Sigmonsay

Something that is always annoying to me is the setup, scripting and management of keeping a hosts files and scripts in a safe place. Well i’ve made various reincarnations of various scripts that attempt to do this. I’ll ommit the history here but wanted to drop a quick note of a drop dead simple solution that has worked pretty well for me.

drop the contents below into Makefile and git init it.

.PHONY: backup

all:
 @echo try 'make backup' or 'make restore'

backup:
 @echo backup file from system started
 rsync -arv --files-from manifest.txt / backup/
 python filemeta.py backup -P backup/
restore:
 @echo restore file to system started
 rsync -arv --files-from manifest.txt backup/ /
 python filemeta.py restore

Since git does not preserve file mode and permission I hacked up a quick script to handle backup and restore of the key file meta data (mode and ownership). Save the contents here as filemeta.py

import sys, os, stat
from optparse import OptionParser

_, cmd = sys.argv.pop(0), sys.argv.pop(0)

parser = OptionParser()
parser.add_option("-c", "--config", dest="config", help="config file", metavar="FILE", default=None)
parser.add_option("-v", "--verbose", dest="verbose", action="store_true", default=False)

parser.add_option("-f", "--file-meta", dest="file_meta", default="./file.meta", help="store file meta data path [%default]")
parser.add_option("-P", "--path", dest="path", default=".", help="path to scan [%default]")

if cmd == 'backup':
   (options, args) = parser.parse_args(sys.argv)
   path = os.path.realpath(options.path)
   file_meta = os.path.realpath(options.file_meta)
   file_meta_tmp = file_meta + ".tmp"

   fh = open(file_meta_tmp, "w+")
   for dirpath, dirnames, filenames in os.walk(path):

      st = os.stat(dirpath)
      fh.write("%d %d %d %s\n" % (st.st_mode, st.st_uid, st.st_gid, dirpath))

      for filename in filenames:
         fullpath = os.path.join(dirpath, filename)
         st = os.stat(fullpath)
         abspath = fullpath.replace(path, '')
         fh.write("%d %d %d %s\n" % (st.st_mode, st.st_uid, st.st_gid, abspath))

   fh.close()
   os.rename(file_meta_tmp, file_meta)
   print "Created", file_meta

elif cmd == 'restore':
   (options, args) = parser.parse_args(sys.argv)
   path = os.path.realpath(options.path)
   file_meta = os.path.realpath(options.file_meta)

   for line in file(file_meta):
      st_mode, st_uid, st_gid, abspath = line.split(None, 3)
      st_mode, st_uid, st_gid = int(st_mode), int(st_uid), int(st_gid)
      abspath = abspath.strip()

      if stat.S_ISDIR(st_mode) or stat.S_ISREG(st_mode):
         os.chmod(abspath, st_mode)
         os.chown(abspath, st_uid, st_gid)
      else:
         continue

else:
   raise Exception("invalid command: %s" % (cmd))

Now all you have to do is place the filenames to backup (files or directories) in manifest.txt and run ‘sudo make backup’ or ‘sudo make restore’. git commit or add backup/* and push it off to a origin of your choice. This is nothing that complex but the simple approach to this has made box recovery and migration a breeze. Lots of times you want to track something but don’t have a good place to put it. This is that place. all of those pesky $HOME/.bash_profile files are now in one place and can easily be fetched from a single location. I’ll leave branching and cherry picking to the reader.

Written by sig

May 23rd, 2011 at 1:26 am

Posted in Uncategorized