#!/usr/bin/env python
import time
import os
import cPickle as p
import tarfile
import hashlib
baseDir = '/root/backup'
srcDir = 'src'
dstDir = 'dst'
fullName = "full_%s_%s.tar.gz" % (srcDir, time.strftime('%Y%m%d'))
incrName = "incr_%s_%s.tar.gz" % (srcDir, time.strftime('%Y%m%d'))
md5file = 'md5.data'
def md5sum(fname):
 m = hashlib.md5()
 with file(fname) as f:
  while True:
   data = f.read(4096)
   if len(data) == 0:
    break
   m.update(data)
 return m.hexdigest()
def fullBackup():
 md5Dict = {}
 fileList = os.listdir(os.path.join(baseDir,srcDir))
 for eachFile in fileList:
  md5Dict[eachFile] = md5sum(os.path.join(baseDir,srcDir,eachFile))
 with file(os.path.join(baseDir,dstDir,md5file),'w') as f:
  p.dump(md5Dict,f)
 tar = tarfile.open(os.path.join(baseDir,dstDir,fullName),'w:gz')
 os.chdir(baseDir)
 tar.add(srcDir)
 tar.close()
def incrBackup():
 newmd5 = {}
 fileList = os.listdir(os.path.join(baseDir,srcDir))
 for eachFile in fileList:
  newmd5[eachFile] = md5sum(os.path.join(baseDir,srcDir,eachFile))
 with file(os.path.join(baseDir,dstDir,md5file)) as f:
  storedmd5 = p.load(f)
 tar = tarfile.open(os.path.join(baseDir,dstDir,incrName),'w:gz')
 os.chdir(baseDir)
 for eachKey in newmd5:
  if (eachKey not in storedmd5) or (newmd5[eachKey] != storedmd5[eachKey]):
   tar.add(os.path.join(srcDir,eachKey))
 tar.close()
 with file(os.path.join(baseDir,dstDir,md5file),'w') as f:
  p.dump(newmd5,f)
def main():
 if time.strftime('%a') == 'Mon':
  fullBackup()
 else:
  incrBackup()
if __name__ == '__main__':
 main()
~