf_name=nginx_vhost_conf_path+zuidaima_conf_name%(_port)
         if(os.path.exists(tomcat_conf_name)):
             port=_port
             break
    if not is_tomcat_port_running(port):
        return -1
    return port

#判断指定的tomcat端口是否在运行
def is_tomcat_port_running(tomcat_port):
    ret=request_share_url(tomcat_port)
    if ret==200:
        return 1
    return 0

#请求带端口的share地址
def request_share_url(tomcat_port):
    socket.setdefaulttimeout(10)
    url=zuidaima_domain+":"+tomcat_port+"/share.htm"
    ret=-1
    try:
        res=urllib2.urlopen(url)
	ret=res.code
    except URLError, e:
        print "request url#"+url+" error"
    return ret

#切换nginx的tomcat端口
def switch_nginx_conf(running_tomcat_port, stoped_tomcat_port):
    running_tomcat_conf_name=nginx_vhost_conf_path+zuidaima_conf_name%(running_tomcat_port)
    if(not os.path.exists(running_tomcat_conf_name)):
        return -1
    stoped_tomcat_conf_name=nginx_vhost_conf_path+zuidaima_conf_name%(stoped_tomcat_port)
    if(not os.path.exists(stoped_tomcat_conf_name+zuidaima_conf_name_bak_suffix)):
        return -2
    os.rename(running_tomcat_conf_name, running_tomcat_conf_name+zuidaima_conf_name_bak_suffix)
    os.rename(stoped_tomcat_conf_name+zuidaima_conf_name_bak_suffix, stoped_tomcat_conf_name)
    return 1

#启动指定端口的tomcat服务
def startup_tomcat(tomcat_port):
    shutdown_tomcat(tomcat_port)
    outputs=commands.getoutput(tomcat_path+tomcat_port+tomcat_startup_bin_path)
    time.sleep(5) # 休眠5秒
    while(not is_tomcat_port_running(tomcat_port)):
        print "start tomcat "+tomcat_port
        time.sleep(5) # 休眠5秒
    return 1

#停止指定端口的tomcat服务
def shutdown_tomcat(tomcat_port):
    commands.getoutput(kill_tomcat_pid%(tomcat_port))
    while(is_tomcat_port_running(tomcat_port)):
        print "stop tomcat "+tomcat_port
        time.sleep(5) # 休眠5秒
    return 1

#切换tomcat服务
def switch_tomcat(running_tomcat_port, stoped_tomcat_port):
    startup_tomcat(stoped_tomcat_port)
    shutdown_tomcat(running_tomcat_port)
    return 1
#reload nginx conf
def reload_nginx_conf():
    commands.getoutput(nginx_bin_path+" -s reload")
    return 1

def start():
    print "start to switch tomcat"

    running_tomcat_port=find_running_tomcat_port()
    if running_tomcat_port==-1:
        print "running tomcat & conf is invalid"
        return
    ports.remove(running_tomcat_port)
    stoped_tomcat_port=ports[0]

    print "start to switch tomcat from "+running_tomcat_port+" to "+stoped_tomcat_port
    ret=switch_tomcat(running_tomcat_port, stoped_tomcat_port)
    if(ret!=1):
        print "fail to switch_tomcat,ret:", ret
        return

    print "start to switch nginx conf"
    ret=switch_nginx_conf(running_tomcat_port, stoped_tomcat_port)
    if(ret!=1):
        print "fail to switch_nginx_conf,ret:", ret
        return

    print "start to reload nginx conf"
    ret=reload_nginx_conf()
    if(ret!=1):
        print "fail to reload_nginx_conf,ret:", ret
        return

    print "finish to switch tomcat"

start()

有图有真相：

另外阿里云服务器自带的python版本是Python 2.4.3 (#1, Jan  9 2013, 06:49:54)的，在编写脚本的过程中很多语法都是高版本才有的，所以大家在学习python的过程中要注意版本的问题。

该版本的实现上因为python是高级语言，所以业务实现上很严密，比如启动时根据conf文件的后缀来确认谁是正在运行的tomcat，执行完tomcat的startup.sh后，再次通过urllib去请求该端口的share.htm确保启动确实成功。

enjoy it.