+ core: provide generic way to scale time and memory metrics

3 files changed, 138 insertions, 1 deletions

diff --git a/kamon-core/src/test/scala/kamon/metric/instrument/CounterSpec.scala b/kamon-core/src/test/scala/kamon/metric/instrument/CounterSpec.scala
index 094baf4c..850200d4 100644
--- a/kamon-core/src/test/scala/kamon/metric/instrument/CounterSpec.scala
+++ b/kamon-core/src/test/scala/kamon/metric/instrument/CounterSpec.scala
@@ -56,6 +56,15 @@ class CounterSpec extends WordSpec with Matchers {
       counterBSnapshot.merge(counterASnapshot, collectionContext).count should be(300)
     }
 
+    "produce a snapshot that can be scaled" in new CounterFixture {
+      counter.increment(100)
+
+      val counterSnapshot = takeSnapshotFrom(counter)
+
+      val scaledSnapshot = counterSnapshot.scale(Time.Milliseconds, Time.Microseconds)
+      scaledSnapshot.count should be(100000)
+    }
+
   }
 
   trait CounterFixture {
diff --git a/kamon-core/src/test/scala/kamon/metric/instrument/HistogramSpec.scala b/kamon-core/src/test/scala/kamon/metric/instrument/HistogramSpec.scala
index 9a50e149..ff71cd56 100644
--- a/kamon-core/src/test/scala/kamon/metric/instrument/HistogramSpec.scala
+++ b/kamon-core/src/test/scala/kamon/metric/instrument/HistogramSpec.scala
@@ -48,7 +48,7 @@ class HistogramSpec extends WordSpec with Matchers {
     }
 
     "produce a snapshot" which {
-      "supports min, max, percentile, sum and numberOfMeasurements operations" in new HistogramFixture {
+      "supports min, max, percentile, sum, numberOfMeasurements and recordsIterator operations" in new HistogramFixture {
         histogram.record(100)
         histogram.record(200, count = 200)
         histogram.record(300)
@@ -64,6 +64,36 @@ class HistogramSpec extends WordSpec with Matchers {
         snapshot.sum should be(41300)
         snapshot.numberOfMeasurements should be(203)
 
+        val records = snapshot.recordsIterator.map(r => r.level -> r.count).toSeq
+        records.size should be (4)
+        records(0) should be(100 -> 1)
+        records(1) should be(200 -> 200)
+        records(2) should be(300 -> 1)
+        records(3) should be(900 -> 1)
+      }
+
+      "can be scaled" in new HistogramFixture {
+        histogram.record(100)
+        histogram.record(200, count = 200)
+        histogram.record(300)
+        histogram.record(900)
+
+        val snapshot = takeSnapshot().scale(Time.Seconds, Time.Milliseconds)
+
+        snapshot.min should equal(100000L +- 1000L)
+        snapshot.max should equal(900000L +- 9000L)
+        snapshot.percentile(50.0D) should be(200000)
+        snapshot.percentile(99.5D) should be(300000)
+        snapshot.percentile(99.9D) should be(900000)
+        snapshot.sum should be(41300000)
+        snapshot.numberOfMeasurements should be(203)
+
+        val records = snapshot.recordsIterator.map(r => r.level -> r.count).toSeq
+        records.size should be (4)
+        records(0) should be(100000 -> 1)
+        records(1) should be(200000 -> 200)
+        records(2) should be(300000 -> 1)
+        records(3) should be(900000 -> 1)
       }
 
       "can be merged with another snapshot" in new MultipleHistogramFixture {
diff --git a/kamon-core/src/test/scala/kamon/metric/instrument/UnitOfMeasurementSpec.scala b/kamon-core/src/test/scala/kamon/metric/instrument/UnitOfMeasurementSpec.scala
new file mode 100644
index 00000000..7133579e
--- /dev/null
+++ b/kamon-core/src/test/scala/kamon/metric/instrument/UnitOfMeasurementSpec.scala
@@ -0,0 +1,98 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013-2015 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 kamon.metric.instrument.UnitOfMeasurement.Unknown
+import org.scalatest.{Matchers, WordSpec}
+
+class UnitOfMeasurementSpec extends WordSpec with Matchers {
+
+  "Time unit" should {
+    "resolve Time Unit by valid name" in {
+      Time("s") should be(Time.Seconds)
+      Time("n") should be(Time.Nanoseconds)
+      Time("ms") should be(Time.Milliseconds)
+      Time("µs") should be(Time.Microseconds)
+    }
+    "fail to resolve Time Unit by invalid name" in {
+      val ex = intercept[IllegalArgumentException](Time("boo"))
+      ex.getMessage should be("Can't recognize time unit 'boo'")
+    }
+    "scale time properly" in {
+      val epsilon = 0.0001
+
+      Time.Nanoseconds.scale(Time.Nanoseconds)(1000000D) should be(1000000D +- epsilon)
+      Time.Nanoseconds.scale(Time.Microseconds)(1000000D) should be(1000D +- epsilon)
+      Time.Nanoseconds.scale(Time.Milliseconds)(1000000D) should be(1D +- epsilon)
+      Time.Nanoseconds.scale(Time.Seconds)(1000000D) should be(0.001D +- epsilon)
+      Time.Seconds.scale(Time.Nanoseconds)(1D) should be(1000000000D +- epsilon)
+    }
+    "allow scale only time" in {
+      intercept[IllegalArgumentException](Time.Nanoseconds.tryScale(Unknown)(100))
+        .getMessage should be("Can't scale different types of units `time` and `unknown`")
+      intercept[IllegalArgumentException](Time.Nanoseconds.tryScale(Memory.Bytes)(100))
+        .getMessage should be("Can't scale different types of units `time` and `bytes`")
+      val epsilon = 0.0001
+
+      Time.Nanoseconds.tryScale(Time.Nanoseconds)(100D) should be(100D +- epsilon)
+    }
+  }
+
+  "Memory unit" should {
+    "resolve Memory Unit by valid name" in {
+      Memory("b") should be(Memory.Bytes)
+      Memory("Kb") should be(Memory.KiloBytes)
+      Memory("Mb") should be(Memory.MegaBytes)
+      Memory("Gb") should be(Memory.GigaBytes)
+    }
+    "fail to resolve Memory Unit by invalid name" in {
+      val ex = intercept[IllegalArgumentException](Memory("boo"))
+      ex.getMessage should be("Can't recognize memory unit 'boo'")
+    }
+    "scale memory properly" in {
+      val epsilon = 0.0001
+
+      Memory.Bytes.scale(Memory.Bytes)(1000000D) should be(1000000D +- epsilon)
+      Memory.Bytes.scale(Memory.KiloBytes)(1000000D) should be(976.5625D +- epsilon)
+      Memory.Bytes.scale(Memory.MegaBytes)(1000000D) should be(0.9536D +- epsilon)
+      Memory.Bytes.scale(Memory.GigaBytes)(1000000D) should be(9.3132E-4D +- epsilon)
+      Memory.MegaBytes.scale(Memory.Bytes)(1D) should be(1048576D +- epsilon)
+    }
+    "allow scale only memory" in {
+      intercept[IllegalArgumentException](Memory.Bytes.tryScale(Unknown)(100))
+        .getMessage should be("Can't scale different types of units `bytes` and `unknown`")
+      intercept[IllegalArgumentException](Memory.Bytes.tryScale(Time.Nanoseconds)(100))
+        .getMessage should be("Can't scale different types of units `bytes` and `time`")
+      val epsilon = 0.0001
+
+      Memory.Bytes.tryScale(Memory.Bytes)(100D) should be(100D +- epsilon)
+    }
+
+  }
+
+  "Unknown unit" should {
+    "allow scale only Unknown" in {
+      intercept[IllegalArgumentException](Unknown.tryScale(Memory.Bytes)(100))
+        .getMessage should be("Can't scale different types of units `unknown` and `bytes`")
+      intercept[IllegalArgumentException](Unknown.tryScale(Time.Nanoseconds)(100))
+        .getMessage should be("Can't scale different types of units `unknown` and `time`")
+
+      Unknown.scale(Unknown)(100D) should be(100D)
+    }
+
+  }
+}