@ogcio/o11y-sdk-node/lib/url-sampler.ts

Opentelemetry standard instrumentation SDK for NodeJS based project

import { Attributes, Context, Link, SpanKind } from "@opentelemetry/api";
import {
  Sampler,
  SamplingDecision,
  SamplingResult,
} from "@opentelemetry/sdk-trace-base";
import { SamplerCondition } from "./index.js";

export class UrlSampler implements Sampler {
  private _samplerCondition: SamplerCondition[];
  private _nextSampler: Sampler;

  constructor(samplerCondition: SamplerCondition[] = [], nextSampler: Sampler) {
    this._samplerCondition = samplerCondition;
    this._nextSampler = nextSampler;
  }

  shouldSample(
    _context: Context,
    traceId: string,
    _spanName: string,
    _spanKind: SpanKind,
    attributes: Attributes,
    _links: Link[],
  ): SamplingResult {
    const url: string | undefined = attributes["http.target"]?.toString();

    if (url) {
      for (const condition of this._samplerCondition) {
        if (
          (condition.type === "equals" && url === condition.url) ||
          (condition.type === "endsWith" && url.endsWith(condition.url)) ||
          (condition.type === "includes" && url.includes(condition.url))
        ) {
          return { decision: SamplingDecision.NOT_RECORD };
        }
      }
    }

    return this._nextSampler.shouldSample(
      _context,
      traceId,
      _spanName,
      _spanKind,
      attributes,
      _links,
    );
  }
  toString(): string {
    return "UrlSampler";
  }
}