Implement per-backend session limit for clusters.

grpc_backend.proto

@@ -0,0 +1,38 @@
+/**
+ * Standalone signaling server for the Nextcloud Spreed app.
+ * Copyright (C) 2022 struktur AG
+ *
+ * @author Joachim Bauch <bauch@struktur.de>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+ syntax = "proto3";
+
+ option go_package = "github.com/strukturag/nextcloud-spreed-signaling;signaling";
+
+ package signaling;
+
+ service RpcBackend {
+   rpc GetSessionCount(GetSessionCountRequest) returns (GetSessionCountReply) {}
+ }
+
+ message GetSessionCountRequest {
+  string url = 1;
+ }
+
+ message GetSessionCountReply {
+   uint32 count = 1;
+ }