gRPC for C++: Libraries, Examples, and Usage Guide

gRPC for C++: Libraries, Examples, and Practical Guide

gRPC is a modern, high-performance remote procedure call (RPC) framework developed by Google. It allows client and server applications in different languages (including C++, Python, Go, Java) to communicate with each other as easily as if they were local function calls. For C++, gRPC provides a powerful, strictly typed interface based on Protocol Buffers (protobuf), making it an ideal choice for building microservices and distributed systems.

In this article, we will cover the key libraries, the installation process, and write a complete example of a gRPC server and client in C++.

Key Libraries for gRPC in C++

To work with gRPC in C++, you will need the following components:

• grpc (libgrpc++) — the core gRPC library. Contains the transport layer implementation (HTTP/2), channels, servers, and asynchronous stacks.
• protobuf (libprotobuf) — a library for serializing structured data. Defines the message format (.proto files) and generates C++ code.
• grpc++ (libgrpc++_unsecure or libgrpc++_reflection) — a high-level C++ wrapper for gRPC. Provides synchronous and asynchronous APIs for services.
• grpc_cpp_plugin — a plugin for the protobuf compiler (protoc) that generates C++ code for gRPC servers and clients.
• abseil-cpp — a library from Google used by gRPC for strings, threads, and synchronization (often included automatically).

Installation and Setup

The recommended installation method is building from source or using the vcpkg/conan package manager. Here we show installation via vcpkg:

# Install vcpkg (if not already installed)git clone https://github.com/Microsoft/vcpkg.gitcd vcpkg./bootstrap-vcpkg.sh

# Install gRPC with C++ support./vcpkg install grpc[ssl]

After installation, link the libraries in CMakeLists.txt:

cmake_minimum_required(VERSION 3.15)project(GrpcExample CXX)

set(CMAKE_CXX_STANDARD 17)find_package(gRPC CONFIG REQUIRED)find_package(Protobuf CONFIG REQUIRED)

# Generate proto filesset(PROTO_FILE proto/hello.proto)set(GENERATED_PROTO_SRC ${CMAKE_CURRENT_BINARY_DIR}/hello.pb.cc)set(GENERATED_PROTO_HDR ${CMAKE_CURRENT_BINARY_DIR}/hello.pb.h)set(GENERATED_GRPC_SRC ${CMAKE_CURRENT_BINARY_DIR}/hello.grpc.pb.cc)set(GENERATED_GRPC_HDR ${CMAKE_CURRENT_BINARY_DIR}/hello.grpc.pb.h)

add_custom_command(    OUTPUT ${GENERATED_PROTO_SRC} ${GENERATED_PROTO_HDR} ${GENERATED_GRPC_SRC} ${GENERATED_GRPC_HDR}    COMMAND protobuf::protoc    ARGS --grpc_out ${CMAKE_CURRENT_BINARY_DIR}         --cpp_out ${CMAKE_CURRENT_BINARY_DIR}         --plugin=protoc-gen-grpc=$<TARGET_FILE:gRPC::grpc_cpp_plugin>         -I ${CMAKE_CURRENT_SOURCE_DIR}/proto         ${CMAKE_CURRENT_SOURCE_DIR}/${PROTO_FILE}    DEPENDS ${PROTO_FILE}    COMMENT "Generating gRPC code from proto files")add_library(generated_proto ${GENERATED_PROTO_SRC} ${GENERATED_GRPC_SRC})target_include_directories(generated_proto PUBLIC ${CMAKE_CURRENT_BINARY_DIR})target_link_libraries(generated_proto gRPC::grpc++ protobuf::libprotobuf)

Creating a .proto File

First, define the service and messages in the hello.proto file:

syntax = "proto3";

package hello;

// Request: send a namemessage HelloRequest {  string name = 1;}

// Response: receive a greetingmessage HelloReply {  string message = 1;}

// Define the gRPC serviceservice Greeter {  // Unary RPC (one request — one response)  rpc SayHello (HelloRequest) returns (HelloReply);}

Implementing the Server in C++

Create a file se