Microservices Architecture Lecture Notes

Introduction

• Discussion with the development team about architecture and technologies.
• Chosen technology stack: Microservices architecture, Spring Boot 3, Spring Cloud.

Application Overview

• Microservices will handle different functionalities of the e-commerce application.
• Mention of a mail confirmation feature.

Implementation Steps

1. Business Requirements

   • Client operates without a digital solution.
   • Requirements include managing products, customer interactions, and payment processing.

2. Application Design

   • Identified domains: Customer, Product, Order, Payment, Notification.
   • Each domain corresponds to a microservice.

3. Microservices Communication

   • Synchronous communication via REST and OpenFeign.
   • Asynchronous communication via Kafka.
   • Configuration management using a config server.
   • Service discovery through Eureka.

4. Email Notification Service

   • Implemented to handle notification emails.
   • Uses Kafka to send and receive messages.

5. Order Microservice

   • Handles order processing, interacts with Product and Payment microservices.
   • Implements order confirmation notifications.
   • Uses Spring Data JPA for database interaction.

6. Payment Microservice

   • Manages payment processing.
   • Interacts with Kafka for sending payment notifications.
   • Utilizes similar structure and design patterns as other microservices.

7. Notification Microservice

   • Handles sending emails based on order and payment confirmations.
   • Utilizes Spring Boot Mail and Kafka for message processing.

8. API Gateway

   • Acts as a single entry point for all microservices.
   • Implemented using Spring Cloud Gateway.
   • Configured to route requests to the appropriate microservice based on URL patterns.

9. Security Integration

   • Integrated Keycloak for authentication and authorization.
   • Configured API Gateway to validate tokens using Keycloak.

10. Distributed Tracing

    • Set up Zipkin to monitor and trace requests across microservices.
    • Implemented tracing for better debugging and performance monitoring.

Environment Setup

• Used Docker for container orchestration.
• Each microservice runs in its own container.
• Config server and Eureka service run in separate containers.

Testing the Application

• Utilized Postman to test API endpoints for customer creation, order processing, and payment handling.
• Verified email notifications and successful order processing.

Summary

• Successfully built and tested an e-commerce application using microservices architecture.
• Demonstrated key principles of microservices, including communication patterns, service discovery, and API management.