Clean Architecture & Design Patterns in Practice · 강의

마이크로서비스의 클린 아키텍처

개별 마이크로서비스에 클린 아키텍처 원칙을 적용해 내부 일관성과 자율성을 유지하는 방법을 살펴봅니다.

마이크로서비스의 클린 아키텍처은(는) CoddyKit의 무료 Clean Architecture & Design Patterns in Practice 강의입니다. 이것은 4개 중 3번째 강의입니다. 아래에서 전체 강의를 무료로 읽을 수 있으며, 내장 코드 에디터와 24/7 AI 튜터와 함께 브라우저에서 직접 실습할 수 있습니다. 이 강의는 Clean Architecture & Design Patterns in Practice 학습 경로의 일부이며, 진행 상황이 웹과 CoddyKit 앱에 동기화됩니다. Clean Architecture & Design Patterns in Practice 강의에는 총 4개의 강의가 포함되어 있습니다.

이 강의의 일부는 아직 번역되지 않았으며 영어로 표시됩니다.

Microservices Meet Clean Arch

Welcome! In this lesson, we'll explore how the powerful principles of Clean Architecture can be applied within individual microservices.

Microservices are small, independent services that communicate with each other. Combining them with Clean Architecture helps each service stay robust, maintainable, and truly autonomous.

Bounded Contexts & Microservices

A key concept in microservices is the Bounded Context. This means each service defines its own domain model and terminology, separate from others.

A microservice naturally forms a bounded context.
Clean Architecture provides a structured way to manage the internal complexity of this context.
It keeps the core business rules of the microservice isolated.

CA Inside a Microservice

Think of each microservice as having its own miniature Clean Architecture structure. The concentric circles apply internally:

Entities: Core business objects (e.g., User, Product).
Use Cases: Application-specific rules (e.g., CreateUser, PlaceOrder).
Interface Adapters: How the microservice interacts with the outside world (e.g., REST controllers, message queues) and its own data store (e.g., repositories).
Frameworks & Drivers: External tools and technologies used (e.g., Spring Boot, database drivers).

Microservice Communication Layers

For other services or clients to interact with a microservice, they typically do so through its Interface Adapters layer.

This means a microservice exposes its functionality via:

REST API endpoints (e.g., a UserController).
Message queue consumers (e.g., processing an event).
GraphQL endpoints.

These adapters translate external requests into calls to the microservice's internal Use Cases.

Data Ownership in Microservices

A fundamental principle of microservices is that each service owns its data. This means:

No shared databases between services.
The data persistence mechanism is an internal detail of the microservice.

Clean Architecture's Repository Pattern fits perfectly here, abstracting the actual database implementation from the core Use Cases.

Dependency Rule: Microservice Edition

The Dependency Rule is crucial: inner circles must not depend on outer circles. This holds true within a microservice.

Your core Entities and Use Cases should know nothing about your web framework or database.
This keeps your business logic truly independent and testable.
It allows you to swap out frameworks or databases without affecting the core.

Defining Core Contracts

Let's look at a simple example for a 'User' microservice. Here, we define the core User entity and the interfaces for our UserRepository and CreateUserUseCase.

class User {
  private String id;
  private String name;
  private String email;

  public User(String id, String name, String email) {
    this.id = id;
    this.name = name;
    this.email = email;
  }

  public String getId() { return id; }
  public String getName() { return name; }
  public String getEmail() { return email; }
}

interface UserRepository {
  User save(User user);
  User findById(String id);
}

interface CreateUserUseCase {
  User createUser(String name, String email);
}

Implementing Core Logic

Now, we implement the CreateUserUseCase, called an Interactor. It takes a UserRepository (an outer layer interface) as a dependency, adhering to the Dependency Rule.

Run this code to see how the core logic can be tested independently!

import java.util.UUID;
import java.util.HashMap;
import java.util.Map;

class User {
  private String id;
  private String name;
  private String email;

  public User(String id, String name, String email) {
    this.id = id;
    this.name = name;
    this.email = email;
  }

  public String getId() { return id; }
  public String getName() { return name; }
  public String getEmail() { return email; }
}

interface UserRepository {
  User save(User user);
  User findById(String id);
}

interface CreateUserUseCase {
  User createUser(String name, String email);
}

class InMemoryUserRepository implements UserRepository {
  private final Map<String, User> users = new HashMap<>();

  @Override
  public User save(User user) {
    users.put(user.getId(), user);
    return user;
  }

  @Override
  public User findById(String id) {
    return users.get(id);
  }
}

class CreateUserInteractor implements CreateUserUseCase {
  private final UserRepository userRepository;

  public CreateUserInteractor(UserRepository userRepository) {
    this.userRepository = userRepository;
  }

  @Override
  public User createUser(String name, String email) {
    String id = UUID.randomUUID().toString();
    User newUser = new User(id, name, email);
    return userRepository.save(newUser);
  }
}

public class Main {
  public static void main(String[] args) {
    // This simulates the wiring and interaction in a microservice
    UserRepository repo = new InMemoryUserRepository();
    CreateUserUseCase useCase = new CreateUserInteractor(repo);

    User user1 = useCase.createUser("Alice", "alice@example.com");
    System.out.println("Created User: " + user1.getName());

    User foundUser = repo.findById(user1.getId());
    System.out.println("Found User Email: " + foundUser.getEmail());
  }
}

The API Adapter Role

In a real microservice, a UserController (part of the Interface Adapters layer) would receive an HTTP request, map it to a DTO, call the CreateUserUseCase, and then return an HTTP response.

This controller depends on the Use Case, but the Use Case doesn't depend on the controller.

Why This Approach Works

Applying Clean Architecture to microservices offers significant benefits:

High Cohesion: Each microservice's core logic is tightly focused.
Loose Coupling: Core logic is decoupled from frameworks, databases, and even other services.
Independent Deployment: Changes to the UI or database don't affect core business rules.
Enhanced Testability: Business logic can be unit-tested without needing a database or web server.
Maintainability: Easier to understand, modify, and extend over time.

Check Your Understanding

Why is applying Clean Architecture principles within individual microservices particularly beneficial?

Microservices & CA: Summary

In this lesson, we've seen how Clean Architecture provides a robust internal structure for individual microservices. By adhering to the Dependency Rule and separating concerns into layers, each microservice becomes:

Highly autonomous
Easily testable
Flexible and maintainable

This combination ensures that your microservice ecosystem remains agile and resilient.

자주 묻는 질문

“마이크로서비스의 클린 아키텍처” 강의는 무료인가요?

네 — “마이크로서비스의 클린 아키텍처” 전체 내용을 이 웹사이트에서 무료로 읽을 수 있습니다. 인터랙티브하게 실습하려면(내장 코드 에디터와 24/7 AI 튜터), CoddyKit PRO로 업그레이드하면 Clean Architecture & Design Patterns in Practice 강의 전체를 잠금 해제할 수 있습니다. Clean Architecture & Design Patterns in Practice 강의에는 총 4개의 강의가 포함되어 있습니다.

“마이크로서비스의 클린 아키텍처”에서 뭘 배우나요?

개별 마이크로서비스에 클린 아키텍처 원칙을 적용해 내부 일관성과 자율성을 유지하는 방법을 살펴봅니다. 브라우저에서 직접 실행하는 실습 코드로 Clean Architecture & Design Patterns in Practice을(를) 배우며, 24/7 AI 튜터가 강의를 진행하면서 질문에 답변해줍니다.

Clean Architecture & Design Patterns in Practice을(를) 시작하는 데 경험이 필요한가요?

사전 경험은 필요하지 않습니다. CoddyKit의 Clean Architecture & Design Patterns in Practice은(는) 초급자부터 고급 학습자까지를 위해 구성되어 있으므로, 여기서 시작하거나 처음부터 시작할 수 있으며 자신의 속도대로 진행할 수 있습니다. 이것은 4개 중 3번째 강의입니다.

“마이크로서비스의 클린 아키텍처” 강의는 얼마나 걸리나요?

대부분의 CoddyKit 강의는 약 5~10분이 소요됩니다. 각 강의는 간결하고 인터랙티브하여 꾸준한 진행이 가능하며, 웹과 앱에서 중단한 부분부터 바로 시작할 수 있습니다.

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