Automatically Activating a Virtual Environment with direnv

When working with Python projects, activating a virtual environment (venv) manually every time you switch to a project directory can be tedious. Fortunately, direnv provides a way to automate this process.

Automatically Activating a Virtual Environment

When navigating to a project’s root directory, you likely want the associated virtual environment to activate automatically. A common approach is using direnv with a .envrc file:

source .venv/bin/activate

With this setup, direnv loads the virtual environment when you enter the directory and unloads it when you leave:

❯ cd blog/
direnv: loading ~/Projects/blog/.envrc
direnv: export +VIRTUAL_ENV +VIRTUAL_ENV_PROMPT ~PATH
❯ cd ..
direnv: unloading

An Official Approach

A better and officially supported method for achieving this in direnv is:

export VIRTUAL_ENV=".venv"
layout python

This approach leverages direnv’s built-in layout function which is available for range of programming languages, editors, & tools.

Reusing the Setup Across Projects

For even greater convenience, you can define a custom function to standardize environment activation across all your projects. Check out the direnv wiki for more details.