How to use application insights in .net standard library?

Question

I have used application insights in web api. It works well. Currently, our controller need call a class library (referred by nuget package). I need to use application insight in class library. There is no exception but nothing logged in Application insights. I write the code as following. Our TelemetryConfiguration have initialized in controller already.

var telemetryClient = new TelemetryClient();
var customEvent = new Microsoft.ApplicationInsights.DataContracts.EventTelemetry
{
    Name = "helloworld",
};
// customEvent.Metrics.Add({ "latency", 42});
telemetryClient.TrackEvent(customEvent);

What should I do to make the application insights work?

Answer 1

Normally the following steps are enough to log to App Insights:

1- In your WebApi startup class and your library project add App Insights assembly thru nuget.

Microsoft.ApplicationInsights

2- Register App Insights in your startup class:

services.AddApplicationInsightsTelemetry(Configuration);

3- Setup your instrumentation key in appsettings.json:

"ApplicationInsights": {
  "InstrumentationKey": "<Your instrumentation key here>"
}

4- In any class you need, inject a TelemetryClient and use it.

using Microsoft.ApplicationInsights

namespace MyNamesPace
{
    public class MyClass
    {
        private readonly TelemetryClient _telemetryClient;

        public MyClass(TelemetryClient telemetryClient)
        {
            _telemetryClient= telemetryClient;
        }

        public myClassMethod()
        {
            // Use your _telemetryClient instance
            _telemetryClient.TrackEvent("Your Telemetry Event");
        }
    }
}

4- In your controller inject your class

namespace MyApiNamesPace
{
    public class MyController : ControllerBase
    {
        private readonly IMyClass _myClass;

        public MyClass(IMyClass myClass)
        {
            _myClass = myClass;
        }

        public IActionResult myAction()
        {
            _myClass.MyClassMethod();
        }
    }
}

5- Don't forget to register your class in your DI container, in startup class:

services.AddScoped<IMyClass, MyClass>();

Happy programming!!