[instrumentation-document-load] option to ignore resource spans

[longility]

If this is acceptable, I can do a PR to expedite our needs and contribute for others to leverage as well.

Is your feature request related to a problem? Please describe

I would like to minimize the number of spans created that may not be important to us, specifically resource spans.

Describe the solution you'd like to see

For this line, https://github.com/open-telemetry/opentelemetry-js-contrib/blob/2dc2f72e5a86aa9e1220a26f78878070acde8424/plugins/web/opentelemetry-instrumentation-document-load/src/instrumentation.ts#L138

to be similar to this: https://github.com/open-telemetry/opentelemetry-js-contrib/blob/2dc2f72e5a86aa9e1220a26f78878070acde8424/plugins/web/opentelemetry-instrumentation-document-load/src/instrumentation.ts#L160C7-L162C8

to where the end result may look something like this:

      if (!this._getConfig().ignoreResourceSpans) {
        this._addResourcesSpans(rootSpan);
      }

Describe alternatives you've considered

None.

Additional context

None.

[scheler]

We are working on a new set of instrumentations using the new Events API, one of which is to emit ResourceTiming events for the resources loaded (https://github.com/open-telemetry/opentelemetry-js-contrib/issues/2152), and another to emit PageView event (https://github.com/open-telemetry/opentelemetry-sandbox-web-js/issues/81). As part of this effort, I envision an instrumentation to emit a standalone documentFetch span. We have not created an issue yet to track this as this hasn't been discussed much in the Client SIG.

For your use-case does it work if you configure a custom sampler to drop these spans?

[longility]

We are working on a new set of instrumentations using the new Events API, one of which is to emit ResourceTiming events for the resources loaded (#2152), and another to emit PageView event (open-telemetry/opentelemetry-sandbox-web-js#81). As part of this effort, I envision an instrumentation to emit a standalone documentFetch span. We have not created an issue yet to track this as this hasn't been discussed much in the Client SIG.

For your use-case does it work if you configure a custom sampler to drop these spans?

@scheler thanks for the status update and a workaround! I think that could be sufficient. Do you know of a sampler that could be a good starting point? I have not done one of those before.

[scheler]

@longility something like this -

const provider = new WebTracerProvider({
  resource,
  sampler: {
    shouldSample: (context, traceId, spanName, spanKind, attributes, links) => {
      return spanName == 'resourceFetch' ? SamplingDecision.NOT_RECORD : SamplingDecision.RECORD_AND_SAMPLED;
    }
  }
});