### MongoDB C# Driver: Using Standard GUIDs

Source: https://github.com/mehdihadeli/awesome-software-architecture/blob/main/docs/database/nosql/mongodb.md

Demonstrates the configuration for using standard GUID representations in the MongoDB C# driver. This ensures consistent handling of GUIDs across different systems.

```csharp
BsonSerializer.RegisterSerializer(new GuidSerializer(BsonGuidRepresentation.Standard));
```

--------------------------------

### MongoDB Shell/Compass: Query with GUID

Source: https://github.com/mehdihadeli/awesome-software-architecture/blob/main/docs/database/nosql/mongodb.md

Demonstrates how to query MongoDB using a GUID in the shell or Compass. This is useful when your application uses GUIDs as identifiers and you need to find specific records.

```javascript
db.collection.find({ _id: "a1b2c3d4-e5f6-7890-1234-567890abcdef" });
```

--------------------------------

### OpenTelemetry Extensions for ASP.NET Core

Source: https://github.com/mehdihadeli/awesome-software-architecture/blob/main/docs/microservices/observability/distributed-tracing.md

Example of extending OpenTelemetry services in an ASP.NET Core application. This snippet shows how to configure OpenTelemetry, which is essential for distributed tracing.

```csharp
using OpenTelemetry.Extensions.Hosting;
using OpenTelemetry.Trace;

namespace TodoApi
{
    public static class OpenTelemetryExtensions
    {
        public static IServiceCollection AddOpenTelemetryTracing(this IServiceCollection services)
        {
            services.AddOpenTelemetry()
                .WithTracing(builder =>
                {
                    builder
                        .AddAspNetCoreInstrumentation()
                        .AddHttpClientInstrumentation()
                        .AddOtlpExporter();
                });

            return services;
        }
    }
}
```

--------------------------------

### Basic Concurrency Handling in Entity Framework Core

Source: https://github.com/mehdihadeli/awesome-software-architecture/blob/main/docs/concurrency.md

Demonstrates basic optimistic concurrency handling in Entity Framework Core. Ensure your entity has a concurrency token property.

```csharp
public class Blog
{
    public int BlogId { get; set; }
    public string Url { get; set; }

    // Concurrency token
    [Timestamp]
    public byte[] RowVersion { get; set; }
}
```

--------------------------------

### HostingApplicationDiagnostics in ASP.NET Core

Source: https://github.com/mehdihadeli/awesome-software-architecture/blob/main/docs/microservices/observability/diagnostics.md

This snippet illustrates the HostingApplicationDiagnostics class in ASP.NET Core, which manages diagnostic events related to the application's lifecycle and request processing.

```csharp
internal class HostingApplicationDiagnostics
{
    private readonly DiagnosticListener _diagnosticListener;
    private readonly HostingEventSource _hostingEventSource;

    public HostingApplicationDiagnostics(DiagnosticListener diagnosticListener, HostingEventSource hostingEventSource)
    {
        _diagnosticListener = diagnosticListener ?? throw new ArgumentNullException(nameof(diagnosticListener));
        _hostingEventSource = hostingEventSource ?? throw new ArgumentNullException(nameof(hostingEventSource));
    }

    public void BeginRequest(HttpContext httpContext)
    {
        var requestId = httpContext.Connection.Id;
        var request = httpContext.Request;
        var requestPath = request.Path.ToString();
        var requestMethod = request.Method;

        _hostingEventSource.RequestStarting(requestId, requestPath, requestMethod);
        _diagnosticListener.Write("Microsoft.AspNetCore.Hosting.BeginRequest", new { httpContext });
    }

    public void EndRequest(HttpContext httpContext)
    {
        var requestId = httpContext.Connection.Id;
        var response = httpContext.Response;
        var responseStatusCode = response.StatusCode;
        var requestMethod = httpContext.Request.Method;

        _hostingEventSource.RequestFinished(requestId, responseStatusCode, requestMethod);
        _diagnosticListener.Write("Microsoft.AspNetCore.Hosting.EndRequest", new { httpContext });
    }

    public void Shutdown()
    {
        _hostingEventSource.HostShutdown();
        _diagnosticListener.Write("Microsoft.AspNetCore.Hosting.Shutdown", null);
    }

    public void ApplicationStopping()
    {
        _hostingEventSource.ApplicationStopping();
        _diagnosticListener.Write("Microsoft.AspNetCore.Hosting.ApplicationStopping", null);
    }

    public void ApplicationStopped()
    {
        _hostingEventSource.ApplicationStopped();
        _diagnosticListener.Write("Microsoft.AspNetCore.Hosting.ApplicationStopped", null);
    }
}
```