编写一个备份程序需要考虑多个方面，包括备份类型（完全备份和增量备份）、文件校验（如MD5值）、备份存储位置、备份时间戳、以及备份过程的异常处理等。以下是一个简单的Python备份程序示例，它实现了完全备份和增量备份，并包含了文件MD5值的校验：

```python

import os

import hashlib

import tarfile

import shutil

from datetime import datetime

def check_md5(fname):

"""计算文件的MD5值"""

m = hashlib.md5()

with open(fname, 'rb') as fobj:

while True:

data = fobj.read(4096)

if not data:

break

m.update(data)

return m.hexdigest()

def full_backup(src_dir, dst_dir, md5file):

"""执行完全备份，并更新MD5值文件"""

fname = os.path.basename(src_dir.rstrip(' / '))

backup_filename = f'{fname}_full_{datetime.now().strftime("%Y%m%d")}.tar.gz'

backup_path = os.path.join(dst_dir, backup_filename)

md5dict = {}

创建tar包

with tarfile.open(backup_path, 'w:gz') as tar:

tar.add(src_dir, arcname=fname)

计算源目录下所有文件的MD5值

for root, dirs, files in os.walk(src_dir):

for file in files:

file_path = os.path.join(root, file)

md5dict[file_path] = check_md5(file_path)

将MD5值写入文件

with open(md5file, 'w') as md5file:

for file_path, md5 in md5dict.items():

md5file.write(f'{file_path}:{md5}\n')

def incremental_backup(src_dir, dst_dir, last_backup_file):

"""执行增量备份，只备份变化的文件"""

last_backup_md5 = {}

if os.path.exists(last_backup_file):

with open(last_backup_file, 'r') as f:

for line in f:

path, md5 = line.strip().split(':')

last_backup_md5[path] = md5

获取当前时间，用作备份文件夹名

current_time = datetime.now().strftime("%Y%m%d_%H%M%S")

backup_path = os.path.join(dst_dir, f'backup_{current_time}')

os.makedirs(backup_path, exist_ok=True)

遍历源目录，只备份变化或新增的文件

for root, dirs, files in os.walk(src_dir):

for file in files:

file_path = os.path.join(root, file)

if file_path not in last_backup_md5 or last_backup_md5[file_path] != check_md5(file_path):

复制文件到备份目录

shutil.copy2(file_path, backup_path)

更新MD5值

last_backup_md5[file_path] = check_md5(file_path)

将最新的MD5值写入文件

with open(last_backup_file, 'w') as md5file:

for file_path, md5 in last_backup_md5.items():

md5file.write(f'{file_path}:{md5}\n')

示例使用

if __name__ == "__main__":

source_directory = '/path/to/source'

destination_directory = '/path/to/destination'

full_backup_file = '/path/to/last_full_backup.md5'

incremental_backup_file = '/path/to/last_incremental_backup.md5'

执行完全备份

full_backup(source_directory, destination_directory, full_backup_file)

执行增量备份

incremental_backup(source_directory, destination_directory, incremental_backup_file)

```

备份程序说明

完全备份 （`full_backup`）:

打包源目录下的所有内容