[BUG] Instrumentation Options delegates get called multiple times

[TimothyMothra]

Library name and version

Azure.Monitor.OpenTelemetry.AspNetCore

Describe the bug

The AzureMonitor Distro (Azure.Monitor.OpenTelemetry.AspNetCore) automatically includes some Instrumentation libraries. If a user adds the same Instrumentation library again, we expect there should be no conflict.

Unfortunately, it seems that the delegate methods can get executed multiple times. This has only been confirmed with the AspNetCore Instrumentation's EnrichWithHttpRequest library, but I suspect it applies to each Instrumentation library.

Example

builder.Services.AddOpenTelemetry().UseAzureMonitor()
    .WithTracing(builder =>
    {
        builder.AddAspNetCoreInstrumentation(options =>
        {
            options.EnrichWithHttpRequest = (activity, HttpResponse) =>
            {
                // this will be called twice
                Console.WriteLine($"EnrichWithHttpRequest was called for activity: {activity.Id}");
            };
        });
    });

Workaround

The workaround is to use the Configure Api to set an Instrumentation library's options. This is already described in our Readme and public docs, but users are not discovering this pattern and doing the above instead.

builder.Services.AddOpenTelemetry().UseAzureMonitor()
builder.Services.Configure<AspNetCoreTraceInstrumentationOptions>(options =>
{
    options.EnrichWithHttpRequest = (activity, HttpResponse) =>
    {
        // this will be called once
        Console.WriteLine($"EnrichWithHttpRequest was called for activity: {activity.Id}");
    };
});

Expected behavior

N/A

Actual behavior

N/A

Reproduction Steps

N/A

Environment

No response

[TimothyMothra]

I've opened an issue with the Instrumentation libraries as I believe this issue needs to be addressed there. https://github.com/open-telemetry/opentelemetry-dotnet-contrib/issues/2247

[TimothyMothra]

Confirmed this is an issue in the Instrumentation libraries and not the Azure Monitor libraries. I'm closing this issue in favor of continuing the conversation in the OpenTelemetry repo