Backend .NET Home Task by Rashid Kashafutdinov

[mrRashidkk]

1. Organised the solution into 4 modules:

• ExchangeRateUpdater.Domain (Contracts, models, enums, and constants belonging to the domain layer)
• ExchangeRateUpdater.Infrastructure (For now, external API clients. Later there might be caching, database, etc.)
• ExchangeRateUpdater.UnitTests
• ExchangeRateUpdater (The entry point of the app)

2. Implemented ExchangeRateProvider which now gets exchange rates from the Czech National Bank's API. I used the Factory pattern to make it easy to add new exchange rate API clients for other target currencies.
3. Added retries with Polly to make the integration with Czech National Bank's API more resilient.
4. Added logging with Serilog.
5. Added unit tests

Ideas for further improvements:

• Cache the exchange rates since they change once per day. But the invalidation of the cache might be tricky, because it depends on when the bank updates exchange rates. So probably the risk is higher than the benefit
• Add integration with some performance monitoring system to persist logs, monitor metrics and receive alerts about critical issues
• Add integration tests to make sure all parts of the app work well together

Thanks for the task, I had fun working on it :)