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Pods/gRPC-C++/include/grpcpp/xds_server_builder.h

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+//
+//
+// Copyright 2020 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+//
+
+#ifndef GRPCPP_XDS_SERVER_BUILDER_H
+#define GRPCPP_XDS_SERVER_BUILDER_H
+
+#include <grpc/support/port_platform.h>
+
+#include <grpcpp/server_builder.h>
+
+namespace grpc {
+
+class XdsServerServingStatusNotifierInterface {
+ public:
+  struct ServingStatusUpdate {
+    grpc::Status status;
+  };
+
+  virtual ~XdsServerServingStatusNotifierInterface() = default;
+
+  // \a uri contains the listening target associated with the notification. Note
+  // that a single target provided to XdsServerBuilder can get resolved to
+  // multiple listening addresses.
+  // The callback is invoked each time there is an update to the serving status.
+  // The API does not provide any guarantees around duplicate updates.
+  // Status::OK signifies that the server is serving, while a non-OK status
+  // signifies that the server is not serving.
+  virtual void OnServingStatusUpdate(std::string uri,
+                                     ServingStatusUpdate update) = 0;
+};
+
+class XdsServerBuilder : public grpc::ServerBuilder {
+ public:
+  // NOTE: class experimental_type is not part of the public API of this class
+  // TODO(yashykt): Integrate into public API when this is no longer
+  // experimental.
+  class experimental_type : public grpc::ServerBuilder::experimental_type {
+   public:
+    explicit experimental_type(XdsServerBuilder* builder)
+        : ServerBuilder::experimental_type(builder), builder_(builder) {}
+
+    // EXPERIMENTAL: Sets the drain grace period in ms for older connections
+    // when updates to a Listener is received.
+    void set_drain_grace_time(int drain_grace_time_ms) {
+      builder_->drain_grace_time_ms_ = drain_grace_time_ms;
+    }
+
+   private:
+    XdsServerBuilder* builder_;
+  };
+
+  // It is the responsibility of the application to make sure that \a notifier
+  // outlasts the life of the server. Notifications will start being made
+  // asynchronously once `BuildAndStart()` has been called. Note that it is
+  // possible for notifications to be made before `BuildAndStart()` returns.
+  void set_status_notifier(XdsServerServingStatusNotifierInterface* notifier) {
+    notifier_ = notifier;
+  }
+
+  /// NOTE: The function experimental() is not stable public API. It is a view
+  /// to the experimental components of this class. It may be changed or removed
+  /// at any time.
+  experimental_type experimental() { return experimental_type(this); }
+
+ private:
+  // Called at the beginning of BuildAndStart().
+  ChannelArguments BuildChannelArgs() override;
+
+  static void OnServingStatusUpdate(void* user_data, const char* uri,
+                                    grpc_serving_status_update update) {
+    if (user_data == nullptr) return;
+    XdsServerServingStatusNotifierInterface* notifier =
+        static_cast<XdsServerServingStatusNotifierInterface*>(user_data);
+    notifier->OnServingStatusUpdate(
+        uri, {grpc::Status(static_cast<StatusCode>(update.code),
+                           update.error_message)});
+  }
+
+  XdsServerServingStatusNotifierInterface* notifier_ = nullptr;
+  int drain_grace_time_ms_ = -1;
+};
+
+}  // namespace grpc
+
+#endif  // GRPCPP_XDS_SERVER_BUILDER_H