Program.cs

using HealthChecks.UI.Client;
using Microsoft.AspNetCore.Diagnostics.HealthChecks;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
var assembly = typeof(Program).Assembly;

// Add services to the container
builder.Services.AddCarter();
builder.Services.AddMediatR(config =>
{
    config.RegisterServicesFromAssembly(assembly);
    config.AddBehavior(typeof(IPipelineBehavior<,>), typeof(ValidationBehavior<,>));
    config.AddOpenBehavior(typeof(LoggingBehavior<,>));

});
if (builder.Environment.IsDevelopment())
    builder.Services.InitializeMartenWith<CatalogInitialData>();

builder.Services.AddCors(options =>
{
    options.AddPolicy("AllowAllOrigins",
        policy =>
        {
            policy.WithOrigins("http://localhost:5050");
        });
});
builder.Services.AddValidatorsFromAssembly(assembly);

builder.Services.AddMarten(opt =>
{
    opt.Connection(builder.Configuration.GetConnectionString("Database")!);
}).UseLightweightSessions();

builder.Services.AddExceptionHandler<CustomExceptionHandler>();
builder.Services.AddHealthChecks()
    .AddNpgSql(builder.Configuration.GetConnectionString("Database")!);

var app = builder.Build();

if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

// Configure the HTTP request pipeline.
app.UseCors("AllowAllOrigins");
app.UseHttpsRedirection();
app.MapCarter();
app.UseExceptionHandler(options => { });

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