Ylan Segal

Per-Project Environment Variables

I wrote before about using foreman to manage you app’s processes. An additional feature is that it enables you to configure your unix environment when starting an app, by reading environment variables located in a .env file at the root of your project, that looks something like this:

.env
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MY_VARIABLE=/some/path
SECRET_STUFF=get_a_better_password

It is certainly a great feature for setting an common environment for processes that your start with foreman. However, processes that are started manually, like for example a rails console, don’t have this environment setup. Of course, you can always set them manually in your shell profile, but now they need to be maintained in two different places.

Adding to that problem, I have recently started working on a project that is split up into smaller sub-projects that are in different stages of development. They share some environment variables, which are common to the whole application, but vary during development between sub-projects. Since, I can’t be bothered to remember to change the variables each time I am about to work on a sub-project, I came up with a way to solve all my problems at once:

.profile
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# Overriding cd function. Looking for .env and sourcing it if found
function cd {
  builtin cd "$@"
  if [[ -f .env ]]; then
    echo "### Setting up environment variables from .env"
    cat .env | grep -v '#' | while read line; do
      echo $line
      export $line
    done
  fi
}

The code above lives inside my shell profile and basically overrides built-in cd function to source each non-comment line from the .env file (if found) after changing directories. This way, when I change into a sub-project directory my environment is setup for me, and variables are available to foreman and non-foreman processes alike.

Gotcha: Since it’s unlikely that you want to share the .env variables with other members of your team, I suggest adding an entry to your global gitignore file.