Dumbattr is a layer on top of xattr. As well as saving and loading xattr-based metadata, it maintains the same information in the least clever way possible: a directory-level JSON file. If for some reason you lose your xattrs (via a backup roundtrip, or a copy program that doesn't respect xattrs), the next time you use dumbattr to load a file's metadata (for any file in that directory), it'll repopulate all missing xattr data as long as you've copied whole directory.

Dumbattr only supports user-level data (i.e xattrs that start with "user."). You do not need to specify this in your attribute names, it is implied. That is:

>>> import dumbattr
>>> dumbattr.set("/path/to/file", "attr_name", "attr_value")

Will set the underlying xattr key "user.attr_name" to "attr_value".

As well as being a python library, dumbattr is a runnable program (via the ZeroInstall feed). It has a few sub-commands:

• ls: show the user attributes on a file or files
• set / get: query / modify a specific key of a file or files
• fix: recursively scan a location for discrepencies between xattr / JSON metadata, and update the results (by setting xattrs, updating the JSON serialization, or both). You should definitely run this after restoring files from a backup system that does not preserve xattr data, for example.

Run it with --help for the full rundown.

• Persisted metadata takes precedence. If you have set the same key on a file using both plain xattr and dumbattr, dumbattr attributes will take priority when you read the file (and will overwrite the plain xattr accordingly. This only applies to conflicting keys for the one file - i.e it won't touch plain xattrs under a different key for that same file.

• Obviously, the restore from lost xattrs only works on a per-directory level. If you move just one file and not its containing directory and simultaneously strip its xattr data, then dumbattr can't help you there.