DEMO - Quote Generator - Microservices Architecture

A modern quote generator built with microservices architecture, demonstrating best practices in web development. Built with Node.js, ASP.NET Core, TypeScript, React, Nodejs, MongoDB, PostgreSQL, RabbitMQ, Docker, Prometheus, Grafana and Kubernetes. Features include: Clean Architecture, DDD, Event-Driven Architecture, CQRS, automated testing, and comprehensive API documentation.

Overview

Built with a focus on scalability, reliability and performance, this application demonstrates modern backend development best practices including:

Clean Architecture principles
Domain-Driven Design
Event-Driven Architecture
SOLID principles
Comprehensive testing
Docker containerization

🛠 Tech Stack

Backend Services

Auth Service: Node.js + TypeScript + Fastify + MongoDB
Quote Service: Node.js + TypeScript + Fastify + MongoDB
User Service: ASP.NET Core 8.0 + PostgreSQL
API Gateway: Node.js + TypeScript + Fastify

Frontend

Framework: React 18
State Management: Redux Toolkit
Styling: CSS Modules
Build Tool: Vite

Infrastructure

Message Broker: RabbitMQ
Databases:
- MongoDB (Auth & Quotes)
- PostgreSQL (Users)
Containerization: Docker + Docker Compose
API Documentation: Swagger/OpenAPI

🏗 Architecture & Patterns

Clean Architecture

Domain Layer (Entities, Value Objects)
Application Layer (Use Cases, DTOs)
Infrastructure Layer (Repositories, External Services)
Interface Layer (Controllers, Presenters)

Domain-Driven Design (DDD)

Bounded Contexts
Aggregates
Value Objects
Domain Events
Repository Pattern

Event-Driven Architecture

Asynchronous Communication
Message Queues
Event Publishing/Subscription
Event Sourcing

CQRS (Command Query Responsibility Segregation)

Separate Command and Query Models
Optimized Read/Write Operations

🔧 Design Patterns

Repository Pattern
Factory Pattern
Strategy Pattern
Observer Pattern
Circuit Breaker
Retry Pattern
Decorator Pattern

🏭 CI/CD & DevOps

GitHub Actions
Docker Containerization
Infrastructure as Code
Automated Testing
Continuous Integration
Continuous Deployment

📊 Testing Strategies

Unit Tests (Jest, xUnit)
Integration Tests
E2E Tests
Test Coverage Reports
Mocking & Stubbing

🛡 Security

JWT Authentication
Role-Based Access Control
API Gateway Security
Input Validation
Rate Limiting
CORS Configuration

🎯 Best Practices

Code Quality

TypeScript for Type Safety
ESLint & Prettier
SOLID Principles
Clean Code Practices
Code Reviews
Documentation

Architecture

The application consists of several independent microservices:

API Gateway: Single entry point for clients
Auth Service: Authentication and JWT management
Quote Service: Quote management and retrieval
User Service: User profiles and preferences management
Frontend: React user interface

Service Communication

Synchronous communication via HTTP/REST between services
Asynchronous communication via RabbitMQ for events
JWT for inter-service security

Authentication process and retrieval of a quote

sequenceDiagram
    participant Client
    participant Gateway
    participant AuthService
    participant QuoteService
    participant UserService
    participant RabbitMQ

    Client->>Gateway: POST /auth/login
    Gateway->>AuthService: Forward login request
    AuthService->>AuthService: Validate credentials
    AuthService-->>Gateway: Return JWT token
    Gateway-->>Client: Return JWT token

    Client->>Gateway: GET /quotes/random (with JWT)
    Gateway->>Gateway: Validate JWT
    Gateway->>QuoteService: Forward request
    QuoteService->>QuoteService: Generate random quote
    QuoteService->>RabbitMQ: Publish quote.viewed event
    QuoteService-->>Gateway: Return quote
    Gateway-->>Client: Return quote

    RabbitMQ->>UserService: Consume quote.viewed event
    UserService->>UserService: Update user history

Add to Favorites process

sequenceDiagram
    participant Client
    participant Gateway
    participant QuoteService
    participant UserService
    participant RabbitMQ

    Client->>Gateway: POST /quotes/:id/favorite
    Gateway->>Gateway: Validate JWT
    Gateway->>QuoteService: Forward favorite request
    QuoteService->>RabbitMQ: Publish quote.favorited event
    QuoteService-->>Gateway: Return success
    Gateway-->>Client: Return success

    RabbitMQ->>UserService: Consume quote.favorited event
    UserService->>UserService: Add to favorites
    UserService->>UserService: Update user stats

New user registration process

sequenceDiagram
    participant Client
    participant Gateway
    participant AuthService
    participant UserService
    participant RabbitMQ

    Client->>Gateway: POST /auth/register
    Gateway->>AuthService: Forward register request
    AuthService->>AuthService: Validate input
    AuthService->>AuthService: Hash password
    AuthService->>AuthService: Create user
    AuthService->>RabbitMQ: Publish user.created event
    AuthService-->>Gateway: Return success + JWT
    Gateway-->>Client: Return success + JWT

    RabbitMQ->>UserService: Consume user.created event
    UserService->>UserService: Create user profile
    UserService->>UserService: Initialize preferences

Getting Started

Prerequisites

Node.js >= 20.x
Docker & Docker Compose

Installation

Clone the repository:

git clone https://github.com/your-username/quote-generator.git
cd quote-generator

Install dependencies:

npm install

Configuration:

Copy .env.example to .env
Adjust environment variables

Start services:

# Development mode
npm run dev

# Production mode
npm run prod

Service Architecture

1. API Gateway (Port 3000)

Single entry point
Request routing
JWT validation
CORS configuration

2. Auth Service (Port 3001)

User registration/login
JWT generation/validation
User event publishing

3. Quote Service (Port 3002)

Quote CRUD operations
Search and filtering
Random quote generation
Tags and categories

4. User Service (Port 3003)

User profiles
Reading preferences
Favorite quotes
Usage statistics

5. Frontend (Port 3006)

Modern React interface
Redux state management
Offline support
Responsive design

Event-Driven Architecture

The application leverages RabbitMQ for asynchronous service communication:

User Events

USER_CREATED
USER_UPDATED
USER_DELETED

Quote Events

QUOTE_VIEWED
QUOTE_FAVORITED
QUOTE_UNFAVORITED

Testing

# Unit tests
npm run test

# Coverage report
npm run test:coverage

API Documentation

Swagger documentation is available at:

Gateway: /documentation
Auth: /documentation
Quote: /documentation
User: /documentation

Environment Variables

Key environment variables needed:

# JWT Configuration
JWT_SECRET=your_jwt_secret
JWT_EXPIRES_IN=1h

# Services URLs
AUTH_SERVICE_URL=http://localhost:3001
QUOTE_SERVICE_URL=http://localhost:3002
USER_SERVICE_URL=http://localhost:3003

# MongoDB Configuration
MONGO_URL=mongodb://localhost:27017/quote_generator

# RabbitMQ
MESSAGE_BROKER_URL=amqp://guest:guest@localhost:5672

Docker Support

Build and run with Docker Compose:

# Build services
docker-compose build

# Start services
docker-compose up

# Start services with build
docker-compose up --build

# Stop services
docker-compose down

Accessing the Application

Once all services are running, you can access the application through your web browser:

http://localhost:3006

Development

Code Style

ESLint for linting
Prettier for code formatting
Husky for pre-commit hooks

Security

JWT authentication
Rate limiting
CORS protection
Input validation
Security headers

License

Distributed under the MIT License. See LICENSE for more information.

Name		Name	Last commit message	Last commit date
.github/workflows		.github/workflows
.vscode		.vscode
image/README		image/README
k8s/base		k8s/base
mongo-init		mongo-init
monitoring		monitoring
scripts		scripts
services		services
shared		shared
.env		.env
.env.example		.env.example
.env.production		.env.production
.gitignore		.gitignore
CLAUDE.md		CLAUDE.md
LICENSE		LICENSE
README.md		README.md
docker-compose.prod.yml		docker-compose.prod.yml
docker-compose.yml		docker-compose.yml
package.json		package.json

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DEMO - Quote Generator - Microservices Architecture

Overview

🛠 Tech Stack

Backend Services

Frontend

Infrastructure

🏗 Architecture & Patterns

Clean Architecture

Domain-Driven Design (DDD)

Event-Driven Architecture

CQRS (Command Query Responsibility Segregation)

🔧 Design Patterns

🏭 CI/CD & DevOps

📊 Testing Strategies

🛡 Security

🎯 Best Practices

Code Quality

Architecture

Service Communication

Authentication process and retrieval of a quote

Add to Favorites process

New user registration process

Getting Started

Prerequisites

Installation

Service Architecture

1. API Gateway (Port 3000)

2. Auth Service (Port 3001)

3. Quote Service (Port 3002)

4. User Service (Port 3003)

5. Frontend (Port 3006)

Event-Driven Architecture

User Events

Quote Events

Testing

API Documentation

Environment Variables

Docker Support

Accessing the Application

Development

Code Style

Security

License

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