Python recursive functions and examples

This article mainly introduces the Python file full backup and differential backup details, for more information about how to implement full backup and differential backup of Python files, see the following article.

Python implements full backup and differential backup of files

Previously, the md5 mode was used for differential backup, but the md5 mode has the following problems:

• An error occurred while obtaining the MD5 value of some soft connections by using md5sum.

• Empty directory backup is not supported because md5sum cannot obtain the md5 value of the empty directory

• Permission modification md5sum cannot be judged
  

Solution:

Use the mtime ctime of the file

Mtime (Modified time) is changed as the file content changes when the file is written.

Ctime (Create time) is changed as Inode content changes when the file is written, the owner, permission, or link settings are changed.

Let's talk a little bit about the code:

#!/usr/bin/env pythonimport time,os,sys,cPicklefileInfo = {}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()

Test:

$ Python file_backup.py data. pk 1 data _ $ (date + % F) # full backup $> data/www.linuxeye.com # test file creation and modify file permissions $ chmod 777 data/py/eshop_bk/data. db $ python file_backup.py data. pk 2 data _ $ (date + % F) _ 1 # back up the changed File 2 data/py/eshop_bk/data. db data/www.linuxeye.com

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