Go Authentication Exercise

A RESTful API service built with Go that provides user authentication and management. This project demonstrates clean architecture principles with a domain-driven design approach and includes:

• User authentication (login/signup) with JWT token
• User management with pagination support
• Middleware for protected routes
• PostgreSQL database integration

Requirements

This project is tested with:

• Go 1.22
• Postgres 16

Installation

Clone the project

git clone git@github.com:appleinautumn/go-authentication-exercise.git

Go to the project directory

cd go-authentication-exercise

This service contains a .env.example file that defines environment variables you need to set. Copy and set the variables to a new .env file.

cp .env.example .env

Start the app

go run main.go

Database

If you have not created the database, please create one before going to the next step.

We're using golang-migrate for the migration.

Without Docker

Install the package

go install -tags 'postgres' github.com/golang-migrate/migrate/v4/cmd/migrate@latest

Run the migration (change the value accordingly)

migrate -path=migrations -database "postgres://postgres:password@127.0.0.1:5432/database?sslmode=disable" up

To rollback

migrate -path=migrations -database "postgres://postgres:password@127.0.0.1:5432/database?sslmode=disable" down 1

With Docker

Run the migration (change the value accordingly)

docker run -v "$(pwd)"/migrations:/migrations --network host migrate/migrate -path=/migrations/ -database "postgres://postgres:password@127.0.0.1:5432/database?sslmode=disable" up

To rollback

docker run -v "$(pwd)"/migrations:/migrations --network host migrate/migrate -path=/migrations/ -database "postgres://postgres:password@127.0.0.1:5432/database?sslmode=disable" down 1

Deployment

Build the binary

go build -o go-auth

Run it

./go-auth

API Endpoints

Method	Endpoint	Description	Authentication
GET	/	Root endpoint (health check)	No
POST	/auth/signup	Create a new user account	No
POST	/auth/login	Authenticate and receive JWT token	No
GET	/user/list	List users with pagination (page & limit query)	Yes (JWT)

Example requests can be found in the requests.http file, which can be used with REST client extensions in various IDEs.

Project Structure

The codebase follows a domain-driven design with clear separation of concerns and standard Go project layout:

├── internal/           # Application-specific code
│   ├── auth/           # Authentication domain
│   │   ├── handler/    # HTTP request handlers
│   │   ├── request/    # Request validation
│   │   └── service/    # Business logic
│   ├── middleware/     # HTTP middleware components
│   ├── user/           # User domain
│   │   ├── entity/     # Data models
│   │   ├── handler/    # HTTP request handlers
│   │   ├── repository/ # Data access layer
│   │   └── service/    # Business logic
│   └── util/           # Shared utilities
├── migrations/         # Database migrations
└── main.go             # Application entry point

The project uses the internal package pattern to indicate code that is private to this application and not intended for reuse by other packages.