Snowberry.Mediator.OpenTelemetry.Shared 2.0.0

Snowberry.Mediator.OpenTelemetry.Shared

Core, container-agnostic OpenTelemetry instrumentation for Snowberry.Mediator.

This package contains:

• InstrumentedMediator: an IMediator decorator that emits an Activity and metric measurements for every SendAsync, CreateStreamAsync, and PublishAsync dispatch.
• MediatorInstrumentation: owns the ActivitySource, Meter, and the six per-operation Counter<long> / Histogram<double> instruments.
• MediatorTelemetryOptions: configures the instrumentation (source name, tracing/metrics toggles, per-step span opt-ins, enrichment callbacks, filter).
• TracerProviderBuilderExtensions.AddSnowberryMediatorInstrumentation and MeterProviderBuilderExtensions.AddSnowberryMediatorInstrumentation: subscribe the OpenTelemetry SDK to the activity sources and the meter.

Consumers normally do not reference this package directly. Pick the DI integration package matching the container in use:

Emitted telemetry

Activities

All activities use ActivityKind.Internal.

{RequestType} / {NotificationType} / {BehaviorType} / {HandlerType} and the corresponding *.type tags use the fully-qualified type name (e.g. MyApp.Orders.PlaceOrder), so types that share a simple name across namespaces are not conflated into the same span name or metric series.

Metrics

Meter name: Snowberry.Mediator (configurable via MediatorTelemetryOptions.SourceName).

status is "success" or "failure".

Per-step spans

Per-pipeline-behavior and per-notification-handler spans are opt-in. Enable them via MediatorTelemetryOptions:

o.EnablePipelineBehaviorSpans   = true;
o.EnableNotificationHandlerSpans = true;

Subscribe the OpenTelemetry SDK to all three sources via the builder extensions:

using var tracerProvider = Sdk.CreateTracerProviderBuilder()
    .AddSnowberryMediatorInstrumentation()
    .AddConsoleExporter()
    .Build();

using var meterProvider = Sdk.CreateMeterProviderBuilder()
    .AddSnowberryMediatorInstrumentation()
    .AddConsoleExporter()
    .Build();

Enrichment and filtering

MediatorTelemetryOptions exposes enrichment callbacks (EnrichWithRequest, EnrichWithResponse, EnrichWithNotification, EnrichWithException) and a Filter that short-circuits instrumentation for a given dispatch. Exceptions thrown from enrichment callbacks are recorded as an Activity event named snowberry.mediator.enrichment.failed and do not propagate to the caller.

The Filter callback is the exception: it is evaluated before any Activity exists, so a throwing Filter is not swallowed and instead propagates out of the dispatch call. Keep Filter total (non-throwing). EnrichWithException fires for failed SendAsync, PublishAsync, and CreateStreamAsync dispatches; for a stream it does not fire when the consumer merely stops enumerating early (no exception occurred), though the span is still marked Error.