Autofac IContainer and DiagnosticTracer for ASP.NET Core 5

How I can get an IContainer instance for my ASP.NET Core 5 app?

I need to enable diagnostics, and based on official documentation SubscribeToDiagnostics method is accessible only from IContainer, and ASP.NET Core 3+ Integration this.AutofacContainer = app.ApplicationServices.GetAutofacRoot(); exposes only ILifetimeScope.

I have also noticed that Autofac supports DiagnosticListener - is this the way I should trace for information?

Does Autofac provide build in formatters for example for RequestDiagnosticData?

I've updated the ASP.NET Core 3 example for Autofac to show how this works. The secret is using a build callback.

In your ConfigureContainer method, you register a callback to subscribe to diagnostics.

public void ConfigureContainer(ContainerBuilder builder)
{
    // Add any Autofac modules or registrations, then...
    //
    // If you want to enable diagnostics, you can do that via a build
    // callback. Diagnostics aren't free, so you shouldn't just do this
    // by default. Note: since you're diagnosing the container you can't
    // ALSO resolve the logger to which the diagnostics get written, so
    // writing directly to the log destination is the way to go.
    var tracer = new DefaultDiagnosticTracer();
    tracer.OperationCompleted += (sender, args) =>
    {
        Console.WriteLine(args.TraceContent);
    };

    builder.RegisterBuildCallback(c =>
    {
        var container = c as IContainer;
        container.SubscribeToDiagnostics(tracer);
    });
}