+ newrelic: add possibility to send akka metrics to the newrelic

Added possibility to send akka metrics to the newrelic as custom metrics.
Externalized categories of newrelic subscription into the configuration file.
This allow to define which metrics categories should be send to newrelic
independent upon which metrics are actually collected.

Akka metrics exported to the newrelic as custom metrics and available in custom
dashboards in some format similar to:

Cusom/akka-actor/{ActorSystemName[user|system|...]\{ActorName}/{MetricName}

for actors and

Custom/akka-thread-pool-executor\Some-Service\akka.io.pinned-dispatcher/ProcessedTasks

for thread pools.

Same metrics for multiple actors can be displayed as a single chart by using *
(star) for part of the actor name. For example

Cusom/akka-actor\MyActor\user\*DatabaseWorker/ProcessingTime

will show processing time for all database workers.

Example of actor metrics displayed by newrelic:
http://s4.postimg.org/sfn9vjzgt/Screen_Shot_2015_04_22_at_11_24_15.png

Example of pool metrics displayed by newrelic:
http://s4.postimg.org/gchy7zoel/Screen_Shot_2015_04_22_at_11_24_24.png

1 files changed, 21 insertions, 9 deletions

diff --git a/kamon-newrelic/src/main/scala/kamon/newrelic/CustomMetricExtractor.scala b/kamon-newrelic/src/main/scala/kamon/newrelic/CustomMetricExtractor.scala
index 6919a967..012ae1dc 100644
--- a/kamon-newrelic/src/main/scala/kamon/newrelic/CustomMetricExtractor.scala
+++ b/kamon-newrelic/src/main/scala/kamon/newrelic/CustomMetricExtractor.scala
@@ -16,22 +16,34 @@
 
 package kamon.newrelic
 
-import kamon.metric.{ EntitySnapshot, Entity }
+import kamon.metric.{ MetricKey, EntitySnapshot, Entity }
 import kamon.metric.instrument.CollectionContext
 
 object CustomMetricExtractor extends MetricExtractor {
 
   def extract(settings: AgentSettings, collectionContext: CollectionContext, metrics: Map[Entity, EntitySnapshot]): Map[MetricID, MetricData] = {
-    def onlySimpleMetrics(kv: (Entity, EntitySnapshot)): Boolean =
-      kamon.metric.SingleInstrumentEntityRecorder.AllCategories.contains(kv._1.category)
+    val (simple, complex) = metrics filter customMetric partition simpleMetrics
+    simple.flatMap(toNewRelicMetric(simpleName)) ++ complex.flatMap(toNewRelicMetric(complexName))
+  }
+
+  def simpleName(entity: Entity, metricKey: MetricKey) = s"Custom/${entity.category}/${normalize(entity.name)}"
+
+  def complexName(entity: Entity, metricKey: MetricKey) = s"${simpleName(entity, metricKey)}/${metricKey.name}"
 
-    def toNewRelicMetric(kv: (Entity, EntitySnapshot)): (MetricID, MetricData) = {
-      val (entity, entitySnapshot) = kv
-      val (metricKey, instrumentSnapshot) = entitySnapshot.metrics.head
+  def normalize(name: String) = name.replace('/', '#').replaceAll("""[\]\[\|\*]""", "_")
 
-      Metric(instrumentSnapshot, metricKey.unitOfMeasurement, s"Custom/${entity.name}", None)
-    }
+  def customMetric(kv: (Entity, EntitySnapshot)): Boolean =
+    !MetricsSubscription.isTraceOrSegmentEntityName(kv._1.category)
 
-    metrics.filter(onlySimpleMetrics).map(toNewRelicMetric)
+  def simpleMetrics(kv: (Entity, EntitySnapshot)): Boolean =
+    kamon.metric.SingleInstrumentEntityRecorder.AllCategories.contains(kv._1.category)
+
+  def toNewRelicMetric(name: (Entity, MetricKey) ⇒ String)(kv: (Entity, EntitySnapshot)) = {
+    val (entity, entitySnapshot) = kv
+    for {
+      (metricKey, instrumentSnapshot) ← entitySnapshot.metrics
+      nameStr = name(entity, metricKey)
+    } yield Metric(instrumentSnapshot, metricKey.unitOfMeasurement, nameStr, None)
   }
+
 }