应用场景：ini类型配置文件由于升级改动了，我想看看升级后的配置文件相对于之前的改动了哪些配置项
ini类型的配置文件的特点：
就像这样子：
[isamchk]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M
[myity]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M
每个配置块内容前有一个[xxx]的section
现在我们要对比的是升级后改动的配置文件相对于升级前哪些section中改了哪些配置，是
新增的，还是值更新了
这里面用Python解决的难点，一个是每个section要和下面的配置项进行绑定，第二个问题是对比配置的不同，可以提取旧文件的key存起来，再通过遍历新文件中的键是不是在旧文件的key中
以下是实现的代码：

import re
import sys
def data_block(file_stream):
    flag = False
    for line in file_stream:
        line = line.strip()
        if line.startswith('[') and line.endswith("]"):

            if flag:
                yield var
            line_list = []
            line_list.append(("tag",line))
        elif line == "":
            continue
        else:
            line = line.split("=",1)
            line = tuple(line)
            line_list.append(line)
            var = dict(line_list)
            flag = True
    yield var

def line_count(keywords, filename):
    """
    :param keywords: 对比旧文件，在新文件中改变值的键名或新增的键
    :return: 返回键所在的行号
    ：filename 文件名称
    """
    with open(filename) as fp:
        for index, line in enumerate(fp):
            if keywords in line:
                return index+1

def compare_config(dict1, dict2):
    """
    遍历新文件中的每个键是否在旧文件中存在，如果存在，则比较值是否相同，不相同则打印配置更新，和所在的位置
    否则视为在新文件中新增的项
    :return:
    """
    for k2 in dict2.keys():
        k1 = list(dict1.keys())
        if k2 in k1:
            if dict2[k2] != dict1[k2]:
                count = line_count(dict2['tag'], file2)
                print("%s中配置项值更新：%s=%s-->%s=%s,位置在第%s行" %(dict2['tag'], k2, dict1[k2],k2, dict2[k2], count))
        else:
            count = line_count(k2,file2)
            print("%s中新增配置项：%s=%s,位置在第%s行" %(dict2['tag'], k2, dict2[k2], count))

    # 新文件中删除了哪些项，在旧文件中有，在新文件中没有的项
    set1 = set(dict1.keys())
    set2 = set(dict2.keys())
    deleteKeys = set1 - set2
    for k1 in deleteKeys:
        count = line_count(dict1['tag'], file1)
        print("新文件%s中删除了配置：%s=%s，位置在旧文件中的第%s行" %(dict2['tag'], k1, dict1[k1],count))

def delete_config(dict1_tag, dict2_tag, data_list1):
    delete_section = set(dict1_tag) - set(dict2_tag)
    for dict1 in data_list1:
        if dict1['tag'] in delete_section:
            count = line_count(dict1['tag'], file1)
            print("新文件中已经删除了配置%s，位置在旧文件中的第%s行" %(dict1['tag'],count))
            dict1.pop("tag")
            for k1,v1 in dict1.items():
                print(k1 + " = " + v1)

if __name__ == '__main__':

    try:
        file1 = sys.argv[1]
        file2 = sys.argv[2]
    except:
        print("userage:xxx.py oldfile newfile")
        sys.exit(1)
    fp1 = open(file1, 'r')
    fp2 = open(file2, 'r')

    data_list1 = []
    a1 = data_block(fp1)
    for i in a1:
        data_list1.append(i)

    data_list2 = []

    a2 = data_block(fp2)
    for i in a2:
        data_list2.append(i)

    dict1_tag = []
    for dict1 in data_list1:
        dict1_tag.append(dict1['tag'])

    dict2_tag = []
    for dict2 in data_list2:
        dict2_tag.append(dict2['tag'])

    for dict2 in data_list2:
        if dict2['tag'] in dict1_tag:
            for dict1 in data_list1:
                if dict1['tag'] == dict2['tag']:
                    """dict1,dict2是键值对字典"""
                    compare_config(dict1, dict2)

        else:
            print("新文件中新增%s配置,配置项如下：" % dict2["tag"])
            dict2.pop("tag")
            for k2,v2 in dict2.items():
                print(k2 + " = " + v2)
    delete_config(dict1_tag, dict2_tag, data_list1)

    fp1.close()
    fp2.close()

测试：
1.准备两个配置文件，新文件中有的配置删了，有的是新增的
config1.ini:
[isamchk]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[sfsdamchk]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[myisamchk]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M
[myity]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M
config2.ini:
[isamchk]

sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M
hello = world
[sfsdamchk]

sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[myity]
key_buffer = 1288M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M
[myity2]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

[myisamchk]
key_buffer = 128M
sort_buffer_size = 128M
read_buffer = 2M
write_buffer = 2M

python compare-config2.py config1.ini config2.ini

2. 输出结果：
   [isamchk]中新增配置项：hello=world,位置在第6行
   新文件[isamchk]中删除了以下配置：key_buffer=128M，位置在旧文件中的第2行
   新文件[sfsdamchk]中删除了以下配置：key_buffer=128M，位置在旧文件中的第2行
   [myity]配置项值更新：key_buffer=128M-->key_buffer=1288M,位置在第15行
   新文件中新增[myity2]配置,配置项如下：
   key_buffer = 128M
   sort_buffer_size = 128M
   read_buffer = 2M
   write_buffer = 2M