OpenTelemetry traces

@skelm/otel ships an attachOpenTelemetry(events) adapter that maps skelm's run events onto OTel spans (one span per run, nested spans per step, exception recording on errors). It does not ship an exporter — that's deliberate. Pick the OTLP exporter that matches your collector and wire it once at process startup.

Minimal wiring (OTLP over HTTP)

import { NodeSDK } from '@opentelemetry/sdk-node'
import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-http'
import { attachOpenTelemetry } from '@skelm/otel'
import { Runner } from '@skelm/core'

const sdk = new NodeSDK({
  traceExporter: new OTLPTraceExporter({ url: 'http://localhost:4318/v1/traces' }),
  serviceName: 'skelm-app',
})
sdk.start()

const runner = new Runner({ /* ... */ })
attachOpenTelemetry(runner.events) // subscribe before starting runs

// On shutdown:
process.on('SIGTERM', async () => {
  await sdk.shutdown()
  process.exit(0)
})

That's the entire integration. The adapter creates a parent span for each run.started, child spans for each step.start, and closes them on matching step.completed / run.completed events. Failures call span.recordException(error) and set the status code.

Gateway-hosted

The gateway constructs runners internally. Subscribe its event bus the same way:

import { Gateway } from '@skelm/gateway'
import { attachOpenTelemetry } from '@skelm/otel'

const gw = new Gateway({ /* ... */ })
await gw.start()
gw.attachMetricsBus = (bus) => attachOpenTelemetry(bus)

(attachMetricsBus is the same hook the Prometheus collector uses; attaching OTel and metrics together is fine — they both subscribe.)

Collector configuration

Any OTLP-compatible collector accepts the traffic — Tempo, Jaeger, Grafana Cloud, Honeycomb, Datadog. The skelm side does not care which. Use whatever your existing infrastructure already runs.

Why no exporter ships in @skelm/otel

Each exporter pulls in transport-specific deps (@opentelemetry/exporter-trace-otlp-grpc, -http, vendor-specific shippers). Bundling one would force every skelm install to pay for it; bundling all of them would make the package heavyweight. Keeping the adapter exporter-agnostic is the same call @opentelemetry/api made — record spans here, ship them however the deployment wants.