18.python HAproxy配置修改作业

程序需求如下：

1. 根据用户输入输出对应的backend下的server信息

2. 可添加backend 和sever信息

3. 可修改backend 和sever信息

4. 可删除backend 和sever信息

5. 操作配置文件前进行备份

6 添加server信息时，如果ip已经存在则修改;如果backend不存在则创建；若信息与已有信息重复则不操作

代码如下：

#!/usr/bin/env python3
# -*-conding:utf-8-**

import json, shutil

def fetch(backend):
    """
        根据用户输入站点查找对应配置项目
        :param backend: 从主程序读取的用户输入的站点配置条目
        :return: 返回配置的值
        """
    config_list = []
    with open('haproxy','r',encoding='utf-8') as f:
        flag = False  # 用于标志所读内容是否为需要的数据
        for line in f:
            if line.strip().startswith('backend') and line.strip() == 'backend ' +backend:
                # 判断以backend开始，且后面内容和用户输入的域名相同，即所需要查询的配置条目
                flag = True
                continue
            if line.strip().startswith('backend'):
                # 判断以backend开头，与用户输入域名不相同、即不是要查询的配置项目
                flag = False
            if flag and line.strip():
                config_list.append(line.strip())
    return config_list

def add(backend,record):
    """
        用于增加用户输入的配置项目
        :param backend: 用户输入的要增加的backend和域名
        :param record: 用户输入的服务器记录
        :return:
        """
    record_list = fetch(backend)
    if not record_list:
        # 用户输入的backend不存在
        with open('haproxy','r') as old,open('new_haproxy','w') as new:
            for line in old:
                new.write(line)
            new.write('\nbackend ' + backend +'\n')
            new.write(" " * 8 + record + '\n')
    else: # 用户输入的backend存在
        if record in record_list:
            shutil.copy('haproxy','new_haproxy') # 复制配置文件到新文件中
            print("配置列表添加退出,没有配置文件被改变!")
        else: # 用户输入的backend已经存在，record不存在
            record_list.append(record)
            with open('haproxy','r') as old,open('new_haproxy','w') as new:
                flag = False
                for line in old:
                    if line.strip().startswith("backend ") and line.strip() == "backend " + backend:
                        # 如果该行以backend开始并且等于用户输入的backend域名
                        flag = True
                        new.write(line)
                        for new_line in record_list:
                            new.write(" " * 8 + new_line + '\n')
                        continue
                    if flag and line.strip().startswith('backend'):
                        flag = False
                        new.write(line)
                        continue
                    if line.strip() and not flag:
                        new.write(line)
    print("新增成功，新纪录为%s%s"%(backend,record))
    shutil.copy('haproxy','haproxy_history') # 备份原文件
    shutil.copy('new_haproxy','haproxy') # 把新修改好的文件改成正式文件

def del_item(backend):
    """
        用于删除用户输入的配置项目
        :param backend: 用户输入的要删除的backend和域名
        :param record: 用户输入的要删除的服务器记录
        :return:
        """
    record_list = fetch(backend)
    print(record_list)
    if not record_list:
        with open('haproxy','r') as old, open('new_haproxy','w') as new:
            for line in old:
                new.write(line)
        print("没有此项目，不需要删除")
    else:
        with open('haproxy', 'r') as old, open('new_haproxy', 'w') as new:
            flag = False
            for line in old:
                if line.strip().startswith("backend ") and line.strip() == "backend " + backend:
                    flag = True
                    continue
                if flag and line.strip().startswith('backend'):
                    flag = False
                    new.write(line)
                    continue
                if line.strip() and not flag:
                    new.write(line)
    print("%s已删除"%backend)
    shutil.copy('haproxy','haproxy_history')
    shutil.copy('new_haproxy','haproxy')

if __name__ == '__main__':
    while True:
        print("欢迎来到ha配置工具".center(50,'-'))
        start_choice = input("1.获取ha记录\n2.增加ha记录\n3.删除ha记录\n请输入你想要做什么:[q=quit]")
        print(''.center(50,'-'))
        if start_choice == 'q':
            exit()
        elif start_choice == '1':
            option1_choice = input('1.查询配置，请输入backend项目域名:')
            print_conf = fetch(option1_choice)
            print('你要查询的配置为：')
            print(print_conf)
        elif start_choice == '2':
            str_exa = '{"backend":"www.oldboy.org","record":{"server":"100.1.7.9","weight":"20","maxconn":3000}}'
            mod_config = input('2.选择要增加的配置项目及配置条目，格式%s:\n' % str_exa)
            dic = json.loads(mod_config)
            bk = dic['backend']
            rd =  "server %s %s weight %s maxconn %s" % (dic['record']['server'],
                                                        dic['record']['server'],
                                                        dic['record']['weight'],
                                                        dic['record']['maxconn'])
            add(bk,rd)
        elif start_choice == '3':
            str_del = '{"backend":"www.oldboy.org","record":{"server":"100.1.7.9","weight":"20","maxconn":3000}}'
            del_config = input('2.选择要删除的配置项目及配置条目，格式%s:\n' % str_del)
            del_dic = json.loads(del_config)
            del_bk = del_dic['beckend']
            del_item(del_bk)
        else:
            print("输入错误")