add PeriodSnapshotAccumulator, successor of 0.6.x TickMetricSnapshotBuffer

1 files changed, 129 insertions, 0 deletions

diff --git a/kamon-core-tests/src/test/scala/kamon/metric/PeriodSnapshotAccumulatorSpec.scala b/kamon-core-tests/src/test/scala/kamon/metric/PeriodSnapshotAccumulatorSpec.scala
new file mode 100644
index 00000000..202fe5b9
--- /dev/null
+++ b/kamon-core-tests/src/test/scala/kamon/metric/PeriodSnapshotAccumulatorSpec.scala
@@ -0,0 +1,129 @@
+package kamon.metric
+
+import java.time.temporal.ChronoUnit
+import java.time.Duration
+
+import kamon.Kamon
+import kamon.testkit.{MetricInspection, Reconfigure}
+import org.scalatest.{BeforeAndAfterAll, Matchers, OptionValues, WordSpec}
+
+class PeriodSnapshotAccumulatorSpec extends WordSpec with Reconfigure with MetricInspection with Matchers
+    with BeforeAndAfterAll with OptionValues {
+
+  "the PeriodSnapshotAccumulator" should {
+    "allow to peek on an empty accumulator" in {
+      val accumulator = newAccumulator(10, 1)
+      val periodSnapshot = accumulator.peek()
+      periodSnapshot.metrics.histograms shouldBe empty
+      periodSnapshot.metrics.rangeSamplers shouldBe empty
+      periodSnapshot.metrics.gauges shouldBe empty
+      periodSnapshot.metrics.counters shouldBe empty
+    }
+
+    "bypass accumulation if the configured duration is equal to the metric tick-interval, regardless of the snapshot" in {
+      val accumulator = newAccumulator(10, 1)
+      accumulator.add(tenSeconds).value should be theSameInstanceAs(tenSeconds)
+      accumulator.add(fiveSecondsOne).value should be theSameInstanceAs(fiveSecondsOne)
+    }
+
+    "bypass accumulation if snapshots have a period longer than duration minus margin" in {
+      val accumulator = newAccumulator(4, 1)
+      accumulator.add(almostThreeSeconds) shouldBe empty
+      accumulator.add(threeSeconds).value should be theSameInstanceAs(threeSeconds)
+      accumulator.add(fourSeconds).value should be theSameInstanceAs(fourSeconds)
+      accumulator.add(nineSeconds).value should be theSameInstanceAs(nineSeconds)
+    }
+
+    "allow to peek into the data that has been accumulated" in {
+      val accumulator = newAccumulator(20, 1)
+      accumulator.add(fiveSecondsOne) shouldBe empty
+      accumulator.add(fiveSecondsTwo) shouldBe empty
+
+      for(_ <- 1 to 10) {
+        val peekSnapshot = accumulator.peek()
+        val mergedHistogram = peekSnapshot.metrics.histograms.head
+        val mergedRangeSampler = peekSnapshot.metrics.rangeSamplers.head
+        peekSnapshot.metrics.counters.head.value shouldBe (55)
+        peekSnapshot.metrics.gauges.head.value shouldBe (33)
+        mergedHistogram.distribution.buckets.map(_.value) should contain allOf(22L, 33L)
+        mergedRangeSampler.distribution.buckets.map(_.value) should contain allOf(22L, 33L)
+      }
+
+      accumulator.add(fiveSecondsThree) shouldBe empty
+
+      for(_ <- 1 to 10) {
+        val peekSnapshot = accumulator.peek()
+        val mergedHistogram = peekSnapshot.metrics.histograms.head
+        val mergedRangeSampler = peekSnapshot.metrics.rangeSamplers.head
+        peekSnapshot.metrics.counters.head.value shouldBe (67)
+        peekSnapshot.metrics.gauges.head.value shouldBe (12)
+        mergedHistogram.distribution.buckets.map(_.value) should contain allOf(22L, 33L, 12L)
+        mergedRangeSampler.distribution.buckets.map(_.value) should contain allOf(22L, 33L, 12L)
+      }
+    }
+
+    "produce a snapshot when enough data has been accumulated" in {
+      val accumulator = newAccumulator(15, 1)
+      accumulator.add(fiveSecondsOne) shouldBe empty
+      accumulator.add(fiveSecondsTwo) shouldBe empty
+
+      val snapshotOne = accumulator.add(fiveSecondsThree).value
+      snapshotOne.from shouldBe fiveSecondsOne.from
+      snapshotOne.to shouldBe fiveSecondsThree.to
+
+      val mergedHistogram = snapshotOne.metrics.histograms.head
+      val mergedRangeSampler = snapshotOne.metrics.rangeSamplers.head
+      snapshotOne.metrics.counters.head.value shouldBe(67)
+      snapshotOne.metrics.gauges.head.value shouldBe(12)
+      mergedHistogram.distribution.buckets.map(_.value) should contain allOf(22L, 33L, 12L)
+      mergedRangeSampler.distribution.buckets.map(_.value) should contain allOf(22L, 33L, 12L)
+
+      val emptySnapshot = accumulator.peek()
+      emptySnapshot.metrics.histograms shouldBe empty
+      emptySnapshot.metrics.rangeSamplers shouldBe empty
+      emptySnapshot.metrics.gauges shouldBe empty
+      emptySnapshot.metrics.counters shouldBe empty
+
+      accumulator.add(fiveSecondsFour) shouldBe empty
+    }
+  }
+
+  val zeroTime = Kamon.clock().instant().truncatedTo(ChronoUnit.SECONDS)
+
+  val fiveSecondsOne = PeriodSnapshot(zeroTime, zeroTime.plusSeconds(5), createMetricsSnapshot(22))
+  val fiveSecondsTwo = PeriodSnapshot(zeroTime.plusSeconds(5), zeroTime.plusSeconds(10), createMetricsSnapshot(33))
+  val fiveSecondsThree = PeriodSnapshot(zeroTime.plusSeconds(10), zeroTime.plusSeconds(15), createMetricsSnapshot(12))
+  val fiveSecondsFour = PeriodSnapshot(zeroTime.plusSeconds(15), zeroTime.plusSeconds(20), createMetricsSnapshot(37))
+
+  val almostThreeSeconds = PeriodSnapshot(zeroTime, zeroTime.plusSeconds(3).minusMillis(1), createMetricsSnapshot(22))
+  val threeSeconds = PeriodSnapshot(zeroTime, zeroTime.plusSeconds(3), createMetricsSnapshot(22))
+  val fourSeconds = PeriodSnapshot(zeroTime, zeroTime.plusSeconds(4), createMetricsSnapshot(22))
+  val nineSeconds = PeriodSnapshot(zeroTime, zeroTime.plusSeconds(9), createMetricsSnapshot(22))
+  val tenSeconds = PeriodSnapshot(zeroTime, zeroTime.plusSeconds(10), createMetricsSnapshot(36))
+
+
+  def newAccumulator(duration: Long, margin: Long) =
+    new PeriodSnapshotAccumulator(Duration.ofSeconds(duration), Duration.ofSeconds(margin))
+
+  def createMetricsSnapshot(value: Long) = MetricsSnapshot(
+    histograms = Seq(createDistributionSnapshot(s"histogram", Map("metric" -> "histogram"), MeasurementUnit.time.microseconds, DynamicRange.Fine)(value)),
+    rangeSamplers = Seq(createDistributionSnapshot(s"gauge", Map("metric" -> "gauge"), MeasurementUnit.time.microseconds, DynamicRange.Default)(value)),
+    gauges = Seq(createValueSnapshot(s"gauge", Map("metric" -> "gauge"), MeasurementUnit.information.bytes, value)),
+    counters = Seq(createValueSnapshot(s"counter", Map("metric" -> "counter"), MeasurementUnit.information.bytes, value))
+  )
+
+  def createValueSnapshot(metric: String, tags: Map[String, String], unit: MeasurementUnit, value: Long): MetricValue = {
+    MetricValue(metric, tags, unit, value)
+  }
+
+  def createDistributionSnapshot(metric: String, tags: Map[String, String], unit: MeasurementUnit, dynamicRange: DynamicRange)(values: Long*): MetricDistribution = {
+    val histogram = Kamon.histogram(metric, unit, dynamicRange).refine(tags)
+    values.foreach(histogram.record)
+    val distribution = histogram.distribution(resetState = true)
+    MetricDistribution(metric, tags, unit, dynamicRange, distribution)
+  }
+
+  override protected def beforeAll(): Unit = {
+    applyConfig("kamon.metric.tick-interval = 10 seconds")
+  }
+}