Python 实现文件的全备份和差异备份详解_Python

Python 实现文件的全备份和差异备份详解

2020-09-15 13:38Python教程网 Python

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Python实现文件的全备份和差异备份

之前有写利用md5方式来做差异备份，但是这种md5方式来写存在以下问题：

md5sum获取有些软连接的MD5值存在问题
不支持对空目录进行备份，因为md5sum无法获取空目录的md5值
权限的修改md5sum无法判断

解决方案：

利用文件的mtime ctime

mtime（Modified time）是在写入文件时随文件内容的更改而更改的

ctime（Create time）是在写入文件、更改所有者、权限或链接设置时随Inode的内容更改而更改的

废话不多说直接上代码：

									#!/usr/bin/env python

									import time,os,sys,cPickle

									fileInfo = {}

									def logger(time,fileName,status,fileNum):

									  f = open('backup.log','a')

									  f.write("%s\t%s\t%s\t\t%s\n" % (time,fileName,status,fileNum))

									def tar(sDir,dDir,fileNum):

									  command = "tar zcf %s %s >/dev/null 2>&1" % (dDir + ".tar.gz",sDir)

									  if os.system(command) == 0:

									    logger(time.strftime('%F %X'),dDir + ".tar.gz",'success',fileNum)

									  else:

									    logger(time.strftime('%F %X'),dDir + ".tar.gz",'failed',fileNum)

									def fullBak(path):

									  fileNum = 0

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

									    for name in files:

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

									      mtime = os.path.getmtime(file)

									      ctime = os.path.getctime(file)

									      fileInfo[file] = (mtime,ctime)

									      fileNum += 1

									  f = open(P,'w')

									  cPickle.dump(fileInfo,f)

									  f.close()

									  tar(S,D,fileNum)

									def diffBak(path):

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

									    for name in files:

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

									      mtime = os.path.getmtime(file)

									      ctime = os.path.getctime(file)

									      fileInfo[file] = (mtime,ctime)

									  if os.path.isfile(P) == 0:

									    f = open(P,'w')

									    f.close()

									  if os.stat(P).st_size == 0:

									    f = open(P,'w')

									    cPickle.dump(fileInfo,f)

									    fileNum = len(fileInfo.keys())

									    f.close()

									    print fileNum

									    tar(S,D,fileNum)

									  else:

									    f = open(P)

									    old_fileInfo = cPickle.load(f)

									    f.close()

									    difference = dict(set(fileInfo.items())^set(old_fileInfo.items()))

									    fileNum = len(difference)

									    print fileNum

									    difference_file = ' '.join(difference.keys())

									    print difference_file

									    tar(difference_file,D,fileNum)

									    f = open(P,'w')

									    cPickle.dump(fileInfo,f)

									    f.close()

									def Usage():

									  print '''

									    Syntax: python file_bakcup.py pickle_file model source_dir filename_bk

									      model: 1:Full backup 2:Differential backup

									    example: python file_backup.py fileinfo.pk 2 /etc etc_$(date +%F)

									      explain: Automatically add '.tar.gz' suffix

									  '''

									  sys.exit()

									if len(sys.argv) != 5:

									  Usage()

									P = sys.argv[1]

									M = int(sys.argv[2])

									S = sys.argv[3]

									D = sys.argv[4]

									if M == 1:

									  fullBak(S)

									elif M == 2:

									  diffBak(S)

									else:

									  print "\033[;31mDoes not support this mode\033[0m"

									  Usage()

测试：

									$ python file_backup.py data.pk 1 data data_$(date +%F) #全备份

									$ > data/www.linuxeye.com #测试创建文件，修改文件权限

									$ chmod 777 data/py/eshop_bk/data.db

									$ python file_backup.py data.pk 2 data data_$(date +%F)_1 #备份改变的文件

									2

									data/py/eshop_bk/data.db data/www.linuxeye.com