feat: write these as modules

remote/rss-service/flake.nix

@@ -38,6 +38,8 @@
     {
       packages.${system}.default = noisebell-rss;
 
+      nixosModules.default = import ./module.nix self;
+
       devShells.${system}.default = craneLib.devShell {
         packages = [ pkgs.rust-analyzer ];
       };

remote/rss-service/module.nix

@@ -0,0 +1,78 @@
+self:
+{ config, lib, ... }:
+
+let
+  cfg = config.services.noisebell-rss;
+  bin = "${self.packages.x86_64-linux.default}/bin/noisebell-rss";
+in
+{
+  options.services.noisebell-rss = {
+    enable = lib.mkEnableOption "noisebell RSS/Atom feed";
+
+    domain = lib.mkOption {
+      type = lib.types.str;
+      description = "Domain for the Caddy virtual host.";
+    };
+
+    port = lib.mkOption {
+      type = lib.types.port;
+      default = 3002;
+    };
+
+    webhookSecretFile = lib.mkOption {
+      type = lib.types.path;
+      description = "Path to file containing the webhook secret.";
+    };
+
+    dataDir = lib.mkOption {
+      type = lib.types.str;
+      default = "/var/lib/noisebell-rss";
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    users.users.noisebell-rss = {
+      isSystemUser = true;
+      group = "noisebell-rss";
+    };
+    users.groups.noisebell-rss = {};
+
+    services.caddy.virtualHosts.${cfg.domain}.extraConfig = ''
+      reverse_proxy localhost:${toString cfg.port}
+    '';
+
+    systemd.services.noisebell-rss = {
+      description = "Noisebell RSS/Atom feed";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network-online.target" ];
+      wants = [ "network-online.target" ];
+      environment = {
+        NOISEBELL_RSS_PORT = toString cfg.port;
+        NOISEBELL_RSS_DATA_DIR = cfg.dataDir;
+        NOISEBELL_RSS_SITE_URL = "https://${cfg.domain}";
+        RUST_LOG = "info";
+      };
+      script = ''
+        export NOISEBELL_RSS_WEBHOOK_SECRET="$(cat ${cfg.webhookSecretFile})"
+        exec ${bin}
+      '';
+      serviceConfig = {
+        Type = "simple";
+        Restart = "on-failure";
+        RestartSec = 5;
+        User = "noisebell-rss";
+        Group = "noisebell-rss";
+        StateDirectory = "noisebell-rss";
+        NoNewPrivileges = true;
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        PrivateTmp = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+        RestrictSUIDSGID = true;
+        ReadWritePaths = [ cfg.dataDir ];
+      };
+    };
+  };
+}