gRPC for C++: Libraries, Setup, and Code Examples

Introduction to gRPC for C++

gRPC is a modern Remote Procedure Call (RPC) framework developed by Google. It uses Protocol Buffers (protobuf) for data serialization and HTTP/2 as the transport protocol. For the C++ language, gRPC provides native libraries that allow you to build high-performance microservices and distributed systems.

In this article, we will cover the main libraries, environment setup, and write a complete client-server application example in C++.

Main gRPC Libraries for C++

To work with gRPC in C++, you need to install several components:

• grpc — the core library containing server and client implementations.
• grpc++ — a C++ wrapper over gRPC providing a convenient API.
• protobuf — a library for working with Protocol Buffers (class generation, serialization/deserialization).
• grpc_cpp_plugin — a plugin for the protoc compiler that generates C++ code from .proto files.

Dependencies may also be required: abseil-cpp, openssl, zlib, and c-ares.

Installing gRPC and protobuf

The recommended method is building from source using CMake. Example for Linux/macOS:

git clone --recurse-submodules -b v1.60.0 https://github.com/grpc/grpccd grpcmkdir build && cd buildcmake .. -DgRPC_INSTALL=ON -DCMAKE_INSTALL_PREFIX=/usr/localmake -j$(nproc)sudo make install

After installation, verify the availability of the protobuf compiler and plugin:

protoc --versionwhich grpc_cpp_plugin

Defining a Service via a .proto File

Create a file example.proto:

syntax = "proto3";

package example;

service Greeter {  rpc SayHello (HelloRequest) returns (HelloReply);}

message HelloRequest {  string name = 1;}

message HelloReply {  string message = 1;}

Generate the C++ code:

protoc --cpp_out=. --grpc_out=. --plugin=protoc-gen-grpc=`which grpc_cpp_plugin` example.proto

As a result, the following files will appear: example.pb.h, example.pb.cc, example.grpc.pb.h, example.grpc.pb.cc.

Implementing the Server in C++

Create a file server.cc:

#include <iostream>#include <memory>#include <string>

#include <grpcpp/grpcpp.h>#include "example.grpc.pb.h"

using grpc::Server;using grpc::ServerBuilder;using grpc::ServerContext;using grpc::Status;using example::Greeter;using example::HelloRequest;using example::HelloReply;

class GreeterServiceImpl final : public Greeter::Service {  Status SayHello(ServerContext* context,                  const HelloRequest* request,                  HelloReply* reply) override {    std::string prefix("Hello, ");    reply->set_message(prefix + request->name());    return Status::OK;  }};

void RunServer() {  std::string server_address("0.0.0.0:50051");  GreeterServiceImpl service;

  ServerBuilder builder;  builder.AddListeningPort(server_address, grpc::InsecureServerCredentials());  builder.RegisterService(&service);

  std::unique_ptr<Server> server(builder.BuildAndStart());  std::cout << "Server listening on " << server_address << std::endl;  server->Wait();}

int main() {  RunServer();  return 0;}

Implementing the Client in C++

Create a file client.cc:

#include <iostream>#include <memory>#include <string>

#include <grpcpp/grpcpp.h>#include "example.grpc.pb.h"

using grpc::Channel;using grpc::ClientContext;using grpc::Status;using example::Gree