feat(pikachu): add Fabric Minecraft guest

Manage the user Flatpak through nix-flatpak and enable printer discovery through the host firewall.

configs/nixos/guests/minecraft.nix

@@ -0,0 +1,48 @@
+{
+  config,
+  lib,
+  ...
+}:
+let
+  cfg = config.guests.minecraft;
+  minecraftUid = config.registry."stable-uid".${config.networking.hostName}.minecraft;
+in
+{
+  options.guests.minecraft.statePath = lib.mkOption {
+    type = lib.types.nullOr lib.types.str;
+    default = null;
+    example = "/srv/minecraft/main";
+    description = "Host path bind-mounted as Minecraft's durable server state.";
+  };
+
+  config = lib.mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = cfg.statePath != null;
+        message = "guests.minecraft.statePath must point at the host directory that stores Minecraft state.";
+      }
+    ];
+
+    registry."stable-uid".${config.networking.hostName}.minecraft = 20008;
+
+    guests.minecraft = {
+      interior = {
+        modules.services.games.minecraft.enable = true;
+        users.users.minecraft.uid = minecraftUid;
+      };
+
+      mounts."/data" = {
+        directory = cfg.statePath;
+        owner = minecraftUid;
+        group = "storage";
+        mode = "0770";
+      };
+
+      limits = {
+        memory = lib.mkDefault "5G";
+        cpu = lib.mkDefault "400%";
+        tasksMax = lib.mkDefault 1024;
+      };
+    };
+  };
+}

configs/nixos/hosts/pikachu/default.nix

@@ -38,7 +38,7 @@
   };
 
   guests.valheim = {
-    enable = true;
+    enable = false;
     vlan = 20;
     address = "10.23.20.197";
     steamPath = "/pikachu/data/steamcmd";
@@ -58,6 +58,12 @@
     };
   };
 
+  guests.minecraft = {
+    enable = true;
+    vlan = 20;
+    statePath = "/pikachu/media/games/servers/minecraft/main";
+  };
+
   guests.palworld = {
     enable = true;
     vlan = 20;

configs/nixos/hosts/zeus/default.nix

@@ -43,7 +43,9 @@
   modules.shell.omp.enable = true;
 
   modules.desktop.enable = true;
+  modules.desktop.apps.bambu-studio.enable = true;
   modules.desktop.apps.obsidian.enable = true;
+  modules.desktop.apps.prismlauncher.enable = true;
   modules.desktop.apps.r2modman.enable = true;
   modules.desktop.emulation.enable = true;
   modules.desktop.apps.signal.enable = true;

configs/nixos/modules/desktop/apps/bambu-studio.nix

@@ -0,0 +1,36 @@
+{
+  config,
+  inputs,
+  lib,
+  util,
+  ...
+}:
+# Bambu Studio for preparing and monitoring Bambu Lab prints.
+let
+  user = config.user.name;
+in
+{
+  options.modules.desktop.apps.bambu-studio.enable =
+    lib.mkEnableOption "Bambu Studio for preparing and monitoring Bambu Lab prints";
+
+  config = lib.mkIf config.modules.desktop.apps.bambu-studio.enable {
+    services.flatpak.enable = true;
+
+    home-manager.sharedModules = [ inputs.nix-flatpak.homeManagerModules.nix-flatpak ];
+    home-manager.users.${user}.services.flatpak = {
+      enable = true;
+      packages = [ "com.bambulab.BambuStudio" ];
+    };
+
+    # Bambu printers announce themselves with SSDP multicast or broadcast traffic.
+    networking.firewall.allowedUDPPorts = [
+      1990
+      2021
+    ];
+
+    registry.window-icon.${config.networking.hostName}.bambu-studio = {
+      class = "[Bb]ambu[Ss]tudio";
+      icon = util.glyph "f1b2";
+    };
+  };
+}

configs/nixos/modules/desktop/apps/prismlauncher.nix

@@ -0,0 +1,24 @@
+{
+  config,
+  lib,
+  pkgs,
+  util,
+  ...
+}:
+# Prism Launcher manages Minecraft instances.
+let
+  user = config.user.name;
+in
+{
+  options.modules.desktop.apps.prismlauncher.enable =
+    lib.mkEnableOption "Prism Launcher, a Minecraft launcher";
+
+  config = lib.mkIf config.modules.desktop.apps.prismlauncher.enable {
+    home-manager.users.${user}.home.packages = [ pkgs.prismlauncher ];
+
+    registry.window-icon.${config.networking.hostName}.prismlauncher = {
+      class = "PrismLauncher";
+      icon = util.glyph "f11b";
+    };
+  };
+}

configs/nixos/modules/services/games/minecraft.nix

@@ -0,0 +1,42 @@
+{
+  config,
+  inputs,
+  lib,
+  pkgs,
+  ...
+}:
+{
+  imports = [ inputs.nix-minecraft.nixosModules.minecraft-servers ];
+
+  options.modules.services.games.minecraft.enable = lib.mkEnableOption "Fabric Minecraft server";
+
+  config = lib.mkIf config.modules.services.games.minecraft.enable {
+    nixpkgs.overlays = [ inputs.nix-minecraft.overlays.default ];
+
+    services.minecraft-servers = {
+      enable = true;
+      eula = true;
+      openFirewall = true;
+      dataDir = "/data";
+
+      managementSystem = {
+        tmux.enable = false;
+        systemd-socket.enable = true;
+      };
+
+      servers.main = {
+        enable = true;
+        package = pkgs.fabricServers.fabric-1_21_1;
+        jvmOpts = [
+          "-Xms1G"
+          "-Xmx4G"
+        ];
+        serverProperties = {
+          "enable-rcon" = false;
+          "online-mode" = true;
+          "white-list" = false;
+        };
+      };
+    };
+  };
+}

configs/nixos/registry/stable-uid.nix

@@ -12,7 +12,7 @@ let
 
 in
 {
-  # Next stable UID: 20007
+  # Next stable UID: 20009
 
   type = lib.types.ints.positive;
 

flake.lock

@@ -147,6 +147,22 @@
         "type": "github"
       }
     },
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1747046372,
+        "narHash": "sha256-CIVLLkVgvHYbgI2UpXvIIBJ12HWgX+fjA8Xf8PUmqCY=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "9100a0f413b0c601e0533d1d94ffd501ce2e7885",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
     "flake-parts": {
       "inputs": {
         "nixpkgs-lib": [
@@ -321,6 +337,44 @@
         "type": "github"
       }
     },
+    "nix-flatpak": {
+      "locked": {
+        "lastModified": 1767983141,
+        "narHash": "sha256-7ZCulYUD9RmJIDULTRkGLSW1faMpDlPKcbWJLYHoXcs=",
+        "owner": "gmodena",
+        "repo": "nix-flatpak",
+        "rev": "440818969ac2cbd77bfe025e884d0aa528991374",
+        "type": "github"
+      },
+      "original": {
+        "owner": "gmodena",
+        "ref": "v0.7.0",
+        "repo": "nix-flatpak",
+        "type": "github"
+      }
+    },
+    "nix-minecraft": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "nixpkgs": [
+          "nixpkgs"
+        ],
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1793597892,
+        "narHash": "sha256-uyZuURB0yrD2yCSfCLAtCdB6EYlf0oGRCaYMnOFO36c=",
+        "owner": "Infinidoge",
+        "repo": "nix-minecraft",
+        "rev": "87ca2dedb204ecf30ae060beaea10b986ab92dd9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "Infinidoge",
+        "repo": "nix-minecraft",
+        "type": "github"
+      }
+    },
     "nixos-hardware": {
       "inputs": {
         "nixpkgs": [
@@ -408,7 +462,7 @@
         "nixpkgs": [
           "nixpkgs"
         ],
-        "systems": "systems"
+        "systems": "systems_2"
       },
       "locked": {
         "lastModified": 1792012326,
@@ -456,6 +510,8 @@
         "firefox-addons": "firefox-addons",
         "gitea-axi": "gitea-axi",
         "home-manager": "home-manager_3",
+        "nix-flatpak": "nix-flatpak",
+        "nix-minecraft": "nix-minecraft",
         "nixos-hardware": "nixos-hardware",
         "nixpkgs": "nixpkgs_2",
         "nixpkgs-stable": "nixpkgs-stable",
@@ -499,7 +555,7 @@
           "nixpkgs"
         ],
         "nur": "nur",
-        "systems": "systems_2",
+        "systems": "systems_3",
         "tinted-kitty": "tinted-kitty",
         "tinted-schemes": "tinted-schemes",
         "tinted-tmux": "tinted-tmux",
@@ -520,6 +576,21 @@
       }
     },
     "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    },
+    "systems_2": {
       "flake": false,
       "locked": {
         "lastModified": 1791244623,
@@ -536,7 +607,7 @@
         "type": "github"
       }
     },
-    "systems_2": {
+    "systems_3": {
       "locked": {
         "lastModified": 1774449309,
         "narHash": "sha256-brhZ8DmuGtzkCYHJg4HEd602amKm89Y9ytsFZ5uWD1w=",

flake.nix

@@ -16,6 +16,15 @@
       inputs.nixpkgs.follows = "nixpkgs";
     };
 
+    # Installs Flatpak applications declaratively.
+    nix-flatpak.url = "github:gmodena/nix-flatpak/?ref=v0.7.0";
+
+    # Packages reproducible Minecraft servers and modpacks.
+    nix-minecraft = {
+      url = "github:Infinidoge/nix-minecraft";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
     # Provides signed AMO extensions pinned by version and hash.
     firefox-addons = {
       url = "gitlab:rycee/nur-expressions?dir=pkgs/firefox-addons";