opentelemetry, how to disable some of the default spans?

[ceastman-r7]

Summary

Specifically I would like to disable a couple of apis from having spans created for them. namely the /liveness and /readiness endpoints that kubernetes uses to see if the app is ready and alive. these endpoints get hit alot from the kubernetes api server.

I followed this doc
https://nextjs.org/docs/app/building-your-application/optimizing/open-telemetry#manual-opentelemetry-configuration

Additional information

No response

Example

No response

[tomdohnal]

I haven't found a way to disable producing the spans but I've been experimenting with using a custom Sampler to filter out Next.js spans:

class CustomSampler implements Sampler {
  shouldSample(
    context: Context,
    traceId: string,
    spanName: string,
    spanKind: SpanKind,
    attributes: Attributes,
  ): SamplingResult {
    if (attributes['next.span_type']) {
      return {
        decision: SamplingDecision.NOT_RECORD,
      }
    }

    return {
      decision: SamplingDecision.RECORD_AND_SAMPLED,
    }
  }
}

I think you could adopt this for your usecase by looking into the attributes (probably something like attributes['next.route'] !== '/readiness').

Although it'd be defintely appreciated to have a way to control span generation baked into Next.js itself.

[stefann42]

Another workaround is to filter at the level of the exporter. For example, you can override OTLPTraceExporter.send in your own derived class:

class OTLPTraceExporterWithFilter extends OTLPTraceExporter {
  override send(objects: ReadableSpan[], onSuccess: () => void, onError: (error: OTLPExporterError) => void): void {
    const objectsToSend = objects.filter(i => !Object.keys(i.attributes).some(key => key.startsWith("next.")))
    super.send(objectsToSend, onSuccess, onError);
  }
}

Above is a very coarse criteria for dropping everything that comes from the next.js framework itself, but you can tweak the filter criteria to whatever you need.

As of next.js 15.0.1 default spans are documented at Default Spans https://nextjs.org/docs/pages/building-your-application/optimizing/open-telemetry#default-spans-in-nextjs and the resulting Span object that comes into the exporter looks like this:

Span {
    attributes: {
      'next.clientComponentLoadCount': 14,
      'next.span_type': 'NextNodeServer.clientComponentLoading'
    },
    links: [],
    events: [],
    _droppedAttributesCount: 0,
    _droppedEventsCount: 0,
    _droppedLinksCount: 0,
    status: { code: 0 },
    endTime: [ 1730167368, 619089053 ],
    _ended: true,
    _duration: [ 0, 431007800 ],
    name: 'NextNodeServer.clientComponentLoading',
    _spanContext: {
      traceId: 'aea97a60b42591fdc822dfa50f4768e6',
      spanId: '7a910d1be40c6eb7',
      traceFlags: 1,
      traceState: undefined
    },
    parentSpanId: undefined,
    kind: 0,
    _performanceStartTime: 16518.2834,
    _performanceOffset: -0.578369140625,
    _startTimeProvided: true,
    startTime: [ 1730167368, 188081253 ],
    resource: Resource {
      _attributes: [Object],
      asyncAttributesPending: false,
      _syncAttributes: [Object],
      _asyncAttributesPromise: [Promise]
    },
    instrumentationLibrary: { name: 'next.js', version: '0.0.1', schemaUrl: undefined },
    _spanLimits: {
      attributeValueLengthLimit: Infinity,
      attributeCountLimit: 128,
      linkCountLimit: 128,
      eventCountLimit: 128,
      attributePerEventCountLimit: 128,
      attributePerLinkCountLimit: 128
    },
    _attributeValueLengthLimit: Infinity,
    _spanProcessor: MultiSpanProcessor { _spanProcessors: [Array] }
  }

[trieu-hphuc96]

It's working for me, thanks for the solution ❤️