Instrument .NET application for OpenTelemetry

ar builder = WebApplication.CreateBuilder(args);
var resourceBuilder = ResourceBuilder
.CreateDefault()
.AddService("OpenTelemetry-Dotnet-Example")
.AddTelemetrySdk();

// Configure the OpenTelemetry SDK for traces
builder.Services.AddOpenTelemetryTracing(tracerProviderBuilder =>
{
// Step 1. Declare the resource to be used by this tracer provider.
tracerProviderBuilder.SetResourceBuilder(resourceBuilder);
// Step 2. Configure the SDK to listen to the following auto-instrumentation
tracerProviderBuilder.AddAspNetCoreInstrumentation(options =>
{
options.RecordException = true;
}).AddHttpClientInstrumentation();
// Step 3. Configure the SDK to listen to custom instrumentation.
tracerProviderBuilder.AddSource("WeatherForecast");
// Step 4. Configure the OTLP exporter to export to Site24x7
// The OTEL_EXPORTER_OTLP_ENDPOINT environment variable should be set to Site24x7's OTLP endpoint:
// OTEL_EXPORTER_OTLP_ENDPOINT=https://otel.site24x7rum.com:4318
//
// The OTEL_EXPORTER_OTLP_HEADERS environment variable should be set to include your Site24x7 API key:
// OTEL_EXPORTER_OTLP_HEADERS=api-key=<YOUR_API_KEY_HERE>
tracerProviderBuilder.AddOtlpExporter(options =>
{
options.Endpoint = new Uri($"{Environment.GetEnvironmentVariable("OTEL_EXPORTER_OTLP_ENDPOINT")}");
options.Headers = Environment.GetEnvironmentVariable("OTEL_EXPORTER_OTLP_HEADERS");
options.Protocol = OpenTelemetry.Exporter.OtlpExportProtocol.HttpProtobuf;
});
});

// An ActivitySource is .NET's term for an OpenTelemetry Tracer.
// Spans generated from this ActivitySource are associated with the ActivitySource's name and version.
private static ActivitySource _tracer = new ActivitySource("WeatherForecast", "1.2.3");
private void DoSomeWork()
{
// Start a span using the OpenTelemetry API
using var span = _tracer.StartActivity("DoSomeWork", ActivityKind.Internal);
// Decorate the span with additional attributes
span?.AddTag("SomeKey", "SomeValue");
// Do some work
Thread.Sleep(50);// Make an external call
_httpClient.GetString("https://www.site24x7.com").GetAwaiter().GetResult();
// Do some more work
Thread.Sleep(50);
}
public IActionResult Index()
{
DoSomeWork();
return View();
}