NLog.Web: ActivityId id is empty in async context in ASP.NET Web API

Hi I am using the activityid in our logging for getting a correlation ID, and i followed the guide that is provided on GitHub. That states i only need to add a method in global asax, where we set the activity id.

All my api’s calls are mostly async methods and some times the activity id is empty?

NLog version: 4.6.2 NLog.Config version: 4.6.2 NLog.Schema version: 4.6.2 NLog.Web version: 4.8.1

Platform: .Net 4.5

Current NLog config (xml or C#, if relevant)

  <nlog throwConfigExceptions="true">
    <targets>
      <target name="debugger" type="Debugger" layout="${logger}::${message}" />
      <target name="database" type="Database" dbProvider="sqlserver" connectionStringName="Nlog">
        <commandText>
          INSERT INTO [dbo].[Log] (MachineName, Service, Logged, CorrelationId, Level, Message, Logger, Callsite, Exception) VALUES (@MachineName, 'My service name', @Logged, @CorrelationId, @Level, @Message, @Logger, @Callsite, @Exception);
        </commandText>
        <parameter name="@MachineName" layout="${machinename}" />
        <parameter name="@Logged" layout="${date}" />
        <parameter name="@CorrelationId" layout="${activityid}" />
        <parameter name="@Level" layout="${level}" />
        <parameter name="@Message" layout="${message}" />
        <parameter name="@Logger" layout="${logger}" />
        <parameter name="@Callsite" layout="${callsite}" />
        <parameter name="@Exception" layout="${exception:tostring}" />
      </target>
    </targets>
    <rules>
      <logger name="*" minlevel="Trace" writeTo="debugger" />
      <logger name="*" minlevel="Trace" writeTo="database" />
    </rules>
  </nlog>

I was reading about this specific problem with async calls and the global asax not being called and I found a solution to this.

I created my own DelegatingHandler that intercepts all messages sent to the service. Where i get a correlation Id and manually sets the ActivityId.

using System;
using System.Diagnostics;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;

public class CorrelationHandler : DelegatingHandler
    {
        protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            Guid correlationId = request.GetCorrelationId();
            Trace.CorrelationManager.ActivityId = correlationId;

            return await base.SendAsync(request, cancellationToken);
        }
    }

Finally I registered my new handler in the WebApiConfig.cs file like so:

    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            ...
            // Web API message handlers
            config.MessageHandlers.Add(new CorrelationHandler());
            ...
        }
    }