Background and Motivation

The .NET runtime provides APIs to generate Activity, which can be adopted and processed as trace context and eventually emitted to multiple backend vendors by OpenTelemetry .NET SDK for the purpose of tracing. Currently .NET runtime only allows an activity's trace id to be randomly generated and there is no public API available to override it. While for some backend vendors, trace context with a non-random customized trace id is more preferred. For instance, AWS X-Ray backend will only process trace context with a trace id containing a timestamp. In this case, is it possible for the runtime to support customized activity trace id in Activity class, like adding API similar as Activity.SetTraceId()?

Previous discussion: open-telemetry/opentelemetry-specification#896

Proposal Edited by @tarekgh

Proposed API

namespace System.Diagnostics
{
    public partial class Activity : IDisposable
    {
        // alternative proposed names: 
        //     GenerateTraceId 
        //     TraceIdCreationFunction
        public static Func<ActivityTraceId>? TraceIdGenerationFunction { get; set; } 
    }
}

Usage Examples

    Activity.TraceIdGenerationFunction = () => ActivityTraceId.CreateRandom();
    
    ...


    using (Activity activity = source.StartActivity("OperationName"))
    {
        Console.WriteLine(activity?.TraceId);
    }