exchange-rate-calculator

README

Exchange Rate Calculator API

Description

This project is an Exchange Rate Calculator API designed to provide real-time conversion rates between cryptocurrency and fiat currencies. The API accepts a source and target currency along with an amount, and returns the converted amount using the latest exchange rates. The exchange rates are updated every minute through a background task.

Features

• Real-Time Conversion: Converts between specified source and target currencies in real-time.
• Background Rate Updates: Exchange rates are updated every minute in the background.
• Database-Driven: Exchange rates are fetched from a PostgreSQL database.
• Currency Availability: The API only processes conversions for available currencies. Unavailable currencies will return an error.
• Supported Currencies: EUR, USD, CNY, USDT, USDC, ETH.

Technical Requirements

• Language: Go 1.20 or higher
• Logging: Using zerolog
• Data Structures: Go data structures for storing currency pairs
• Framework: Go Fiber for the API
• Performance: API response time should not exceed 100ms
• Exchange Rates API: Using FastForex for obtaining exchange rates
• Database: PostgreSQL for storing exchange rates

Clean Architecture

Project was completed via the Clean Architecture practises

Relations between Clean Architecture layers and project folders:

Template path	Clean Architecture Layer Color
internal/entity	Yellow (Enterprise Business Rules)
internal/usecase	Red (Application Business Rules)
internal/adapter	Green (Interface Adapters)
internal/infrastructure	Blue (Frameworks & Drivers)

Open API Spec

• api/openapi-spec/httpapi.openapi.yaml

Dependencies

Infrastructure:

• Postgres 12
• Fast Forex API

Start

• Add FAST_FOREX_API_KEY to the .env file (See: .env.example file)

make start

• Wait for the "INFO Server started on: ${...}" message

make logs-httpapi

make start-swagger

Update currency pairs

If you want to update currency pairs then update - internal/infrastructure/config/currency-pairs.json file

It is an embedded file that processed when app inited