nix_builder/flake.nix

{
  description = "nix_builder nix package builder";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    rust-overlay = {
      url = "github:oxalica/rust-overlay";
      inputs = {
        nixpkgs.follows = "nixpkgs";
      };
    };
  };

  outputs =
    {
      self,
      nixpkgs,
      rust-overlay,
    }:
    let
      forAllSystems =
        func:
        builtins.listToAttrs (
          map (system: {
            name = system;
            value = func system;
          }) nixpkgs.lib.systems.flakeExposed
        );

    in
    {
      devShells = forAllSystems (
        system:
        let
          overlays = [ (import rust-overlay) ];
          pkgs = import nixpkgs {
            inherit system overlays;
          };
          rustToolchain = pkgs.pkgsBuildHost.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
        in
        {
          default = pkgs.mkShell {
            nativeBuildInputs = [
              pkgs.pkg-config
              rustToolchain
            ];
            buildInputs = with pkgs; [
              sqlx-cli # For sqlx CLI to manage migrations
              sqlite # To access the database (sqlite is bundled into the nix_builder binary but this is for manually accessing the db).
            ];
            shellHook = ''
              cat <<EOF
              nix_builder dev shell

              Create new migrations with:
                sqlx migrate add -r <name>

              Generate metadata for query!() macros:
                cargo sqlx prepare
              EOF
            '';
          };
        }
      );
      packages = forAllSystems (
        system:
        let
          overlays = [ (import rust-overlay) ];
          pkgs = import nixpkgs {
            inherit system overlays;
          };
          cargoToml = (pkgs.lib.importTOML ./Cargo.toml);
          rustToolchain = pkgs.pkgsBuildHost.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
          rustPlatform = pkgs.makeRustPlatform {
            cargo = rustToolchain;
            rustc = rustToolchain;
          };
        in
        rec {
          app = rustPlatform.buildRustPackage {
            pname = "nix_builder";
            version = cargoToml.package.version;
            src = pkgs.lib.cleanSource ./.;

            cargoLock.lockFile = ./Cargo.lock;

            buildType = "lto";
            # RUSTFLAGS = "-C target-cpu=x86-64-v3";

            meta = with pkgs.lib; {
              description = "A builder of nix configs for a build server.";
              homepage = "https://code.fizz.buzz/talexander/nix_builder";
              license = licenses.bsd0;
              maintainers = [ ];
            };

            nativeBuildInputs = [ pkgs.makeWrapper ];

            postInstall = ''
              wrapProgram $out/bin/nix-builder --prefix PATH : ${
                pkgs.lib.makeBinPath [
                  pkgs.git
                  pkgs.nix
                  pkgs.nixos-rebuild
                ]
              }
            '';

            # nativeBuildInputs = [
            #   pkgs.pkg-config
            # ];
            # buildInputs = [
            #   pkgs.openssl
            # ];
          };
          docker_env = pkgs.buildEnv {
            name = "nix_builder";
            paths = with pkgs; [
              app
              # bash
              # uutils-coreutils-noprefix
              # toybox # Smaller than uutils-coreutils?
            ];
          };
          default = app;
        }
      );
    };
}