Note: I’ve had this post drafted for 3 YEARS!!! It’s finally time to publish it.

I like to mess with my dotfiles and every so often, I find out about a new way to do things and I spend more time than I should learning how to use it.

A few years ago I learned about includeIf for including specific files if some condition was met for git. The example that I first saw was doing:

[includeIf "gitdir:~/code/**"]
  path = ~/.config/git/personal
[includeIf "gitdir:~/work/**"]
  path = ~/.config/git/work

So that ~/.config/git/personal is only included for git directories under ~/code and ~/.config/git/work is only included for directories under ~/work. The contents of those included files varies but usually it contains your git identity, signing keys, etc. Here’s an example of what that could look like:

[user]
  name = benji
  email = benji@work.com
  signingkey = ~/.ssh/work.id_ed25519.pub

That works pretty well but I usually organize all my code in ~/workspace regardless of whether its personal, work-1, work-2, etc. I wanted to be able to configure git depending on where that repo actually lives instead of where the directory is in my machine. Then I found out about hasconfig:remote.*.url:!

This makes it so that I can configure git conditionally if the given remote URL exists for that directory I’m currently working in.

A few examples of what I do is:

[includeIf "hasconfig:remote.*.url:git@github.com:orgname/**"]
  path = ~/.config/git/config-gh-org

[includeIf "hasconfig:remote.*.url:git@github.com:*/**"]
  path = ~/.config/git/config-gh

[includeIf "hasconfig:remote.*.url:git@gitlab.com:*/**"]
  path = ~/.config/git/config-gl

[includeIf "hasconfig:remote.*.url:git@git.sr.ht:*/**"]
  path = ~/.config/git/config-srht

Now if I’m in a directory where the remote matches github.com:orgname/** it would use ~/.config/git/config-gh-org, otherwise it uses the general config file for any other GitHub repo.

While that handles git identities, I still need to configure SSH keys separately to be able to pull and push to remotes. The simple version of my ~/.ssh/config looks like this:

Host gitlab.com
Hostname gitlab.com
User git
IdentityFile ~/.ssh/gitlab.id_ed25519

Host github.com
Hostname github.com
User git
IdentityFile ~/.ssh/github.id_ed25519

The only problem with this is that in order to use a different IdentityFile for the same Hostname so that I could use a different key for repos under github.com/orgname, I’d have to use a different value for Host. So in my case I would add the following to my ~/.ssh/config:

Host gh-work
Hostname github.com
User git
IdentityFile ~/.ssh/work.id_ed25519

Finally, to use that Host when I’m looking for a repo in github.com/orgname, I would add the following to my git config:

[url "gh-work:orgname"]
  insteadOf = git@github.com:orgname

So when I clone, pull, or push a repo that’s under my work’s org account I can do:

git clone git@github.com:orgname/project

and insteadOf would replace github.com:orgname with gh-work:orgname so that it uses the right info from my SSH config. It’s a neat trick which I saw referenced in this article.

Are there any issues with this approach? Is there a better way to do this? I’m not sure so please let me know as I’d love to learn and I’ll update this post accordingly.

References