feat: Added nixos module.

README.md

@@ -94,6 +94,33 @@ run the built binary (`result/libexec/omnisearch`) from a directory containing
 Docker also builds from `vendor/beaker`; non-Nix local builds still require
 Beaker to be installed separately.
 
+### NixOS service
+
+Import the module from this flake and enable the service:
+
+```nix
+{
+  imports = [ omnisearch.nixosModules.default ];
+
+  services.omnisearch = {
+    enable = true;
+    openFirewall = true;
+    settings = {
+      server = { host = "127.0.0.1"; port = 8087; };
+      engines.engines = "*";
+      rate_limit = { search_requests = 10; search_interval = 60; };
+    };
+  };
+}
+```
+
+The module manages a system user, systemd service, persistent cache/state
+directories and the asset links needed by OmniSearch. `settings` uses INI
+sections and keys matching `example-config.ini`; `extraConfig` appends raw INI
+text after those generated settings. Both are embedded in the world-readable
+Nix store, so do not put credentials or other secrets in them. The firewall
+remains closed unless `openFirewall` is enabled.
+
 ## Deploy with Docker Compose
 
 You need Docker or Podman and Docker Compose installed on your system.

flake.nix

@@ -81,5 +81,7 @@
           '';
         };
       });
+
+      nixosModules.default = import ./nixos-module.nix { inherit self; };
     };
 }

nixos-module.nix

@@ -0,0 +1,121 @@
+{ self }:
+{ config, lib, pkgs, ... }:
+let
+  inherit (lib) mkEnableOption mkIf mkOption types;
+  cfg = config.services.omnisearch;
+  generatedConfig = pkgs.writeText "omnisearch-config.ini" ''
+    ${lib.generators.toINI {} cfg.settings}
+    ${cfg.extraConfig}
+  '';
+  assetDir = "${cfg.package}/share/omnisearch";
+in
+{
+  options.services.omnisearch = {
+    enable = mkEnableOption "OmniSearch metasearch server";
+
+    package = mkOption {
+      type = types.package;
+      default = self.packages.${pkgs.stdenv.hostPlatform.system}.default;
+      defaultText = lib.literalExpression "packages.${pkgs.stdenv.hostPlatform.system}.default";
+      description = "OmniSearch package to run.";
+    };
+
+    user = mkOption {
+      type = types.str;
+      default = "omnisearch";
+      description = "User account under which OmniSearch runs.";
+    };
+
+    group = mkOption {
+      type = types.str;
+      default = "omnisearch";
+      description = "Group under which OmniSearch runs.";
+    };
+
+    settings = mkOption {
+      type = types.attrsOf (types.attrsOf (types.oneOf [ types.str types.int types.bool ]));
+      default = {
+        server = {
+          host = "0.0.0.0";
+          port = 8087;
+        };
+        cache.dir = "/var/cache/omnisearch";
+        engines.engines = "*";
+      };
+      example = {
+        server = { host = "127.0.0.1"; port = 8087; };
+        engines.engines = "ddg,startpage";
+        rate_limit = { search_requests = 10; search_interval = 60; };
+      };
+      description = ''
+        INI settings grouped by section. Section and key names follow
+        `example-config.ini`; values are written as strings, integers or
+        booleans. The generated INI is stored in the world-readable Nix store,
+        so do not put secrets here.
+      '';
+    };
+
+    extraConfig = mkOption {
+      type = types.lines;
+      default = "";
+      example = ''
+        [proxy]
+        proxy = "socks5://127.0.0.1:9050"
+      '';
+      description = ''
+        Additional raw INI text appended after the generated `settings`.
+        This text is also embedded in the world-readable Nix store; avoid
+        including secrets.
+      '';
+    };
+
+    openFirewall = mkOption {
+      type = types.bool;
+      default = false;
+      description = "Whether to open the configured TCP port in the firewall.";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    users.groups.${cfg.group} = {};
+    users.users.${cfg.user} = {
+      isSystemUser = true;
+      group = cfg.group;
+      description = "OmniSearch service user";
+    };
+
+    networking.firewall.allowedTCPPorts = lib.mkIf cfg.openFirewall [
+      (cfg.settings.server.port or 8087)
+    ];
+
+    systemd.services.omnisearch = {
+      description = "OmniSearch metasearch server";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+      wants = [ "network-online.target" ];
+      serviceConfig = {
+        Type = "simple";
+        User = cfg.user;
+        Group = cfg.group;
+        StateDirectory = "omnisearch";
+        CacheDirectory = "omnisearch";
+        WorkingDirectory = "/var/lib/omnisearch";
+        ExecStartPre = pkgs.writeShellScript "omnisearch-prepare" ''
+          ln -sfn ${lib.escapeShellArg "${assetDir}/templates"} templates
+          ln -sfn ${lib.escapeShellArg "${assetDir}/static"} static
+          ln -sfn ${lib.escapeShellArg "${assetDir}/locales"} locales
+          ln -sfn ${lib.escapeShellArg (toString generatedConfig)} config.ini
+        '';
+        ExecStart = "${cfg.package}/bin/omnisearch";
+        Restart = "on-failure";
+        RestartSec = "5s";
+        PrivateTmp = true;
+        NoNewPrivileges = true;
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        ReadWritePaths = [ "/var/lib/omnisearch" "/var/cache/omnisearch" ];
+        RestrictAddressFamilies = [ "AF_UNIX" "AF_INET" "AF_INET6" ];
+      };
+    };
+  };
+}