MySQL Auto DB Proxy

A MySQL proxy that automatically creates databases when clients connect to them. This is designed for development and testing environments where you need to automatically provision databases for multiple services.

Purpose

This proxy is intended for automated deployments with Docker Swarm stacks where each service needs its own MySQL database. It's NOT suitable for production use.

Features

• Automatic database creation
• Environment-based configuration
• Robust error handling
• Connection timeouts
• Structured logging with Logrus
• MySQL 8.3 compatibility

How it works

1. The proxy listens on a configurable port (default: 3308)
2. When a client connects, it intercepts the MySQL handshake
3. Extracts the requested database name from the connection
4. Validates the database name for security
5. Creates the database if it doesn't exist
6. Forwards the connection to the real MySQL server

Configuration

The proxy can be configured using environment variables:

Variable	Default	Description
PROXY_PORT	3308	Port for the proxy to listen on
MYSQL_HOST	localhost	MySQL server hostname
MYSQL_PORT	3306	MySQL server port
MYSQL_USER	root	MySQL username for database creation
MYSQL_PASSWORD	test	MySQL password for database creation
LOG_LEVEL	info	Logging level (debug, info, warn, error, fatal, panic)
CONNECTION_TIMEOUT	10s	Timeout for initial MySQL connection
READ_TIMEOUT	30s	Timeout for read operations
WRITE_TIMEOUT	30s	Timeout for write operations
MIGRATION_TIMEOUT	5m	Timeout for long-running database operations (e.g., migrations)
KEEPALIVE_PERIOD	30s	TCP keepalive period for connection management

Usage

Docker (Recommended)

# Pull the latest image
docker pull ghcr.io/ibmurai/mysql-auto-db-proxy:latest

# Run with default configuration
docker run -d \
  --name mysql-proxy \
  -p 3308:3308 \
  ghcr.io/ibmurai/mysql-auto-db-proxy:latest

# Run with custom configuration
docker run -d \
  --name mysql-proxy \
  -p 3308:3308 \
  -e MYSQL_HOST=mysql-server \
  -e MYSQL_PORT=3306 \
  -e MYSQL_USER=admin \
  -e MYSQL_PASSWORD=secure_password \
  -e LOG_LEVEL=debug \
  ghcr.io/ibmurai/mysql-auto-db-proxy:latest

Basic Usage (Local Build)

# Start the proxy with default configuration
go run main.go

# Connect to a database (will be created automatically)
mysql -h localhost -P 3308 -u root -p -D myapp_db

Docker Compose Example

services:
  mysql:
    image: mysql:8.3
    environment:
      MYSQL_ROOT_PASSWORD: password
    ports:
      - "3306:3306"

  mysql-auto-db-proxy:
    image: ghcr.io/ibmurai/mysql-auto-db-proxy:latest
    ports:
      - "3308:3308"
    environment:
      MYSQL_HOST: mysql
      MYSQL_PORT: 3306
      MYSQL_USER: root
      MYSQL_PASSWORD: password
      LOG_LEVEL: info
    depends_on:
      - mysql
    networks:
      - app-network

  myapp:
    image: myapp:latest
    environment:
      ConnectionStrings__DefaultConnection: "Server=mysql-auto-db-proxy;Port=3308;Database=myapp;User Id=root;Password=password;SslMode=none;AllowPublicKeyRetrieval=true;"
    depends_on:
      - mysql-auto-db-proxy
    networks:
      - app-network

networks:
  app-network:
    driver: bridge

Entity Framework Core Compatibility

The MySQL Auto DB Proxy is fully compatible with Entity Framework Core and supports multiple MySQL client libraries.

Supported MySQL Client Libraries

• Pomelo.EntityFrameworkCore.MySql
• MySql.EntityFrameworkCore
• MySQL CLI

EF Core Connection String Example

// In appsettings.json or environment variable
"ConnectionStrings__DefaultConnection": "Server=mysql-auto-db-proxy;Port=3308;Database=myapp;User Id=root;Password=password;SslMode=none;AllowPublicKeyRetrieval=true;"

Important Connection String Parameters

Parameter	Value	Description
Server	mysql-auto-db-proxy	Proxy hostname
Port	3308	Proxy port (default)
Database	your_database_name	Database name (auto-created)
User Id	root	MySQL username
Password	your_password	MySQL password
SslMode	none	Required - SSL must be disabled
AllowPublicKeyRetrieval	true	Required - Allows client to request public key from server

Automatic Database Creation

When your EF Core application connects:

1. Database specified in connection string is automatically created
2. EF Core migrations can run normally
3. Multiple services can use different database names
4. No manual database setup required

Testing with MySQL CLI

# Connect to proxy (SSL disabled)
mysql -h mysql-auto-db-proxy -P 3308 -u root -ppassword --ssl-mode=DISABLED

# Connect to specific database (auto-creates if doesn't exist)
mysql -h mysql-auto-db-proxy -P 3308 -u root -ppassword --ssl-mode=DISABLED -D my_new_database

# Execute commands directly
mysql -h mysql-auto-db-proxy -P 3308 -u root -ppassword --ssl-mode=DISABLED -e "SHOW DATABASES;"

Development

Building

# Build locally
go build -o mysql-auto-db-proxy main.go

# Build Docker image
docker build -t mysql-auto-db-proxy .

Limitations

• Not for production
• No connection pooling
• No SSL support

License

This project is licensed under the MIT License.