Quick Tip: Multiple User Configs with Git
On my personal laptop I often write code for multiple organizations as well as
my own personal projects. Being the git neat freak I am sometimes I prefer to
use different user configurations in git depending on what project I’m working
on (e.g., personal projects might use my email address here at
whereas non-personal projects might use a different email address). The
solution for a small number of projects is simple: just use
git config to set
local user configuration for a given repo. However, that breaks down very
easily. For instance, sometimes I would clone down a repo just to make a quick
change and I would forget to set local user configuration. A quick Google
search revealed that I’m not alone. What follows is my
solution to make using multiple users in git easy and convenient.
Authorship With Environment Variables
A look around the git docs shows that you can set the name and email for a commit through environment variables. For instance:
$ export GIT_AUTHOR_NAME="Foo Barrington" $ export GIT_AUTHOR_EMAIL="email@example.com" $ git commit -am "Foo" [master b51714c] Foo Author: Foo Barrington <firstname.lastname@example.org> 1 file changed, 21 insertions(+)
GIT_AUTHOR_EMAIL are now set for that shell session.
All commits until the shell exits will use the name
Foo Barrington and the
email@example.com for their user configuration. What we need is a way to
make sure we always have these variables set for a given set of projects.
direnv describes itself as an environment switcher for the shell. If you’ve
ever used tools like
rvm then you’re already familiar with the concept.
Essentially it lets you change your environment variables depending on what
your current working directory is. Unlike
rvm, it’s just a small, static
binary with no external dependencies and it is language-agnostic.
Part One: Installation and Setup
On macOS installation is simple enough with Homebrew:
$ brew install direnv
Installation for other platforms (or from source) is covered on the
You will also need to set it up to hook in to your shell. For
zsh, I have the
following in my
# Load direnv if hash direnv 2>/dev/null; then eval "$(direnv hook zsh)" fi
Because I use my dotfiles on multiple machines I check to make sure
direnv is installed before attempting to hook it into the shell.
Documentation for other shells is available on the
direnv website, though
it’s very similar.
Now that you have
direnv setup you can create
.envrc files that export
variables. For our purposes we can create a
.envrc file with the following
export GIT_AUTHOR_NAME="Foo Barrington" export GIT_AUTHOR_EMAIL="firstname.lastname@example.org"
Now whenever we change in to this directory, or any directory underneath this
directory, those environment variables will be set. Note that the first time
you encounter any given
direnv will ask you to whitelist the
direnv: error .envrc is blocked. Run `direnv allow` to approve its content.
This is a security feature. Essentially since
direnv is just executing
arbitrary code it wants to make sure that you are aware of what is going on in
your shell. That way if you clone down a project that contains a
you won’t just be blindly executing code whenever you enter the project.
Also note that when you enter a directory that contains a
.envrc file (or a
sub-directory as previously noted) you will get a little notice indicating that
you have new variables in your shell:
direnv: loading .envrc direnv: export +GIT_AUTHOR_EMAIL +GIT_AUTHOR_NAME
Let’s whitelist that
.envrc file, initialize a new git repository, and make
an initial commit:
$ direnv allow direnv: loading .envrc direnv: export +GIT_AUTHOR_EMAIL +GIT_AUTHOR_NAME $ git init foo Initialized empty Git repository in /Users/kpowers/Workspace/tmp/foo/.git/ $ cd foo $ echo "# foo" > README.md $ git add README.md $ git commit -m "Initial commit." [master (root-commit) 9a31ade] Initial commit. Author: Foo Barrington <email@example.com> 1 file changed, 1 insertion(+) create mode 100644 README.md
Looks like we’re in business!
Part Two: Workspace Structure
The a-ha moment is that the
.envrc file cascades to deeper directories. The
trick to get this working the way we want relies on structuring your workspace
in a certain way. In my home directory I have a workspace directory that looks
like the following:
workspace ├── git.my.org │ ├── .envrc # User configuration when I'm working on my.org. │ └── team │ ├── proj1 │ ├── proj2 │ └── proj3 └── github.com └── knpwrs ├── .envrc # User configuration when I'm working on my personal projects. ├── proj1 ├── proj2 └── proj3
Essentially I can set user configuration on a per-subtree basis rather than
a per-repo basis. It doesn’t matter where in the tree the
.envrc files are
located, as long as relevant projects are kept at the same level or lower in
the directory tree.
For the Gophers
If you are a Go developer you might already be using direnv to manage your
GOPATH. To implement what I am writing about here you would have a
.envrc in the root of your workspace for
GOPATH (and probably
that matter) and then you may want individual
.envrc files for packages or
. ├── .envrc # Go workspace configuration (GOPATH, etc). ├── bin ├── pkg └── src └── github.com ├── knpwrs │ ├── .envrc # Git user configuration for knpwrs. │ └── proj1 ├── mattn └── nsf
But there’s a problem! By default
direnv will only use the closest
file. What we want is to combine the root
.envrc with the project or
.envrc so we can have our
PATH correct but still
have granual authorship configuration. Fortunately,
direnv has a mechanism
source_up export GIT_AUTHOR_NAME="Foo Barrington" export GIT_AUTHOR_EMAIL="firstname.lastname@example.org"
source_up is a command in
direnv-stdlib which looks for
.envrc files in
parent directories. Now whenever I am working inside of
I will be known as
Foo Barrington <email@example.com> and my
PATH variables will be properly set up. Sweet!
My Original (Failed) Idea
I thought that
.gitconfig might be able to cascade much like
does inside a repo (or rather, I was hoping it would scan up through the
directory tree and apply settings from any
.gitconfig files it finds, much
direnv). Essentially instead of creating
files I would create
.gitconfig files. Unfortunately git doesn’t work this
way. It checks for config in three places:
$(prefix)/etc/gitconfig. For more information, see
The problem may seem a little convoluted at first (I was internally debating
whether or not to even write this) but the existence of that Stack Overflow
thread shows that I’m not alone in my desire for easily switching user
configuration in git. Unfortunately my original idea of just using
files didn’t work and so I had to introduce an external tool to solve the
problem. That said,
direnv is very useful on its own outside of this
context anyway (like for
GOPATH), so I’m happy to have it installed.