added stuff

nyx/modules/core/roles/iso/image/default.nix

@@ -0,0 +1,71 @@
+{
+  modulesPath,
+  self,
+  config,
+  pkgs,
+  lib,
+  ...
+}: let
+  inherit (lib) mkImageMediaOverride;
+in {
+  imports = [
+    "${modulesPath}/installer/cd-dvd/iso-image.nix"
+
+    # make sure our installer can detect and interact with all hardware that is supported in Nixpkgs
+    # this loads basically every hardware related kernel module
+    "${modulesPath}/profiles/all-hardware.nix"
+  ];
+
+  # the ISO image must be completely immutable in the sense that we do not
+  # want the user to be able modify the ISO image after booting into it
+  # the below option will disable rebuild switches (i.e nixos-rebuild switch)
+  system.switch.enable = false;
+
+  isoImage = let
+    # hostname will be set as a "top-level" attribute in hosts.nix, per-host.
+    # therefore we can use the networking.hostName to get the hostname of the live
+    # system without defining it explicitly in the system-agnostic ISO role module
+    hostname = config.networking.hostName or "nixos";
+
+    # if the system is built from a git repository, we want to include the git revision
+    # in the ISO name. if the tree is dirty, we use the term "dirty" to make it explicit
+    rev = self.shortRev or "dirty";
+
+    # the format of the iso will always be uniform:
+    # $hostname-$release-$rev-$arch
+    # therefore we can set it once to avoid repetition later on
+    name = "${hostname}-${config.system.nixos.release}-${rev}-${pkgs.stdenv.hostPlatform.uname.processor}";
+  in {
+    # this will cause the resulting .iso file to be named as follows:
+    # $hostname-$release-$rev-$arch.iso
+    isoName = mkImageMediaOverride "${name}.iso";
+    # this will cause the label or volume ID of the generated ISO image to be as follows:
+    # $hostname-$release-$rev-$arch
+    # volumeID is used is used by stage 1 of the boot process, so it must be distintctive
+    volumeID = mkImageMediaOverride "${name}";
+
+    # maximum compression, in exchange for build speed
+    squashfsCompression = "zstd -Xcompression-level 10"; # default uses gzip
+
+    # ISO image should be an EFI-bootable volume
+    makeEfiBootable = true;
+
+    # ISO image should be bootable from USB
+    # FIXME: the module decription is as follows:
+    # "Whether the ISO image should be bootable from CD as well as USB."
+    # is this supposed to make the ISO image bootable from *CD* instead of USB?
+    makeUsbBootable = true;
+
+    # my module system already contains an option to add memtest86+
+    # to the boot menu at will but in case our system is unbootable
+    # lets include memtest86+ in the ISO image
+    # so that we may test the memory of the system
+    # exclusively from the ISO image
+    contents = [
+      {
+        source = pkgs.memtest86plus + "/memtest.bin";
+        target = "boot/memtest.bin";
+      }
+    ];
+  };
+}