WCF-client and ASMX-service can share the same traceparent

[olahallvall]

Hi!
I have made an exemple that shows how the TelemetryHttpModule can support WCF-client calling a ASMX-service.

App.config looks like this:

   <system.serviceModel>
        <extensions>
          <behaviorExtensions>
            <add name="telemetryExtension"         type="OpenTelemetry.Contrib.Instrumentation.Wcf.TelemetryEndpointBehaviorExtensionElement, 
           OpenTelemetry.Contrib.Instrumentation.Wcf" />
          </behaviorExtensions>
        </extensions>
        <behaviors>
          <endpointBehaviors>
            <behavior name="telemetry">
              <telemetryExtension />
            </behavior>
          </endpointBehaviors>
        </behaviors>
        
          <bindings>
              <basicHttpBinding>
                  <binding name="StatusServiceSoap" />
              </basicHttpBinding>
          </bindings>
          <client>         
              <endpoint address="http://localhost:5617/StatusService.asmx" behaviorConfiguration="telemetry"
                  binding="basicHttpBinding" bindingConfiguration="StatusServiceSoap"
                  contract="StatusServiceRef.StatusServiceSoap" name="StatusServiceSoap" />
          </client>
      </system.serviceModel>

web.config looks like this:

    <configuration>
      <system.web>
        <compilation debug="true" targetFramework="4.7.2" />
        <httpRuntime targetFramework="4.7.2" />   
      </system.web>
    
      <system.webServer>
        <directoryBrowse enabled="true" />
        
        <modules>
          <remove name="TelemetryHttpModule" />
          <add name="TelemetryHttpModule" type="OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule, OpenTelemetry.Instrumentation.AspNet.TelemetryHttpModule"/>
        </modules>
        
        <security>
          <requestFiltering>
            <requestLimits maxAllowedContentLength="4294967295" />
          </requestFiltering>
        </security>
        
      </system.webServer>
    </configuration>

Inside OpenTelemetry.Instrumentation.AspNet.ActivityHelper I have added this prototyp code:

     public static Activity StartAspNetActivity(TextMapPropagator textMapPropagator, HttpContext context, Action<Activity, HttpContext> onRequestStartedCallback)
            {
                Debug.Assert(context != null, "Context is null.");
    
                if (context.Request.InputStream != null && context.Request.InputStream.Length > 0)
                {
                    var prevPos = context.Request.InputStream.Position;
                    context.Request.InputStream.Position = 0;
                    var xml = new StreamReader(context.Request.InputStream, Encoding.UTF8).ReadToEnd();
                    context.Request.InputStream.Position = prevPos;
    
                    XElement doc = XElement.Parse(xml);
                    XNamespace ns = @"http://schemas.xmlsoap.org/soap/envelope/";
                    XNamespace nsa = @"https://www.w3.org/TR/trace-context/";
    
                    // traceparent
                    var traceparent = doc.Elements(ns + "Header")
                                            .Select(m => m.Element(nsa + "traceparent")?.Value).SingleOrDefault();
    
                    if (!string.IsNullOrEmpty(traceparent))
                    {
                        context.Request.Headers.Add("traceparent", traceparent);
                    }
    
                    // tracestate
                    var tracestate = doc.Elements(ns + "Header")
                                            .Select(m => m.Element(nsa + "tracestate")?.Value).SingleOrDefault();
    
                    if (!string.IsNullOrEmpty(tracestate))
                    {
                        context.Request.Headers.Add("tracestate", tracestate);
                    }
    
                    // baggage
                    var baggage = doc.Elements(ns + "Header")
                                            .Select(m => m.Element(nsa + "baggage")?.Value).FirstOrDefault();
    
                    if (!string.IsNullOrEmpty(baggage))
                    {
                        context.Request.Headers.Add("baggage", baggage);
                    }
                }
    
                PropagationContext propagationContext = textMapPropagator.Extract(default, context.Request, HttpRequestHeaderValuesGetter);

In Jaeger is looks like this:

Do I break some kind of design with my code?