com.twitter.finagle.stats.MetricsRegistry.scala Maven / Gradle / Ivy

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package com.twitter.finagle.stats

import scala.collection.mutable

private object MetricsRegistry {
  case class StatEntryImpl(delta: Double, value: Double, metricType: String) extends StatEntry

  private def instantaneous(value: Double, metricType: String): StatEntry =
    StatEntryImpl(value.doubleValue, value.doubleValue, metricType)

  private def cumulative(delta: Double, value: Double, metricType: String): StatEntry =
    StatEntryImpl(delta, value, metricType)
}

private[twitter] trait MetricsRegistry extends StatsRegistry {
  import MetricsRegistry._

  /**
   * A reference to the underlying Metrics representation.
   * Note, this may be null.
   */
  val registry: MetricsView

  val latched: Boolean = useCounterDeltas()

  private[this] val metrics = mutable.Map.empty[String, StatEntry]

  def apply(): Map[String, StatEntry] = synchronized {
    updateMetrics()
    metrics.toMap
  }

  private[this] def updateMetrics(): Unit =
    if (registry != null) {
      for (counter <- registry.counters) {
        val key = counter.hierarchicalName
        val newValue = counter.value
        val newMetric = metrics.get(key) match {
          case Some(prev) => cumulative(newValue - prev.value, newValue, "counter")
          case None => cumulative(newValue, newValue, "counter")
        }
        metrics.put(key, newMetric)
      }

      for (gauge <- registry.gauges) {
        val key = gauge.hierarchicalName
        val newValue = gauge.value.doubleValue
        metrics.put(key, instantaneous(newValue, "gauge"))
      }
    }
}