Microservices in C++: Architecture and Practice from A to Z

Microservices in C++: Architecture and Practice from A to Z

Microservice architecture has long become the standard for building scalable and fault-tolerant systems. However, most examples on the internet are written in Java, Go, or Python. What if you need maximum performance and control over resources? The answer is microservices in C++. In this article, we will analyze the architecture, key technologies, and write a real example of a microservice in C++.

Why C++ for Microservices?

C++ is traditionally associated with system programming, games, and embedded development. However, its advantages for microservices are obvious:

• Maximum performance — minimal overhead on memory and CPU.
• Fine-grained resource control — manual memory management (or modern smart pointers).
• Low latency — ideal for high-frequency trading, game servers, and IoT.
• Rich library selection — from Boost to gRPC and Poco.

There are also downsides: development complexity, slow compilation, and lack of "quick" prototypes. But with a competent approach, C++ becomes a powerful tool for microservices.

Microservice Architecture in C++

A typical microservice in C++ consists of the following layers:

• Transport layer — HTTP/REST (cpprestsdk), gRPC, WebSocket, or TCP/UDP.
• Business logic — pure C++17/20, data processing, algorithms.
• Data layer — database interaction (PostgreSQL via libpqxx, Redis via hiredis).
• Communication — inter-service communication (gRPC, RabbitMQ, Kafka).

It is important to separate these layers so that each microservice is independent and easily testable.

Practical Example: REST API Microservice in C++

Let's write a simple microservice for task management (Task Manager) using the cpprestsdk (Casablanca) library.

1. Installing Dependencies

For Ubuntu/Debian:

sudo apt-get install libcpprest-dev libboost-all-dev libssl-dev

2. Microservice Code

Create a file task_service.cpp:

#include <cpprest/http_listener.h>#include <cpprest/json.h>#include <iostream>#include <map>#include <mutex>

using namespace web;using namespace web::http;using namespace web::http::experimental::listener;

class TaskService {private:    std::map<int, std::string> tasks;    std::mutex mtx;    int next_id = 1;

    void handle_get(http_request request) {        json::value response;        std::lock_guard<std::mutex> lock(mtx);        for (const auto& [id, desc] : tasks) {            response[std::to_string(id)] = json::value::string(desc);        }        request.reply(status_codes::OK, response);    }

    void handle_post(http_request request) {        request.extract_json().then([this, &request](json::value body) {            std::lock_guard<std::mutex> lock(mtx);            int id = next_id++;            tasks[id] = body.at("description").as_string();            json::value response;            response["id"] = id;            request.reply(status_codes::Created, response);        }).wait();    }

public:    TaskService() {        uri_builder uri("http://localhost:8080");        auto addr = uri.to_uri().to_string();        http_listener listener(addr);

        listener.support(methods::GET,             std::bind(&TaskService::handle_get, this, std::placeholders::_1));        listener.support(methods::POST,             std::bind(&TaskService::handle_post, this, std::placeholders::_1));

        listener.open().then([&addr]() {            std::c