WIP: NixOS

.github/workflows/ci.yaml

@@ -4,6 +4,7 @@ on:
     branches:
       - main
       - update_flake_lock_action
+      - nixos
   pull_request:
 jobs:
   nix:
@@ -18,6 +19,31 @@ jobs:
         run: om show .
       - name: om ci
         run: om ci --extra-access-tokens "github.com=${{ secrets.GITHUB_TOKEN }}" run --systems "${{ matrix.system }}"
+
+      # Make sure that the templates at least build after initialized
+      # TODO: Ideally, we want to let `omnix` run these tests
+      # https://github.com/juspay/omnix/issues/282
+      - name: NixOS test
+        if: matrix.system == 'x86_64-linux'
+        run: |
+          om init .#nixos -o /tmp/nixconfig \
+            --non-interactive \
+            --params '{"hostname": "example", "username": "srid", "git-name": "Srid", "git-email": "srid@srid.ca"}'
+          set -x
+          nix build /tmp/nixconfig#nixosConfigurations.example.config.system.build.toplevel
+          type -f ./result/etc/profiles/per-user/srid/bin/git
+
+      - name: nix-darwin test
+        if: matrix.system == 'aarch64-darwin' || matrix.system == 'x86_64-darwin'
+        run: |
+          om init .#darwin -o /tmp/nixconfig \
+            --non-interactive \
+            --params '{"hostname": "example", "username": "srid", "git-name": "Srid", "git-email": "srid@srid.ca"}'
+          set -x
+          nix build /tmp/nixconfig#darwinConfigurations.example.config.system.build.toplevel
+          type -f ./result/etc/profiles/per-user/srid/bin/git
+
+      # TODO: Use `om init` like above
       - name: activate-test
         if: matrix.system == 'x86_64-linux'
         run: nix run .#test-home-manager-config

README.md

@@ -21,6 +21,25 @@ We currently support [home-manager] (see `./modules/home`) and [nix-darwin] (see
 
 ## Getting Started
 
+### On NixOS
+
+1. Install NixOS from [Graphical ISO image](https://nixos.org/download/#download-nixos) and reboot.
+1. Ensure that `/etc/nixos/{configuration.nix, hardware-configuration.nix}` are in place.
+1. In a terminal, become `root` and initialize our template under `/etc/nixos`:
+  ```sh-session
+  sudo su -
+  cd /etc/nixos
+  nix --accept-flake-config --extra-experimental-features "nix-command flakes" \
+    run github:juspay/omnix -- \
+    init github:juspay/nixos-unified-template#nixos -o .
+  # Replace HOSTNAME with the hostname you entered above.
+  mv configuration.nix hardware-configuration.nix ./configurations/nixos/HOSTNAME/
+  nix --extra-experimental-features "nix-command flakes" run
+  ```
+1. At this point, you can move `/etc/nixos` to anywhere, and initialize a Git repository to track future changes.
+
+### On non-NixOS
+
 1. [Install Nix](https://nixos.asia/en/install):
     ```sh-session
     curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | \

configurations/nixos/example/configuration.nix

@@ -0,0 +1,17 @@
+{
+  # These are normally in hardware-configuration.nix
+  boot.loader.grub.device = "nodev";
+  fileSystems."/" = { device = "/dev/disk/by-label/nixos"; fsType = "btrfs"; };
+
+  nixpkgs.hostPlatform = "x86_64-linux";
+  networking.hostName = "example";
+
+  # For home-manager to work.
+  # https://github.com/nix-community/home-manager/issues/4026#issuecomment-1565487545
+  # users.users."runner".home = "/Users/runner";
+  users.users."runner".isNormalUser = true;
+
+  # Used for backwards compatibility, please read the changelog before changing.
+  # $ darwin-rebuild changelog
+  system.stateVersion = "24.05";
+}

configurations/nixos/example/default.nix

@@ -0,0 +1,20 @@
+# See /modules/nixos/* for actual settings
+# This file is just *top-level* configuration.
+{ flake, ... }:
+
+let
+  inherit (flake) inputs;
+  inherit (inputs) self;
+in
+{
+  imports = [
+    self.nixosModules.default
+    ./configuration.nix
+  ];
+
+  # Enable home-manager for "runner" user
+  home-manager.users."runner" = {
+    imports = [ (self + /configurations/home/runner.nix) ];
+  };
+
+}

modules/flake-parts/template.nix

@@ -9,11 +9,14 @@
 
         filters = path: with inputs.nixpkgs.lib; {
           homeOnly =
-            hasInfix "configurations/home" path
-            || hasSuffix "activate-home.nix" path;
+            # NOTE: configurations/home/* is imported in nix-darwin and NixOS
+            hasSuffix "activate-home.nix" path;
           darwinOnly =
             hasInfix "configurations/darwin" path
             || hasInfix "modules/darwin" path;
+          nixosOnly =
+            hasInfix "configurations/nixos" path
+            || hasInfix "modules/nixos" path;
           alwaysExclude =
             hasSuffix "LICENSE" path
             || hasSuffix "README.md" path
@@ -48,10 +51,33 @@
           path = builtins.path {
             path = parent.path;
             filter = path: _:
-              !(filters path).darwinOnly;
+              let f = filters path;
+              in
+                !(f.nixosOnly || f.darwinOnly);
           };
         };
 
+        nixos = let parent = templates.default; in {
+          description = mkDescription "NixOS";
+          welcomeText = ''
+            You have just created a nixos-unified-template flake.nix using NixOS.
+
+            - Edit `./modules/nixos/*.nix` to customize your configuration.
+            - Run `mv /etc/nixos/*.nix ./configurations/nixos/HOSTNAME/` to import your existing configuration.
+            - Run `nix --extra-experimental-features "nix-command flakes" run` to apply the configuration.
+
+            Enjoy!
+          '';
+          path = builtins.path {
+            path = parent.path;
+            filter = path: _:
+              let f = filters path;
+              in
+                !(f.darwinOnly || f.homeOnly);
+          };
+
+        };
+
         nix-darwin = let parent = templates.default; in {
           description = mkDescription "nix-darwin";
           welcomeText = ''
@@ -75,7 +101,9 @@
           path = builtins.path {
             path = parent.path;
             filter = path: _:
-              !(filters path).homeOnly;
+              let f = filters path;
+              in
+                !(f.nixosOnly || f.homeOnly);
           };
         };
       };
@@ -111,6 +139,17 @@
         ];
       };
 
+      nixos = {
+        template = templates.nixos;
+        params = [
+          {
+            name = "hostname";
+            description = "Your system hostname as shown by `hostname -s`";
+            placeholder = "example";
+          }
+        ] ++ om.templates.home.params;
+      };
+
       darwin = {
         template = templates.nix-darwin;
         params = [

modules/nixos/default.nix

@@ -0,0 +1,11 @@
+# This is your nix-darwin configuration.
+# For home configuration, see /modules/home/*
+{ flake, pkgs, lib, ... }:
+
+let
+  inherit (flake) inputs;
+  inherit (inputs) self;
+in
+{
+  services.openssh.enable = true;
+}