dd-trace/packages/dd-trace/src/standalone/tracesource_priority_sampler.js

Datadog APM tracing client for JavaScript

'use strict'

const PrioritySampler = require('../priority_sampler')
const { MANUAL_KEEP } = require('../../../../ext/tags')
const { USER_KEEP, AUTO_KEEP, AUTO_REJECT } = require('../../../../ext/priority')
const { SAMPLING_MECHANISM_DEFAULT } = require('../constants')
const { addTraceSourceTag, hasTraceSourcePropagationTag } = require('./tracesource')
const { getProductRateLimiter } = require('./product')

class TraceSourcePrioritySampler extends PrioritySampler {
  configure (env, sampler, config) {
    // rules not supported
    this._env = env
    this._limiter = getProductRateLimiter(config)
  }

  _getPriorityFromTags (tags, context) {
    if (Object.hasOwn(tags, MANUAL_KEEP) &&
      tags[MANUAL_KEEP] !== false &&
      hasTraceSourcePropagationTag(context._trace.tags)
    ) {
      return USER_KEEP
    }
  }

  _getPriorityFromAuto (span) {
    const context = this._getContext(span)

    context._sampling.mechanism = SAMPLING_MECHANISM_DEFAULT

    if (hasTraceSourcePropagationTag(context._trace.tags)) {
      return USER_KEEP
    }

    return this._isSampledByRateLimit(context) ? AUTO_KEEP : AUTO_REJECT
  }

  setPriority (span, samplingPriority, product) {
    super.setPriority(span, samplingPriority, product)

    const context = this._getContext(span)
    addTraceSourceTag(context?._trace?.tags, product)
  }
}

module.exports = TraceSourcePrioritySampler