一，程序要求

对后台的数据(以一个文件为例)实现简单的增删改查功能，语句的语法为提示信息的示例

二，代码部分

#! /usr/bin/env python# -*- coding: utf-8 -*-# __author__ = "Jiang Feng"# Date: 2018/12/28import osdef file_processing(backend_data, type, res = None):    if type == 'grep':        with open('aaa', 'r') as read_f:            results = []            tag = False            for read_line in read_f:                if read_line.strip() == backend_data:                    tag = True                    continue                if tag and read_line.strip().startswith('backend'):                    break                if tag:                    results.append(read_line.strip())        return results    elif type == 'change':        with open('aaa','r') as read_f ,open('aaa_new','w') as write_f:            tag = False            for read_line in read_f:                if read_line.strip() == backend_data:                    write_f.write(read_line)                    tag = True                    for server in res:                        server = ' ' * 8 + server                        server = '%s' % server                        write_f.write(server)                    continue                if tag and read_line.startswith('backend'):                    tag = False                if not tag:                    write_f.write(read_line)        os.rename('aaa', 'aaa.bak')        os.rename('aaa_new', 'aaa')        os.remove('aaa.bak')        return '数据已经修改完成'def add(data):    backend = data[0]['backend']    backend_data = 'backend %s' % backend    adddata = data[0]['server']    add_list = grep(backend)    if adddata in add_list:        print('你想要添加的数据已经存在')    else:        add_list.append(adddata)        return file_processing(backend_data, type='change', res=add_list)def remove(data):    backend = data[0]['backend']    backend_data = 'backend %s'%backend    rmdata = data[0]['server']    remove_list = grep(backend)    if rmdata in remove_list:        remove_list.remove(rmdata)        return file_processing(backend_data, type='change', res=remove_list)    else:        print('你想要修改的数据不存在')def change(data):    backend = data[0]['backend']    backend_data = 'backend %s'%backend    old_data = data[0]['server']    new_data = data[1]['server']    grep_list = grep(backend)    if not new_data or old_data not in grep_list:        print('你想要修改的数据不存在')    else:        index = grep_list.index(old_data)        grep_list[index] = new_data        return file_processing(backend_data, type='change', res=grep_list)def grep(data):    backend_data = 'backend %s' %data    return file_processing(backend_data, type='grep')if __name__ == '__main__':    tip = '''        欢迎使用:请根据提示输入数字        1:增(例：[{'backend':'www.baidu2.com','server':'server 2.2.2.9 2.2.2.9 weight 20 maxconn 4000'}])             2:删(例：[{'backend':'www.baidu2.com','server':'server 2.2.2.9 2.2.2.9 weight 20 maxconn 4000'}])        3:改[{'backend':'www.baidu1.com','server':'server 10.10.10.1 10.10.10.1 weight 22 maxconn 2000'},        {'backend':'www.baidu1.com','server':'server 10.10.10.1 10.10.10.1 weight 22 maxconn 22222'}]        4:查(例：www.baidu1.com)        5:退出    '''    msg = {        '1': add,        '2': remove,        '3': change,        '4': grep,    }    while True:        print(tip)        choice = input('请输入你的选项：')        if not choice: continue        if choice == '5': break        data = input('请输入代码：')        if choice != '4':            data = eval(data)        res = msg[choice](data)        print(res)

三，文件中的变量

backend:为了使用查询，获得查询功能返回的列表

backend_data：为了与后台数据进行判断

file_processing：文件处理函数，为了实现程序的解耦性四，附上仿制的后台数据

global        log 127.0.0.1 local2        daemon        maxconn 256        log 127.0.0.1 local2 infodefaults        log global        mode http        timeout connect 5000ms        timeout client 50000ms        timeout server 50000ms        option  dontlognulllisten stats :8888        stats enable        stats uri       /admin        stats auth      admin:1234frontend www.baidu.com        bind 0.0.0.0:80        option httplog        option httpclose        option  forwardfor        log global        acl www hdr_reg(host) -i www.oldboy.org        use_backend www.oldboy.org if wwwbackend www.baidu.combackend www.baidu1.com        server 101.1000.7.9 101.1000.7.9 weight 20 maxconn 30        server 10.10.10.1 10.10.10.1 weight 22 maxconn 2000        server 2.2.2.5 2.2.2.5 weight 20 maxcoon 3333        server 2.2.2.7 2.2.2.7 weight 20 maxcoon 3333backend www.baidu2.com        server 3.3.3.3 3.3.3.3 weight 20 maxconn 3000        server 2.2.22.221 2.2.22.221 weight 20 maxconn 3333backend www.baidu3.com        server 10.10.0.10 10.10.0.10 weight 9999 maxconn 33333333333        server 2.2.2.111 2.2.2.111 weight 20 maxconn 3333

测试的示例代码：

增：[{'backend':'www.baidu2.com','server':'server 2.2.2.9 2.2.2.9 weight 20 maxconn 4000'}]     删例：[{'backend':'www.baidu2.com','server':'server 2.2.2.9 2.2.2.9 weight 20 maxconn 4000'}]改：[{'backend':'www.baidu1.com','server':'server 10.10.10.1 10.10.10.1 weight 22 maxconn 2000'},{'backend':'www.baidu1.com','server':'server 10.10.10.1 10.10.10.1 weight 22 maxconn 22222'}]查：www.baidu1.com