📧📱 Implement Email & SMS Notification Service

[Sakeeb91]

📧📱 Implement Email & SMS Notification Service

Addresses: #8 Email & SMS Notification Service

🎯 Overview

This PR implements a comprehensive Email & SMS Notification Service that provides robust notification capabilities for the LifeLine-ICT system. The implementation includes email notifications via SMTP, SMS notifications via Twilio, a template system, retry logic, and seamless integration with the existing alert system.

✅ Requirements Completed

All checklist items from Issue #8 have been implemented:

• ✅ SMTP / email provider integration - Full SMTP support with aiosmtplib
• ✅ SMS provider integration - Twilio integration for SMS delivery
• ✅ Templates for messages (HTML / text) - Complete template system with Jinja2
• ✅ Send verification / reset / alert messages - All message types supported
• ✅ Logging / retry logic for failures - Comprehensive error handling and retry mechanism

🏗️ Architecture

Core Components

1. Notification Model - Database schema with status tracking and retry logic
2. Email Service - SMTP integration with HTML/text support and templates
3. SMS Service - Twilio integration with phone validation and templates
4. Notification Service - Orchestrates email/SMS services with unified API
5. API Router - RESTful endpoints for notification management
6. Repository Layer - Database operations with advanced querying
7. Enhanced Alert Service - Integrated notification support

Key Features

• 🔄 Multi-Channel Support: Email and SMS notifications
• 📝 Template System: Rich HTML templates and SMS templates
• 🔁 Retry Logic: Automatic retry with exponential backoff
• 📊 Status Tracking: Complete delivery status monitoring
• 📦 Bulk Operations: Efficient bulk notification sending
• 🛡️ Error Handling: Comprehensive error logging and recovery
• 🔗 Integration Ready: Seamless integration with existing alert system
• ⚙️ Configurable: Environment-based configuration
• 🧪 Testable: Comprehensive test suite with mocking
• 📚 Documented: Complete documentation with usage examples

📁 Files Added

New Files

• backend/app/models/notification.py - Notification database model
• backend/app/schemas/notification.py - Pydantic schemas for API
• backend/app/repositories/notification_repository.py - Database operations
• backend/app/services/email_service.py - SMTP email service
• backend/app/services/sms_service.py - Twilio SMS service
• backend/app/services/notification_service.py - Main orchestration service
• backend/app/api/notification_router.py - API endpoints
• backend/tests/services/test_notification_service.py - Comprehensive tests
• backend/NOTIFICATION_SERVICE.md - Complete documentation

Modified Files

• backend/requirements.txt - Added notification dependencies
• backend/app/core/config.py - Added email/SMS configuration
• backend/app/main.py - Registered notification router
• backend/app/api/__init__.py - Added notification router import
• backend/app/services/alert_service.py - Enhanced with notifications
• backend/app/models/__init__.py - Added notification model exports
• backend/app/repositories/__init__.py - Added notification repository
• backend/app/schemas/__init__.py - Added notification schemas
• backend/migrations/env.py - Added notification model import

🔧 Configuration

Environment Variables Added

# Email/SMTP Configuration
LIFELINE_SMTP_HOST=smtp.gmail.com
LIFELINE_SMTP_PORT=587
LIFELINE_SMTP_USERNAME=your-email@gmail.com
LIFELINE_SMTP_PASSWORD=your-app-password
LIFELINE_SMTP_USE_TLS=true
LIFELINE_FROM_EMAIL=noreply@lifeline.edu
LIFELINE_FROM_NAME=LifeLine-ICT

# SMS/Twilio Configuration
TWILIO_ACCOUNT_SID=your-twilio-account-sid
TWILIO_AUTH_TOKEN=your-twilio-auth-token
TWILIO_FROM_NUMBER=+1234567890

Dependencies Added

• aiosmtplib>=2.0.0 - Async SMTP client
• jinja2>=3.1.0 - Template engine
• twilio>=8.10.0 - SMS service provider
• python-multipart>=0.0.6 - Multipart form support

🚀 API Endpoints

Core Endpoints

• POST /notifications/send - Send individual notification
• POST /notifications/send/bulk - Send multiple notifications
• GET /notifications/ - List notifications with filtering
• GET /notifications/{id} - Get specific notification
• GET /notifications/stats/overview - Get notification statistics
• POST /notifications/retry - Retry failed notifications
• POST /notifications/test - Test service connections

Convenience Endpoints

• POST /notifications/email/send - Send email directly
• POST /notifications/sms/send - Send SMS directly

📧 Email Templates

Built-in templates include:

• Welcome - User registration confirmation
• Password Reset - Password reset requests
• Alert Notification - System alerts and warnings
• Maintenance Reminder - Scheduled maintenance notifications
• Verification Code - Two-factor authentication codes
• Ticket Update - Maintenance ticket status updates

📱 SMS Templates

SMS templates optimized for 160 characters:

• Welcome - Registration confirmation
• Password Reset - Reset link notifications
• Alert Notification - Critical system alerts
• Maintenance Reminder - Maintenance notifications
• Verification Code - Authentication codes
• Ticket Update - Status updates

🔗 Alert System Integration

Enhanced alert service with automatic notifications:

# Create alert with automatic notifications
await alert_service.create_alert(
    sensor_id=1,
    metric="temperature",
    value=85.5,
    threshold=80.0,
    send_notifications=True,
    notification_recipients=["admin@example.com", "+256700000000"],
    notification_types=[NotificationType.EMAIL, NotificationType.SMS]
)

🧪 Testing

Comprehensive test suite covering:

• Email service functionality
• SMS service functionality
• Template rendering
• Error handling and retry logic
• API endpoint testing
• Integration scenarios

Run tests with:

cd backend
python -m pytest tests/services/test_notification_service.py -v

📊 Database Schema

The notification table includes:

• Basic Info: ID, type, recipient, subject, message
• Status Tracking: Status, retry count, max retries
• Timestamps: Created, sent, delivered, failed
• Error Handling: Error messages and failure tracking
• Context: Template data and related entity IDs
• Priority: Low, medium, high, urgent

🔄 Error Handling & Retry Logic

• Automatic Retries: Failed notifications retried up to 3 times
• Exponential Backoff: Increasing delays between retries
• Error Logging: Comprehensive error tracking
• Manual Retry: API endpoint for manual retry
• Status Tracking: Real-time status updates

🎯 Usage Examples

Send Welcome Email

await notification_service.send_email_notification(
    to_email="user@example.com",
    subject="Welcome to LifeLine-ICT",
    template_name="welcome",
    context={"user_name": "John Doe"}
)

Send Alert SMS

await notification_service.send_sms_notification(
    to_number="+256700000000",
    template_name="alert_notification",
    context={"alert_type": "Temperature Alert", "severity": "HIGH"}
)

Bulk Notifications

requests = [
    NotificationRequest(notification_type="email", recipient="user1@example.com"),
    NotificationRequest(notification_type="sms", recipient="+256700000000")
]
await notification_service.send_bulk_notifications(requests)

🛡️ Security Considerations

• SMTP credentials secured via environment variables
• Twilio tokens properly stored
• Phone number validation and formatting
• Email address validation
• Rate limiting considerations documented

📚 Documentation

Complete documentation provided in backend/NOTIFICATION_SERVICE.md including:

• Architecture overview
• Configuration guide
• API reference
• Usage examples
• Security considerations
• Monitoring and maintenance

🔄 Migration Required

A database migration is needed to create the notification table. The migration file needs to be generated and run:

cd backend
alembic revision --autogenerate -m "Add notification table"
alembic upgrade head

✅ Testing Checklist

• All new dependencies installed
• Models and schemas created
• Services implemented with error handling
• API endpoints functional
• Integration with alert system
• Comprehensive test suite
• Documentation complete
• Configuration management
• Template system working
• Retry logic implemented

🎉 Summary

This PR delivers a production-ready notification service that fully addresses Issue #8 requirements. The implementation provides:

1. Complete Email/SMS Support - Both channels fully functional
2. Template System - Rich templates for all use cases
3. Robust Error Handling - Comprehensive retry and logging
4. API Integration - Full RESTful API for notification management
5. Alert Integration - Seamless integration with existing alert system
6. Production Ready - Proper configuration, testing, and documentation

The service is ready for deployment and can be immediately used to send notifications throughout the LifeLine-ICT system.