增、删、查、改和退出功能

#!/user/bin/python
# -*- coding:utf-8 -*-
#定义查询功能
def fetch(data):
    print("\033[1;43m这是查询功能\033[0m")
    print("\033[1;43m用户数据是\033[0m",data)
    backend_data = "backend %s" %data
    with open("haproxy.conf","r") as read_f :
        #tag用来表示状态
        tag = False
        ret = []
        for read_line in read_f:
            if read_line.strip() == backend_data:
                tag = True
                continue
            if tag and read_line.startswith("backend"):
                    break
            if tag :
                print("\033[1;45m%s\033[0m" %read_line,end= "")
                ret.append(read_line)
    return ret
def add():
    pass
def change(data):
    print("这是修改功能")
    print("用户输入的数据是",data)
    backend = data[0]["backend"] #定义data0是要修改的记录、data0是字典的形式，再加["backend"]根据key取value值也就是www.oldboy1.org并且再返回定义backend
    backend_data = "backend %s" %backend
    old_server_record = "%sserver %s %s weight %s maxconn %s\n" %(" "* 8,data[0]["record"]["server"],
                                                                data[0]["record"]["server"],
                                                                data[0]["record"]["weight"],
                                                                data[0]["record"]["maxconn"])
    new_server_record = "%sserver %s %s weight %s maxconn %s\n" %(" "* 8,data[1]["record"]["server"],
                                                                data[1]["record"]["server"],
                                                                data[1]["record"]["weight"],
                                                                data[1]["record"]["maxconn"])
    print("用户想要修改的记录是",old_server_record)
    res = fetch(backend) #执行查询的操作调fetch函数并且再传入上面取得backend作为参数并且再返回定义res
    print("来自change函数--",res)
    if not res or old_server_record not in res:
        return "你要修改的记录不存在"
    else:
        index = res.index(old_server_record)
        res[index] = new_server_record
    with open("haproxy.conf","r") as read_f,\
            open("haproxy.conf_new","w") as write_f :
        tag = False
        for read_line in read_f:
            if read_line.strip() == backend_data:
                tag = True
                continue
            if not tag:
                write_f.write(read_line)
            else:
                for record in res:
                    write_f.write(record)
def delete():
    pass
if __name__ == '__main__':
    msg = """
    1: 查询，
    2 ： 增加，
    3 ： 修改，
    4 ： 删除，
    5 ： 退出
    """
    msg_dic = {
        "1" : fetch,
        "2" : add,
        "3" : change,
        "4" : delete
    }
    while True:
        print(msg)
        choice = input("请输入选项：").strip()
        if not choice : continue
        if choice == "5" : break
        data = input("请输入用户数据：").strip()
        if choice != "1" :
            data = eval（data)   #把传入的字符串进行提取出来
        res = msg_dic[choice](data)
        print("最终结果是-->",res)
#定义原纪录和修改后的记录
# [{"backend" : "www.oldboy1.org" , "record" : {"server" : "2.2.2.4" , "weight" : 20,"maxconn" : 3000 }},{"backend" : "www.oldboy1.org","record" : {"server" : "2.2.2.5","weight": 30,"maxconn":4000}}]