How easy would it be to flakify the Lemmy repo to add a fourth build option for those of us in the Nix world?

I had the (perhaps foolishly ambitious) idea of creating a rolling fork of Lemmy with the intent of modifying the codebase for use in an open source pub sub implementation of retail inventory. But I have to get standard Lemmy working first…and I like to use Nix for everything I do in the dev world (where feasible).

So, I forked the repo and was immediately brought into dev environment hell.

They only offer a choice between:

A.) Docker B.) Ansible C.) Building from scratch.

Two hours of fighting with the scratch build instructions and I eventually had to admit defeat due to some vague dependencies (and general malaise). Though I have completely flakified my Purescript and Haskell dev environments, I have found Rust to be a lot more challenging even on simple projects.

Anyway, I decided to come here to ask: **How easy would it be to flakify the Lemmy repo to add a fourth build option for those of us in the Nix world? **

Can I reference the build instructions from nixpkgs to get close to my intended goal? I need all of the help I can get. Be as pedantic or defeatist as you will. I currently have no skin in this game and merely want to help the Lemmy devs welcome people that are more nixy like myself (if nothing else).

---

edit: here’s a naive attempt. I haven’t tested anything other than it being a valid flake. Here’s the link to my rolling flakification fork.

{
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    flake-parts.url = "github:hercules-ci/flake-parts";
    systems.url = "github:nix-systems/default";

    # Dev tools
    treefmt-nix.url = "github:numtide/treefmt-nix";
  };

  outputs = inputs:
    inputs.flake-parts.lib.mkFlake { inherit inputs; } {
      systems = import inputs.systems;
      imports = [
        inputs.treefmt-nix.flakeModule
      ];
      perSystem = { config, self', pkgs, lib, system, ... }:
        let
          cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
          nonRustDeps = [
            pkgs.libiconv
            # Derived from Documentation on Dev installation for Linux
            pkgs.cacert
            pkgs.postgresql
            pkgs.openssl
            pkgs.pkg-config
            pkgs.libpqxx
          ];
          rust-toolchain = pkgs.symlinkJoin {
            name = "rust-toolchain";
            paths = [ pkgs.rustc pkgs.cargo pkgs.cargo-watch pkgs.rust-analyzer pkgs.rustPlatform.rustcSrc pkgs.cacert pkgs.postgresql pkgs.openssl pkgs.pkg-config pkgs.libpqxx ];
          };
        in
        {
          # Rust package
          packages.default = pkgs.rustPlatform.buildRustPackage {
            inherit (cargoToml.package) name version;
            src = ./.;
            cargoLock.lockFile = ./Cargo.lock;
          };

          # Rust dev environment
          devShells.default = pkgs.mkShell {
            inputsFrom = [
              config.treefmt.build.devShell
            ];
            shellHook = ''
              # For rust-analyzer 'hover' tooltips to work.
              export RUST_SRC_PATH=${pkgs.rustPlatform.rustLibSrc}
              export CARGO_PROFILE_DEV_BUILD_OVERRIDE_DEBUG=true

              echo
              echo "🍎🍎 Run 'just <recipe>' to get started"
              just
            '';
            buildInputs = nonRustDeps;
            nativeBuildInputs = with pkgs; [
              just
              rust-toolchain
            ];
            RUST_BACKTRACE = 1;
          };

          # Add your auto-formatters here.
          # cf. https://numtide.github.io/treefmt/
          treefmt.config = {
            projectRootFile = "flake.nix";
            programs = {
              nixpkgs-fmt.enable = true;
              rustfmt.enable = true;
            };
          };
        };
    };
}

and here’s the lemmy-ui flake (which, judging by past forays into tsc with nix last summer, should be a lot easier to create and work with than the Rust library):

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    systems.url = "github:nix-systems/default";
  };

  outputs = {
    systems,
    nixpkgs,
    ...
  } @ inputs: let
    eachSystem = f:
      nixpkgs.lib.genAttrs (import systems) (
        system:
          f nixpkgs.legacyPackages.${system}
      );
  in {
    devShells = eachSystem (pkgs: {
      default = pkgs.mkShell {
        buildInputs = [
          pkgs.nodejs
          # You can set the major version of Node.js to a specific one instead
          # of the default version
          # pkgs.nodejs-19_x

          # You can choose pnpm, yarn, or none (npm).
          pkgs.nodePackages.pnpm
          # pkgs.yarn

          pkgs.nodePackages.typescript
          pkgs.nodePackages.typescript-language-server
        ];
      };
    });
  };
}