Therry

My personal space on the www.

Different Git configuration per directory

Mon 31 October 2022

Article is updated at 2023-02-14

I have multiple accounts for GitLab and Github. The reason for this is that I work for multiple companies and they require me to use a unique email address and account for those services.

In some cases I perform the development on the same device. So I need to make sure that I perform my work with the correct account details and SSH credentials.

Also I want to be able to push work to my personal accounts from the work device. So in that case I need a similar setup.

By setting up my SSH and Git config in a specific way I can commit with the correct details and authenticate using the required keys.

The following examples are using GitLab, but you can alter the examples to your needs.

Gitconfig

Using a .gitconfigfile I can control how Git behaves. In my root I a gitconfig like this:

user@computer:~$ cat ~/.gitconfig
[user]
    email = user@domain.nl
    name = Therry van Neerven

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

This config does two things:

  1. It sets a default user setting
  2. When I'm in a git directory which starts with ~/Projects/company it loads ~/Projects/company/.gitconfig

The second gitconfig loads specific data for the project of the company:

user@computer:~$ cat ~/Projects/company/.gitconfig
[user]
    email = user@company.com
    name = Therry van Neerven

[core]
    sshCommand=ssh -i ~/.ssh/id_ed25519.company -F /dev/null

The user key overrides the previous user key and now my commits are using the company email. Also the sshCommand is overriden, it now uses the specific key that is registered in the GitLab account.

In this way I always commit with the correct email address, and push my changes with the correct ssh key.

SSH config (Old approach)

The approach below is an older alternative to defining the sshCommand in the .gitconfig file. You can use it as a replacement of the sshCommand, in case you are running a git version older than 2.10.0.

When pulling and pushing code I also need to make sure that I use the right SSH keys. This is done using a SSH config like this:

user@computer:~$ cat ~/.ssh/config
Host gitlab.com
     IdentityFile ~/.ssh/id_rsa

Host gitlab.company.com
     IdentityFile ~/.ssh/id_rsa.company

The first item picks the standard private for communication with GitLab. The second item matches a different private key with the domain of the GitLab instance of the company.

I also use a variant which allows me to use different keys for the same domain:

user@computer:~$ cat ~/.ssh/config
Host personal-gitlab
   Hostname gitlab.com
   IdentityFile ~/.ssh/id_rsa

Host company-gitlab
   Hostname gitlab.com
   IdentityFile ~/.ssh/id_rsa

In this case I need to change the repository url a little bit by swapping the hostname.

So git@gitlab.com:user/repo.git becomes git@company-gitlab:user/repo.git in case I want to use the personal SSH key for communication.

Resources

SSH config