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Learn Microservices with Spring Boot - Chapter 7

This repository contains the source code of the practical use case described in the book Learn Microservices with Spring Boot (2nd Edition).

The book follows a pragmatic approach to building a Microservice Architecture. You start with a small monolith and examine the pros and cons that come with a move to microservices.

Chapter 7 version

In Chapter 7, you learn how to achieve loose coupling with an Event-Driven Architecture using a RabbitMQ message broker. Besides, you go through the extra advantages like the ability to implement different messaging patterns, load balancing, and resilience.

Logical View - Chapter 7

The main concepts included in this chapter are:

  • Event-Driven Architectures: Pros and Cons
  • Embracing Eventual Consistency, all the way up to the UI
  • RabbitMQ main concepts, messaging patterns, and practical implementation
  • Refactoring the microservices towards an Event-Driven strategy
  • Resilience with persistent messages

As usual, the book uses this practical implementation to teach you why introducing a message broker between our microservices is a good idea. You learn the patterns before the tools, so you can use your knowledge to build similar architectures using a different technology stack - e.g. Kafka.

Check the Book's Web Page to see the complete list of chapters.

Running the app


  • JDK 14+
  • Node.js v13.10+
  • npm 6.13.7+
  • RabbitMQ 3.8.3+
  1. You need a RabbitMQ server running. Run the server according to the instructions for your OS, for example:
    $ rabbitmq-server
  2. To start the Multiplication microservice, you can use the command line with the included Maven wrapper:
    multiplication$ ./mvnw spring-boot:run
  3. To start the Gamification microservice, you do the same from its corresponding folder:
    gamification ./mvnw spring-boot:run
  4. The React application can be started with npm. First, you need to download the dependencies with:
    challenges-frontend$ npm install
  5. Then, you start the server with:
    challenges-frontend$ npm start

Once the backend and the fronted are started, you can navigate to http://localhost:3000 in your browser and start resolving multiplication challenges. This time, you'll see the Leaderboard.

Application - Screenshot


  • Do you have questions about how to make this application work?
  • Did you get the book and have questions about any concept explained within this chapter?
  • Have you found issues using updated dependencies?

Don't hesitate to create an issue in this repository and post your question/problem there.

About the book

Are you interested in building a microservice architecture from scratch? You'll face all the challenges of designing and implementing a distributed system one by one, and will be able to evaluate if it's the best choice for your project.

Visit for all the details about the book.


You can buy the book online from these stores:

Source code by chapter (all repositories are available on Github)

Extra chapters: