configs/nixos/guests/reverse-proxy.nix

@@ -12,43 +12,22 @@ in
       interior = {
         modules.services.reverse-proxy.enable = true;
 
-        services.nginx.virtualHosts = {
-          "games.alexion.dev" = {
+        services.nginx.virtualHosts =
+          lib.genAttrs
+            [
+              "games.alexion.dev"
+              "git.alexion.dev"
+              "photos.alexion.dev"
+              "plex.alexion.dev"
+              "servers.alexion.dev"
+              "todo.alexion.dev"
+              "wings.alexion.dev"
+            ]
+            (_domain: {
               forceSSL = true;
               enableACME = true;
               locations."/".proxyPass = "http://10.23.20.32";
-          };
-          "git.alexion.dev" = {
-            forceSSL = true;
-            enableACME = true;
-            locations."/".proxyPass = "http://10.23.20.32";
-          };
-          "photos.alexion.dev" = {
-            forceSSL = true;
-            enableACME = true;
-            locations."/".proxyPass = "http://10.23.20.32";
-          };
-          "plex.alexion.dev" = {
-            forceSSL = true;
-            enableACME = true;
-            locations."/".proxyPass = "http://10.23.20.32";
-          };
-          "servers.alexion.dev" = {
-            forceSSL = true;
-            enableACME = true;
-            locations."/".proxyPass = "http://10.23.20.32";
-          };
-          "todo.alexion.dev" = {
-            forceSSL = true;
-            enableACME = true;
-            locations."/".proxyPass = "http://10.23.20.32";
-          };
-          "wings.alexion.dev" = {
-            forceSSL = true;
-            enableACME = true;
-            locations."/".proxyPass = "http://10.23.20.32";
-          };
-        };
+            });
 
         networking.firewall.allowedTCPPorts = [ 2022 ];
 

configs/nixos/hosts/pikachu/default.nix

@@ -60,7 +60,6 @@
     serverName = "Tracion";
     autoStart = false;
     adminPasswordSecret = "services/game-servers/admin/password";
-    publicIP = config.guests.palworld.address;
     reverseProxy = {
       enable = true;
       route = {

configs/nixos/hosts/zeus/default.nix

@@ -1,6 +1,5 @@
 {
   config,
-  lib,
   ...
 }:
 # zeus — Ryzen desktop with AMD graphics.
@@ -8,9 +7,9 @@
 # `fileSystems` are derived from it, none declared here.
 {
   imports = [
+    ./hardware-configuration.nix
     ./disk.nix
-  ]
-  ++ lib.optional (builtins.pathExists ./hardware-configuration.nix) ./hardware-configuration.nix;
+  ];
 
   nixpkgs.hostPlatform = "x86_64-linux";
 

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

@@ -62,18 +62,6 @@
       description = "Start the Palworld server after the guest reaches network readiness.";
     };
 
-    rcon = {
-      enable = lib.mkEnableOption "Palworld RCON" // {
-        default = true;
-      };
-
-      port = lib.mkOption {
-        type = lib.types.port;
-        default = 25575;
-        description = "TCP port for Palworld RCON.";
-      };
-    };
-
     passwordFile = lib.mkOption {
       type = lib.types.path;
       description = "Runtime file containing the Palworld server password.";
@@ -89,65 +77,120 @@
     let
       service = config.modules.services.games.palworld;
       savedDir = "${service.installDir}/Pal/Saved";
+      defaultSettingsFile = "${service.installDir}/DefaultPalWorldSettings.ini";
+      settingsFile = "${savedDir}/Config/LinuxServer/PalWorldSettings.ini";
+      renderSettingsScript = pkgs.writeText "render-palworld-settings.py" ''
+        import json
+        import os
+        from pathlib import Path
+        import re
+        import sys
+        import tempfile
+
+        default_path, settings_path, server_name, password_path, admin_password_path = sys.argv[1:]
+        default_path = Path(default_path)
+        settings_path = Path(settings_path)
+
+        source_path = settings_path if settings_path.exists() else default_path
+        text = source_path.read_text(encoding="utf-8")
+
+        def read_secret(path):
+            return Path(path).read_text(encoding="utf-8").rstrip("\r\n")
+
+        def set_string_setting(text, name, value):
+            assignment = f"{name}={json.dumps(value, ensure_ascii=False)}"
+            pattern = re.compile(rf'(?<![A-Za-z0-9_]){re.escape(name)}="(?:[^"\\]|\\.)*"')
+            text, replacements = pattern.subn(lambda _match: assignment, text, count=1)
+            if replacements:
+                return text
+
+            marker = "OptionSettings=("
+            if marker not in text:
+                raise ValueError(f"{source_path} has no OptionSettings declaration")
+            return text.replace(marker, f"{marker}{assignment},", 1)
+
+        settings = {
+            "ServerName": server_name,
+            "ServerPassword": read_secret(password_path),
+            "AdminPassword": read_secret(admin_password_path),
+        }
+        for name, value in settings.items():
+            text = set_string_setting(text, name, value)
+
+        settings_path.parent.mkdir(parents=True, exist_ok=True)
+        descriptor, temporary_name = tempfile.mkstemp(
+            prefix=f".{settings_path.name}.",
+            dir=settings_path.parent,
+        )
+        temporary_path = Path(temporary_name)
+        try:
+            os.fchmod(descriptor, 0o600)
+            with os.fdopen(descriptor, "w", encoding="utf-8", newline="\n") as settings_file:
+                settings_file.write(text)
+            os.replace(temporary_path, settings_path)
+        finally:
+            temporary_path.unlink(missing_ok=True)
+      '';
       startScript = pkgs.writeShellScript "palworld-start" ''
         set -eu
 
-        ${pkgs.coreutils}/bin/install -d \
+        ${lib.getExe' pkgs.coreutils "install"} -d \
           -m 0770 \
+          -- \
           ${lib.escapeShellArg service.stateDir} \
           ${lib.escapeShellArg (builtins.dirOf savedDir)}
 
         if [ -L ${lib.escapeShellArg savedDir} ]; then
-          current_target="$(${pkgs.coreutils}/bin/readlink ${lib.escapeShellArg savedDir})"
+          current_target="$(${lib.getExe' pkgs.coreutils "readlink"} -- ${lib.escapeShellArg savedDir})"
           if [ "$current_target" != ${lib.escapeShellArg service.stateDir} ]; then
-            ${pkgs.coreutils}/bin/rm ${lib.escapeShellArg savedDir}
+            ${lib.getExe' pkgs.coreutils "rm"} -- ${lib.escapeShellArg savedDir}
           fi
         fi
 
         if [ -d ${lib.escapeShellArg savedDir} ] && [ ! -L ${lib.escapeShellArg savedDir} ]; then
-          if ${pkgs.findutils}/bin/find ${lib.escapeShellArg service.stateDir} -mindepth 1 -maxdepth 1 | ${pkgs.gnugrep}/bin/grep -q .; then
-            ${pkgs.coreutils}/bin/rm -rf ${lib.escapeShellArg savedDir}
+          if ${lib.getExe' pkgs.findutils "find"} -- ${lib.escapeShellArg service.stateDir} -mindepth 1 -maxdepth 1 | ${lib.getExe pkgs.gnugrep} -q .; then
+            ${lib.getExe' pkgs.coreutils "rm"} -rf -- ${lib.escapeShellArg savedDir}
           else
-            ${pkgs.coreutils}/bin/cp -a ${lib.escapeShellArg savedDir}/. ${lib.escapeShellArg service.stateDir}/
-            ${pkgs.coreutils}/bin/rm -rf ${lib.escapeShellArg savedDir}
+            ${lib.getExe' pkgs.coreutils "cp"} -a -- ${lib.escapeShellArg savedDir}/. ${lib.escapeShellArg service.stateDir}/
+            ${lib.getExe' pkgs.coreutils "rm"} -rf -- ${lib.escapeShellArg savedDir}
           fi
         fi
 
         if [ ! -e ${lib.escapeShellArg savedDir} ]; then
-          ${pkgs.coreutils}/bin/ln -s ${lib.escapeShellArg service.stateDir} ${lib.escapeShellArg savedDir}
+          ${lib.getExe' pkgs.coreutils "ln"} -s -- ${lib.escapeShellArg service.stateDir} ${lib.escapeShellArg savedDir}
         fi
 
-        password="$(${pkgs.coreutils}/bin/tr -d '\n' < ${lib.escapeShellArg service.passwordFile})"
-        admin_password="$(${pkgs.coreutils}/bin/tr -d '\n' < ${lib.escapeShellArg service.adminPasswordFile})"
+        ${lib.getExe pkgs.python3} \
+          ${renderSettingsScript} \
+          ${lib.escapeShellArg defaultSettingsFile} \
+          ${lib.escapeShellArg settingsFile} \
+          ${lib.escapeShellArg service.serverName} \
+          ${lib.escapeShellArg service.passwordFile} \
+          ${lib.escapeShellArg service.adminPasswordFile}
 
-        exec ./PalServer.sh \
-          "$@" \
-          "-serverpassword=$password" \
-          "-adminpassword=$admin_password"
+        exec ./PalServer.sh "$@"
       '';
     in
     {
       modules.services.steamcmd = {
         enable = true;
         inherit (service) steamDir installDir stateDir;
-        serviceName = "palworld-${lib.toLower service.serverName}";
+        serviceName = "palworld";
         appId = 2394010;
         inherit (service) autoStart;
         executable = "${startScript}";
         arguments = [
-          "-useperfthreads"
-          "-NoAsyncLoadingThread"
-          "-UseMultithreadForDS"
           "-port=${toString service.port}"
-          "-publicport=${toString service.port}"
-          "-servername=${service.serverName}"
           "-players=${toString service.maxPlayers}"
         ]
-        ++ lib.optional service.publicLobby "-publiclobby"
+        ++ lib.optionals service.publicLobby (
+          [
+            "-publiclobby"
+            "-publicport=${toString service.port}"
+          ]
           ++ lib.optionals (service.publicIP != null) [ "-publicip=${service.publicIP}" ]
-        ++ lib.optional service.rcon.enable "-rcon";
+        );
         udpPorts = [ service.port ];
-        tcpPorts = [ service.port ];
       };
     }
   );

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

@@ -51,7 +51,7 @@
       startScript = pkgs.writeShellScript "valheim-start" ''
         set -eu
 
-        password="$(${pkgs.coreutils}/bin/tr -d '\n' < ${lib.escapeShellArg service.passwordFile})"
+        password="$(${lib.getExe' pkgs.coreutils "tr"} -d '\n' < ${lib.escapeShellArg service.passwordFile})"
         exec ./valheim_server.x86_64 "$@" -password "$password"
       '';
     in

configs/nixos/modules/services/steamcmd.nix

@@ -15,7 +15,7 @@
     };
 
     serviceName = lib.mkOption {
-      type = lib.types.str;
+      type = lib.types.strMatching "[A-Za-z0-9_.@-]+";
       example = "valheim";
       description = "Name of the systemd service that runs the game server.";
     };
@@ -87,10 +87,11 @@
         prepareScript = pkgs.writeShellScript "steamcmd-${service.serviceName}-prepare" ''
           set -eu
 
-          ${pkgs.coreutils}/bin/install -d \
+          ${lib.getExe' pkgs.coreutils "install"} -d \
             -o ${user} \
             -g ${group} \
             -m 0770 \
+            -- \
             ${lib.escapeShellArg service.steamDir} \
             ${lib.escapeShellArg service.installDir} \
             ${lib.escapeShellArg service.stateDir}
@@ -110,7 +111,7 @@
         startScript = pkgs.writeShellScript "steamcmd-${service.serviceName}-start" ''
           set -eu
 
-          cd ${lib.escapeShellArg service.installDir}
+          cd -- ${lib.escapeShellArg service.installDir}
           export LD_LIBRARY_PATH=linux64:''${LD_LIBRARY_PATH-}
           exec ${lib.getExe pkgs.steam-run} ${lib.escapeShellArg service.executable} ${lib.escapeShellArgs service.arguments}
         '';
@@ -155,7 +156,7 @@
             wantedBy = lib.mkIf service.autoStart [ "multi-user.target" ];
             serviceConfig = {
               Type = "oneshot";
-              ExecStart = "${pkgs.systemd}/bin/systemctl --no-block start ${service.serviceName}.service";
+              ExecStart = "${lib.getExe' pkgs.systemd "systemctl"} --no-block -- start ${service.serviceName}.service";
             };
           };
 

configs/nixos/modules/shell/fish/default.nix

@@ -86,7 +86,7 @@ in
           backup = {
             description = "Copy <file> to <file>.bak";
             argumentNames = "filename";
-            body = "cp $filename $filename.bak";
+            body = "cp -- $filename $filename.bak";
           };
 
           copy = {

src/dotfiles/default.nix

@@ -22,21 +22,21 @@ let
     root = root + "/registry";
   };
 
-  # TODO: Refactor guest-module composition.
   guestModules = import ./guests.nix {
     inherit
       inputs
       registry
+      repositoryModules
       specialArgs
       util
       ;
-    repositoryModules = modules;
     root = root + "/guests";
   };
-  modules.imports = [
+  repositoryModules.imports = [
     {
       nixpkgs.overlays = [ self.overlays.custom ];
     }
+    registry.module
   ]
   ++ util.collectNixFiles (root + "/modules");
 
@@ -47,8 +47,7 @@ import ./hosts.nix {
     lib
     specialArgs
     guestModules
+    repositoryModules
     ;
-  registryModule = registry.module;
-  repositoryModules = modules;
   root = root + "/hosts";
 }

src/dotfiles/guests.nix

@@ -10,7 +10,12 @@ let
   files = util.collectNixFiles root;
   mkGuest =
     name:
-    { config, lib, ... }:
+    {
+      config,
+      lib,
+      pkgs,
+      ...
+    }:
     let
       cfg = config.guests.${name};
 
@@ -18,10 +23,11 @@ let
 
       directoryScript = lib.concatStringsSep "\n" (
         lib.mapAttrsToList (_: mount: ''
-          ${config.system.path}/bin/install -d \
+          ${lib.getExe' pkgs.coreutils "install"} -d \
             ${lib.optionalString (mount.owner != null) "-o ${lib.escapeShellArg (toString mount.owner)}"} \
             ${lib.optionalString (mount.group != null) "-g ${lib.escapeShellArg mount.group}"} \
             ${lib.optionalString (mount.mode != null) "-m ${lib.escapeShellArg mount.mode}"} \
+            -- \
             ${lib.escapeShellArg mount.directory}
         '') directoryMounts
       );
@@ -254,7 +260,6 @@ let
               inputs.stylix.nixosModules.stylix
 
               repositoryModules
-              registry.module
               cfg.interior
 
               {

src/dotfiles/hosts.nix

@@ -6,7 +6,6 @@
   repositoryModules,
 
   guestModules,
-  registryModule,
 }:
 let
   names = lib.attrNames directories;
@@ -27,8 +26,6 @@ let
         repositoryModules
         guestModules
 
-        # TODO: refactor
-        registryModule
         (root + "/${name}")
 
         {

src/flake/apps.nix

@@ -10,6 +10,7 @@ in
 {
   fix = {
     type = "app";
+    meta.description = "Formats and cleans repository files.";
     program = lib.getExe (
       pkgs.writeShellApplication {
         name = "fix";

src/skills/style/nix/rules/flake.md

@@ -11,3 +11,13 @@ Use `flake.nix` to pass inputs into that implementation.
 ### Rationale
 
 This keeps dependency declarations separate from output logic.
+
+## Describe flake apps
+
+### Rule
+
+Set `meta.description` on every flake app.
+
+### Rationale
+
+Flake tools can display each app's purpose without emitting a missing-metadata warning.

src/skills/style/nix/rules/general.md

@@ -50,3 +50,91 @@ Do not read `config.home-manager.users.<user>.programs.<name>.package` for comma
 Home Manager uses the NixOS package set in this repository.
 `pkgs.<name>` avoids dependency paths through the user tree under Home Manager.
 Configured NixOS package options preserve package selection when a module owns the tool.
+
+## Configure services through documented interfaces
+
+### Rule
+
+Use current upstream documentation when mapping Nix options to service arguments or configuration files.
+Do not expose undocumented service arguments as module options.
+
+### Rationale
+
+Documented interfaces preserve configuration behavior across service updates.
+
+## Keep module options effective
+
+### Rule
+
+Every custom module option must change the generated configuration or behavior.
+Remove unused options instead of exposing speculative configuration.
+
+### Rationale
+
+An inert option promises behavior that the module does not provide.
+
+## Separate public and private addresses
+
+### Rule
+
+Do not assign a private guest address to an option that advertises a public service address.
+Leave optional public-address settings unset when the service can detect them.
+
+### Rationale
+
+Private addresses are not routable by public clients.
+
+## Separate display names from identifiers
+
+### Rule
+
+Do not derive systemd unit names or other machine identifiers from unrestricted display names.
+Give identifiers constrained types or fixed values.
+
+### Rationale
+
+Display names can contain characters that machine interfaces reject or reinterpret.
+
+## Terminate command options before variable paths
+
+### Rule
+
+In generated shell text, pass `--` before variable-derived path operands when the command supports it.
+
+### Rationale
+
+Values that start with a hyphen remain operands instead of command options.
+
+## Compose repository modules once
+
+### Rule
+
+Add shared NixOS modules to `repositoryModules` in `src/dotfiles/default.nix`.
+Import `repositoryModules` into each host and guest.
+Do not pass a shared module through a separate parallel parameter.
+
+### Rationale
+
+A single module collection prevents host and guest configurations from diverging.
+
+## Generate identical named attributes
+
+### Rule
+
+Use `lib.genAttrs` when a fixed list of attribute names shares one value.
+Do not repeat identical attribute bodies.
+
+### Rationale
+
+One definition prevents copied settings from diverging.
+
+## Import tracked host hardware directly
+
+### Rule
+
+Import each tracked `hardware-configuration.nix` directly from its host module.
+Do not guard the import with `builtins.pathExists`.
+
+### Rationale
+
+A missing hardware description must fail evaluation instead of silently changing the host configuration.