Description

This is a simple flake on how to configure a project based flake.

Literate Programming Nix Flake

Flake Structure

{

Description

Define the flake's purpose and functionality

description = "Development environment with Python and custom packages";

Inputs

Essential dependencies for the flake.

inputs = {
  nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
  flake-utils.url = "github:numtide/flake-utils";
};

Outputs

Main flake output function.

outputs =
  {
    nixpkgs,
    flake-utils,
    ...
  }:

System Configuration

Multi-system support using flake-utils. Ensuring the flake works on all supported plattforms.

flake-utils.lib.eachDefaultSystem (
  system:
  let
    pkgs = nixpkgs.legacyPackages.${system};

Python Environment

Configure Python version for the project. In this case it is defined to Python version 3.13

python = pkgs.python313;

• Custom Python Package Definition

  Create packages for libraries not available in nixpkgs.

  • Package Configuration

    Define the package metadata and build configuration.

    org-python = python.pkgs.buildPythonPackage rec {
      pname = "org-python";
      version = "0.3.2";
    

  • Source Repository

    Fetch source code from upstream repository

    src = pkgs.fetchFromGitHub {
      owner = "honmaple";
      repo = "org-python";
      rev = "v${version}";
    

    • Hash Generation

      Generate the required hash for source verification:

      Use nix-prefetch-github for quick hash generation:

      nix-prefetch-github honmaple org-python
      

      Replace the placeholder hash with the actual value:

        hash = "sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
      };
      

  • Build System Configuration

    Configure the Python build system

    pyproject = true;
    

  • Build Dependencies

    Define packages needed during compilation

    nativeBuildInputs = with python.pkgs; [
      hatchling
      hatch-vcs
    ];
    

  • Testing Configuration

    Disable tests to avoid Nix compatibility issues.

    doCheck = false;
    

  • Package Metadata

    Provide package information and licensing.

      meta = with pkgs.lib; {
        description = "Python library for reading Emacs org-mode files";
        homepage = "https://github.com/honmaple/org-python";
        license = licenses.bsd3;
        maintainers = [ ];
      };
    };
    

• Development Environment Dependencies

  Define core development tools.

  nativeBuildInputs = [
    python
  ];
  

• Runtime Dependencies

  Specify Python packages and libraries required at runtime

  buildInputs = with python.pkgs; [
    fastapi
    uvicorn
    jinja2
    bcrypt
    python-multipart
    qrcode
    isort
    pyflakes
    org-python
  ];
  

Output Configuration

Define the flake's outputs and environments

in
{

• Development Shell

  Create an interactive development environment.

  devShells.default = pkgs.mkShell {
    inherit nativeBuildInputs;
    buildInputs =
      buildInputs
      ++ (with pkgs; [
        nodejs
        nodePackages.pnpm
        nodePackages.prettier
        black
        sqlite-web
        tailwindcss_4
      ]);
  };
  

• Application Package

  Build the main application package.

      packages.default = python.pkgs.buildPythonApplication {
        pname = "rabatzz";
        version = "0.1.0";
        pyproject = true;
  
        src = ./.;
  
        nativeBuildInputs = with python.pkgs; [
          hatchling
        ];
  
        propagatedBuildInputs = buildInputs;
  
        doCheck = false;
      };
    }
  );
  

Flake Closure

}

pyproject.toml declaration

build-system

Here we add the hatchling build system, the same as we declared it before in the flake.nix

[build-system]
requires = ["hatchling"]
build-backend = "hatchling.build"

project specification

Here you may define some information about your project, which Python version is required and also its dependencies.

[project]
name = "Example project"
version = "0.1.0"
description = "Example description"
readme = "README.org"
requires-python = ">=3.10"
dependencies = [
    "fastapi",
    "uvicorn[standard]",
    "jinja2"
]

Scripts declaration

When I package my python projects i like to run them in the terminal as any other cli tool. So after packaging if I would run example-project-run then the application would start without the need to run it with the python3 prefix.

[project.scripts]
example-project-run = "src.main:main"

Folder project specification

Last but not least we need to specify the folder, were our package is specified. I like to work with src/ as any other common programming language.

[tool.hatch.build.targets.wheel]
packages = ["src"]