Simple HTTP Server

A Go-based web service that exposes user-related endpoints (status, leaderboard, task completion, referral assignment) backed by PostgreSQL. The project uses Gin for HTTP routing and pgx for database access.

Features

• Retrieve user status with balance and profile information.
• View a leaderboard of users sorted by balance with optional limit/offset.
• Mark user tasks as completed and return updated task metadata.
• Assign a referrer to a user while enforcing validation rules (self-referral, duplicates, missing users).

Project Structure

cmd/api             # Application entry point
internal/adapter    # HTTP handlers, routing, and PostgreSQL repository implementation
internal/core       # Domain models, use cases, and repository ports
migrations          # SQL migrations for users/tasks tables and seed data

Requirements

• Go 1.24+
• Docker and Docker Compose (optional but recommended)
• PostgreSQL (Docker setup provided)
• golang-migrate CLI if running migrations locally

Environment Variables

Create a .env file (sample used by Docker Compose):

POSTGRES_USER=postgres
POSTGRES_PASSWORD=postgres
POSTGRES_DB=simple_http_server
POSTGRES_HOST=postgres
POSTGRES_PORT=5432
APP_DB_DSN=postgres://postgres:postgres@postgres:5432/simple_http_server?sslmode=disable

Adjust credentials/hostnames as needed for your environment.

Run with Docker Compose

docker compose up --build

This starts:

1. postgres – PostgreSQL 17 with persistence via pgdata volume.
2. migrate – Applies SQL migrations on startup.
3. app – Gin server compiled with Delve debugger support (ports 8080 for HTTP, 40000 for DAP).

The API becomes available at http://localhost:8080 once migrations finish and the app starts.

Local Development (without Docker)

1. Ensure PostgreSQL is running and migrations are applied via migrate CLI:

   migrate -path migrations -database "$APP_DB_DSN" up

2. Export APP_DB_DSN to match your database.
3. Run the server:

   go run ./cmd/api

API Overview

• GET /users/:id/status – Fetch user profile and balance.
• GET /users/leaderboard?limit=&offset= – List users sorted by balance.
• POST /users/:id/task/complete – Body { "task_id": number }; marks the task as done.
• POST /users/:id/referrer – Body { "referrer_id": number }; assigns a referrer.

Responses follow JSON structures defined in internal/core/usecase DTOs. Errors are mapped to HTTP status codes via internal/adapter/http/user_handler.go.