Adding custom dimension to Application Insights traces from .NET Core

Question

How to add custom dimension to Application Insights traces from .NET Core? Any pointers are welcome.

Answer 1

If it's a .net core web project, you can use ITelemetryInitializer to add custom dimension.

First, add a new class named MyTelemetryInitializer to the project:

public class MyTelemetryInitializer: ITelemetryInitializer
{
    public MyTelemetryInitializer()
    {
    }

    public void Initialize(ITelemetry telemetry)
    {

        if (telemetry is TraceTelemetry traceTelemetry)
        {
                
            if (!traceTelemetry.Properties.ContainsKey("my_custom_1"))
            {
                //add the custom dimension here
                traceTelemetry.Properties["my_custom_1"] = "test 12346"; 
            }

        }

    }
 }

Then in the Startup.cs -> ConfigureServices method, add these lines of code:

services.AddApplicationInsightsTelemetry();
services.AddSingleton<ITelemetryInitializer, MyTelemetryInitializer>();

And for testing purpose, in the HomeController, I have this Index method to send trace message:

public IActionResult Index()
{
    TelemetryClient client = new TelemetryClient();
    client.TrackTrace("it is a trace message from index page");

    return View();
}

At last, run the project. Then nav to azure portal -> application insights, you can see the custom dimension is added.