👋 Realtime-Communication

A cloud-native microservices application built using Spring Boot, Apache Kafka, MySQL, Docker, and Kubernetes. This project demonstrates the fundamentals of distributed systems using event-driven architecture, REST APIs, and modern container orchestration.

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📌 Project Overview

The Hello Application is a microservices-based system that includes:

• Producer Service – Publishes messages to Kafka.
• Consumer Service – Consumes messages from Kafka and writes to MySQL.
• Hello Service – Serves simple REST-based greetings.
• API Gateway – Exposes a unified entry point for routing client requests to internal services.

All services are containerized and managed with Docker Compose and Kubernetes for scalable deployment.

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📂 Folder Structure

      hello-app/
      │
      ├── producer-service/
      │   ├── src/...
      │   ├── Dockerfile
      │
      ├── consumer-service/
      │   ├── src/...
      │   ├── Dockerfile
      │
      ├── hello-service/
      │   ├── src/...
      │   ├── Dockerfile
      │
      ├── api-gateway/
      │   ├── src/...
      │   ├── Dockerfile
      │
      ├── docker/
      │   ├── docker-compose.yml (Kafka + MySQL)
      │
      └── k8s/
            ├── producer-deployment.yml
            ├── consumer-deployment.yml
            ├── mysql-deployment.yml
            ├── kafka-deployment.yml
            ├── gateway-ingress.yml

🧱 Architecture

Components:

• Microservices: Spring Boot services (producer, consumer, hello-service)
• Event Broker: Kafka (Confluent Platform)
• Database: MySQL
• Gateway: Spring Cloud Gateway

                          +------------------------+
                          |      API Gateway       |
                          |    (Spring Cloud)      |
                          +-----------+------------+
                                      |
        +-----------------------------+-----------------------------+
        |                             |                             |
        v                             v                             v
  +-------------+             +---------------+               +-------------+
  | Hello       |             | Producer      |               |   Kafka     |
  | Service     |             | Service       |-------------->| (Broker)    |
  +-------------+             +---------------+               +-------------+
        |                                                          |
        |                                                          v
        |                                                  +---------------+
        |                                                  |  Consumer     |
        +----------------------------------------------->  |  Service      |
                                                           | (writes to DB)|
                                                           +-------+-------+
                                                                   |
                                                                   v
                                                           +---------------+
                                                           |    MySQL      |
                                                           |   hello_db    |
                                                           +---------------+

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🐳 Docker Setup

📁 Prerequisites

• Docker
• Docker Compose

⚙️ Steps to Run

1. Open your terminal and navigate to the Docker setup folder:

   cd docker

2. Build and start all containers:

   docker compose up --build -d

Steps to Run Locally (Outside of the Docker)

🌐 Services will be available on:

• API Gateway: http://localhost:8080
• Producer Service: http://localhost:8081
• Consumer Service: http://localhost:8082
• Hello Service: http://localhost:8083
• Kafka Broker: localhost:9092
• MySQL Database: localhost:3307 (mapped to container's port 3306)

☸️ Kubernetes Setup

All Kubernetes manifests are in the k8s/ directory.

📂 Kubernetes Files

      k8s/
      ├── producer-deployment.yml
      ├── consumer-deployment.yml
      ├── hello-deployment.yml
      ├── kafka-deployment.yml
      ├── mysql-deployment.yml
      └── gateway-ingress.yml

⚙️ Steps to Deploy

1. Ensure your Kubernetes cluster is running
   You can use tools like Docker Desktop (with Kubernetes enabled) or Minikube.

2. Apply all the Kubernetes manifests
   Run the following command from the project root:

   kubectl apply -f k8s/
   

3. Verify the resources are up and running

   kubectl get pods
   kubectl get svc

4. If using an Ingress Controller (like NGINX), make sure it's installed and running The gateway will be exposed via the gateway-ingress.yml.

📦 Technologies Used

• Java 21, Spring Boot
• Apache Kafka
• MySQL
• Docker & Docker Compose
• Kubernetes
• Spring Cloud Gateway

👨‍💻 Author

• Pranav Singh Solanki

Feel free to open issues or contribute to the project!