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/* =========================================================================================
* Copyright © 2013-2014 the kamon project <http://kamon.io/>
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the
* License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied. See the License for the specific language governing permissions
* and limitations under the License.
* =========================================================================================
*/
package kamon.metric.instrument
import java.nio.LongBuffer
import akka.actor._
import akka.testkit.TestProbe
import kamon.Kamon
import kamon.metric.instrument.Histogram.{DynamicRange, MutableRecord}
import kamon.testkit.BaseKamonSpec
import scala.concurrent.duration._
class MinMaxCounterSpec extends BaseKamonSpec("min-max-counter-spec") {
"the MinMaxCounter" should {
"track ascending tendencies" in new MinMaxCounterFixture {
mmCounter.increment()
mmCounter.increment(3)
mmCounter.increment()
val snapshot = collectCounterSnapshot()
snapshot.min should be(0)
snapshot.max should be(5)
snapshot.recordsIterator.toStream should contain allOf (
MutableRecord(0, 1), // min
MutableRecord(5, 2)
) // max and current
}
"track descending tendencies" in new MinMaxCounterFixture {
mmCounter.increment(5)
mmCounter.decrement()
mmCounter.decrement(3)
mmCounter.decrement()
val snapshot = collectCounterSnapshot()
snapshot.min should be(0)
snapshot.max should be(5)
snapshot.recordsIterator.toStream should contain allOf (
MutableRecord(0, 2), // min and current
MutableRecord(5, 1)
) // max
}
"reset the min and max to the current value after taking a snapshot" in new MinMaxCounterFixture {
mmCounter.increment(5)
mmCounter.decrement(3)
val firstSnapshot = collectCounterSnapshot()
firstSnapshot.min should be(0)
firstSnapshot.max should be(5)
firstSnapshot.recordsIterator.toStream should contain allOf (
MutableRecord(0, 1), // min
MutableRecord(2, 1), // current
MutableRecord(5, 1)
) // max
val secondSnapshot = collectCounterSnapshot()
secondSnapshot.min should be(2)
secondSnapshot.max should be(2)
secondSnapshot.recordsIterator.toStream should contain(
MutableRecord(2, 3)
) // min, max and current
}
"report zero as the min and current values if the current value fell bellow zero" in new MinMaxCounterFixture {
mmCounter.decrement(3)
val snapshot = collectCounterSnapshot()
snapshot.min should be(0)
snapshot.max should be(0)
snapshot.recordsIterator.toStream should contain(
MutableRecord(0, 3)
) // min, max and current (even while current really is -3
}
"never record values bellow zero in very busy situations" in new MinMaxCounterFixture {
val monitor = TestProbe()
val workers = for (workers ← 1 to 50) yield {
system.actorOf(Props(new MinMaxCounterUpdateActor(mmCounter, monitor.ref)))
}
workers foreach (_ ! "increment")
for (refresh ← 1 to 1000) {
collectCounterSnapshot()
Thread.sleep(1)
}
monitor.expectNoMsg()
workers foreach (_ ! PoisonPill)
}
}
trait MinMaxCounterFixture {
val collectionContext = new CollectionContext {
val buffer: LongBuffer = LongBuffer.allocate(64)
}
val mmCounter = MinMaxCounter(DynamicRange(1, 1000, 2), 1 hour, Kamon.metrics.settings.refreshScheduler)
mmCounter.cleanup // cancel the refresh schedule
def collectCounterSnapshot(): Histogram.Snapshot = mmCounter.collect(collectionContext)
}
}
class MinMaxCounterUpdateActor(mmc: MinMaxCounter, monitor: ActorRef) extends Actor {
val x = Array.ofDim[Int](4)
def receive = {
case "increment" ⇒
mmc.increment()
self ! "decrement"
case "decrement" ⇒
mmc.decrement()
self ! "increment"
try {
mmc.refreshValues()
} catch {
case _: IndexOutOfBoundsException ⇒ monitor ! "failed"
}
}
}
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