Coin Fetcher App

A Go-based service for fetching and storing cryptocurrency prices using the CoinGecko API, built with a Hexagonal Architecture (Ports and Adapters). The application supports multiple cryptocurrencies (e.g., Bitcoin, Ethereum) by their coin (e.g., bitcoin, ethereum), stores price data in a Redis then PostgreSQL database, and provides RESTful endpoints to retrieve prices and supported coins. It uses Docker for containerization and includes context-based timeout handling for API and database operations.

Features

• Fetch real-time cryptocurrency prices from the CoinGecko API using coins (e.g., bitcoin, ethereum).
• You can change scheduler timer or coin name from .env
• Store price data in a PostgreSQL database with fields for coin ID, price, and timestamp.
• Retrieve the latest price or average price for a given coin over specified intervals (1min, 5min, 1day).
• Use Redis to save coin's price
• Containerized deployment using Docker.

Project Structure

The project follows a Hexagonal Architecture to ensure modularity and testability:

coin-fetcher-app/
├── cmd/
│   └── server/
│       └── main.go           # Entry point of the application
├── internal/
│   ├── adapters/
│   │   ├── external/        # External service adapters (e.g., CoinGecko API)
│   │   ├── http/            # HTTP handlers and routes
│   │   ├── repository/      # Database repository (PostgreSQL with GORM AND REDIS)
│   │   └── scheduler/       # Background price fetching scheduler
│   ├── application/         # Business logic (PriceService)
│   └── domain/              # Domain models and interfaces
├── Dockerfile               # Docker configuration for building and running
├── go.mod                   # Go module dependencies
├── go.sum                   # Go module checksums
└── README.md                # Project documentation

Prerequisites

• Go: Version 1.22 or higher
• Docker: For containerized deployment
• PostgreSQL: For storing price data
• REDIS: For storing price data
• Git: For cloning the repository
• Access to the CoinGecko API (no authentication required for public endpoints)

Installation

Clone the Repository

git clone https://github.com/rzmsv/coin-fetcher-app.git
cd coin-fetcher-app

Build and Run Locally

1. Install dependencies:

   go mod tidy

2. Build the application:

   go run ./cmd/server

Build and Run with Docker

*** USE PROXY ***

1. Build the Docker image:

   docker-compose build --no-cache

2. Run

   docker-compose down (If you have already run it )

3. Run

   docker-compose up

Usage

The service exposes the following RESTful endpoints:

• GET /api/price/history/:coin: Retrieve the latest price (for 1min) or average price (for 5min, 1day) for a given coin (e.g., bitcoin, ethereum).

  • Example: curl http://localhost:8080/api/price/history/bitcoin
  • Response: {"price": 65000.12345678}

  NOTICE: You want 2 APIs for get hestory and latest price (I know ) but I write all of this in one API for axample if you dont add interval you get latest price of coin from database (1min ago) and if you add interval=5min you get average price of 5min ******

Database Schema

The Coin table is automatically created by GORM with the following schema:

	ID        uint
	Price     float64
	Coin      string
	Timestamp time.Time

## Contact
For questions or support, contact [rmussavi@gmail.com].