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author | Ivan Topolnjak <ivantopo@gmail.com> | 2017-12-13 00:48:14 +0100 |
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committer | Ivan Topolnjak <ivantopo@gmail.com> | 2017-12-13 00:48:42 +0100 |
commit | d9cd75db039b31eec8d7271b162ea822d1d4d5e3 (patch) | |
tree | 5c7319823da604af4093a7c1cc2a9df09b718832 /kamon-core/src/main | |
parent | c10d93c4594b25b82fd2acc89fea18035ffcbc6f (diff) | |
download | Kamon-d9cd75db039b31eec8d7271b162ea822d1d4d5e3.tar.gz Kamon-d9cd75db039b31eec8d7271b162ea822d1d4d5e3.tar.bz2 Kamon-d9cd75db039b31eec8d7271b162ea822d1d4d5e3.zip |
add PeriodSnapshotAccumulator, successor of 0.6.x TickMetricSnapshotBuffer
Diffstat (limited to 'kamon-core/src/main')
-rw-r--r-- | kamon-core/src/main/scala/kamon/metric/Accumulator.scala | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/kamon-core/src/main/scala/kamon/metric/Accumulator.scala b/kamon-core/src/main/scala/kamon/metric/Accumulator.scala index 9f7c6d70..79713336 100644 --- a/kamon-core/src/main/scala/kamon/metric/Accumulator.scala +++ b/kamon-core/src/main/scala/kamon/metric/Accumulator.scala @@ -15,6 +15,13 @@ package kamon.metric +import java.time.{Duration, Instant} + +import kamon.{Kamon, Tags} +import kamon.metric.PeriodSnapshotAccumulator.{MetricDistributionKey, MetricValueKey} + +import scala.collection.mutable + class DistributionAccumulator(dynamicRange: DynamicRange) { private val accumulatorHistogram = new HdrHistogram("metric-distribution-accumulator", @@ -26,3 +33,137 @@ class DistributionAccumulator(dynamicRange: DynamicRange) { def result(resetState: Boolean): Distribution = accumulatorHistogram.snapshot(resetState).distribution } + +/** + * Merges snapshots over the specified duration and produces a snapshot with all merged metrics provided to it within + * the period. This class is mutable, not thread safe and assumes that all snapshots passed to the `accumulate(...)` + * function are ordered in time. + * + * The typical use of this class would be when writing metric reporters that have to report data at a specific interval + * and wants to protect from users configuring a more frequent metrics tick interval. Example: + * + * {{{ + * class Reporter extends MetricsReporter { + * val accumulator = new PeriodSnapshotAccumulator(Duration.ofSeconds(60), Duration.ofSeconds(1)) + * + * def reportPeriodSnapshot(snapshot: PeriodSnapshot): Unit = { + * accumulator.add(snapshot).foreach(accumulatedSnapshot => { + * // Process your snapshot here, will only be called when the expected period has passed. + * } + * } + * + * ... + * } + * }}} + * + * The margin time is used to determine how close the current accumulated interval can to be to the expected interval + * and still get reported. In the example above a accumulated period of 59.6 seconds has a margin to 60 seconds of + * 0.4 seconds, thus, getting reported immediately instead of waiting for the next snapshot. + * + * A detail of what has been accumulated by calling the `.peek()` function. + * + * @param duration for how long to accumulate snapshots + * @param margin error margin for expected reporting period + */ +class PeriodSnapshotAccumulator(duration: Duration, margin: Duration) { + private val minimumDuration = duration.minus(margin) + private val counters = mutable.Map[MetricValueKey, Long]() + private val gauges = mutable.Map[MetricValueKey, Long]() + private val histograms = mutable.Map[MetricDistributionKey, DistributionAccumulator]() + private val rangeSamplers = mutable.Map[MetricDistributionKey, DistributionAccumulator]() + + private var accumulatingFrom: Option[Instant] = None + + def add(periodSnapshot: PeriodSnapshot): Option[PeriodSnapshot] = { + // short-circuit if there is no need to accumulate (e.g. when metrics tick-interval is the same as duration or the + // snapshots have a longer period than the duration). + if(isSameDurationAsTickInterval() || isWithinDurationMargin(periodSnapshot.from, periodSnapshot.to)) Some(periodSnapshot) else { + if (accumulatingFrom.isEmpty) + accumulatingFrom = Some(periodSnapshot.from) + + periodSnapshot.metrics.counters.foreach(c => accumulateValue(counters, c)) + periodSnapshot.metrics.gauges.foreach(g => replaceValue(gauges, g)) + periodSnapshot.metrics.histograms.foreach(h => accumulateDistribution(histograms, h)) + periodSnapshot.metrics.rangeSamplers.foreach(rs => accumulateDistribution(rangeSamplers, rs)) + + for(from <- accumulatingFrom if isWithinDurationMargin(from, periodSnapshot.to)) yield { + val accumulatedPeriodSnapshot = buildPeriodSnapshot(from, periodSnapshot.to, resetState = true) + accumulatingFrom = None + clearAccumulatedData() + + accumulatedPeriodSnapshot + } + } + } + + def peek(): PeriodSnapshot = { + val now = Kamon.clock().instant() + buildPeriodSnapshot(accumulatingFrom.getOrElse(now), now, resetState = false) + } + + private def isWithinDurationMargin(from: Instant, to: Instant): Boolean = { + !Duration.between(from, to).minus(minimumDuration).isNegative + } + + private def isSameDurationAsTickInterval(): Boolean = { + Kamon.config().getDuration("kamon.metric.tick-interval").equals(duration) + } + + private def buildPeriodSnapshot(from: Instant, to: Instant, resetState: Boolean): PeriodSnapshot = { + val metrics = MetricsSnapshot( + histograms = histograms.map(createDistributionSnapshot(resetState)).toSeq, + rangeSamplers = rangeSamplers.map(createDistributionSnapshot(resetState)).toSeq, + gauges = gauges.map(createValueSnapshot(resetState)).toSeq, + counters = counters.map(createValueSnapshot(resetState)).toSeq + ) + + PeriodSnapshot(from, to, metrics) + } + + private def accumulateValue(cache: mutable.Map[MetricValueKey, Long], metric: MetricValue): Unit = { + val key = MetricValueKey(metric.name, metric.tags, metric.unit) + cache.get(key).map(previousValue => { + cache.put(key, metric.value + previousValue) + }).orElse { + cache.put(key, metric.value) + } + } + + private def replaceValue(cache: mutable.Map[MetricValueKey, Long], metric: MetricValue): Unit = { + val key = MetricValueKey(metric.name, metric.tags, metric.unit) + cache.put(key, metric.value) + } + + private def createValueSnapshot(reset: Boolean)(pair: (MetricValueKey, Long)): MetricValue = { + val (key, value) = pair + MetricValue(key.name, key.tags, key.unit, value) + } + + private def createDistributionSnapshot(resetState: Boolean)(pair: (MetricDistributionKey, DistributionAccumulator)): MetricDistribution = { + val (key, value) = pair + MetricDistribution(key.name, key.tags, key.unit, key.dynamicRange, value.result(resetState)) + } + + private def accumulateDistribution(cache: mutable.Map[MetricDistributionKey, DistributionAccumulator], metric: MetricDistribution): Unit = { + val key = MetricDistributionKey(metric.name, metric.tags, metric.unit, metric.dynamicRange) + cache.get(key).map(previousValue => { + previousValue.add(metric.distribution) + }).orElse { + val distributionAccumulator = new DistributionAccumulator(key.dynamicRange) + distributionAccumulator.add(metric.distribution) + cache.put(key, distributionAccumulator) + } + } + + private def clearAccumulatedData(): Unit = { + histograms.clear() + rangeSamplers.clear() + counters.clear() + gauges.clear() + } +} + +object PeriodSnapshotAccumulator { + case class MetricValueKey(name: String, tags: Tags, unit: MeasurementUnit) + case class MetricDistributionKey(name: String, tags: Tags, unit: MeasurementUnit, dynamicRange: DynamicRange) +} |