21. 对文件进行查询修改等操作

练习目的：

1.函数编程

2.文件处理

3.tag的用法

4.程序的解耦

文件内容：haproxy.conf

global
        log 127.0.0.1 local2
        daemon
        maxconn 256
        log 127.0.0.1 local2 info
defaults
        log global
        mode http
        timeout connect 5000ms
        timeout client 50000ms
        timeout server 50000ms
        option  dontlognull

listen stats :8888
        stats enable
        stats uri       /admin
        stats auth      admin:1234

frontend oldboy.org
        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 www

backend www.oldboy1.org
        server 101.1000.7.9 101.1000.7.9 weight 20 maxconn 30
        server 2.2.2.7 2.2.2.7 weight 30 maxconn 4000
        server 10.10.10.1 10.10.10.1 weight 22 maxconn 2000
        server 2.2.2.5 2.2.2.5 weight 30 maxconn 4000

backend www.oldboy2.org
        server 3.3.3.3 3.3.3.3 weight 20 maxconn 3000
backend www.oldboy20.org
        server 10.10.0.10 10.10.0.10 weight 9999 maxconn 33333333333

代码内容：

import os
def file_handler(backend_data,res=None,type='fetch'):
    if type == 'fetch':
        with open('haproxy.conf','r') as read_f:
            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'):
                        # tag=False
                        break
                if tag:
                    print('33[1;45m%s33[0m' %read_line,end='')
                    ret.append(read_line)
        return ret
    elif type == 'change':
        with open('haproxy.conf', 'r') as read_f, 
                open('haproxy.conf_new', 'w') as write_f:
            tag = False
            has_write = False
            for read_line in read_f:  # server
                if read_line.strip() == backend_data:
                    tag = True
                    continue
                if tag and read_line.startswith('backend'):
                    tag = False
                if not tag:
                    write_f.write(read_line)
                else:
                    if not has_write:
                        for record in res:
                            write_f.write(record)
                        has_write = True
        os.rename('haproxy.conf', 'haproxy.conf.bak')
        os.rename('haproxy.conf_new', 'haproxy.conf')
        os.remove('haproxy.conf.bak')

def fetch(data):
    # print('33[1;43m这是查询功能33[0m')
    # print('33[1;43m用户数据是33[0m',data)
    backend_data='backend %s' %data
    return file_handler(backend_data)



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'] #文件当中的一条记录 www.oldboy1.org
    backend_data='backend %s' %backend #backend www.oldboy1.org
    #       server 2.2.2.4 2.2.2.4 weight 20 maxconn 3000

    old_server_record='%sserver %s %s weight %s maxconn %s
' %(' '*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
' % (' ' * 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) #fetch('www.oldboy1.org')
    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

    res.insert(0,'%s
' %backend_data)
    file_handler(backend_data,res=res,type='change')


def delete():
    pass

if __name__ == '__main__':
    msg='''
    1:查询
    2:添加
    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('请输入你的选项：').strip()
        if not choice:continue
        if choice == '5':break

        data=input('请输入你的数据：').strip()

        if choice != '1':
            data=eval(data)

        res=msg_dic[choice](data)
        print('最终结果是--》',res)
# [{'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}}]