btrfs-snapshots-diff.py is a simple Python3 script that displays the differences between two Btrfs snapshots (from the same subvolume obviously).

Uses btrfs send --no-data to compute the differences, decodes the stream and displays the differences.

   usage: btrfs-snapshots-diff.py [options] -p PARENT -c CHILD
          btrfs-snapshots-diff.py [options] -f FILE

   Display differences between 2 Btrfs snapshots

   optional arguments:
     -h, --help            Show this help message and exit
     -p, --parent PATH     Path to PARENT (older) snapshot (must be readonly)
     -c, --child PATH      Path to CHILD (newer) snapshot 
     -f, --file FILE       Path to diff file generated by 
                           "btrfs send --no-data -p first second > FILE"
     -t, --filter          Do not display temporary files or any time modifications (just latest)
     -a, --by_path         Group commands by path
     -s, --csv             CSV output
     -j, --json            JSON output (commands only)
     -b, --bogus           Add bogus renamed_from action (used only when grouping by path)

• --json (-j), available for commands only, will output a list of commands in JSON format.

• --csv (-s) will produce on line for each modification, instead of formatted output: the first column is the path, then each action taken on the file is in a new column. Separator is ";".

• --by_path (-a) groups command by path, giving a better view of what happenned on the file system.

• --bogus (-b) adds a bogus command to the stream, to better track renaming of files / dir (only usefull with --by_path).

• With option --filter (-t), the script tries to be a bit smarter (only usefull with --by_path):

  • it does not display temporary files created by send stream,
  • it displays 'created' or 'rewritten' on the files renamed from temporary files,
  • it displays only the latest time modifications, if there are two or more.

See ./example.output file as the example of actions made by ./create-example.sh:

touch file
mkdir dir
mkfifo fifo
ln file hardlink
ln -s file symlink
echo 'Hello Btrfs' > 'xxx;yyy;zzz'
mv file file2

Verify all tests by running:

./test.sh

No requirements besides Python-3 (>=3.6) and btrfs command obviously.

There are probably bugs, though it works for me on my own snapshots.

GPL v2, see LICENSE file.

Made in beautiful Tahiti (French Polynesia) by SysNux.

Copyright (c) 2016 Jean-Denis Girard [email protected]