Add Custom Properties to Application Insights Request Telemetry in WCF

I'm trying to get some additional information about the message we received (basically its application-level outcome) into the Application Insights RequestTelemetry object for a WCF service.

Application Insights is logging request telemetry already. I created an ITelemetryInitializer that is being run, but at the time it runs I have no way that I can find to access information about the request, much less application-specific data from the request's context.

Is there somewhere I can put data that will be accessible by the ITelemetryInitializer at the time it runs?

    public class WcfServiceTelemetryInitializer : ITelemetryInitializer
    {
        public void Initialize(ITelemetry telemetry)
        {
            if (telemetry is RequestTelemetry rTelemetry)
            {
                // HttpContext.Current is populated at this point, but doesn't seem to be available within my application code.
                // So is System.ServiceModel.OperationContext.Current
            }
        }
    }

Solution

I had to face similar issue as the author described. Tried by implementing ITelemetryInitializer/ITelemetryProcessor but did not work.

Ended up writing my own MessageTraceTelemetryModule class implementing IWcfTelemetryModule and IWcfMessageTrace.

In the OnTraceResponse method, I added my custom property to the request telemetry by extracting value from OperationContext (which is accessible here!):

internal class MessageTraceTelemetryModule : IWcfTelemetryModule, IWcfMessageTrace
{
    public void OnTraceResponse(IOperationContext operation, ref Message response)
    {
        if (OperationContext.Current.IncomingMessageProperties.TryGetValue("clientID", out object value))
        {
            operation.Request.Properties.Add("clientID", value.ToString());
        }
    }
}

New custom property visible in Application Insights telemetry - ClientID custom property Pic.
Note that the clientID property is being set in the OperationContext in Message Inspector:

public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
{
    if(!OperationContext.Current.IncomingMessageProperties.ContainsKey("clientID"))
        OperationContext.Current.IncomingMessageProperties.Add("clientID", clientID);
}

Brief Context:
I implemented AAD Token based Authentication in a SOAP based WCF Service.
I needed to store the clientID from the token (which is validated in message inspector) and add the same as a custom property in the application insights request telemetry.

References: