git-annex/doc/todo/automatic_bookkeeping_watch_command.mdwn

A "git annex watch" command would help make git-annex usable by users who
don't know how to use git, or don't want to bother typing the git commands. 
It would run, in the background, watching via inotify for changes, and
automatically annexing new files, etc.

The blue sky goal would be something automated like dropbox, except fully
distributed. All files put into the repository would propagate out
to all the other clones of it, as network links allow. Note that while
dropbox allows modifying files, git-annex freezes them upon creation,
so this would not be 100% equivalent to dropbox. --[[Joey]]

----

There is a `watch` branch in git that adds such a command, although currently
it only handles adding new files, and nothing else. To make this really
useful, it needs to:

- notice deleted files and stage the deletion
  (tricky; there's a race with add..)
- notice renamed files, auto-fix the symlink, and stage the new file location
- periodically auto-commit staged changes
- honor .gitignore, not adding files it excludes
    
Also nice to have would be:
    
- Somehow sync remotes, possibly using a push sync like dvcs-autosync
  does, so they are immediately updated.
- Somehow get content that is unavailable. This is problematic with inotify,
  since we only get an event once the user has tried (and failed) to read
  from the file. Perhaps instead, automatically copy content that is added
  out to remotes, with the goal of all repos eventually getting a copy,
  if df allows.
- Drop files that have not been used lately, or meet some other criteria
  (as long as there's a copy elsewhere).
- Perhaps automatically dropunused files that have been deleted,
  although I cannot see a way to do that, since by the time the inotify
  deletion event arrives, the file is deleted, and we cannot see what
  its symlink pointed to! Alternatively, perhaps automatically
  do an expensive unused/dropunused cleanup process.
- Support OSes other than Linux; it only uses inotify currently.