bobvanderlinden/nixos-config/direnv

Project development environments

Most projects load .envrc automatically. Do not manually source it.

Create an environment

Read the project's .envrc, existing flake, and local instructions first. If it has no local development shell, run this from the Git repository root:

devshell-init

devshell-init detects common project files and creates .nix/flake.nix with the matching tools. It creates .envrc.local when the project already tracks .envrc, otherwise it creates .envrc. It excludes the generated paths through .git/info/exclude and runs direnv allow. It stops rather than overwriting an existing flake or environment file.

For manual setup, put development tools in the flake's devShells.<system>.default package list. Put local setup in .envrc.local when the project tracks .envrc. Exclude local files through .git/info/exclude, not .gitignore.

Use use flake path:$PWD/.nix for a local ignored flake. A plain relative flake path inside a Git repository can hide ignored files from Nix. Test it without adding it to Git:

nix develop path:./.nix --command <command>

Python projects

Provide python3 and uv in the flake. Create the virtual environment in .envrc.local and install the pinned requirements:

use flake path:$PWD/.nix
 
if [ ! -x .venv/bin/python ]; then
    uv venv .venv
fi
 
source .venv/bin/activate
uv pip install --requirements requirements.txt

Activate .venv before running project Python commands when the project instructions require it.