core/default.nix

@@ -1,8 +1,10 @@
+{ lib, ... }:
+let
+    settings = import ./../settings.nix;
+in
 {
-    imports = [
-        ./java.nix
-        ./dotnet.nix
-        ./printing.nix
-        ./xdg.nix
-    ];
+    imports = lib.optionals settings.printing.enable [ ./printing.nix ]
+        ++ lib.optionals settings.xdg.enable [ ./xdg.nix ]
+        ++ lib.optionals settings.java [ ./java.nix ]
+        ++ lib.optionals settings.dotnet [ ./dotnet.nix ];
 }

core/printing.nix

@@ -1,13 +1,24 @@
-{ pkgs, config, ... }: {
-    services.printing.enable = true;
-    services.avahi.enable = true;
-    # for a WiFi printer
-    services.avahi.openFirewall = true;
-    services.avahi.nssmdns = false; # Use the settings from below
-    # settings from avahi-daemon.nix where mdns is replaced with mdns4
-    system.nssModules = pkgs.lib.optional (!config.services.avahi.nssmdns) pkgs.nssmdns;
-    system.nssDatabases.hosts = with pkgs.lib; optionals (!config.services.avahi.nssmdns) (mkMerge [
-        (mkBefore [ "mdns4_minimal [NOTFOUND=return]" ]) # before resolve
-        (mkAfter [ "mdns4" ]) # after dns
-    ]);
+{ pkgs, lib, config, ... }:
+let
+    settings = import ./../settings.nix;
+in
+{
+    config = lib.mkMerge [
+        {
+            services.printing.enable = true;
+        }
+        # Avahi daemon
+        (lib.mkIf settings.printing.avahi {
+            services.avahi.enable = true;
+            # for a WiFi printer
+            services.avahi.openFirewall = true;
+            services.avahi.nssmdns = false; # Use the settings from below
+            # settings from avahi-daemon.nix where mdns is replaced with mdns4
+            system.nssModules = pkgs.lib.optional (!config.services.avahi.nssmdns) pkgs.nssmdns;
+            system.nssDatabases.hosts = with pkgs.lib; optionals (!config.services.avahi.nssmdns) (mkMerge [
+                (mkBefore [ "mdns4_minimal [NOTFOUND=return]" ]) # before resolve
+                (mkAfter [ "mdns4" ]) # after dns
+            ]);
+        })
+    ];
 }

core/xdg.nix

@@ -1,15 +1,12 @@
-{ pkgs, config, ... }: {
-
+{ pkgs, ... }:
+let
+    settings = import ./../settings.nix;
+in
+{
     xdg.portal = {
         enable = true;
-        extraPortals = [
-            pkgs.xdg-desktop-portal-gtk
-            pkgs.xdg-desktop-portal-kde
-        ];
+        extraPortals = settings.xdg.extraPortals;
     };
 
-    environment.systemPackages = with pkgs; [
-        pkgs.xdg-desktop-portal-gtk
-        pkgs.xdg-desktop-portal-kde
-    ];
+    environment.systemPackages = settings.xdg.extraPortals;
 }

dev/default.nix

@@ -1,10 +1,12 @@
+{ pkgs, lib, config, ... }:
+let
+    settings = import ./../settings.nix;
+in
 {
-    imports = [
-        ./language-server.nix
-        ./dotnet.nix
-        ./docker-rootless.nix
-        ./platformio.nix
-        ./qemu.nix
-        ./latex.nix
-    ];
+    imports = lib.optionals settings.dev.lsp.enable [ ./lsp.nix ]
+    ++ lib.optionals settings.virtualisation.docker-rootless.enable [ ./docker-rootless.nix ]
+    ++ lib.optionals settings.virtualisation.qemu.enable [ ./qemu.nix ]
+    ++ lib.optionals settings.dev.platformio [ ./platformio.nix ]
+    ++ lib.optionals settings.dev.latex [ ./latex.nix ]
+    ++ lib.optionals settings.dev.dotnet [ ./dotnet.nix ];
 }

dev/docker-rootless.nix

@@ -1,9 +1,13 @@
-{ pkgs, config, ... }: {
+{ pkgs, config, ... }:
+let
+    settings = import ./../settings.nix;
+in
+{
     # enable rootless docker for more security
     virtualisation.docker.rootless = {
         enable = true;
         setSocketVariable = true;
     };
     # regulary clean unused docker images
-    virtualisation.docker.autoPrune.enable = true;
+    virtualisation.docker.autoPrune.enable = settings.virtualisation.docker-rootless.autoPrune;
 }

dev/language-server.nix

@@ -1,10 +0,0 @@
-{ pkgs, config, ... }: {
-    # various language server used by IDEs and by my Neovim config
-    environment.systemPackages = with pkgs; [
-        shellcheck
-        lua-language-server
-        pyright
-        arduino-language-server
-        clang
-    ];
-}

dev/lsp.nix

@@ -0,0 +1,13 @@
+{ pkgs, lib, ... }:
+let
+    settings = import ./../settings.nix;
+in
+{
+    # various language server used by IDEs and by Neovim lsp-config
+    environment.systemPackages = with pkgs;
+        lib.optionals settings.dev.lsp.shellcheck [ shellcheck ]
+        ++ lib.optionals settings.dev.lsp.luals [ lua-language-server ]
+        ++ lib.optionals settings.dev.lsp.pyright[ pyright ]
+        ++ lib.optionals settings.dev.lsp.arduino [ arduino-language-server ]
+        ++ lib.optionals settings.dev.lsp.clangd [ clang ];
+}

dev/qemu.nix

@@ -1,10 +1,14 @@
-{ pkgs, config, ... }: {
+{ pkgs, config, ... }:
+let
+    settings = import ./../settings.nix;
+in
+{
     # KVM
     virtualisation.libvirtd.enable = true;
-    # programs.virt-manager.enable = true;  # after 23.11
+    programs.virt-manager.enable = settings.virtualisation.qemu.virt-manager;  # after 23.11
 
     # only before 23.11
-    environment.systemPackages = (with pkgs; [
-        virt-manager
-    ]);
+    # environment.systemPackages = (with pkgs; [
+    #    virt-manager
+    # ]);
 }

extra/default.nix

@@ -1,8 +1,12 @@
+{ lib, ... }:
+let
+    settings = import ./../settings.nix;
+in
 {
-    imports = [
-        ./bluray.nix
-        ./dvd.nix
-        ./yubikey.nix
-        ./wireguard.nix
-    ];
+    # Optionally import modules for non-essential extras
+    imports =
+        lib.optionals settings.hardware.yubikey.enable [ ./yubikey.nix ]
+        ++ lib.optionals settings.dvd [ ./dvd.nix ]
+        ++ lib.optionals settings.bluray [ ./bluray.nix ]
+        ++ lib.optionals settings.networking.wireguard [ ./wireguard.nix ];
 }

extra/yubikey.nix

@@ -1,12 +1,16 @@
-{ pkgs, config, ... }: {
-
+{ pkgs, lib, ... }:
+let
+    settings = import ./../settings.nix;
+in
+{
     services.pcscd.enable = true; # enable support for smart cards
 
-    environment.systemPackages = with pkgs; [
-        # Yubikey stuff
-        yubioath-flutter    # Yubico authentictor app for managing accounts
-        yubikey-manager     # CLI tool for ykman
-        yubikey-manager-qt  # GUI tool for ykman
-        pcsclite
-    ];
+    environment.systemPackages = with pkgs; [ pcsclite ]
+        # Yubico authentictor app for managing accounts
+        ++ (lib.optionals settings.hardware.yubikey.authenticator [ yubioath-flutter ])
+        # ykman CLI and Qt-GUI
+        ++ (lib.optionals settings.hardware.yubikey.ykman [
+            yubikey-manager     # CLI tool for ykman
+            yubikey-manager-qt  # GUI tool for ykman
+        ]);
 }

games/default.nix

@@ -1,6 +1,10 @@
+{ lib, ... }:
+let
+    settings = import ./../settings.nix;
+in
 {
-    imports = [
-        ./steam.nix
-        ./prismlauncher.nix
-    ];
+    # Optionally import modules for game launchers, games or compatability layers
+    imports =
+        lib.optionals settings.games.prismlauncher [ ./prismlauncher.nix ]
+        ++ lib.optionals settings.games.steam [ ./steam.nix ];
 }

hardware/amdgpu.nix

@@ -1,8 +1,14 @@
-{ pkgs, config, ... }: {
+{ pkgs, lib, ... }:
+{
+    # Adapted from: https://github.com/NixOS/nixos-hardware/blob/master/common/gpu/amd/default.nix
 
     # Make the kernel use the correct driver early
     boot.initrd.kernelModules = [ "amdgpu" ];
 
+    # Make sure Xserver uses the `amdgpu` driver
+    services.xserver.enable = true;
+    services.xserver.videoDrivers = [ "amdgpu" ];
+
     # For 32 bit applications
     hardware.opengl.driSupport32Bit = true;
 
@@ -12,6 +18,11 @@
         rocmPackages.clr.icd
     ];
 
+    # For 32 bit applications 
+    hardware.opengl.extraPackages32 = with pkgs; [
+        driversi686Linux.amdvlk
+    ];
+
     environment.systemPackages = with pkgs; [
         nvtop-amd
         clinfo

hardware/default.nix

@@ -1,5 +1,11 @@
+{ lib, ... }:
+let
+    settings = import ./../settings.nix;
+in
 {
-    imports = [
-        ./amdgpu.nix
-    ];
+    # Optionally import modules for specific hardware
+    imports = 
+        lib.optionals settings.hardware.amdgpu [ ./amdgpu.nix ]
+        ++ lib.optionals settings.hardware.intelgpu [ ./intelgpu.nix ]
+        ++ lib.optionals settings.hardware.nvidiagpu [ ./nvidiagpu.nix ];
 }

hardware/intelgpu.nix

@@ -0,0 +1,16 @@
+{ pkgs, lib, ... }:
+{
+    # Excerpt: https://github.com/NixOS/nixos-hardware/blob/master/common/gpu/intel/default.nix
+
+    boot.initrd.kernelModules = [ "i915" ];
+
+    environment.variables = {
+        VDPAU_DRIVER = lib.mkIf config.hardware.opengl.enable (lib.mkDefault "va_gl");
+    };
+
+    hardware.opengl.extraPackages = with pkgs; [
+        (if (lib.versionOlder (lib.versions.majorMinor lib.version) "23.11") then vaapiIntel else intel-vaapi-driver)
+        libvdpau-va-gl
+        intel-media-driver
+    ];
+}

hardware/nvidia.nix

@@ -0,0 +1,8 @@
+{ pkgs, lib, ... }:
+{
+    # Excerpt from: https://github.com/NixOS/nixos-hardware/blob/master/common/gpu/nvidia/default.nix
+    services.xserver.videoDrivers = lib.mkDefault [ "nvidia" ];
+    hardware.opengl.extraPackages = with pkgs; [
+        vaapiVdpau
+    ];
+}

settings.nix

@@ -0,0 +1,67 @@
+with import <nixpkgs> {}; {
+    hardware = {
+        # support for GPUs
+        amdgpu = true;
+        intelgpu = false;
+        nvidiagpu = false;
+
+        # support for yubikey and additional software
+        yubikey = {
+            enable = true;
+            # additional software
+            ykman = false;
+            authenticator = true;   # flutter yubico authenticator
+        };
+    };
+
+    virtualisation = {
+        docker-rootless = {
+            enable = true;
+            autoPrune = true;
+        };
+        qemu = {
+            enable = true;
+            virt-manager = true;
+        };
+    };
+    dev = {
+        platformio = true;
+        latex = true;
+        dotnet = false;
+
+        lsp = {
+            enable = true;
+            # various language server
+            shellcheck = true;
+            luals = true;
+            pyright = true;
+            arduino = true;
+            clangd = true;
+        };
+    };
+
+    dvd = true;     # enable DVD decryption + ripping via Handbrake
+    bluray = true;  # enable Bluray decryption (requires additional setup)
+    printing = {
+        enable = true;
+        avahi = true;
+    };
+    xdg = {
+        enable = true;
+        extraPortals = with pkgs; [
+            xdg-desktop-portal-gtk
+            xdg-desktop-portal-kde
+        ];
+    };
+    java = true;
+    dotnet = true;
+
+    networking = {
+        wireguard = true;   # enable wireguard protocol
+    };
+
+    games = {
+        prismlauncher = true;
+        steam = true;
+    };
+}