Multi-Tenant ASP.NET Core Application

A robust multi-tenant ASP.NET Core application using database-per-tenant architecture with enhanced performance, security, and monitoring features.

🏗️ Architecture Overview

This application implements a Database-per-Tenant multi-tenancy pattern where:

• Each tenant has their own dedicated database
• Tenant resolution is based on HTTP request host/domain
• Centralized tenant metadata management
• Enhanced caching and performance optimizations

🚀 Features

Core Multi-Tenancy

• ✅ Database-per-tenant isolation
• ✅ Domain-based tenant resolution
• ✅ Dynamic database context creation
• ✅ Tenant metadata management

Performance & Caching

• ✅ In-memory caching for tenant resolution
• ✅ Database connection pooling
• ✅ Async/await throughout
• ✅ Connection health testing

Monitoring & Health Checks

• ✅ Application health checks
• ✅ Per-tenant database health monitoring
• ✅ Structured logging with Serilog
• ✅ Performance metrics

Security

• ✅ Connection string masking in logs
• ✅ Input validation
• ✅ Secure error handling
• ✅ CORS configuration

Developer Experience

• ✅ Swagger/OpenAPI documentation
• ✅ Docker support
• ✅ Development environment setup
• ✅ Comprehensive error messages

🛠️ Technology Stack

• Framework: ASP.NET Core 7.0
• Database: MySQL 8.0+ / 9.0+
• ORM: Entity Framework Core
• Logging: Serilog
• Caching: MemoryCache
• Containerization: Docker
• API Documentation: Swagger/OpenAPI

🏃‍♂️ Quick Start

Prerequisites

• .NET 7.0 SDK
• MySQL Server
• Docker (optional)

1. Clone the repository

git clone <repository-url>
cd MultiTenant

2. Update connection strings

Edit appsettings.json:

{
  "ConnectionStrings": {
    "DefaultConnection": "server=localhost;Port=3306;user=root;password=yourpassword;database=MultiTenantDb;"
  }
}

3. Install dependencies

dotnet restore

4. Run database migrations

dotnet ef database update --context ApplicationDbContext

5. Run the application

dotnet run

6. Test the endpoints

• API Documentation: https://localhost:7067
• Health Check: https://localhost:7067/health
• Tenant Info: https://localhost:7067/api/MultiTenant/tenant-info

🐳 Docker Setup

Using Docker Compose (Recommended)

# Start all services (MySQL + API)
docker-compose up -d

# View logs
docker-compose logs -f

# Stop services
docker-compose down

Manual Docker Build

# Build image
docker build -t multitenant-api .

# Run container
docker run -d -p 5075:80 -p 7067:443 multitenant-api

🗄️ Database Configuration

Main Database (ApplicationDbContext)

• Purpose: Store tenant metadata
• Tables: Tenants, Roles
• Connection: Configured in appsettings.json

Tenant Databases (TenantDbContext)

• Purpose: Store tenant-specific data
• Tables: Tokens (example)
• Connection: Dynamic, based on tenant configuration

Default Tenants

The system seeds two default tenants:

1. ssprintl - Domain: localhost
2. infisquare - Domain: localhost2

📡 API Endpoints

Tenant Management

GET /api/MultiTenant/tenant-info          # Get current tenant info
GET /api/MultiTenant/health                # Tenant health check

Token Management

GET /api/MultiTenant/tokens                # Get all tokens
GET /api/MultiTenant/tokens/{id}           # Get specific token
POST /api/MultiTenant/tokens               # Create new token

System Health

GET /health                                 # Overall system health

🔧 Configuration

appsettings.json Structure

{
  "ConnectionStrings": {
    "DefaultConnection": "server=localhost;Port=3306;..."
  },
  "TenantSettings": {
    "CacheExpirationMinutes": 30,
    "ConnectionTimeoutSeconds": 120,
    "DefaultMySqlVersion": "9.0.1"
  },
  "AllowedOrigins": ["http://localhost:3000"],
  "Serilog": {
    "MinimumLevel": "Information"
  }
}

Environment Variables

ASPNETCORE_ENVIRONMENT=Development
ConnectionStrings__DefaultConnection="server=localhost;..."

🔍 Monitoring & Logging

Health Checks

• Application health: /health
• Database connectivity for all tenants
• Tenant resolution functionality

Logging

• Console: Development environment
• File: logs/multitenant-YYYY-MM-DD.log
• Structured: JSON format with correlation IDs

Metrics

• Tenant resolution performance
• Database connection health
• Request/response timing

🧪 Testing

Testing Different Tenants

Use different hosts in your requests:

# Test tenant 1 (ssprintl)
curl -H "Host: localhost" https://localhost:7067/api/MultiTenant/tokens

# Test tenant 2 (infisquare)  
curl -H "Host: localhost2" https://localhost:7067/api/MultiTenant/tokens

Health Check Testing

# Overall health
curl https://localhost:7067/health

# Tenant-specific health
curl -H "Host: localhost" https://localhost:7067/api/MultiTenant/health

🚀 Deployment

Production Checklist

• Update connection strings
• Configure logging levels
• Set up SSL certificates
• Configure CORS origins
• Set up monitoring
• Database backups
• Security scanning

Environment Variables for Production

ASPNETCORE_ENVIRONMENT=Production
ASPNETCORE_URLS=https://+:443;http://+:80
ConnectionStrings__DefaultConnection="Production connection string"

🤝 Contributing

1. Fork the repository
2. Create feature branch: git checkout -b feature/amazing-feature
3. Commit changes: git commit -m 'Add amazing feature'
4. Push to branch: git push origin feature/amazing-feature
5. Open Pull Request

📝 Migration from Previous Version

Breaking Changes

None - all improvements are backward compatible.

Recommended Updates

1. Update appsettings.json with new configuration sections
2. Install new NuGet packages
3. Update any custom tenant resolution logic if applicable

🔒 Security Considerations

• Connection strings are masked in logs
• Input validation on all endpoints
• Secure error handling (no internal details exposed)
• CORS properly configured
• Database connections properly disposed

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

🙋‍♂️ Support

For support and questions:

• Create an issue in the repository
• Check existing documentation
• Review logs for troubleshooting

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Made with ❤️ using ASP.NET Core