EventCounters Instrumentation for OpenTelemetry .NET

This is an Instrumentation Library , which republishes EventCounters using OpenTelemetry Metrics API.

Steps to enable OpenTelemetry.Instrumentation.EventCounters

You can view an example project using EventCounters at /examples/event-counters/Examples.EventCounters.

Step 1: Install Package

Add a reference to the OpenTelemetry.Instrumentation.EventCounters package.

dotnet add package OpenTelemetry.Instrumentation.EventCounters --prerelease

Step 2: Enable EventCounters Instrumentation

EventCounters instrumentation should be enabled at application startup using the AddEventCountersInstrumentation extension on the MeterProviderBuilder:

using var meterProvider = Sdk.CreateMeterProviderBuilder()
    .AddEventCountersInstrumentation(options => {
        options.RefreshIntervalSecs = 1;
        options.AddEventSources("MyEventSource");
    })
    .AddPrometheusHttpListener()
    .Build();

Additionally, the above snippet sets up the OpenTelemetry Prometheus exporter, which requires adding the package OpenTelemetry.Exporter.Prometheus to the application.

When using dependency injection (Microsoft.Extensions.DependencyInjection), EventCounters instrumentation can be registered using AddOpenTelemetry().WithMetrics():

services.AddOpenTelemetry()
    .WithMetrics(builder => builder
        .AddEventCountersInstrumentation(options =>
        {
            options.RefreshIntervalSecs = 1;
            options.AddEventSources("MyEventSource");
        }));

Options can also be bound to configuration via services.Configure<EventCountersInstrumentationOptions>(...).

Step 3: Create EventCounters

Learn about EventCounters in .NET .

EventSource eventSource = new("MyEventSource");

EventCounter eventCounter = new("MyEventCounterName", eventSource);
eventCounter.WriteMetric(0);
eventCounter.WriteMetric(1000);

PollingCounter pollingCounter = new("MyPollingCounterName", eventSource, () => new Random().NextDouble());

Notes

The metrics will only be available after EventCounterIntervalSec seconds. Before that nothing will be exported, if anything is present at the Prometheus metrics endpoint it is from a prior execution. This is more evident when using longer polling intervals.

References

• OpenTelemetry Project