How to specify a particular SSH key on a per-JJ repo basis?

[xpe]

I'm familiar with the usual recommendations to use ~/.ssh/config and setup different hosts with different SSH keys.

But there appear to a be a lot of interesting ways to do this with Git. I'm not sure which (if any) work with Jujutsu -- in particular, non-colocated JJ repos.

See also: https://stackoverflow.com/questions/3225862/multiple-github-accounts-ssh-config

[ilyagr]

You could try something like this if you really want to:

https://stackoverflow.com/a/79696990 (from https://stackoverflow.com/questions/79144586/how-to-match-ssh-config-based-on-directory-path)

Even in a non-colocated repo, jj will shell out to git, which will shell out to ssh, so it should work (if you are curious, jj git push --debug will show you the git command that's being executed; you could also try GIT_SSH_COMMAND='ssh -v' jj git push --debug.

This is not really a recommendation, only try this if it seems fun. I haven't tested it, and there will likely be rough edges to figure out. For example it may not work correctly in a workspace and it will not work correctly with jj -R path/to/repo since it's the current dir that matters rather than the repo dir. You could change the Match exec command to ask jj for the repo dir, maybe -- I forget if this is implemented in jj -- but then make sure to add --ignore-working-copy, and be aware that all uses of ssh will be slowed down by waiting for the jj binary to be invoked.

If somebody can think of a better way, that could be more useful.

[xpe]

Thanks for taking a look and offering some ideas.

[xpe]

Here is what worked for me:

# ~/.ssh/config
Host gitlab-bigfoot
  Hostname gitlab.com
  User git   # convenient, used below...
  IdentityFile ~/.ssh/id_bigfoot_gitlab_ed25519
  IdentitiesOnly yes    # often recommended in this situation
  AddKeysToAgent yes    # might be macOS specific
  UseKeychain yes    # macOS specific

This works because Host maps to Hostname. When adding a Git remote to JJ use e.g.:

jj git remote add origin gitlab-bigfoot:forest/lurking.git