example grpc ciena server

ciena_server.cc

// Code sample. May need minor fixes to compile.

// Create a sync service handling class
class OpenConfigImpl : public openconfigs::OpenConfig::Service {
 public:
  ::grpc::Status::Subscribe(::grpc::ServerContext* context, ::grpc::ServerReaderWriter<SubscribeResponse, SubscribeRequest>* stream) override;
  ::grpc::Status::Set(::grpc::ServerContext* context, ::grpc::ServerReaderWriter<SetResponse, SetRequest>* stream) override;
  // Get will be handled async.
};

// wrapper for data related with one async Get rpc
struct GetRpcData {
  GetRequest get_request;
  GetResponse get_response;
  ::grpc::ServerContext context;
  ::grpc::ServerAsyncResponseWriter<GetResponse> response_writer {&context};
};

// Request to handle a new Get rpc from library.
void RequestGet(::grpc::Service* service, ::grpc::ServerCompletionQueue* cq) {
  // request a new rpc
  auto* data = new GetRpcData;
  service->RequestGet(&data->context, &data->get_request, &data->response_writer, cq, cq, new HandleRpcTag(service, cq, data));
}

// Interface for completion queue tag
class TagInterface {
 public:
  virtual ~TagInterface() {};
  virtual void Run() = 0;
};

class HandleRpcTag : public TagInterface {
 public:
  HandleRpcTag(::grpc::Service* service, ::grpc::ServerCompletionQueue* cq, GetRpcData* data) : service_(service), cq_(cq), data_(data) {}
  void Run() override {
    // Handle request, set response etc here
    RequestGet(service_, cq_);
    data_->response_writer->Finish(data->get_response, ::grpc::Status::OK, new DeleteRpcTag(data));
    delete this;
  }
  
 private:
  ::grpc::Service* service_;
  ::grpc::ServerCompletionQueue* cq_;
  GetRpcData* data_;
};

class DeleteRpcTag : public TagInterface {
 public:
  explicit DeleteRpcTag(GetRpcData* data) : data_(data) {}
  void Run() override { delete data_; delete this; }
 private:
  GetRpcData* data_;
};

void HandleGetRpcs(::grpc::CompletionQueue* cq) {
  void* tag;
  bool ok;
  while (cq->Next(&tag, &ok)) {
    static_cast<TagInterface *>(tag)->Run();
  }
}

int main() {
  // Creating a service
  openconfigs::OpenConfig::WithAsyncMethod_Get<OpenConfigImpl> service;
  ::grpc::ServerBuilder builder;
  builder.AddListeningPort("0.0.0.0:12345", ::grpc::InsecureServerCredentials());
  builder.RegisterService(&service);
  auto cq = builder.AddCompletionQueue();
  auto server = builder.BuildAndStart();
  
  RequestGet(&service, cq.get();
  // This can be run in multiple threads.
  HandleGetRpcs(cq.get());
}