🧩 Building a Multi-Datasource Go Application

In many enterprise systems, you may need to work with multiple databases — for example, customer data in PostgreSQL, legacy records in Oracle, and transactional data in MySQL. Managing these connections efficiently while keeping the code clean can be challenging.

The Multi-Datasource Go project — a Go-based demo showing how to connect to MySQL, PostgreSQL, and Oracle XE within one modular application.

⚙️ Project Overview

The project follows a clean architecture pattern, ensuring clear separation between layers:

• Handlers → handle HTTP routes using Gin
• Services → contain business logic
• Repositories → handle database operations per datasource
• Models → define entity structures

Each datasource is completely independent, configured through a simple YAML file, and initialized at runtime with connection pooling.

🧱 Features

🔌 Multiple database connections (MySQL, PostgreSQL, Oracle)

🌐 RESTful API with Gin

🧠 Domain-driven design with repository pattern

📝 Configurable via YAML and Viper

🐳 Docker Compose setup for quick local testing

⚡ Built-in health checks and auto table creation

🏗️ Clean architecture (domain, repository, service layers)

🧰 Tech Stack

Layer                          Technology 

Web Framework         Gin

Configuration              Viper

Databases                   MySQL • PostgreSQL • Oracle XE

Drivers                        go-sql-driver/mysql, pgx, go-ora

Environment               Go 1.25.1 • Docker Compose

🗂️ Project Structure

multi-datasource-go/
├─ cmd/api/main.go      # Application entry point
├─ internal/config          # Configuration loader (Viper)
├─ internal/db                # Database connection pools
├─ internal/http              # API routes and handlers
├─ internal/domain        # Entities, repos, services
└─ internal/repo             # Database-specific repositories

🚀 Getting Started

1. Clone the Repository

git clone https://github.com/HenryXiloj/golang-demos.git
cd golang-demos/multi-datasource-go

2. Start Databases

docker compose -f docker-compose-multiple-db.yml up -d

3. Run the Application

go run cmd/api/main.go

🧪 Test the APIs

# MySQL
curl -X POST http://localhost:9000/api/v1/users \
  -H "Content-Type: application/json" \
  -d '{"name":"Henry","lastName":"x"}'

# PostgreSQL
curl -X POST http://localhost:9000/api/v2/companies \
  -H "Content-Type: application/json" \
  -d '{"name":"Test"}'

# Oracle
curl -X POST http://localhost:9000/api/v3/brands \
  -H "Content-Type: application/json" \
  -d '{"name":"Acme"}'

You’ll see all three databases responding independently with auto-created tables.

You can explore the full source code here:👉 multi-datasource-go