Program.cs

using System.Net.Mime;
using System.Text.Json;
using Catalog.Repositories;
using Catalog.Settings;
using Microsoft.AspNetCore.Diagnostics.HealthChecks;
using MongoDB.Bson;
using MongoDB.Bson.Serialization;
using MongoDB.Bson.Serialization.Serializers;
using MongoDB.Driver;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.

// Initialzer and setup for mongo db connection
BsonSerializer.RegisterSerializer(new GuidSerializer(BsonType.String));
BsonSerializer.RegisterSerializer(new DateTimeOffsetSerializer(BsonType.String));

var mongoDbSettings = builder.Configuration.GetSection(nameof(MongoDbSettings)).Get<MongoDbSettings>();

builder.Services.AddSingleton<IMongoClient>(serviceProvider => 
    {
        return new MongoClient(mongoDbSettings.ConnectionString);
    });

builder.Services.AddSingleton<IItemsRepository, MongoDbItemsRepository>(); 

builder.Services.AddControllers(options => options.SuppressAsyncSuffixInActionNames = false);
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();

builder.Services.AddHealthChecks()
.AddMongoDb(
    mongoDbSettings.ConnectionString, 
    name: "mongodb", 
    timeout: TimeSpan.FromSeconds(3),
    tags: new[] {"ready"}
    );

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();

    app.UseHttpsRedirection();
}


app.UseAuthorization();

app.MapControllers();

app.MapHealthChecks("/healthz/ready", new HealthCheckOptions{ // Customizing how to render ready message 
    Predicate = (check) => check.Tags.Contains("ready"),
    ResponseWriter = async (context, report) =>
    {
        var result = JsonSerializer.Serialize(
            new {
                status = report.Status.ToString(),
                checks = report.Entries.Select(entry => new {
                    name = entry.Key,
                    status = entry.Value.Status.ToString(),
                    exception = entry.Value.Exception != null ?
                        entry.Value.Exception.Message: "none",
                    duration = entry.Value.Duration.ToString()
                })
            }
        );

        context.Response.ContentType = MediaTypeNames.Application.Json;
        await context.Response.WriteAsync(result);
    }
});

app.MapHealthChecks("/healthz/live", new HealthCheckOptions{
    Predicate = (_) => false
});

app.Run();