Learn Microservices with Spring Boot 3: A Practical Approach Using Event-Driven Architecture, Cloud-Native Patterns, and Containerization

This book will show you how to build Java-based microservices architecture using the popular Spring Boot framework by evolving a small monolith application to an event-driven architecture composed of several services. This third edition has been updated to cover Spring Boot 3, including its compatibility with Java 17 and Jakarta EE 10, and employs an incremental approach to teach the structure of microservices, test-driven development, and common patterns in distributed systems such as service discovery, load balancing, routing, centralized logs, per-environment configuration, and containerization. Authors Moisés Macero and Tarun Telang get the ball rolling by introducing you to the fundamentals of microservices and Spring Boot before walking you through the development of a basic Spring Boot application. You’ll then see how to build a front end using React, and learn how to use the data layer to read and write data from and to other systems via Spring Boot and its access to Spring Data and its available APIs. Putting together what you've learned thus far, you’ll begin to transform an application from a monolith to a microservice. This pragmatic approach will enable you to better grasp the benefits of using this type of software architecture, instead of keeping you distracted with theoretical concepts. The emphasis is on what matters most, starting with the minimum viable product, while maintaining the ability to adapt and improve your application as needed. After completing this book, you will have the foundational knowledge necessary to build your own microservice-based applications using Spring Boot. What You Will Learn: Gain a thorough understanding of microservices architecture and how it differs from monolithic architectures. Discover the step-by-step process of breaking down a monolithic application into smaller, focused services Build microservices with Spring Boot 3, Spring Data, Spring Cloud, React.js, Docker, Cucumber, and more Develop Java-based microservices using the latest version of Spring Boot, compatible with Java 17 and Jakarta EE 10. Discover architecture patterns for distributed systems such as asynchronous processing, eventual consistency, resilience, scalability, and more Gain insight into event-driven communication patterns and understand how to design and build event-driven microservices Trace every request from beginning to end with Sleuth and centralized logging Deploy your microservices anywhere as Docker containers Who This Book Is For: Those with at least some prior experience with Java programming. Some prior exposure to Spring Boot recommended but not required. Table of Contents About the Authors About the Technical Reviewer Acknowledgments About this Book Chapter 1: Setting the Scene Who Are You? How Is This Book Different from Other Books and Guides? Learning: An Incremental Process Is This a Guide or a Book? From Basics to Advanced Topics Skeleton with Spring Boot, the Professional Way Test-Driven Development Microservices Event-Driven Systems Nonfunctional Requirements Online Content Summary Chapter 2: Basic Concepts Spring Spring Boot Lombok and Java Testing Basics Test-Driven Development Behavior-Driven Development JUnit 5 Mockito AssertJ Testing in Spring Boot Logging Summary and Achievements Chapter 3: A Basic Spring Boot Application Setting Up the Development Environment Java Development Kit 17 Integrated Development Environment (IDE) HTTPie Working with JSON GET Request POST Request cURL The Skeleton Web App Spring Boot Autoconfiguration Three-Tier, Three-Layer Architecture Modeling the Domain Domain Definition and Domain-Driven Design Domain Classes Business Logic What You Need Random Challenges Attempt Verification Presentation Layer REST REST APIs with Spring Boot Designing the APIs Your First Controller How Automatic Serialization Works Testing Controllers with Spring Boot Valid Attempt Test Validating Data in Controllers Summary and Achievements Chapter 4: A Minimal Frontend with React A Quick Intro to React and Node Setting Up the Development Environment The React Skeleton A JavaScript Client The Challenge Component The Main Structure of a Component Rendering Integration with the App Running the Frontend the First Time Debugging Adding CORS Configuration to the Spring Boot App Playing with the Application Deploying the React App Summary and Achievements Chapter 5: The Data Layer The Data Model Choosing a Database SQL vs. NoSQL H2, Hibernate, and JPA Spring Boot Data JPA Dependencies and Autoconfiguration Spring Boot Data JPA Technology Stack Data Source (Auto)configuration Entities Repositories Storing Users and Attempts Displaying Last Attempts Service Layer Controller Layer User Interface Playing with the New Feature Summary and Achievements Chapter 6: Starting with Microservices The Small Monolith Approach Why a Small Monolith? The Problems with Microservices from Day Zero Small Monoliths Are for Small Teams Embracing Refactoring Planning the Small Monolith for a Future Split New Requirements and Gamification Gamification: Points, Badges, and Leaderboards Moving to Microservices Independent Workflows Horizontal vs. Vertical Scalability Fine-Grained Nonfunctional Requirements Other Advantages Disadvantages Architecture Overview Designing and Implementing the New Service Interfaces The Spring Boot Skeleton for Gamification Domain Service Data Controller Configuration Changes in Multiplication Microservice UI Playing with the System Fault Tolerance The Challenges Ahead Tight Coupling Synchronous Interfaces vs. Eventual Consistency Transactions API Exposure Summary and Achievements Chapter 7: Event-Driven Architectures Core Concepts The Message Broker Events and Messages Thinking in Events Asynchronous Messaging Reactive Systems Pros and Cons of Going Event-Driven Messaging Patterns Publish-Subscribe Work Queues Filtering Data Durability Message Broker Protocols, Standards, and Tools AMQP and RabbitMQ Overall Description Exchange Types and Routing Message Acknowledgments and Rejection Setting Up RabbitMQ Spring AMQP and Spring Boot Solution Design Adding the AMQP Starter Event Publishing from Multiplication Gamification as a Subscriber Analysis of Scenarios Happy Flow Gamification Becomes Unavailable The Message Broker Becomes Unavailable Transactionality Scaling Up Microservices Summary and Achievements Chapter 8: Common Patterns in Microservice Architectures Gateway Spring Cloud Gateway The Gateway Microservice Changes in Other Projects Running the Gateway Microservice Next Steps Health Spring Boot Actuator Including Actuator in Your Microservices Service Discovery and Load Balancing Consul Spring Cloud Consul Spring Cloud Load Balancer Service Discovery and Load Balancing in the Gateway Playing with Service Discovery and Load Balancing Configuration per Environment Configuration in Consul Spring Cloud Consul Config Implementing Centralized Configuration Centralized Configuration in Practice Centralized Logs Log Aggregation Pattern A Simple Solution for Log Centralization Consuming Logs and Printing Them Distributed Tracing Spring Cloud Sleuth Implementing Distributed Tracing Containerization Docker Spring Boot and Buildpacks Running Your System in Docker Dockerizing Microservices Dockerizing the UI Dockerizing the Configuration Importer Docker Compose Scaling Up the System with Docker Sharing Docker Images Platforms and Cloud-Native Microservices Container Platforms Application Platforms Cloud Providers Making a Decision Cloud-Native Microservices Conclusions Index