Nix Rails Setup

.bundle-slash-config

---
BUNDLE_PATH: "vendor/bundle"

README.md

Prerequisite

Install nix with

• https://determinate.systems/posts/determinate-nix-installer

Ensure that you run can run your Rails app with bin/rails. An example bin/rails has been provided for version 7 Rails.

Place all these files within the root of your Rails app

Run development workspace

Open the development workspace with:

nix develop .#devspace -c $SHELL

Build and run your application using Nix:

Build the application:

nix build .#my-rails-app

Run the application:

./result/bin/my-rails-app

Build and run your application using Docker:

Build the Docker image:

docker build -t my-rails-app .

Run the Docker container:

docker run --rm my-rails-app

Explanation

default.nix: Defines the build process for your Rails application using Nix. It specifies the build inputs, build commands, and install commands.

flake.nix: Defines the Nix flake, including inputs (Nixpkgs and flake-utils) and outputs (packages for different systems).

Dockerfile: Sets up a NixOS environment in a Docker container, installs Nix Flakes, copies your project files, builds your application using the flake, and sets the command to run your application.

By following these steps, you can build and run your Rails application both directly using Nix and within a Docker container.

bin-slash-rails

#!/usr/bin/env ruby
APP_PATH = File.expand_path("../config/application", __dir__)
require_relative "../config/boot"
require "rails/commands"

default.nix

{ pkgs ? import <nixpkgs> { } }:

pkgs.stdenv.mkDerivation {
  pname = "my-rails-app";
  version = "1.0.0";
  src = ./.;
  buildInputs = [ pkgs.ruby_3_3 ];

  buildPhase = ''
    bundle install
  '';

  installPhase = ''
    mkdir -p $out/bin
    cp -r . $out/bin/
    echo "./bin/rails server" >> $out/bin/my-rails-app
    chmod +x $out/bin/my-rails-app
  '';
}

devspace.nix

{ pkgs }:

pkgs.devshell.mkShell {
  name = "rails-devspace.dev";
  packages = [
    pkgs.pkg-config
    pkgs.gcc
    pkgs.sqlite
    pkgs.gnumake
    pkgs.yarn
    pkgs.ruby_3_3
    pkgs.libyaml.dev
    pkgs.openssl_3_3.dev
    pkgs.postgresql
    pkgs.autoconf269
    pkgs.automake
    pkgs.autogen
    pkgs.libtool
    pkgs.libffi.dev
    pkgs.gnum4
    pkgs.secp256k1
    pkgs.shared-mime-info
  ];
  env = [
    {
      name = "PKG_CONFIG_PATH";
      value =
        "${pkgs.pkg-config}:${pkgs.openssl_1_1.dev}/lib/pkgconfig:${pkgs.libyaml.dev}/lib/pkgconfig:${pkgs.postgresql}/lib/pkgconfig:${pkgs.libffi.dev}/lib/pkgconfig:${pkgs.secp256k1}/lib/pkgconfig";
    }
    {
      name = "LIBTOOL";
      value = "${pkgs.libtool}";
    }
    {
      name = "FREEDESKTOP_MIME_TYPES_PATH";
      value =
        "${pkgs.shared-mime-info}/share/mime/packages/freedesktop.org.xml";
    }
    {
      name = "NIXPKGS_ALLOW_INSECURE";
      value = "1";
    }
  ];
  commands = [{
    name = "devspace";
    category = "devshell";
    help = "opens devspace shell";
    command = ''
      zellij -l layout.kdl
    '';
  }];
}

Dockerfile

FROM nixos/nix

# Install Nix Flakes
RUN nix-env -iA nixpkgs.nixFlakes

# Copy the flake files
COPY . /app
WORKDIR /app

# Build the application
RUN nix --extra-experimental-features "nix-command flakes" build .#my-rails-app

# Run the application
CMD ["./result/bin/my-rails-app"]

flake.nix

{
  description = "Devspace";

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

  outputs = { self, nixpkgs, flake-utils, devshell, ... }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs {
          inherit system;
          overlays = [ devshell.overlays.default ];
          config.permittedInsecurePackages = [ "openssl-1.1.1w" ];
        };
      in {
        # system = "aarch64-darwin";
        packages.${system} = {
          default = pkgs.callPackage ./default.nix { };
          my-rails-app = pkgs.callPackage ./default.nix { };
        };
        devShells = {
          devspace = import ./devspace.nix { inherit pkgs; };
        };
      });
}