feat: add liveusb generator to flake via nixos-generators (#291)

create liveusb

flake.nix

@@ -17,6 +17,12 @@
       url = "github:nix-community/home-manager/release-24.05";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    # Supports generating liveusbs
+    nixos-generators = {
+      url = "github:nix-community/nixos-generators/7c60ba4bc8d6aa2ba3e5b0f6ceb9fc07bc261565";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
     # Replaces the need to have a git submodule.
     seekSdk = {
       url = "github:worldcoin/seek-thermal-sdk";

nix/machines/flake-outputs.nix

@@ -3,7 +3,7 @@
 # It gets directly combined with the toplevel flake.nix.
 { inputs, p, ... }:
 let
-  inherit (inputs) nixpkgs home-manager;
+  inherit (inputs) nixpkgs home-manager nixos-generators;
 in
 let
   # Helper function for all worldcoin NixOS machines.
@@ -15,6 +15,7 @@ let
     };
     modules = [
       ./${hostname}/configuration.nix
+      inputs.nixos-generators.nixosModules.all-formats
       # setup home-manager
       home-manager.nixosModules.home-manager
       {
@@ -51,4 +52,23 @@ in
   nixosConfigurations."worldcoin-hil-munich-1" = hilConfig {
     hostname = "worldcoin-hil-munich-1";
   };
+  packages.x86_64-linux.liveusb = nixos-generators.nixosGenerate {
+    system = "x86_64-linux";
+    modules = [
+      {
+        # Pin nixpkgs to the flake input, so that the packages installed
+        # come from the flake inputs.nixpkgs.url.
+        nix.registry.nixpkgs.flake = nixpkgs;
+      }
+      ./liveusb.nix
+    ];
+    format = "raw-efi";
+
+    # optional arguments:
+    # explicit nixpkgs and lib:
+    # pkgs = nixpkgs.legacyPackages.x86_64-linux;
+    # lib = nixpkgs.legacyPackages.x86_64-linux.lib;
+    # additional arguments to pass to modules:
+    # specialArgs = { myExtraArg = "foobar"; };
+  };
 }

nix/machines/liveusb.nix

@@ -0,0 +1,11 @@
+{ config, pkgs, modulesPath, ... }:
+{
+  imports = [
+    (modulesPath + "/installer/cd-dvd/installation-cd-minimal.nix")
+  ];
+  environment.systemPackages = with pkgs; [
+    neovim
+    parted
+    usbutils
+  ];
+}