nixos/invidious: add options for configuring inv-sig-helper

nixos/modules/services/web-apps/invidious.nix

@@ -199,6 +199,41 @@ let
     };
   };
 
+  sigHelperConfig = lib.mkIf cfg.sig-helper.enable {
+    services.invidious.settings.signature_server = "tcp://${cfg.sig-helper.listenAddress}";
+    systemd.services.invidious-sig-helper = {
+      script = ''
+        exec ${lib.getExe cfg.sig-helper.package} --tcp "${cfg.sig-helper.listenAddress}"
+      '';
+      wantedBy = [ "multi-user.target" ];
+      before = [ "invidious.service" ];
+      wants = [ "network-online.target" ];
+      after = [ "network-online.target" ];
+      serviceConfig = {
+        User = "invidious-sig-helper";
+        DynamicUser = true;
+        Restart = "always";
+
+        PrivateTmp = true;
+        PrivateUsers = true;
+        ProtectSystem = true;
+        ProtectProc = "invisible";
+        ProtectHome = true;
+        PrivateDevices = true;
+        NoNewPrivileges = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+        ProtectKernelLogs = true;
+        CapabilityBoundingSet = "";
+        SystemCallArchitectures = "native";
+        SystemCallFilter = [ "@system-service" "~@privileged" "~@resources" "@network-io" ];
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
+        RestrictNamespaces = true;
+      };
+    };
+  };
+
   nginxConfig = lib.mkIf cfg.nginx.enable {
     services.invidious.settings = {
       https_only = config.services.nginx.virtualHosts.${cfg.domain}.forceSSL;
@@ -392,12 +427,37 @@ in
 
       package = lib.mkPackageOptionMD pkgs "http3-ytproxy" { };
     };
+
+    sig-helper = {
+      enable = lib.mkOption {
+        type = lib.types.bool;
+        default = false;
+        description = ''
+          Whether to enable and configure inv-sig-helper to emulate the youtube client's javascript. This is required
+          to make certain videos playable.
+
+          This will download and run completely untrusted javascript from youtube! While this service is sandboxed,
+          this may still be an issue!
+        '';
+      };
+
+      package = lib.mkPackageOption pkgs "inv-sig-helper" { };
+
+      listenAddress = lib.mkOption {
+        type = lib.types.str;
+        default = "127.0.0.1:2999";
+        description = ''
+          The IP address/port where inv-sig-helper should listen.
+        '';
+      };
+    };
   };
 
   config = lib.mkIf cfg.enable (lib.mkMerge [
     serviceConfig
     localDatabaseConfig
     nginxConfig
     ytproxyConfig
+    sigHelperConfig
   ]);
 }

nixos/tests/invidious.nix

@@ -37,6 +37,19 @@ import ./make-test-python.nix ({ pkgs, ... }: {
           };
           networking.hosts."127.0.0.1" = [ "invidious.example.com" ];
         };
+        nginx-sig-helper.configuration = {
+          services.invidious = {
+            nginx.enable = true;
+            domain = "invidious.example.com";
+            sig-helper.enable = true;
+            settings.log_level = "Trace";
+          };
+          services.nginx.virtualHosts."invidious.example.com" = {
+            forceSSL = false;
+            enableACME = false;
+          };
+          networking.hosts."127.0.0.1" = [ "invidious.example.com" ];
+        };
         nginx-scale.configuration = {
           services.invidious = {
             nginx.enable = true;
@@ -116,6 +129,14 @@ import ./make-test-python.nix ({ pkgs, ... }: {
     curl_assert_status_code("http://invidious.example.com/vi/dQw4w9WgXcQ/mqdefault.jpg", 502)
     machine.succeed("journalctl -eu http3-ytproxy.service | grep -o 'dQw4w9WgXcQ'")
 
+    activate_specialisation("nginx-sig-helper")
+    machine.wait_for_unit("invidious-sig-helper.service")
+    # we can't really test the sig helper that well without internet connection...
+    # invidious does connect to the sig helper though and crashes when the sig helper is not available
+    machine.wait_for_open_port(80)
+    curl_assert_status_code("http://invidious.example.com/search", 200)
+    machine.succeed("journalctl -eu invidious.service | grep -o \"SigHelper: Using helper at 'tcp://127.0.0.1:2999'\"")
+
     postgres_tcp.wait_for_unit("postgresql.service")
     activate_specialisation("postgres-tcp")
     machine.wait_for_open_port(port)