Conditional sampling

[knightpp]

Sorry, wrong repo. Please close discussion.

Hello. I'm using NodeJS and OpenTelemetry's auto tracing feature and I want to conditionally sample some spans, say any span that has a special attribute (the attributes sets startIncomingSpanHook in http plugin).

class MyAttributeSampler implements Sampler {
    shouldSample(context: Context, traceId: string,
        spanName: string, spanKind: SpanKind,
        attributes: SpanAttributes, links: Link[],
    ): SamplingResult {
        if (attributes[FORCE_TRACING_ATTRIBUTE_KEY]) {
            return { decision: SamplingDecision.RECORD_AND_SAMPLED }
        }
       ...
    }
}

...

function main(){
    const sampler = new MyAttributeSampler(
        new ParentBasedSampler({
            root: new TraceIdRatioBasedSampler(probability)
        })
    )
    // pass sampler to nodeSDK, pass sampler to provider
}

But that doesn't work. It seems to be working only when I create root spans in the app (usually spans come in with HTTP trace context, that is sampler processes only children spans).

How can I ignore parent's sampling decision?