Python之备份文件

1. 需要支持完全和增量备份
2. 周一执行完全备份
3. 其他时间执行增量备份
4. 备份文件需要打包为tar文件并使用gzip格式压缩

from time import strftime
import os,tarfile,hashlib,pickle

def file_md5(path):
    if not path:
        return ''
    m = hashlib.md5()
    with open(path, 'rb') as fobj:
        while True:
            data = fobj.read(4096)
            if len(data) == 0:
                break
            m.update(data)
    hexStr = m.hexdigest()
    return hexStr

#完全备份
def full_backup(src,dst,md5file):
    #打压缩包
    fname =  '%s_full_%s.tar.gz' %(os.path.basename(src),strftime('%y%m%d'))
    fname = os.path.join(dst,fname)
    tar = tarfile.open(fname,'w:gz')
    tar.add(src)
    tar.close()
    #计算每个文件的md5值
    md5_dict = {}
    for path,folders,files in os.walk(src):
        for file in files:
            file_name = os.path.join(path,file)
            file_md5_str = file_md5(file_name)
            md5_dict[file_name] = file_md5_str
    with open(md5file,'wb') as fobj:
        pickle.dump(md5_dict,fobj)

#增量备份
def incr_backup(src,dst,md5file):
    fname = '%s_scr_%s.tar.gz' %(os.path.basename(src),strftime('%y%m%d'))
    fname = os.path.join(dst, fname)
    md5_dict = {}
    original_dict = {}
    with open(md5file,'rb') as fobj:
        original_dict = dict(pickle.load(fobj))
    change_files = []
    for path,folders,files in os.walk(src):
        for file in files:
            file_name = os.path.join(path,file)
            file_md5_str = file_md5(file_name)
            if original_dict.get(file_name) != file_md5_str:
                original_dict[file_name] = file_md5_str  #修改最新文件的md5值
                change_files.append(file_name)  #将变动文件添加到列表中
    if change_files:
        with open(md5file,'wb') as mobj:
            pickle.dump(original_dict,mobj)
        tar = tarfile.open(fname, 'w:gz')
        for i in change_files:
            tar.add(i)
        tar.close()

if __name__ == '__main__':
    src = '/my/tarDemo/security'
    dst = '/my/backup'
    md5file = '/my/backup/md5.data'
    if strftime('%a') == 'Mon':
        full_backup(src,dst,md5file)
    else:
        incr_backup(src,dst,md5file)