Microservices Quiz App

A scalable Quiz Application built using Java Spring Boot and Microservices architecture. The system separates question management from quiz creation and uses a Service Registry for discovery.

Architecture

The project consists of four main modules:

1. Service Registry (Eureka Server)

• Acts as a discovery server for all microservices.

• Runs on port 8761.

2. Question Service

• Responsible for creating, retrieving, and managing the database of questions.

• Runs on port 8080 (Default).

3. Quiz Service

• Manages the creation of specific quizzes.

• Communicates with the Question Service using Spring Cloud OpenFeign.

• Runs on port 8090.

4. API Gateway

• Entry Point: The single entry point for all client requests.

• Routing: Dynamically routes traffic to services based on the URL path using Eureka Service Discovery.

• Port: 8765.

flowchart LR

   subgraph Client

       A[User Request]

   end



   A --> G[API GatewaynPort 8765]



   subgraph Eureka[Service RegistrynEureka ServernPort 8761]

       E[(Eureka Server)]

   end



   G --> E



   subgraph QuestionService[Question ServicenPort 8080]

       QN1[Question Controller]

       QDB[(PostgreSQL)]

       QN1 --> QDB

   end



   subgraph QuizService[Quiz ServicenPort 8090]

       QS1[Quiz Controller]

       QS1 --> QN1

   end



   E --> QuestionService

   E --> QuizService



   G --> QuestionService

   G --> QuizService

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Tech Stack

• Java 17+

• Spring Boot (Web, Data JPA)

• Spring Cloud (Netflix Eureka, OpenFeign, Gateway)

• PostgreSQL

• Lombok

• Maven

Getting Started

Prerequisites

• Java JDK

• Maven

• PostgreSQL

Installation & Running

1. Clone the repository

git clone https://github.com/modhtom/quiz-app-microservices.git

2. Start the Service Registry

• Navigate to /service-registry

• Run: mvn spring-boot:run

• Verify Eureka is running at http://localhost:8761

3. Start the Question Service

• Navigate to /question-service

• Update application.properties with your database credentials.

• Run: mvn spring-boot:run

4. Start the Quiz Service

• Navigate to /quiz-service

• Run: mvn spring-boot:run

5. Start the API Gateway

• Navigate to /api-gateway

• Run: mvn spring-boot:run

API Endpoints (Via Gateway)

Instead of calling services directly, use the Gateway URL: http://localhost:8765.

The Gateway uses the service name (both lowercased and uppercased ) to route requests.

Question Service Endpoints

• GET /question-service/question/allQuestions

• Retrieves all questions from the database.

• GET /question-service/question/category/{category}

• Retrieves questions filtered by a specific category.

• POST /question-service/question/add

• Adds a new question to the database.

Quiz Service Endpoints

• POST /quiz-service/quiz/create

Creates a new quiz with a specific title and number of questions.

• POST /quiz-service/quiz/get/{id}

Fetches the question details for a specific quiz ID.

• POST /quiz-service/quiz/submit/{id}

Submits user answers and calculates the final score.

Feign Client Configuration

The Quiz Service communicates with the Question Service via the QuizInterface.

It creates a proxy that talks to the QUESTION-SERVICE registered in Eureka, ensuring load balancing and loose coupling.