dd-trace/packages/dd-trace/src/datastreams/schemas/schema_sampler.js

Datadog APM tracing client for JavaScript

const SAMPLE_INTERVAL_MILLIS = 30 * 1000

class SchemaSampler {
  constructor () {
    this.weight = 0
    this.lastSampleMs = 0
  }

  trySample (currentTimeMs) {
    if (currentTimeMs >= this.lastSampleMs + SAMPLE_INTERVAL_MILLIS) {
      if (currentTimeMs >= this.lastSampleMs + SAMPLE_INTERVAL_MILLIS) {
        this.lastSampleMs = currentTimeMs
        const weight = this.weight
        this.weight = 0
        return weight
      }
    }
    return 0
  }

  canSample (currentTimeMs) {
    this.weight += 1
    return currentTimeMs >= this.lastSampleMs + SAMPLE_INTERVAL_MILLIS
  }
}

module.exports = {
  SchemaSampler
}