nixos-generate-config: enable overriding configuration.nix

nixos/modules/installer/tools/nixos-generate-config.pl

@@ -607,90 +607,7 @@ EOF
         }
 
         write_file($fn, <<EOF);
-# Edit this configuration file to define what should be installed on
+@configuration@
-# your system.  Help is available in the configuration.nix(5) man page
-# and in the NixOS manual (accessible by running ‘nixos-help’).
-
-{ config, pkgs, ... }:
-
-{
-  imports =
-    [ # Include the results of the hardware scan.
-      ./hardware-configuration.nix
-    ];
-
-$bootLoaderConfig
-  # networking.hostName = "nixos"; # Define your hostname.
-  # networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.
-
-  # Configure network proxy if necessary
-  # networking.proxy.default = "http://user:password\@proxy:port/";
-  # networking.proxy.noProxy = "127.0.0.1,localhost,internal.domain";
-
-  # Select internationalisation properties.
-  # i18n = {
-  #   consoleFont = "Lat2-Terminus16";
-  #   consoleKeyMap = "us";
-  #   defaultLocale = "en_US.UTF-8";
-  # };
-
-  # Set your time zone.
-  # time.timeZone = "Europe/Amsterdam";
-
-  # List packages installed in system profile. To search, run:
-  # \$ nix search wget
-  # environment.systemPackages = with pkgs; [
-  #   wget vim
-  # ];
-
-  # Some programs need SUID wrappers, can be configured further or are
-  # started in user sessions.
-  # programs.mtr.enable = true;
-  # programs.gnupg.agent = { enable = true; enableSSHSupport = true; };
-
-  # List services that you want to enable:
-
-  # Enable the OpenSSH daemon.
-  # services.openssh.enable = true;
-
-  # Open ports in the firewall.
-  # networking.firewall.allowedTCPPorts = [ ... ];
-  # networking.firewall.allowedUDPPorts = [ ... ];
-  # Or disable the firewall altogether.
-  # networking.firewall.enable = false;
-
-  # Enable CUPS to print documents.
-  # services.printing.enable = true;
-
-  # Enable sound.
-  # sound.enable = true;
-  # hardware.pulseaudio.enable = true;
-
-  # Enable the X11 windowing system.
-  # services.xserver.enable = true;
-  # services.xserver.layout = "us";
-  # services.xserver.xkbOptions = "eurosign:e";
-
-  # Enable touchpad support.
-  # services.xserver.libinput.enable = true;
-
-  # Enable the KDE Desktop Environment.
-  # services.xserver.displayManager.sddm.enable = true;
-  # services.xserver.desktopManager.plasma5.enable = true;
-
-  # Define a user account. Don't forget to set a password with ‘passwd’.
-  # users.users.jane = {
-  #   isNormalUser = true;
-  #   extraGroups = [ "wheel" ]; # Enable ‘sudo’ for the user.
-  # };
-
-  # This value determines the NixOS release with which your system is to be
-  # compatible, in order to avoid breaking some software such as database
-  # servers. You should change this only after NixOS release notes say you
-  # should.
-  system.stateVersion = "${\(qw(@release@))}"; # Did you read the comment?
-
-}
 EOF
     } else {
         print STDERR "warning: not overwriting existing $fn\n";

nixos/modules/installer/tools/tools.nix

@@ -38,7 +38,7 @@ let
     src = ./nixos-generate-config.pl;
     path = lib.optionals (lib.elem "btrfs" config.boot.supportedFilesystems) [ pkgs.btrfs-progs ];
     perl = "${pkgs.perl}/bin/perl -I${pkgs.perlPackages.FileSlurp}/${pkgs.perl.libPrefix}";
-    inherit (config.system.nixos) release;
+    inherit (config.system.nixos-generate-config) configuration;
   };
 
   nixos-option = makeProg {
@@ -61,8 +61,111 @@ in
 
 {
 
+  options.system.nixos-generate-config.configuration = mkOption {
+    internal = true;
+    type = types.str;
+    description = ''
+      The NixOS module that <literal>nixos-generate-config</literal>
+      saves to <literal>/etc/nixos/configuration.nix</literal>.
+
+      This is an internal option. No backward compatibility is guaranteed.
+      Use at your own risk!
+
+      Note that this string gets spliced into a Perl script. The perl
+      variable <literal>$bootLoaderConfig</literal> can be used to
+      splice in the boot loader configuration.
+    '';
+  };
+
   config = {
 
+    system.nixos-generate-config.configuration = mkDefault ''
+      # Edit this configuration file to define what should be installed on
+      # your system.  Help is available in the configuration.nix(5) man page
+      # and in the NixOS manual (accessible by running ‘nixos-help’).
+
+      { config, pkgs, ... }:
+
+      {
+        imports =
+          [ # Include the results of the hardware scan.
+            ./hardware-configuration.nix
+          ];
+
+      $bootLoaderConfig
+        # networking.hostName = "nixos"; # Define your hostname.
+        # networking.wireless.enable = true;  # Enables wireless support via wpa_supplicant.
+
+        # Configure network proxy if necessary
+        # networking.proxy.default = "http://user:password\@proxy:port/";
+        # networking.proxy.noProxy = "127.0.0.1,localhost,internal.domain";
+
+        # Select internationalisation properties.
+        # i18n = {
+        #   consoleFont = "Lat2-Terminus16";
+        #   consoleKeyMap = "us";
+        #   defaultLocale = "en_US.UTF-8";
+        # };
+
+        # Set your time zone.
+        # time.timeZone = "Europe/Amsterdam";
+
+        # List packages installed in system profile. To search, run:
+        # \$ nix search wget
+        # environment.systemPackages = with pkgs; [
+        #   wget vim
+        # ];
+
+        # Some programs need SUID wrappers, can be configured further or are
+        # started in user sessions.
+        # programs.mtr.enable = true;
+        # programs.gnupg.agent = { enable = true; enableSSHSupport = true; };
+
+        # List services that you want to enable:
+
+        # Enable the OpenSSH daemon.
+        # services.openssh.enable = true;
+
+        # Open ports in the firewall.
+        # networking.firewall.allowedTCPPorts = [ ... ];
+        # networking.firewall.allowedUDPPorts = [ ... ];
+        # Or disable the firewall altogether.
+        # networking.firewall.enable = false;
+
+        # Enable CUPS to print documents.
+        # services.printing.enable = true;
+
+        # Enable sound.
+        # sound.enable = true;
+        # hardware.pulseaudio.enable = true;
+
+        # Enable the X11 windowing system.
+        # services.xserver.enable = true;
+        # services.xserver.layout = "us";
+        # services.xserver.xkbOptions = "eurosign:e";
+
+        # Enable touchpad support.
+        # services.xserver.libinput.enable = true;
+
+        # Enable the KDE Desktop Environment.
+        # services.xserver.displayManager.sddm.enable = true;
+        # services.xserver.desktopManager.plasma5.enable = true;
+
+        # Define a user account. Don't forget to set a password with ‘passwd’.
+        # users.users.jane = {
+        #   isNormalUser = true;
+        #   extraGroups = [ "wheel" ]; # Enable ‘sudo’ for the user.
+        # };
+
+        # This value determines the NixOS release with which your system is to be
+        # compatible, in order to avoid breaking some software such as database
+        # servers. You should change this only after NixOS release notes say you
+        # should.
+        system.stateVersion = "${config.system.nixos.release}"; # Did you read the comment?
+
+      }
+    '';
+
     environment.systemPackages =
       [ nixos-build-vms
         nixos-install

nixos/tests/all-tests.nix

@@ -183,6 +183,7 @@ in
   nginx = handleTest ./nginx.nix {};
   nginx-sso = handleTest ./nginx-sso.nix {};
   nix-ssh-serve = handleTest ./nix-ssh-serve.nix {};
+  nixos-generate-config = handleTest ./nixos-generate-config.nix {};
   novacomd = handleTestOn ["x86_64-linux"] ./novacomd.nix {};
   nsd = handleTest ./nsd.nix {};
   nzbget = handleTest ./nzbget.nix {};

nixos/tests/nixos-generate-config.nix

@@ -0,0 +1,24 @@
+import ./make-test.nix ({ lib, ... } : {
+  name = "nixos-generate-config";
+  meta.maintainers = with lib.maintainers; [ basvandijk ];
+  machine = {
+    system.nixos-generate-config.configuration = ''
+      # OVERRIDDEN
+      { config, pkgs, ... }: {
+        imports = [ ./hardware-configuration.nix ];
+      $bootLoaderConfig
+      }
+    '';
+  };
+  testScript = ''
+    startAll;
+    $machine->waitForUnit("multi-user.target");
+    $machine->succeed("nixos-generate-config");
+
+    # Test if the configuration really is overridden
+    $machine->succeed("grep 'OVERRIDDEN' /etc/nixos/configuration.nix");
+
+    # Test of if the Perl variable $bootLoaderConfig is spliced correctly:
+    $machine->succeed("grep 'boot\\.loader\\.grub\\.enable = true;' /etc/nixos/configuration.nix");
+  '';
+})