exchange-go-notifier

An app with selectable API's for checking exchange rates and optional automatic notifications using different backends, built with Go.

Features

• Multiple exchange rate API support (ExchangeRate-API, Open Exchange Rates)
• Rate limiting and request tracking
• Simple HTTP API
• Containerized with Docker
• State persistence between restarts

Prerequisites

• Go 1.16+
• Docker and Docker Compose (optional)
• API keys for the desired exchange rate providers

Environment Variables

Create a .env file in the project root with the following variables:

# ExchangeRate-API (er-a) - Get your key from https://www.exchangerate-api.com/
EXCHANGERATE_API_KEY=your_api_key_here

# Open Exchange Rates (oer) - Get your key from https://openexchangerates.org/
OPENEXCHANGERATES_APP_ID=your_app_id_here

Getting Started

1. Copy the example state file:

   cp api_state.example.json api_state.json

2. Set up environment variables (see above)

3. Run the application:

   # Using Go
   go run .
   
   # Or using Docker Compose
   docker compose up

The server will start on http://localhost:8080

API Usage

Get Exchange Rates

GET /exchange-rates?api={provider}&base={currency}

Parameters

• provider (required): The API provider to use (er-a or oer)

Example Requests

# Using curl
curl "http://localhost:8080/exchange-rates?api=er-a&base=USD"

# Using httpie
http ":8080/exchange-rates" api==er-a base==USD

Example Response

{
  "rates": {
    "EUR": 0.92,
    "GBP": 0.79,
    "JPY": 156.42,
    "USD": 1.0
  }
}

Available API Providers

Provider	ID	Request Limit	Documentation
ExchangeRate-API	er-a	1,500/month	docs
Open Exchange Rates	oer	1,000/month	docs

Development

Running Tests

go test -v

Building with Docker

docker build -t exchange-go-notifier .
docker run -p 8080:8080 --env-file .env exchange-go-notifier

License

This project is licensed under the Apache 2.0 License - see the LICENSE file for details.