opentelemetry-dotnet/docs/trace/getting-started.md

Getting Started with OpenTelemetry .NET in 5 Minutes

First, download and install the .NET Core SDK on your computer.

Create a new console application and run it:

dotnet new console --output getting-started
cd getting-started
dotnet run

You should see the following output:

Hello World!

Install the OpenTelemetry.Exporter.Console package:

dotnet add package OpenTelemetry.Exporter.Console -v 0.4.0-beta.2

Update the Program.cs file with the following code:

using System.Diagnostics;
using OpenTelemetry;
using OpenTelemetry.Trace;

class Program
{
    static readonly ActivitySource activitySource = new ActivitySource(
        "MyCompany.MyProduct.MyLibrary");

    static void Main()
    {
        using var otel = Sdk.CreateTracerProvider(b => b
            .AddActivitySource("MyCompany.MyProduct.MyLibrary")
            .UseConsoleExporter());

        using (var activity = activitySource.StartActivity("SayHello"))
        {
            activity?.SetTag("foo", "1");
            activity?.SetTag("bar", "Hello, World!");
        }
    }
}

Run the application again (using dotnet run) and you should see the trace output from the console.

Activity ID - 00-3ae67370100cdc44a8d461d1b2cf846f-d80f2b1ab6d3bc4b-01
Activity DisplayName - SayHello
Activity Kind - Internal
Activity StartTime - 7/24/2020 1:16:21 AM
Activity Duration - 00:00:00.0018754
Activity Tags
         foo : 1
         bar : Hello, World!

Congratulations! You are now collecting traces using OpenTelemetry.

What does the above program do?

The program creates an ActivitySource which represents OpenTelemetry Tracer. The activitysource instance is used to start an Activity which represent OpenTelemetry Span. Sdk.CreateTracerProvider sets up the OpenTelemetry Sdk, and configures it to subscribe to the activities from the source MyCompany.MyProduct.MyLibrary, and export it to ConsoleExporter, which simply displays it on the console.