Microservices Pattern

// Get discount from Discount.Grpc service
foreach (var item in command.Cart.Items)
{
    var coupon = await discountProto.GetDiscountAsync(
        new GetDiscountRequest { ProductName = item.ProductName }, 
        cancellationToken: cancellationToken);
    item.Price -= coupon.Amount;
}

namespace BuildingBlocks.Messaging.Events;

public record BasketCheckoutEvent : IntegrationEvent
{
    public string UserName { get; set; } = default!;
    public Guid CustomerId { get; set; }
    public decimal TotalPrice { get; set; }
    
    // Shipping Address
    public string FirstName { get; set; } = default!;
    public string LastName { get; set; } = default!;
    public string EmailAddress { get; set; } = default!;
    public string AddressLine { get; set; } = default!;
    public string Country { get; set; } = default!;
    public string State { get; set; } = default!;
    public string ZipCode { get; set; } = default!;
    
    // Payment
    public string CardName { get; set; } = default!;
    public string CardNumber { get; set; } = default!;
    public string Expiration { get; set; } = default!;
    public string CVV { get; set; } = default!;
    public int PaymentMethod { get; set; }
}

public class BasketCheckoutEventHandler
    (ISender sender, ILogger<BasketCheckoutEventHandler> logger)
    : IConsumer<BasketCheckoutEvent>
{
    public async Task Consume(ConsumeContext<BasketCheckoutEvent> context)
    {
        logger.LogInformation("Integration Event handled: {IntegrationEvent}", 
            context.Message.GetType().Name);

        var command = MapToCreateOrderCommand(context.Message);
        await sender.Send(command);
    }
}

builder.Services.AddHealthChecks()
    .AddNpgSql(builder.Configuration.GetConnectionString("Database")!);

app.UseHealthChecks("/health",
    new HealthCheckOptions
    {
        ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse
    });