Add GetServer to channelz cpp

src/cpp/server/channelz/channelz_service.cc

@@ -59,6 +59,23 @@ Status ChannelzService::GetServers(
   return Status::OK;
 }
 
+Status ChannelzService::GetServer(ServerContext* unused,
+                                  const channelz::v1::GetServerRequest* request,
+                                  channelz::v1::GetServerResponse* response) {
+  char* json_str = grpc_channelz_get_server(request->server_id());
+  if (json_str == nullptr) {
+    return Status(StatusCode::INTERNAL,
+                  "grpc_channelz_get_server returned null");
+  }
+  grpc::protobuf::util::Status s =
+      grpc::protobuf::json::JsonStringToMessage(json_str, response);
+  gpr_free(json_str);
+  if (!s.ok()) {
+    return Status(StatusCode::INTERNAL, s.ToString());
+  }
+  return Status::OK;
+}
+
 Status ChannelzService::GetServerSockets(
     ServerContext* unused, const channelz::v1::GetServerSocketsRequest* request,
     channelz::v1::GetServerSocketsResponse* response) {

src/cpp/server/channelz/channelz_service.h

@@ -36,6 +36,10 @@ class ChannelzService final : public channelz::v1::Channelz::Service {
   Status GetServers(ServerContext* unused,
                     const channelz::v1::GetServersRequest* request,
                     channelz::v1::GetServersResponse* response) override;
+  // implementation of GetServer rpc
+  Status GetServer(ServerContext* unused,
+                   const channelz::v1::GetServerRequest* request,
+                   channelz::v1::GetServerResponse* response) override;
   // implementation of GetServerSockets rpc
   Status GetServerSockets(
       ServerContext* unused,

test/cpp/end2end/channelz_service_test.cc

@@ -41,6 +41,8 @@
 
 using grpc::channelz::v1::GetChannelRequest;
 using grpc::channelz::v1::GetChannelResponse;
+using grpc::channelz::v1::GetServerRequest;
+using grpc::channelz::v1::GetServerResponse;
 using grpc::channelz::v1::GetServerSocketsRequest;
 using grpc::channelz::v1::GetServerSocketsResponse;
 using grpc::channelz::v1::GetServersRequest;
@@ -460,6 +462,29 @@ TEST_F(ChannelzServerTest, BasicServerTest) {
   EXPECT_EQ(response.server_size(), 1);
 }
 
+TEST_F(ChannelzServerTest, BasicGetServerTest) {
+  ResetStubs();
+  ConfigureProxy(1);
+  GetServersRequest get_servers_request;
+  GetServersResponse get_servers_response;
+  get_servers_request.set_start_server_id(0);
+  ClientContext get_servers_context;
+  Status s = channelz_stub_->GetServers(
+      &get_servers_context, get_servers_request, &get_servers_response);
+  EXPECT_TRUE(s.ok()) << "s.error_message() = " << s.error_message();
+  EXPECT_EQ(get_servers_response.server_size(), 1);
+  GetServerRequest get_server_request;
+  GetServerResponse get_server_response;
+  get_server_request.set_server_id(
+      get_servers_response.server(0).ref().server_id());
+  ClientContext get_server_context;
+  s = channelz_stub_->GetServer(&get_server_context, get_server_request,
+                                &get_server_response);
+  EXPECT_TRUE(s.ok()) << "s.error_message() = " << s.error_message();
+  EXPECT_EQ(get_servers_response.server(0).ref().server_id(),
+            get_server_response.server().ref().server_id());
+}
+
 TEST_F(ChannelzServerTest, ServerCallTest) {
   ResetStubs();
   ConfigureProxy(1);