implement HdrHistogram and Distribution snapshots

4 files changed, 75 insertions, 2 deletions

diff --git a/kamon-core/src/test/scala/kamon/LogInterceptor.scala b/kamon-core/src/test/scala/kamon/LogInterceptor.scala
new file mode 100644
index 00000000..b5b8a79c
--- /dev/null
+++ b/kamon-core/src/test/scala/kamon/LogInterceptor.scala
@@ -0,0 +1,14 @@
+package kamon
+
+import uk.org.lidalia.slf4jext.Level
+import uk.org.lidalia.slf4jtest.{LoggingEvent, TestLogger}
+
+trait LogInterceptor {
+
+  def interceptLog[T](level: Level)(code: => T)(implicit tl: TestLogger): Seq[LoggingEvent] = {
+    import scala.collection.JavaConverters._
+    tl.clear()
+    val run = code
+    tl.getLoggingEvents().asScala.filter(_.getLevel == level)
+  }
+}
diff --git a/kamon-core/src/test/scala/kamon/metric/instrument/CounterSpec.scala b/kamon-core/src/test/scala/kamon/metric/instrument/CounterSpec.scala
new file mode 100644
index 00000000..26b3456d
--- /dev/null
+++ b/kamon-core/src/test/scala/kamon/metric/instrument/CounterSpec.scala
@@ -0,0 +1,46 @@
+package kamon.metric.instrument
+
+import kamon.LogInterceptor
+import kamon.metric.Entity
+import kamon.testkit.DefaultInstrumentFactory
+import org.scalatest.{Matchers, WordSpec}
+import uk.org.lidalia.slf4jext.Level
+import uk.org.lidalia.slf4jtest.TestLoggerFactory
+
+class CounterSpec extends WordSpec with Matchers with LogInterceptor with DefaultInstrumentFactory {
+  implicit val testLogger = TestLoggerFactory.getTestLogger(classOf[LongAdderCounter])
+
+  "a Counter" should {
+
+    "allow unit and bundled increments" in {
+      val counter = buildCounter("unit-increments")
+      counter.increment()
+      counter.increment()
+      counter.increment(40)
+
+      counter.snapshot().value shouldBe(42)
+    }
+
+    "warn the user and ignore attempts to decrement the counter" in {
+      val counter = buildCounter("attempt-to-decrement")
+      counter.increment(100)
+      counter.increment(100)
+      counter.increment(100)
+
+      interceptLog(Level.WARN) {
+        counter.increment(-10L)
+      }.head.getMessage() shouldBe(s"Ignored attempt to decrement counter [attempt-to-decrement] on entity [$defaultEntity]")
+
+      counter.snapshot().value shouldBe(300)
+    }
+
+    "reset the internal state to zero after taking snapshots" in {
+      val counter = buildCounter("reset-after-snapshot")
+      counter.increment()
+      counter.increment(10)
+
+      counter.snapshot().value shouldBe(11)
+      counter.snapshot().value shouldBe(0)
+    }
+  }
+}
diff --git a/kamon-core/src/test/scala/kamon/metric/instrument/InstrumentFactorySpec.scala b/kamon-core/src/test/scala/kamon/metric/instrument/InstrumentFactorySpec.scala
index fc82ddcd..5bf16d4c 100644
--- a/kamon-core/src/test/scala/kamon/metric/instrument/InstrumentFactorySpec.scala
+++ b/kamon-core/src/test/scala/kamon/metric/instrument/InstrumentFactorySpec.scala
@@ -68,7 +68,7 @@ class InstrumentFactorySpec extends WordSpec with Matchers{
           |     modified-histogram {
           |       lowest-discernible-value = 99
           |       highest-trackable-value = 999
-          |       significant-value-digits = 7
+          |       significant-value-digits = 4
           |     }
           |
           |     modified-mm-counter {
@@ -92,7 +92,7 @@ class InstrumentFactorySpec extends WordSpec with Matchers{
 
       modifiedHistogram.dynamicRange.lowestDiscernibleValue shouldBe(99)
       modifiedHistogram.dynamicRange.highestTrackableValue shouldBe(999)
-      modifiedHistogram.dynamicRange.significantValueDigits shouldBe(7)
+      modifiedHistogram.dynamicRange.significantValueDigits shouldBe(4)
 
 
       val defaultMMCounter = factory.buildMinMaxCounter(customEntity, "default-mm-counter")
diff --git a/kamon-core/src/test/scala/kamon/testkit/DefaultInstrumentFactory.scala b/kamon-core/src/test/scala/kamon/testkit/DefaultInstrumentFactory.scala
new file mode 100644
index 00000000..acec5915
--- /dev/null
+++ b/kamon-core/src/test/scala/kamon/testkit/DefaultInstrumentFactory.scala
@@ -0,0 +1,13 @@
+package kamon.testkit
+
+import com.typesafe.config.ConfigFactory
+import kamon.metric.Entity
+import kamon.metric.instrument.InstrumentFactory
+
+trait DefaultInstrumentFactory {
+  val defaultEntity = Entity("default-entity", "default-category", Map.empty)
+  val instrumentFactory = InstrumentFactory(ConfigFactory.load().getConfig("kamon.metric.instrument-factory"))
+
+  def buildCounter(name: String) = instrumentFactory.buildCounter(defaultEntity, name)
+
+}