spanProcessor.ts

import { SpanProcessor, Span, ReadableSpan } from '@opentelemetry/sdk-trace-base';

class RemoveQueryParamsProcessor implements SpanProcessor {
  onStart(span: Span): void {
    // No action on span start for this processor
  }

  onEnd(span: ReadableSpan): void {
    // Check if the span has an attribute that represents a URL
    const url = span.attributes['http.url'] as string | undefined;
    if (url) {
      // Remove query parameters from the URL
      const urlWithoutQuery = url.split('?')[0];
      // Update the span's attributes with the new URL
      span.setAttribute('http.url', urlWithoutQuery);
    }
  }


  shutdown(): Promise<void> {
    return Promise.resolve();
  }

  forceFlush(): Promise<void> {
    return Promise.resolve();
  }
}
    
class DisableSamplingByTagProcessor implements SpanProcessor {
  onStart(span: Span): void {
    // We check for sampling here because we want to modify the sampling behavior before span processing continues
    const samplingEnabled = span.attributes['sampling.enabled'] as string | undefined;
    if (samplingEnabled === 'false') {
      // In OpenTelemetry, setting sampling decision to always sample means setting the sampling priority to 1
      span.setAttribute('sampling.priority', 1);
    }
  }

  onEnd(span: ReadableSpan): void {
    // No action needed on end for this specific use case since we've already set the sampling in onStart
  }

  shutdown(): Promise<void> {
    return Promise.resolve();
  }

  forceFlush(): Promise<void> {
    return Promise.resolve();
  }
}
    
// You would typically register this processor with a TracerProvider or a SpanExporter like so:
// tracerProvider.addSpanProcessor(new DisableSamplingByTagProcessor());