vms/flake.nix

# github.com/brianmcgee has lots of great ideas for going above and beyond for this
{
  description = "Greg's homepage";
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    flake-parts.url = "github:hercules-ci/flake-parts";
    process-compose.url = "github:Platonic-Systems/process-compose-flake";
    hooks.url = "github:cachix/git-hooks.nix";
  };

  outputs =
    { flake-parts, nixpkgs, ... }@inputs:
    let
      lib = nixpkgs.lib;
      providers = [
        "qemu"
        "virtualbox-iso"
        "hyperv-iso"
      ];
      distros = import ./distros;
      # Inserts the distro name into each element in the list
      insertNames = lib.attrsets.mapAttrsToList (
        distro: val: (builtins.map (x: x // { inherit distro; }) val)
      ) distros;
      # Flattens all the distros into a single list
      flat = lib.lists.flatten insertNames;
      # Combines providers list with flattened list
      withProviders = lib.attrsets.mapCartesianProduct ({ d, provider }: d // { inherit provider; }) {
        d = flat;
        provider = providers;
      };
      active = builtins.filter (x: (x ? eol) && (!x.eol)) withProviders;
      name = d: "-${d.distro}-${d.arch}-${d.provider}-${d.version}";
      distroFile = d: "distros/${d.distro}/${d.version}/${d.arch}.pkrvars.hcl";
      cmd = d: ''
        # This is a workaround for a goofy behavior in CI
        if [ -e "''${PACKER_CONFIG_DIR}" ]; then
        	find "''${PACKER_CONFIG_DIR}" -name '*_linux_amd64' -exec chmod +x '{}' ";"
        fi
        packer init sources
        packer build -only=${d.provider}.${d.arch} -var-file=${distroFile d}'';
    in
    flake-parts.lib.mkFlake { inherit inputs; } {
      flake = {
        # Universal things
      };
      systems = [
        "x86_64-linux"
        "aarch64-linux"
      ];
      perSystem =
        {
          pkgs,
          self',
          system,
          ...
        }@inputs':
        {
          _module.args.pkgs = import inputs.nixpkgs {
            inherit system;
            config.allowUnfree = true;
          };

          devShells.default = pkgs.mkShell {
            buildInputs = self'.checks.pre-commit.enabledPackages;
            shellHook = self'.checks.pre-commit.shellHook;

            packages =
              (with pkgs; [
                vagrant
              ])
              ++ (with self'.packages; [
                cache
                generate
                shellcheck
                validate
              ])
              ++ (builtins.map (d: self'.packages."build${name d}") withProviders);
            # These commands will be shown in the motd that users read
            # upon entering the shell
            env = {
              EFI_DIR = "${pkgs.OVMF.fd}/FV/";
              PACKER_CONFIG_DIR = "./packer_config";
              STORAGE_URL = "http://s3.thehellings.lan:9000";
            };
          };

          # This is not special, this is just flakes
          packages =
            let
              base = {
                runtimeInputs = with pkgs; [
                  cdrtools
                  findutils
                  packer
                  qemu_full
                  vagrant
                  xorriso
                ];
              };
              build =
                d:
                let
                  vp =
                    x:
                    if x.provider == "qemu" then
                      "libvirt"
                    else if x.provider == "virtualbox-iso" then
                      "virtualbox"
                    else if x.provider == "hyperv-iso" then
                      "hyperv"
                    else
                      "unknown";
                in
                pkgs.writeShellApplication (
                  base
                  // {
                    name = "build${name d}";
                    text = ''
                      set -x
                      ${cmd d} -except=upload -var headless=false sources/
                      vagrant box add --provider ${vp d} ./output/${vp d}/${d.distro}-${d.version}.box --name test_box --force
                    '';
                  }
                );
              cibuild =
                d:
                pkgs.writeShellApplication (
                  base
                  // {
                    name = "ci${name d}";
                    text = ''
                      set -x
                      ${cmd d} -except=upload sources/
                    '';
                  }
                );
              upload =
                d:
                pkgs.writeShellApplication (
                  base
                  // {
                    name = "upload${name d}";
                    text = ''
                      set -x
                      ${cmd d} sources/
                    '';
                  }
                );
              builds = lib.lists.foldr (d: acc: acc // { "build${name d}" = (build d); }) { } withProviders;
              uploads = lib.lists.foldr (d: acc: acc // { "upload${name d}" = (upload d); }) { } withProviders;
              cibuilds = lib.lists.foldr (d: acc: acc // { "ci${name d}" = (cibuild d); }) { } withProviders;
              qemu_list = builtins.toJSON (
                builtins.map (d: { buildcmd = (name d); }) (builtins.filter (x: x.provider == "qemu") active)
              );
              vbox_list = builtins.toJSON (
                builtins.map (d: { buildcmd = (name d); }) (
                  builtins.filter (x: x.provider == "virtualbox-iso") active
                )
              );
              hyperv_list = builtins.toJSON (
                builtins.map (d: { distro = distroFile d; }) (
                  builtins.filter (x: x.provider == "hyperv-iso") active
                )
              );
            in
            builds
            // uploads
            // cibuilds
            // {
              continue = pkgs.writeText "continue.yml" (
                builtins.replaceStrings
                  [
                    "QEMU_MATRIX"
                    "VBOX_MATRIX"
                    "HYPERV_MATRIX"
                  ]
                  [
                    qemu_list
                    vbox_list
                    hyperv_list
                  ]
                  (builtins.readFile ./.gitlab-ci-build.yml.in)
              );
              cache = pkgs.callPackage (import ./nix/cache.nix) { inherit active distroFile; };
              validate = pkgs.callPackage (import ./nix/validate.nix) { };
              cache-restore = pkgs.writeShellApplication {
                name = "cache-restore";
                runtimeInputs = with pkgs; [
                  jq
                  minio-client
                  packer
                ];
                text = builtins.readFile ./cache-restore.sh;
              };
              generate = pkgs.writeShellApplication {
                name = "generate";
                runtimeInputs = with pkgs; [
                  bash
                  coreutils
                  curl
                  jq
                  pup
                ];
                text = ''
                  shopt -s globstar
                  for vars in distros/**/*.pkrvars.hcl.sh; do
                  	bash "./''${vars}"
                  done
                  set -x
                  echo "BUILD=$(date "+%Y.%m.%d.%H")" >> build.env
                '';
              };
              shellcheck = pkgs.writeShellApplication {
                name = "shellcheck";
                runtimeInputs = with pkgs; [
                  shellcheck
                ];
                text = ''
                  scripts=()
                  shopt -s globstar
                  for f in **/*.sh; do
                  	scripts+=("$f")
                  done
                  shellcheck -e SC2239 "''${scripts[@]}"
                '';
              };
            };

          checks = {
            pre-commit = inputs.hooks.lib.${inputs'.system}.run {
              src = ./.;
              hooks = {
                check-added-large-files.enable = true;
                check-case-conflicts.enable = true;
                check-merge-conflicts.enable = true;
                check-symlinks.enable = true;
                deadnix.enable = true;
                end-of-file-fixer.enable = true;
                fix-byte-order-marker.enable = true;
                mixed-line-endings.enable = true;
                nixfmt-rfc-style.enable = true;
                trim-trailing-whitespace.enable = true;
              };
            };
          };
        };
    };
}