@rpc-bastion/observability

Bridge the RPC Bastion event bus to OpenTelemetry — metrics + traces, then out to Prometheus, Datadog, or any OTLP backend. No logging on the hot path; everything flows through the structured event bus.

Use it

import { createEventBus, registerOtelExporter } from '@rpc-bastion/observability';

const bus = createEventBus(); // re-exported from @rpc-bastion/core
const off = registerOtelExporter(bus, { prefix: 'bastion' });

// pass `bus` to createResilientRpc({ bus }) and createSender({ bus })
// ... later: off();

@opentelemetry/api is an optional peer dependency. Without an OTel SDK registered the exporter is a no-op — safe to call unconditionally. Register a NodeSDK with an OTLP exporter to start shipping data.

What it emits

• Metrics: counters (rpc.requests, rpc.errors, rpc.retries, rpc.failovers, tx.submitted{route}, tx.rebroadcast, tx.route_fallback, tx.confirmed/tx.expired/tx.failed), histograms (rpc.latency, tx.confirmation_time), observable gauges (endpoint.health_score, endpoint.inflight, breaker.open_count).
• Traces: a span tree per sendSmart (tx.send root → tx.attempt children per route, with route-fallback recorded). Per-RPC-call spans are off by default (volume).

Options

| Option | Default | Notes | |---|---|---| | meterProvider | global API | false disables metrics | | tracerProvider | global API | false disables traces | | prefix | none | prepended to every metric/span name | | scope | @rpc-bastion/observability | instrumentation scope |

Backends: Prometheus & Datadog

Point your OTel SDK's OTLP exporter at an OpenTelemetry Collector, which fans out to Prometheus (scrape) and Datadog (OTLP ingest) — one exporter, both backends, no dd-trace. A runnable docker-compose stack and configs are in docs/observability.md and docs/observability/.

Safety

The event bus isolates listeners: a throwing exporter never breaks the hot path or other listeners (it's routed to bus.onListenerError). The exporter also guards its own recorders, so observability can't affect transaction execution.