Autofac IContainer and DiagnosticTracer for ASP .Net 5 - autofac

Question

How I can get IContainer instance for my ASP.Net 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 a way how I should trace for informations?
Does Autofac provide build in formatters for example for RequestDiagnosticData?
What are your recommendations?

Answer 1

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);
});
}