1 files changed, 55 insertions, 0 deletions
diff --git a/kamon-core/src/main/scala/kamon/metric/MetricScaleDecorator.scala b/kamon-core/src/main/scala/kamon/metric/MetricScaleDecorator.scala
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+++ b/kamon-core/src/main/scala/kamon/metric/MetricScaleDecorator.scala
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+/*
+ * =========================================================================================
+ * 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
+
+import akka.actor.{ Actor, ActorRef, Props }
+import kamon.metric.SubscriptionsDispatcher.TickMetricSnapshot
+import kamon.metric.instrument._
+
+/**
+ * Can be used as a decorator to scale TickMetricSnapshot messages to given `timeUnits` and/or `memoryUnits`
+ * before forwarding to original receiver
+ * @param timeUnits Optional time units to scale time metrics to
+ * @param memoryUnits Optional memory units to scale memory metrics to
+ * @param receiver Receiver of scaled metrics snapshot, usually a backend sender
+ */
+class MetricScaleDecorator(timeUnits: Option[Time], memoryUnits: Option[Memory], receiver: ActorRef) extends Actor {
+  require(timeUnits.isDefined || memoryUnits.isDefined,
+    "Use MetricScaleDecorator only when any of units is defined")
+
+  override def receive: Receive = {
+    case tick: TickMetricSnapshot ⇒
+      val scaled = tick.copy(metrics = tick.metrics.mapValues { entitySnapshot ⇒
+        new DefaultEntitySnapshot(entitySnapshot.metrics.map {
+          case (metricKey, metricSnapshot) ⇒
+            val scaledSnapshot = (metricKey.unitOfMeasurement, timeUnits, memoryUnits) match {
+              case (time: Time, Some(to), _)     ⇒ metricSnapshot.scale(time, to)
+              case (memory: Memory, _, Some(to)) ⇒ metricSnapshot.scale(memory, to)
+              case _                             ⇒ metricSnapshot
+            }
+            metricKey -> scaledSnapshot
+        })
+      })
+      receiver forward scaled
+  }
+}
+
+object MetricScaleDecorator {
+  def props(timeUnits: Option[Time], memoryUnits: Option[Memory], receiver: ActorRef): Props =
+    Props(new MetricScaleDecorator(timeUnits, memoryUnits, receiver))
+}
+