Implement Spring Boot email notification system with Docker Compose deployment

[Copilot]

This PR implements a comprehensive email notification system that automatically notifies executives and project leads when new job applications are submitted for their teams, built with Spring Boot and Docker Compose for easy deployment.

Overview

The system provides a REST API backend that receives job applications and immediately sends professional email notifications to the appropriate team members, replacing manual notification processes during executive and project lead hiring.

Key Features

🏗️ Spring Boot Backend Infrastructure

• Spring Boot 3.2 with Java 17 - Modern, enterprise-grade backend framework
• Maven build system with comprehensive dependency management
• Modular architecture with controllers, services, models, and DTOs
• RESTful API with comprehensive endpoints for applications and team management
• JSON-based data persistence with easy database upgrade path

📧 Professional Email System

• Automated notifications sent immediately upon application submission via Spring Mail
• HTML and text email templates with professional formatting and company branding
• Flexible SMTP integration supporting Gmail, Outlook, and custom providers
• Async email processing for non-blocking notifications
• Development-friendly logging when SMTP not configured
• Graceful error handling with fallback mechanisms

🏢 Team Management

• Dynamic team configuration with executives and project leads
• Pre-configured default teams (Engineering, Product, Marketing)
• CRUD operations for team management via API
• Email testing functionality to verify configurations

📊 Application Processing

• Comprehensive validation using Jakarta validation framework
• Status tracking (pending, reviewing, interview, accepted, rejected)
• Statistics and analytics with filtering by team and status
• Resume URL and cover letter support

🐳 Docker Compose Deployment

• Multi-stage Dockerfile for optimized container builds
• Complete docker-compose.yml with nginx reverse proxy
• Production-ready deployment with health checks and monitoring
• NAS server compatibility (Synology, QNAP, TrueNAS)
• Cloud platform support (Firebase, AWS ECS, DigitalOcean Apps)

API Endpoints

The system exposes a complete REST API:

• Applications: Submit, list, view, and update application status
• Teams: Create, update, delete, and manage team configurations
• Statistics: View application metrics and trends
• Testing: Email service testing and health checks

Email Workflow

When an application is submitted:

1. Validation: System validates all required fields and team existence
2. Processing: Application is stored with unique ID and timestamp
3. Team Lookup: System identifies executives and project leads for the specified team
4. Email Generation: Professional HTML and text emails are created with applicant details
5. Notification Delivery: Emails are sent asynchronously to all relevant team members
6. Response: API returns success confirmation with notification details

Example Usage

# Submit an application (triggers automatic email notifications)
curl -X POST http://localhost:3000/api/applications \
  -H "Content-Type: application/json" \
  -d '{
    "applicantName": "John Doe",
    "applicantEmail": "john@example.com", 
    "position": "Senior Software Engineer",
    "team": "Engineering",
    "resumeUrl": "https://example.com/resume.pdf",
    "coverLetter": "I am excited to apply..."
  }'

# Executives and project leads for Engineering team immediately receive:
# Subject: "New Application: Senior Software Engineer - John Doe"
# Professional email with all applicant details, cover letter, and resume link

Deployment Options

Quick Start with Docker Compose

# Basic deployment
./deploy.sh basic

# Production with nginx reverse proxy (perfect for NAS servers)
./deploy.sh production

# Full stack with monitoring (Prometheus + Grafana)
./deploy.sh monitoring

Manual Spring Boot Deployment

# Build and run
mvn clean package
java -jar target/email-backend-*.jar

# Or development mode
mvn spring-boot:run

Configuration

Environment-based configuration via application.properties or environment variables:

# Server Configuration
PORT=3000
APP_NAME=Executive Hiring Notification System

# Email Configuration
EMAIL_HOST=smtp.gmail.com
EMAIL_PORT=587
EMAIL_USER=your-email@gmail.com
EMAIL_PASS=your-app-password

NAS Server Deployment

Perfect for home/office NAS servers:

• Synology NAS: Use Container Manager with docker-compose.yml
• QNAP NAS: Deploy via Container Station
• TrueNAS: Use custom Docker deployment or TrueCharts

# On NAS server
git clone <repository>
cd Email-Backend
./deploy.sh production  # Deploys on port 80 with nginx

Cloud Platform Support

Ready for deployment on popular cloud services:

• Firebase/Google Cloud Run: Container-ready with health checks
• AWS ECS/Fargate: Multi-stage Docker builds for efficiency
• DigitalOcean Apps: Direct GitHub integration support
• Any Docker-compatible platform

Production Features

• Nginx reverse proxy with rate limiting and security headers
• SSL/HTTPS support ready for production certificates
• Health checks and monitoring endpoints via Spring Boot Actuator
• Persistent data volumes for JSON storage
• Non-root container security following best practices
• Optional monitoring stack with Prometheus and Grafana

This implementation fully satisfies the requirement for executives to receive active email notifications for applicants applying to their teams, while providing enterprise-grade Spring Boot architecture and flexible Docker Compose deployment options for NAS servers and cloud platforms.

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[TommyOh0428]

@copilot it will use Spring boot application and easily deployable through docker compose such as NAS server or popular backend server services such as firebase, etc

[Copilot]

@copilot it will use Spring boot application and easily deployable through docker compose such as NAS server or popular backend server services such as firebase, etc

I've successfully migrated the email backend to Spring Boot with Docker Compose deployment support as requested!

Key changes in commit c8d8ec0:

🔧 Spring Boot Migration:

• Converted from Node.js/Express to Java 17 + Spring Boot 3.2
• Professional enterprise architecture with controllers, services, and DTOs
• Maven build system with comprehensive dependency management
• All original API endpoints preserved with identical functionality

🐳 Docker Compose Deployment:

• Multi-stage Dockerfile for optimized container builds
• Complete docker-compose.yml with nginx reverse proxy
• Deployment script (./deploy.sh) with multiple options:
  • ./deploy.sh basic - Simple deployment
  • ./deploy.sh production - With nginx proxy for NAS servers
  • ./deploy.sh monitoring - Full stack with Prometheus/Grafana

📦 NAS Server Ready:

• Perfect for Synology, QNAP, TrueNAS deployment
• Persistent data volumes for JSON storage
• Health checks and restart policies included
• Production-grade security with rate limiting

☁️ Cloud Platform Support:

• Firebase/Google Cloud Run ready
• AWS ECS/Fargate compatible
• DigitalOcean Apps integration
• Any Docker-compatible service

The system maintains all original email notification functionality while now being easily deployable on NAS servers and popular backend services through Docker Compose!