Set Up Rails Dev env

flake.nix

# initdb -D .direnv/postgres/data
# 
{
  description = "Ruby dev";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/release-24.05";
    flake-utils.url = "github:numtide/flake-utils";
  };

  outputs = { nixpkgs, flake-utils, ... }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs {
          inherit system;
          overlays = [ (import ./overlay.nix) ];
        };
      in
      {
        devShell = pkgs.mkShell
          {
            packages = with pkgs; [
              ruby_3_3
              postgresql_14
              process-compose
              sqlfluff
              pnpm_8
              nodejs_20
              imagemagick
              cmake
              ffmpeg
              redis
              libyaml
              openssl_3_3
              heroku
              caddy
              cacert
            ];
            shellHook = ''
              mkdir -p ./.direnv/postgres/data
              rm ./.direnv/process-compose.yml && ln -s ${./process-compose.yml} ./.direnv/process-compose.yml
              export PGDATA=".direnv/postgres/data"
            '';
          };
      });
}

gistfile1.txt

version: "0.5"

processes:
  postgres:
    command: postgres
  redis:
    command: redis-server
  frontend:
    command: pnpm dev
  rails:
    command: bin/rails server
  proxy:
    command: caddy reverse-proxy --from app.zakada.net --to http://localhost:3000 --internal-certs
  clock:
    command: bin/rails clock:run
  worker:
    command: bundle exec sidekiq

overlay.nix

# An overlay allows for a package set to be extended with new or modified packages

# `final` refers to the package set with all overlays applied.
# This allows for added or modified packages to be referenced with
# all relevant changes
final:

# `prev` refers to the previous package set before this current overlay is applied.
# This is cheaper for nix to evaluate, thus should be prefered over final when possible.
prev:

{
  # 16.14 now requires experimental import assertions syntax, pin to 16.13
  # https://github.com/nodejs/node/blob/main/doc/changelogs/CHANGELOG_V16.md
  nodejs_20 = prev.nodejs_20.overrideAttrs (oldAttrs: rec {
    version = "20.11.1";
    sha256 = "sha256-/dU6VynZNmkaKhFRBG+0iXchy4sPyir5V4I6m0D+DDQ=";
    name = "nodejs-${version}";
    src = prev.fetchurl {
      url = "https://nodejs.org/dist/v${version}/node-v${version}.tar.xz";
      sha256 = "sha256-d4E+2/P38W0tNdM1NEPe5OYdXuhNnjE4x1OKPAylIJ4";
    };
  });
}

zsh.nix

# This file is part of the main nix-darwin config, and contains all the customisation to zsh, plugins etc. 
# The alias is in here because you can't add aliases in a shellHook with direnv.

...

    shellAliases = {
    
      ...
      
      up = "process-compose -p 9090 -f .direnv/process-compose.yml";
    };
    
 ...