support for custom metrics

6 files changed, 126 insertions, 6 deletions

diff --git a/kamon-core/src/main/scala/kamon/metrics/ActorMetrics.scala b/kamon-core/src/main/scala/kamon/metrics/ActorMetrics.scala
index 4c8752e5..b3685a93 100644
--- a/kamon-core/src/main/scala/kamon/metrics/ActorMetrics.scala
+++ b/kamon-core/src/main/scala/kamon/metrics/ActorMetrics.scala
@@ -32,7 +32,7 @@ object ActorMetrics extends MetricGroupCategory {
   case object TimeInMailbox extends MetricIdentity { val name, tag = "TimeInMailbox" }
 
   case class ActorMetricRecorder(processingTime: MetricRecorder, mailboxSize: MetricRecorder, timeInMailbox: MetricRecorder)
-      extends MetricGroupRecorder {
+      extends MetricMultiGroupRecorder {
 
     def record(identity: MetricIdentity, value: Long): Unit = identity match {
       case ProcessingTime ⇒ processingTime.record(value)
diff --git a/kamon-core/src/main/scala/kamon/metrics/CustomMetric.scala b/kamon-core/src/main/scala/kamon/metrics/CustomMetric.scala
new file mode 100644
index 00000000..11cb6c3d
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/metrics/CustomMetric.scala
@@ -0,0 +1,51 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013 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.metrics
+
+import kamon.metrics.instruments.ContinuousHighDynamicRangeRecorder
+import org.HdrHistogram.HighDynamicRangeRecorder.Configuration
+import org.HdrHistogram.HighDynamicRangeRecorder
+import com.typesafe.config.Config
+
+case class CustomMetric(name: String) extends MetricGroupIdentity {
+  val category = CustomMetric
+}
+
+object CustomMetric extends MetricGroupCategory {
+  val name = "custom-metric"
+  private val identity = new MetricIdentity { val name, tag = "RecordedValues" }
+
+  def withConfig(highestTrackableValue: Long, significantValueDigits: Int, continuous: Boolean = false) = new MetricGroupFactory {
+    type GroupRecorder = CustomMetricRecorder
+
+    def create(config: Config): CustomMetricRecorder =
+      if (continuous)
+        new CustomMetricRecorder(identity, ContinuousHighDynamicRangeRecorder(Configuration(highestTrackableValue, significantValueDigits)))
+      else
+        new CustomMetricRecorder(identity, HighDynamicRangeRecorder(Configuration(highestTrackableValue, significantValueDigits)))
+  }
+
+  class CustomMetricRecorder(identity: MetricIdentity, underlyingRecorder: HighDynamicRangeRecorder)
+      extends MetricSingleGroupRecorder {
+
+    def collect: MetricGroupSnapshot = new MetricGroupSnapshot {
+      val metrics: Map[MetricIdentity, MetricSnapshot] = Map((identity, underlyingRecorder.collect()))
+    }
+
+    def record(value: Long): Unit = underlyingRecorder.record(value)
+  }
+}
diff --git a/kamon-core/src/main/scala/kamon/metrics/Metrics.scala b/kamon-core/src/main/scala/kamon/metrics/Metrics.scala
index 81475d52..f7ee833b 100644
--- a/kamon-core/src/main/scala/kamon/metrics/Metrics.scala
+++ b/kamon-core/src/main/scala/kamon/metrics/Metrics.scala
@@ -34,11 +34,18 @@ trait MetricIdentity {
   def tag: String
 }
 
-trait MetricGroupRecorder {
-  def record(identity: MetricIdentity, value: Long)
+sealed trait MetricGroupRecorder {
   def collect: MetricGroupSnapshot
 }
 
+trait MetricMultiGroupRecorder extends MetricGroupRecorder {
+  def record(identity: MetricIdentity, value: Long)
+}
+
+trait MetricSingleGroupRecorder extends MetricGroupRecorder {
+  def record(value: Long)
+}
+
 trait MetricGroupSnapshot {
   def metrics: Map[MetricIdentity, MetricSnapshot]
 }
diff --git a/kamon-core/src/main/scala/kamon/metrics/TraceMetrics.scala b/kamon-core/src/main/scala/kamon/metrics/TraceMetrics.scala
index ccffe382..abea3d82 100644
--- a/kamon-core/src/main/scala/kamon/metrics/TraceMetrics.scala
+++ b/kamon-core/src/main/scala/kamon/metrics/TraceMetrics.scala
@@ -31,7 +31,7 @@ object TraceMetrics extends MetricGroupCategory {
   case class HttpClientRequest(name: String, tag: String) extends MetricIdentity
 
   class TraceMetricRecorder(val elapsedTime: HighDynamicRangeRecorder, private val segmentRecorderFactory: () ⇒ HighDynamicRangeRecorder)
-      extends MetricGroupRecorder {
+      extends MetricMultiGroupRecorder {
 
     private val segments = TrieMap[MetricIdentity, HighDynamicRangeRecorder]()
 
diff --git a/kamon-core/src/main/scala/kamon/trace/TraceContext.scala b/kamon-core/src/main/scala/kamon/trace/TraceContext.scala
index dd4a25f8..ee1f949e 100644
--- a/kamon-core/src/main/scala/kamon/trace/TraceContext.scala
+++ b/kamon-core/src/main/scala/kamon/trace/TraceContext.scala
@@ -18,10 +18,11 @@ package kamon.trace
 
 import akka.actor.ActorSystem
 import kamon.Kamon
-import kamon.metrics.{ MetricGroupRecorder, MetricIdentity, TraceMetrics, Metrics }
+import kamon.metrics._
 import java.util.concurrent.ConcurrentLinkedQueue
 import kamon.trace.TraceContextAware.DefaultTraceContextAware
 import kamon.trace.TraceContext.SegmentIdentity
+import kamon.trace.SegmentData
 
 trait TraceContext {
   def name: String
@@ -97,7 +98,7 @@ class SimpleMetricCollectionContext(@volatile private var _name: String, val tok
     }
   }
 
-  private def drainFinishedSegments(metricRecorder: MetricGroupRecorder): Unit = {
+  private def drainFinishedSegments(metricRecorder: MetricMultiGroupRecorder): Unit = {
     while (!finishedSegments.isEmpty) {
       val segmentData = finishedSegments.poll()
       metricRecorder.record(segmentData.identity, segmentData.duration)
diff --git a/kamon-core/src/test/scala/kamon/metrics/CustomMetricSpec.scala b/kamon-core/src/test/scala/kamon/metrics/CustomMetricSpec.scala
new file mode 100644
index 00000000..f5caf6e9
--- /dev/null
+++ b/kamon-core/src/test/scala/kamon/metrics/CustomMetricSpec.scala
@@ -0,0 +1,61 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013 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.metrics
+
+import akka.testkit.TestKitBase
+import org.scalatest.{ Matchers, WordSpecLike }
+import akka.actor.ActorSystem
+import scala.concurrent.duration._
+import com.typesafe.config.ConfigFactory
+import kamon.Kamon
+import kamon.metrics.Subscriptions.TickMetricSnapshot
+
+class CustomMetricSpec extends TestKitBase with WordSpecLike with Matchers {
+  implicit lazy val system: ActorSystem = ActorSystem("actor-metrics-spec", ConfigFactory.parseString(
+    """
+      |kamon.metrics {
+      |  filters = [
+      |    {
+      |      custom-metric {
+      |        includes = [ "test/*" ]
+      |        excludes = [ ]
+      |      }
+      |    }
+      |  ]
+      |}
+    """.stripMargin))
+
+  "the Kamon custom metrics support" should {
+    "allow registering a custom metric with the Metrics extension" in {
+      val recorder = Kamon(Metrics).register(CustomMetric("test/sample-counter"), CustomMetric.withConfig(100, 2))
+
+      recorder should be('defined)
+    }
+
+    "allow subscriptions to custom metrics using the default subscription protocol" in {
+      val recorder = Kamon(Metrics).register(CustomMetric("test/sample-counter"), CustomMetric.withConfig(100, 2))
+      recorder.map(_.record(100))
+
+      Kamon(Metrics).subscribe(CustomMetric, "test/sample-counter", testActor)
+
+      println(within(5 seconds) {
+        expectMsgType[TickMetricSnapshot]
+      }.metrics(CustomMetric("test/sample-counter")))
+    }
+  }
+
+}