Adding custom properties for each request in Application Insights metrics

It looks like adding new properties to existing request is possible using ITelemetryInitializer as mentioned here.

I created sample class as given below and added new property called “LoggedInUser” to request telemetry.

public class CustomTelemetry : ITelemetryInitializer
{
    public void Initialize(ITelemetry telemetry)
    {
        var requestTelemetry = telemetry as RequestTelemetry;
        if (requestTelemetry == null) return;
        requestTelemetry.Properties.Add("LoggedInUserName", "DummyUser");

    }
}

Register this class at application start event.
Example below is carved out of sample MVC application I created

 public class MvcApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);

        TelemetryConfiguration.Active.TelemetryInitializers
    .Add(new CustomTelemetry());
    }
}

Now you can see custom property “LoggedInUserName” is displayed under Custom group of request properties. (please refer screen grab below)

Appinsight with custom property