Different Git configuration per directory

Mon 31 October 2022

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:

It sets a default user setting
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

The user key overrides the previous user key and now my commits are using the company email.

In this way I always commit with the correct email address.

SSH config

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