Observability

Metrics Extension01

The built-in metrics extension tracks operational counters:

import "github.com/xraph/nexus/observability"

metrics := observability.NewMetricsExtension()
gw := nexus.New(
    nexus.WithExtension(metrics),
)

// Read counters
metrics.RequestsCompleted.Value() // int64
metrics.ProviderFailures.Value()
metrics.GuardrailBlocks.Value()

Tracing02

Add OpenTelemetry spans to every request:

nexus.WithTracer(otelTracer)

The tracing middleware (priority 10) creates spans with:

• Request model and provider

• Tenant ID

• Token counts

• Cache hit/miss status

Response Headers03

Every response includes diagnostic headers: