Observability

Vali-Mediator.Observability adds telemetry to every request handled by the mediator — distributed tracing, metrics, and custom observers.

Installation

dotnet add package Vali-Mediator.Observability

Setup

builder.Services.AddValiMediator(config =>
{
    config.RegisterServicesFromAssemblyContaining<Program>();
    config.AddObservabilityBehavior();
});

builder.Services.AddObservability();

Three Pillars

Pillar	Type	Description
Tracing	ValiMediatorDiagnostics.ActivitySource	OpenTelemetry-compatible Activity per request
Metrics	IMetricsCollector	Record duration, success/failure counts
Observers	IRequestObserver	Hook into started/completed/failed lifecycle

What Gets Recorded

For every IRequest<T>, INotification, and IFireAndForget processed:

• Activity started with request type name
• Handler name tagged on the activity
• Duration in milliseconds
• Success/failure status
• ErrorType if applicable

OpenTelemetry Integration

builder.Services.AddOpenTelemetry()
    .WithTracing(tracing => tracing
        .AddSource("Vali-Mediator") // listen to Vali-Mediator activities
        .AddJaegerExporter()
        .AddZipkinExporter());

Disabling for Specific Requests

To opt out of observability for a specific request, don't register AddObservabilityBehavior globally and instead apply it selectively, or implement a custom behavior that skips certain request types.