direnv with python

What is direnv

direnv is a tool that allows you to change your environment based on the configuration in that folder.

e.g. You can set different environment variables for different folders.

The reason I revisited direnv is because for python project, we need to switch to different virtual environment each time we change a project.

Wouldn’t it be nice if correct virtual environment was activated when you change to that directory

and unload everything to the way it was, when you switch away

How to use it with python project ?

Option 1 ¹

Create following in ~/.config/direnv/direnvrc

activate_virtualenv() {
  export VIRTUAL_ENV=$1
  PATH_add "$VIRTUAL_ENV/bin"
}

Then, in the .envrc of that folder, add activate_virtualenv path/to/virtualenv

Option 2 ²

Other option is to add just single line layout python3 to your .envrc This automatically creates and activates .direnv/python-$python-version

If you want to control the name and location of your virtual environment then your .envrc should have the following

export VIRTUAL_ENV="my_venv"
layout python3

In both scenario, you’ll need to type direnv allow on the terminal the first time. Otherwise, contents of .envrc will not be executed.

Go through the README to learn more about this amazing tool.