Python實現在線上環境優雅的修改配置文件

原配置文件：

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.oldboy.org
        server 100.1.7.9 100.1.7.9 weight 20 maxconn 3000

需求：
1、查
    輸入：www.oldboy.org
    獲取當前backend下的所有記錄

2、新建
    輸入：
        arg = {
            'bakend': 'www.oldboy.org',
            'record':{
                'server': '100.1.7.9',
                'weight': 20,
                'maxconn': 30
            }
        }

3、刪除
    輸入：
        arg = {
            'bakend': 'www.oldboy.org',
            'record':{
                'server': '100.1.7.9',
                'weight': 20,
                'maxconn': 30
            }
        }

實現：

#!/usr/bin/env python
# -*- coding:utf-8 -*-
import json
import os

#根據標題獲取配置信息
def fetch(backend):
    backend_title = 'backend %s' % backend
    record_list = []
    with open('ha') as obj:
        flag = False
        for line in obj:
            line = line.strip()
            if line == backend_title:
                flag = True
                continue
            if flag and line.startswith('backend'):
                flag = False
                break
            if flag and line:
                record_list.append(line)

    return record_list




    return record_list
#在指定標題下插入配置信息
def insert(dict_data):
    backend = dict_data.get('backend')
    backend_title = "backend %s" % backend
    content = "server %s %s weight %d maxconn %d" % (dict_data['record']['server'], dict_data['record']['server'], dict_data['record']['weight'], dict_data['record']['maxconn'])
    record_list = fetch(backend)
    flag = True
    count = 0
    if not record_list:
        record_list.append(backend_title)
        record_list.append(content)
        with open('conf.txt','r') as read_file, open('conf.txt.bak','w') as write_file:
            for line in read_file:
                write_file.write(line)
            for l in record_list:
                if l.startswith("backend"):
                    write_file.write(l+'\n')
                else:
                    write_file.write(" "*8 + l)
    else:
        record_list.append(content)
        with open('conf.txt','r') as read_file, open('conf.txt.bak','w') as write_file:
            for line in read_file:
                if flag:
                    write_file.write(line)
                    if line.startswith(backend_title):
                        for l in record_list:
                            write_file.write(" "*8 + l+'\n')
                        flag = False
                else:
                    count = count + 1
                    if(count == record_list.__len__() -1):
                        flag = True
    os.rename('conf.txt.bak','conf.bak')
    os.rename('conf.bak','conf.txt')
#刪除指定標題的信息
def delete(dict_data):
        backend = dict_data.get('backend')
        backend_title = "backend %s" % backend
        content = "server %s %s weight %d maxconn %d" % (dict_data['record']['server'], dict_data['record']['server'], dict_data['record']['weight'], dict_data['record']['maxconn'])
        record_list = fetch(backend)
        content = content.strip()
        print(content)
        if not record_list:
            return
        else:
            if record_list.__contains__(content):
                return
            else:
                print(record_list)
                record_list.__delattr__(record_list.index(content))
                with open('conf.txt','r') as read_file, open('conf.txt.bak','w') as write_file:
                    for line in read_file:
                        if flag:
                            write_file.write(line)
                            if line.startswith(backend_title):
                                for l in record_list:
                                    write_file.write(" "*8 + l+'\n')
                                flag = False
                        else:
                            count = count + 1
                            if(count == record_list.__len__() +1):
                                flag = True
        os.rename('conf.txt.bak','conf.bak')
        os.rename('conf.bak','conf.txt')

if __name__ == '__main__':
    print '1、獲取；2、添加；3、刪除'
    num = raw_input('請輸入序號：')
    data = raw_input('請輸入內容：')
    if num == '1':
        print(fetch(data))
    else:
        dict_data = json.loads(data)
        if num == '2':
            insert(dict_data)
        elif num == '3':
            delete(dict_data)
        else:
            pass
    #data = "www.oldboy.org"
    #fetch(data)
    #data = '{"backend": "www.oldboy.com","record":{"server": "100.1.7.90","weight": 20,"maxconn": 31}}'
    #dict_data = json.loads(data)
    #add(dict_data)
    #remove(dict_data)