Automagic ssh authentication for multiple github accounts

posted 2024-06-11 (updated 2025-04-11)

At $work we have multiple github organizations, some of which are associated with my personal github account, and one of which is an enterprise thing that can't share accounts.

~/.ssh/config: setup different Host entries with different keys for each github account

Host github.com
    IdentityFile ~/.ssh/github_ed25519
Host github.com-$enterprise
    Hostname github.com
    IdentityFile ~/.ssh/github_$enterprise_ed25519

~/.gitconfig: The big thing is to rewrite remote URLs to match the different Host entries in your ~/.ssh/config

[url "git@github.com-$enterprise:$enterpriseOrg/"]
    insteadOf = git@github.com:$enterpriseOrg/
    insteadOf = https://github.com/$enterpriseOrg/
    insteadOf = ssh://git@github.com/$enterpriseOrg/

This will also handle if you clone via https

The last one ist caused by pip stuff, I think it's safe?

per-directory git configuration

One neat feature git has is the ability to include a different config based on what directory it's in, so you can get different config based on where a repo is located on your computer

[includeIf "gitdir:~/work/"]
    path = ~/work/.gitconfig