Hands-On Dependency Injection in Go

Applying method injection to the model layer (the Get, List, and Register packages)

Previously, in places where we called the data or exchange packages, we used context.TODO() to ensure the code could still compile and that our tests continued to do their job. It's now time to apply method injection to the model layer and replace the context.TODO() calls with injected context. First, we change the getPrice() and save() methods to accept a context:

// get price in the requested currencyfunc (r *Registerer) getPrice(ctx context.Context, currency string) (float64, error) {   converter := &exchange.Converter{}   price, err := converter.Do(ctx, config.App.BasePrice, currency)   if err != nil {      logging.L.Warn("failed to convert the price. err: %s",  ...