The problem

Calibre is a ebook manager that is available in debian. I use it to maintain my library, but also to dowload every day an epub version of a French newspaper and then put it on my kobo.

Configuring git annex for this

I wanted to use git-annex, so

$ git init
$ git annex init "some useful name"

But I don't want every thing in annex, because Calibre use some text file to save some metadata, so I used:

$ git config annex.largefiles "include=* exclude=*.opf exclude=*.json"

then lets add everything

$ git annex add *
$ git add *
$ git commit -m "first commit"

Calibre need read and write access on the its database, so let unlock it:

$ git annex unlock metadata.db

On my other computer I only need to do

$ git clone $user@$host:Calibre\ library
$ cd Calibre\ library
$ git annex init "another useful name"
$ git annex get .
$ git annex unlock metadata.db

The problem is that every time you will git annex sync, git annex will lock again the metadata.db, so lets unlock it automatically. I use git hooks, in .git/hooks/post-commit I have


git annex edit metadata.db

don't forget to make this file executable

$ chmod a+x .git/hooks/post-commit

Day to day operation

$ git annex add .

Will put new file into the annex

$ git add .

Will take care of the files that should no go into annex

$ git annex sync

Will make the repositories exchange informations about all this, and make remote change local

$ git annex get .

Will make remote book locally available

Merge conflict

You should not run calibre on the two computer simultaneously, or without syncing before it. If you do, you will have a conflict that git-annex will automatically solve by rename both of the file.

You can then either:

  • Choose one. If no books have been changed or added on one of the computer, to use the other metadata.db will not make you loose any information
  • rebuild it. calibredb restore_database won't do it, but will tell you how to do it.

Checking the library

You can use calibredb check_library to check you library is correct. If you use git for it, it will always tell you that it is not correct: there is this author ".git" it doesn't know about. Just don't care about it.

Maybe this can be solved by using vcsh but apparently vcsh+git annex it not well tested yet.

Automatic stuff

I use mr to automatically run all this, but some config could be done (I believe) to have git annex copy --auto do what it should.

There are also the git annex assistant for this kind of automatic synchronizations of contents, but I don't know if my automatic unlocking of one file will break this.

It might be interesting to find someway to unlock and lock the library only when running calibre, a simple script to launch calibre will do that. Note that each time you will lock and unlock, you will have a new commit in git.