Spring Boot Microservices Course

This repository contains the source code for the Spring Boot Microservices Course.

We will build a BookStore application using Spring Boot, Spring Cloud, and Docker.

Modules

• catalog-service: This services provides REST API for managing catalog of products(books).

  TechStack: Spring Boot, Spring Data JPA, PostgreSQL

• order-service: This service provides the REST API for managing orders and publishes order events to the message broker.

  TechStack: Spring Boot, Spring Security OAuth2, Keycloak, Spring Data JPA, PostgreSQL, RabbitMQ

• notification-service: This service listens to the order events and sends notifications to the users.

  TechStack: Spring Boot, RabbitMQ

• api-gateway: This service is an API Gateway to the internal backend services (catalog-service, order-service).

  TechStack: Spring Boot, Spring Cloud Gateway

• bookstore-webapp: This is the customer facing web application where customers can browse the catalog, place orders, and view their order details.

  TechStack: Spring Boot, Spring Security OAuth2, Keycloak, Thymeleaf, Alpine.js, Bootstrap

Learning Objectives

• Building Spring Boot REST APIs
• Database Persistence using Spring Data JPA, Postgres, Flyway
• Event Driven Async Communication using RabbitMQ
• Implementing OAuth2-based Security using Spring Security and Keycloak
• Implementing API Gateway using Spring Cloud Gateway
• Implementing Resiliency using Resilience4j
• Job Scheduling with ShedLock-based distributed Locking
• Using RestClient, Declarative HTTP Interfaces to invoke other APIs
• Creating Aggregated Swagger Documentation at API Gateway
• Local Development Setup using Docker, Docker Compose and Testcontainers
• Testing using JUnit 5, RestAssured, Testcontainers, Awaitility, WireMock
• Building Web Application using Thymeleaf, Alpine.js, Bootstrap
• Monitoring & Observability using Grafana, Prometheus, Loki, Tempo

Local Development Setup

• Install Java 21. Recommend using SDKMAN for managing Java versions.
• Install Docker Desktop
• Install IntelliJ IDEA or any of your favorite IDE
• Install Taskfile utility
• Install Postman or any REST Client

$ curl -s "https://get.sdkman.io" | bash
$ source "$HOME/.sdkman/bin/sdkman-init.sh"
$ sdk install java 24.0.1-tem
$ sdk install maven
$ brew install go-task
(or)
$ go install github.com/go-task/task/v3/cmd/task@latest

Verify the prerequisites

$ java -version
$ docker info
$ docker compose version
$ task --version

How to run the application locally?

# Clone the repository: 
$ git clone https://github.com/sivaprasadreddy/spring-boot-microservices-course.git
$ cd spring-boot-microservices-course

Option 1: Start the infra components using Docker Compose and run microservices from IDE

1. Start all the required services such as PostgreSQL, RabbitMQ, Keycloak, etc.: $ task start_infra

2. Start individual microservices: You can start individual microservices by running their respective main entrypoint classes from IDE: ApiGatewayApplication, CatalogServiceApplication, OrderServiceApplication, NotificationServiceApplication, BookstoreWebappApplication

3. Access the application at http://localhost:8080

• Catalog Service PostgreSQL DB: jdbc:postgresql://localhost:15432/postgres with credentials postgres/postgres
• Order Service PostgreSQL DB: jdbc:postgresql://localhost:25433/postgres with credentials postgres/postgres
• RabbitMQ: http://localhost:15672 with credentials guest/guest
• Keycloak: http://localhost:9191 with credentials admin/admin1234
• MailHog: http://localhost:8025

Option 2: Working on individual microservices

Each microservice has Testcontainers based configuration to start the required services such as PostgreSQL, RabbitMQ, Keycloak, etc automatically.

You can start individual microservices by running their respective Test main entrypoint classes from IDE: TestCatalogServiceApplication, TestOrderServiceApplication, TestNotificationServiceApplication, ApiGatewayApplication, BookstoreWebappApplication.

Option 3: Run all the infra components and applications using Docker Compose

1. Start all: $ task start

2. Access the application at http://localhost:8080

Run the application with Observability Stack

1. Start Grafana, Tempo, Loki, Prometheus using $ task start_monitoring
2. Set MANAGEMENT_TRACING_ENABLED=true in deployment/docker-compose/.env file
3. Restart the application using $ task restart

Now you can access the observability stack using the following URLs:

• Access Grafana at http://localhost:3000
• Access Prometheus at http://localhost:9090

Other Learning Resources

• SivaLabs Blog
  • Spring Boot Tutorials
  • Kubernetes Tutorials
  • Spring Security OAuth 2.0 Tutorials
  • A Pragmatic Approach to Software Design
• SivaLabs YouTube Channel
  • Spring Boot Tips Series
  • Spring Boot + Kubernetes Series
  • Spring Boot : The Missing Guide
  • Java Testing Made Easy: Learn writing Unit, Integration, E2E & Performance Tests