added stuff from morph

modules/default.nix

@@ -0,0 +1,5 @@
+{
+  imports = [
+    ./gotosocial.nix
+  ];
+}

modules/gotosocial.nix

@@ -0,0 +1,169 @@
+{ config, lib, pkgs, ... }:
+let
+  cfg = config.services.gotosocial;
+  settingsFormat = pkgs.formats.yaml { };
+  configFile = settingsFormat.generate "config.yml" cfg.settings;
+  defaultSettings = {
+    application-name = "gotosocial";
+
+    protocol = "https";
+
+    bind-address = "127.0.0.1";
+    port = 8080;
+
+    storage-local-base-path = "/var/lib/gotosocial/storage";
+
+    db-type = "sqlite";
+    db-address = "/var/lib/gotosocial/database.sqlite";
+  };
+  gotosocial-admin = pkgs.writeShellScriptBin "gotosocial-admin" ''
+    exec systemd-run \
+      -u gotosocial-admin.service \
+      -p Group=gotosocial \
+      -p User=gotosocial \
+      -q -t -G --wait --service-type=exec \
+      ${cfg.package}/bin/gotosocial --config-path ${configFile} admin "$@"
+  '';
+in
+{
+  meta.doc = ./gotosocial.md;
+  meta.maintainers = with lib.maintainers; [ misuzu ];
+
+  options.services.gotosocial = {
+    enable = lib.mkEnableOption (lib.mdDoc "ActivityPub social network server");
+
+    package = lib.mkPackageOptionMD pkgs "gotosocial" { };
+
+    openFirewall = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      description = lib.mdDoc ''
+        Open the configured port in the firewall.
+        Using a reverse proxy instead is highly recommended.
+      '';
+    };
+
+    setupPostgresqlDB = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      description = lib.mdDoc ''
+        Whether to setup a local postgres database and populate the
+        `db-type` fields in `services.gotosocial.settings`.
+      '';
+    };
+
+    settings = lib.mkOption {
+      type = settingsFormat.type;
+      default = defaultSettings;
+      example = {
+        application-name = "My GoToSocial";
+        host = "gotosocial.example.com";
+      };
+      description = lib.mdDoc ''
+        Contents of the GoToSocial YAML config.
+        Please refer to the
+        [documentation](https://docs.gotosocial.org/en/latest/configuration/)
+        and
+        [example config](https://github.com/superseriousbusiness/gotosocial/blob/main/example/config.yaml).
+        Please note that the `host` option cannot be changed later so it is important to configure this correctly before you start GoToSocial.
+      '';
+    };
+
+    environmentFile = lib.mkOption {
+      type = lib.types.nullOr lib.types.path;
+      description = lib.mdDoc ''
+        File path containing environment variables for configuring the GoToSocial service
+        in the format of an EnvironmentFile as described by systemd.exec(5).
+        This option could be used to pass sensitive configuration to the GoToSocial daemon.
+        Please refer to the Environment Variables section in the
+        [documentation](https://docs.gotosocial.org/en/latest/configuration/).
+      '';
+      default = null;
+      example = "/root/nixos/secrets/gotosocial.env";
+    };
+
+  };
+
+  config = lib.mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = cfg.settings.host or null != null;
+        message = ''
+          You have to define a hostname for GoToSocial (`services.gotosocial.settings.host`), it cannot be changed later without starting over!
+        '';
+      }
+    ];
+
+    services.gotosocial.settings = (lib.mapAttrs (name: lib.mkDefault) (
+      defaultSettings // {
+        web-asset-base-dir = "${cfg.package}/share/gotosocial/web/assets/";
+        web-template-base-dir = "${cfg.package}/share/gotosocial/web/template/";
+      }
+    )) // (lib.optionalAttrs cfg.setupPostgresqlDB {
+      db-type = "postgres";
+      db-address = "/run/postgresql";
+      db-database = "gotosocial";
+      db-user = "gotosocial";
+    });
+
+    environment.systemPackages = [ gotosocial-admin ];
+
+    users.groups.gotosocial = { };
+    users.users.gotosocial = {
+      group = "gotosocial";
+      isSystemUser = true;
+    };
+
+    networking.firewall = lib.mkIf cfg.openFirewall {
+      allowedTCPPorts = [ cfg.settings.port ];
+    };
+
+    services.postgresql = lib.mkIf cfg.setupPostgresqlDB {
+      enable = true;
+      ensureDatabases = [ "gotosocial" ];
+      ensureUsers = [
+        {
+          name = "gotosocial";
+          ensurePermissions = {
+            "DATABASE gotosocial" = "ALL PRIVILEGES";
+          };
+        }
+      ];
+    };
+
+    systemd.services.gotosocial = {
+      description = "ActivityPub social network server";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ]
+        ++ lib.optional cfg.setupPostgresqlDB "postgresql.service";
+      requires = lib.optional cfg.setupPostgresqlDB "postgresql.service";
+      restartTriggers = [ configFile ];
+
+      serviceConfig = {
+        EnvironmentFile = lib.mkIf (cfg.environmentFile != null) cfg.environmentFile;
+        ExecStart = "${cfg.package}/bin/gotosocial --config-path ${configFile} server start";
+        Restart = "on-failure";
+        Group = "gotosocial";
+        User = "gotosocial";
+        StateDirectory = "gotosocial";
+        WorkingDirectory = "/var/lib/gotosocial";
+
+        # Security options:
+        # Based on https://github.com/superseriousbusiness/gotosocial/blob/v0.8.1/example/gotosocial.service
+        AmbientCapabilities = lib.optional (cfg.settings.port < 1024) "CAP_NET_BIND_SERVICE";
+        NoNewPrivileges = true;
+        PrivateTmp = true;
+        PrivateDevices = true;
+        RestrictAddressFamilies = "AF_UNIX AF_INET AF_INET6";
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        DevicePolicy = "closed";
+        ProtectSystem = "full";
+        ProtectControlGroups = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        LockPersonality = true;
+      };
+    };
+  };
+}