+ core: create the new KamonStandalone helper, closes #47

3 files changed, 99 insertions, 2 deletions

diff --git a/kamon-core/src/main/scala/kamon/metric/UserMetrics.scala b/kamon-core/src/main/scala/kamon/metric/UserMetrics.scala
index dea03968..f3803d37 100644
--- a/kamon-core/src/main/scala/kamon/metric/UserMetrics.scala
+++ b/kamon-core/src/main/scala/kamon/metric/UserMetrics.scala
@@ -35,6 +35,18 @@ class UserMetricsExtension(system: ExtendedActorSystem) extends Kamon.Extension
   def registerGauge(name: String, precision: Histogram.Precision, highestTrackableValue: Long,
     refreshInterval: FiniteDuration)(currentValueCollector: Gauge.CurrentValueCollector): Gauge =
     userMetricsRecorder.buildGauge(name, precision, highestTrackableValue, refreshInterval, currentValueCollector)
+
+  def removeHistogram(name: String): Unit =
+    userMetricsRecorder.removeHistogram(name)
+
+  def removeCounter(name: String): Unit =
+    userMetricsRecorder.removeCounter(name)
+
+  def removeMinMaxCounter(name: String): Unit =
+    userMetricsRecorder.removeMinMaxCounter(name)
+
+  def removeGauge(name: String): Unit =
+    userMetricsRecorder.removeGauge(name)
 }
 
 object UserMetrics extends ExtensionId[UserMetricsExtension] with ExtensionIdProvider with MetricGroupIdentity {
@@ -86,6 +98,18 @@ object UserMetrics extends ExtensionId[UserMetricsExtension] with ExtensionIdPro
     def buildGauge(name: String)(currentValueCollector: Gauge.CurrentValueCollector): Gauge =
       gauges.getOrElseUpdate(name, Gauge.fromConfig(defaultGaugePrecisionConfig, system)(currentValueCollector))
 
+    def removeHistogram(name: String): Unit =
+      histograms.remove(name)
+
+    def removeCounter(name: String): Unit =
+      counters.remove(name)
+
+    def removeMinMaxCounter(name: String): Unit =
+      minMaxCounters.remove(name).map(_.cleanup)
+
+    def removeGauge(name: String): Unit =
+      gauges.remove(name).map(_.cleanup)
+
     def collect(context: CollectionContext): UserMetricsSnapshot = {
       val histogramSnapshots = histograms.map {
         case (name, histogram) ⇒
diff --git a/kamon-core/src/main/scala/kamon/standalone/KamonStandalone.scala b/kamon-core/src/main/scala/kamon/standalone/KamonStandalone.scala
index 258cc1b2..490bc127 100644
--- a/kamon-core/src/main/scala/kamon/standalone/KamonStandalone.scala
+++ b/kamon-core/src/main/scala/kamon/standalone/KamonStandalone.scala
@@ -1,11 +1,61 @@
 package kamon.standalone
 
 import akka.actor.ActorSystem
+import com.typesafe.config.Config
+import kamon.Kamon
+import kamon.metric.UserMetrics
+import kamon.metric.instrument.{ Gauge, MinMaxCounter, Counter, Histogram }
+
+import scala.concurrent.duration.FiniteDuration
+
+trait KamonStandalone {
+  private[kamon] def system: ActorSystem
+
+  def registerHistogram(name: String, precision: Histogram.Precision, highestTrackableValue: Long): Histogram =
+    Kamon(UserMetrics)(system).registerHistogram(name, precision, highestTrackableValue)
+
+  def registerHistogram(name: String): Histogram =
+    Kamon(UserMetrics)(system).registerHistogram(name)
+
+  def registerCounter(name: String): Counter =
+    Kamon(UserMetrics)(system).registerCounter(name)
+
+  def registerMinMaxCounter(name: String, precision: Histogram.Precision, highestTrackableValue: Long,
+    refreshInterval: FiniteDuration): MinMaxCounter =
+    Kamon(UserMetrics)(system).registerMinMaxCounter(name, precision, highestTrackableValue, refreshInterval)
+
+  def registerMinMaxCounter(name: String): MinMaxCounter =
+    Kamon(UserMetrics)(system).registerMinMaxCounter(name)
+
+  def registerGauge(name: String)(currentValueCollector: Gauge.CurrentValueCollector): Gauge =
+    Kamon(UserMetrics)(system).registerGauge(name)(currentValueCollector)
+
+  def registerGauge(name: String, precision: Histogram.Precision, highestTrackableValue: Long,
+    refreshInterval: FiniteDuration)(currentValueCollector: Gauge.CurrentValueCollector): Gauge =
+    Kamon(UserMetrics)(system).registerGauge(name, precision, highestTrackableValue, refreshInterval)(currentValueCollector)
+
+  def removeHistogram(name: String): Unit =
+    Kamon(UserMetrics)(system).removeHistogram(name)
+
+  def removeCounter(name: String): Unit =
+    Kamon(UserMetrics)(system).removeCounter(name)
+
+  def removeMinMaxCounter(name: String): Unit =
+    Kamon(UserMetrics)(system).removeMinMaxCounter(name)
+
+  def removeGauge(name: String): Unit =
+    Kamon(UserMetrics)(system).removeGauge(name)
+}
 
 object KamonStandalone {
-  private lazy val system = ActorSystem("kamon-standalone")
 
-  def registerHistogram(name: String) = {
+  def buildFromConfig(config: Config): KamonStandalone = buildFromConfig(config, "kamon-standalone")
 
+  def buildFromConfig(config: Config, actorSystemName: String): KamonStandalone = new KamonStandalone {
+    val system: ActorSystem = ActorSystem(actorSystemName, config)
   }
 }
+
+object EmbeddedKamonStandalone extends KamonStandalone {
+  private[kamon] lazy val system = ActorSystem("kamon-standalone")
+}
\ No newline at end of file
diff --git a/kamon-core/src/test/scala/kamon/metric/UserMetricsSpec.scala b/kamon-core/src/test/scala/kamon/metric/UserMetricsSpec.scala
index 1790dc51..385c8404 100644
--- a/kamon-core/src/test/scala/kamon/metric/UserMetricsSpec.scala
+++ b/kamon-core/src/test/scala/kamon/metric/UserMetricsSpec.scala
@@ -112,6 +112,29 @@ class UserMetricsSpec extends TestKitBase with WordSpecLike with Matchers with I
       }
     }
 
+    "allow unregistering metrics from the extension" in {
+      val userMetricsRecorder = Kamon(Metrics).register(UserMetrics, UserMetrics.Factory).get
+      val counter = Kamon(UserMetrics).registerCounter("counter-for-remove")
+      val histogram = Kamon(UserMetrics).registerHistogram("histogram-for-remove")
+      val minMaxCounter = Kamon(UserMetrics).registerMinMaxCounter("min-max-counter-for-remove")
+      val gauge = Kamon(UserMetrics).registerGauge("gauge-for-remove") { () ⇒ 2L }
+
+      userMetricsRecorder.counters.keys should contain("counter-for-remove")
+      userMetricsRecorder.histograms.keys should contain("histogram-for-remove")
+      userMetricsRecorder.minMaxCounters.keys should contain("min-max-counter-for-remove")
+      userMetricsRecorder.gauges.keys should contain("gauge-for-remove")
+
+      Kamon(UserMetrics).removeCounter("counter-for-remove")
+      Kamon(UserMetrics).removeHistogram("histogram-for-remove")
+      Kamon(UserMetrics).removeMinMaxCounter("min-max-counter-for-remove")
+      Kamon(UserMetrics).removeGauge("gauge-for-remove")
+
+      userMetricsRecorder.counters.keys should not contain ("counter-for-remove")
+      userMetricsRecorder.histograms.keys should not contain ("histogram-for-remove")
+      userMetricsRecorder.minMaxCounters.keys should not contain ("min-max-counter-for-remove")
+      userMetricsRecorder.gauges.keys should not contain ("gauge-for-remove")
+    }
+
     "generate a snapshot containing all the registered user metrics and reset all instruments" in {
       val context = Kamon(Metrics).buildDefaultCollectionContext
       val userMetricsRecorder = Kamon(Metrics).register(UserMetrics, UserMetrics.Factory).get