[[!comment format=mdwn
 username="http://olivier.mehani.name/"
 nickname="olivier-mehani"
 subject="Manual solution"
 date="2014-06-14T13:59:38Z"
 content="""
My problem stems from the fact that I manually git clone the git-annex repo, which prevents the assistant from creating the setup to use passwordless keys. I just reverse-engineered a working setup to work up what I was missing. I jot it down here for reference, but I guess the bottomline is that if you want to use the assistant with a repo, do it from the start.

I assume that the client has a clone of the git(-annex) repo of the server.

    client$ git clone server:annex

Our goal is to let git-annex on the client know that there is a specific key to use when connecting to server that will let it access the git-annex-shell (without a password). We first create the key.

    client:~$ ssh-keygen -t rsa -f ~/.ssh/git-annex/key.git-annex-server-user_annex
    [enter an empty passphrase]

We can then create a virtual SSH host on the client that will use this key to connect to the server, in client:~/.ssh/config:

    # Added manually for git-annex
    Host git-annex-server-user_annex
    	Hostname server
    	Port 22
    	IdentityFile ~/.ssh/git-annex/key.git-annex-server-user_annex
    	IdentitiesOnly yes
    	StrictHostKeyChecking yes

(git-annex seems to use .2F (%2F) to encode path separators in the filenames.)

The server then needs to know to let the key in, but only for git-annex in the specific folder. This is done in server:.ssh/authorized_keys:

    command=\"GIT_ANNEX_SHELL_DIRECTORY='annex' ~/.ssh/git-annex-shell\",no-agent-forwarding,no-port-forwarding,no-X11-forwarding,no-pty ssh-rsa AAAA... user@client

The bit starting with ssh-rsa is the public key created in client:.ssh/git-annex/key.git-annex-server-user_annex.pub at the same time as the private key.

Finally, all that remains is to change the remote in the client clone to use the virtual SSH host.

    client:~/annex $ git remote set-url origin ssh://user@git-annex-server-user_annex/~/annex
    client:~/annex $ git remote set-url origin --push ssh://user@git-annex-server-user_annex/~/annex

If everything worked, a sync from the client should now work without asking for a password, and starting the assistant will not either.

"""]]
