integrate trace and metrics into the base project

18 files changed, 784 insertions, 247 deletions

diff --git a/kamon-core/src/main/scala/akka/instrumentation/ActorMessagePassingTracing.scala b/kamon-core/src/main/scala/akka/instrumentation/ActorMessagePassingTracing.scala
new file mode 100644
index 00000000..6cede344
--- /dev/null
+++ b/kamon-core/src/main/scala/akka/instrumentation/ActorMessagePassingTracing.scala
@@ -0,0 +1,93 @@
+/* ===================================================
+ * 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 akka.instrumentation
+
+import org.aspectj.lang.annotation._
+import org.aspectj.lang.ProceedingJoinPoint
+import akka.actor.{ Cell, Props, ActorSystem, ActorRef }
+import akka.dispatch.{ Envelope, MessageDispatcher }
+import kamon.trace.{ TraceContext, ContextAware, Trace }
+import kamon.metrics.{ HdrActorMetricsRecorder, ActorMetrics }
+import kamon.Kamon
+
+@Aspect("perthis(actorCellCreation(*, *, *, *, *))")
+class BehaviourInvokeTracing {
+  var path: Option[String] = None
+  var actorMetrics: Option[HdrActorMetricsRecorder] = None
+
+  @Pointcut("execution(akka.actor.ActorCell.new(..)) && args(system, ref, props, dispatcher, parent)")
+  def actorCellCreation(system: ActorSystem, ref: ActorRef, props: Props, dispatcher: MessageDispatcher, parent: ActorRef): Unit = {}
+
+  @After("actorCellCreation(system, ref, props, dispatcher, parent)")
+  def afterCreation(system: ActorSystem, ref: ActorRef, props: Props, dispatcher: MessageDispatcher, parent: ActorRef): Unit = {
+    val metricsExtension = Kamon(ActorMetrics)(system)
+    val simplePathString = ref.path.elements.mkString("/")
+
+    if (metricsExtension.shouldTrackActor(simplePathString)) {
+      path = Some(ref.path.toString)
+      actorMetrics = Some(metricsExtension.registerActor(simplePathString))
+    }
+  }
+
+  @Pointcut("(execution(* akka.actor.ActorCell.invoke(*)) || execution(* akka.routing.RoutedActorCell.sendMessage(*))) && args(envelope)")
+  def invokingActorBehaviourAtActorCell(envelope: Envelope) = {}
+
+  @Around("invokingActorBehaviourAtActorCell(envelope)")
+  def aroundBehaviourInvoke(pjp: ProceedingJoinPoint, envelope: Envelope): Unit = {
+    val timestampBeforeProcessing = System.nanoTime()
+    val contextAndTimestamp = envelope.asInstanceOf[ContextAndTimestampAware]
+
+    Trace.withContext(contextAndTimestamp.traceContext) {
+      pjp.proceed()
+    }
+
+    actorMetrics.map { am ⇒
+      am.recordProcessingTime(System.nanoTime() - timestampBeforeProcessing)
+      am.recordTimeInMailbox(timestampBeforeProcessing - contextAndTimestamp.timestamp)
+    }
+  }
+
+  @Pointcut("execution(* akka.actor.ActorCell.stop()) && this(cell)")
+  def actorStop(cell: Cell): Unit = {}
+
+  @After("actorStop(cell)")
+  def afterStop(cell: Cell): Unit = {
+    path.map(p ⇒ Kamon(ActorMetrics)(cell.system).unregisterActor(p))
+  }
+}
+
+@Aspect
+class EnvelopeTraceContextMixin {
+
+  @DeclareMixin("akka.dispatch.Envelope")
+  def mixin: ContextAndTimestampAware = new ContextAndTimestampAware {
+    val traceContext: Option[TraceContext] = Trace.context()
+    val timestamp: Long = System.nanoTime()
+  }
+
+  @Pointcut("execution(akka.dispatch.Envelope.new(..)) && this(ctx)")
+  def envelopeCreation(ctx: ContextAware): Unit = {}
+
+  @After("envelopeCreation(ctx)")
+  def afterEnvelopeCreation(ctx: ContextAware): Unit = {
+    // Necessary to force the initialization of ContextAware at the moment of creation.
+    ctx.traceContext
+  }
+}
+
+trait ContextAndTimestampAware extends ContextAware {
+  def timestamp: Long
+}
diff --git a/kamon-core/src/main/scala/akka/instrumentation/ActorSystemMessagePassingTracing.scala b/kamon-core/src/main/scala/akka/instrumentation/ActorSystemMessagePassingTracing.scala
new file mode 100644
index 00000000..7d26016e
--- /dev/null
+++ b/kamon-core/src/main/scala/akka/instrumentation/ActorSystemMessagePassingTracing.scala
@@ -0,0 +1,65 @@
+package akka.instrumentation
+
+import org.aspectj.lang.annotation._
+import kamon.trace.{ Trace, ContextAware }
+import akka.dispatch.sysmsg.EarliestFirstSystemMessageList
+import org.aspectj.lang.ProceedingJoinPoint
+
+@Aspect
+class SystemMessageTraceContextMixin {
+
+  @DeclareMixin("akka.dispatch.sysmsg.SystemMessage+")
+  def mixin: ContextAware = ContextAware.default
+
+  @Pointcut("execution(akka.dispatch.sysmsg.SystemMessage+.new(..)) && this(ctx)")
+  def envelopeCreation(ctx: ContextAware): Unit = {}
+
+  @After("envelopeCreation(ctx)")
+  def afterEnvelopeCreation(ctx: ContextAware): Unit = {
+    // Necessary to force the initialization of ContextAware at the moment of creation.
+    ctx.traceContext
+  }
+}
+
+@Aspect
+class RepointableActorRefTraceContextMixin {
+
+  @DeclareMixin("akka.actor.RepointableActorRef")
+  def mixin: ContextAware = ContextAware.default
+
+  @Pointcut("execution(akka.actor.RepointableActorRef.new(..)) && this(ctx)")
+  def envelopeCreation(ctx: ContextAware): Unit = {}
+
+  @After("envelopeCreation(ctx)")
+  def afterEnvelopeCreation(ctx: ContextAware): Unit = {
+    // Necessary to force the initialization of ContextAware at the moment of creation.
+    ctx.traceContext
+  }
+
+  @Pointcut("execution(* akka.actor.RepointableActorRef.point(..)) && this(repointableActorRef)")
+  def repointableActorRefCreation(repointableActorRef: ContextAware): Unit = {}
+
+  @Around("repointableActorRefCreation(repointableActorRef)")
+  def afterRepointableActorRefCreation(pjp: ProceedingJoinPoint, repointableActorRef: ContextAware): Any = {
+    Trace.withContext(repointableActorRef.traceContext) {
+      pjp.proceed()
+    }
+  }
+
+}
+
+@Aspect
+class ActorSystemMessagePassingTracing {
+
+  @Pointcut("execution(* akka.actor.ActorCell.invokeAll$1(..)) && args(messages, *)")
+  def systemMessageProcessing(messages: EarliestFirstSystemMessageList): Unit = {}
+
+  @Around("systemMessageProcessing(messages)")
+  def aroundSystemMessageInvoke(pjp: ProceedingJoinPoint, messages: EarliestFirstSystemMessageList): Any = {
+    if (messages.nonEmpty) {
+      val ctx = messages.head.asInstanceOf[ContextAware].traceContext
+      Trace.withContext(ctx)(pjp.proceed())
+
+    } else pjp.proceed()
+  }
+}
diff --git a/kamon-core/src/main/scala/akka/instrumentation/AskPatternTracing.scala b/kamon-core/src/main/scala/akka/instrumentation/AskPatternTracing.scala
new file mode 100644
index 00000000..b5b23e61
--- /dev/null
+++ b/kamon-core/src/main/scala/akka/instrumentation/AskPatternTracing.scala
@@ -0,0 +1,49 @@
+/* ===================================================
+ * Copyright © 2013 the kamon project <http://kamon.io/>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ * ========================================================== */
+package akka.instrumentation
+
+import org.aspectj.lang.annotation.{ AfterReturning, Pointcut, Aspect }
+import akka.event.Logging.Warning
+import scala.compat.Platform.EOL
+import akka.actor.ActorRefProvider
+import akka.pattern.{ AskTimeoutException, PromiseActorRef }
+
+@Aspect
+class AskPatternTracing {
+
+  class StackTraceCaptureException extends Throwable
+
+  @Pointcut(value = "execution(* akka.pattern.PromiseActorRef$.apply(..)) && args(provider, *)", argNames = "provider")
+  def promiseActorRefApply(provider: ActorRefProvider): Unit = {
+    provider.settings.config.getBoolean("kamon.trace.ask-pattern-tracing")
+  }
+
+  @AfterReturning(pointcut = "promiseActorRefApply(provider)", returning = "promiseActor")
+  def hookAskTimeoutWarning(provider: ActorRefProvider, promiseActor: PromiseActorRef): Unit = {
+    val future = promiseActor.result.future
+    val system = promiseActor.provider.guardian.underlying.system
+    implicit val ec = system.dispatcher
+    val stack = new StackTraceCaptureException
+
+    future onFailure {
+      case timeout: AskTimeoutException ⇒
+        val stackString = stack.getStackTrace.drop(3).mkString("", EOL, EOL)
+
+        system.eventStream.publish(Warning("AskPatternTracing", classOf[AskPatternTracing],
+          "Timeout triggered for ask pattern registered at: " + stackString))
+    }
+  }
+}
diff --git a/kamon-core/src/main/scala/kamon/Kamon.scala b/kamon-core/src/main/scala/kamon/Kamon.scala
index b5c3d552..b72e8fea 100644
--- a/kamon-core/src/main/scala/kamon/Kamon.scala
+++ b/kamon-core/src/main/scala/kamon/Kamon.scala
@@ -18,10 +18,8 @@ package kamon
 import akka.actor._
 
 object Kamon {
-  trait Extension extends akka.actor.Extension {
-    def manager: ActorRef
-  }
+  trait Extension extends akka.actor.Extension
 
-  def apply[T <: Extension](key: ExtensionId[T])(implicit system: ActorSystem): ActorRef = key(system).manager
+  def apply[T <: Extension](key: ExtensionId[T])(implicit system: ActorSystem): T = key(system)
 }
 
diff --git a/kamon-core/src/main/scala/kamon/instrumentation/ActorLoggingTracing.scala b/kamon-core/src/main/scala/kamon/instrumentation/ActorLoggingTracing.scala
new file mode 100644
index 00000000..297017cf
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/instrumentation/ActorLoggingTracing.scala
@@ -0,0 +1,37 @@
+/* ===================================================
+ * 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.instrumentation
+
+import org.aspectj.lang.annotation.{ Around, Pointcut, DeclareMixin, Aspect }
+import org.aspectj.lang.ProceedingJoinPoint
+import kamon.trace.{ ContextAware, Trace }
+
+@Aspect
+class ActorLoggingTracing {
+
+  @DeclareMixin("akka.event.Logging.LogEvent+")
+  def mixin: ContextAware = ContextAware.default
+
+  @Pointcut("execution(* akka.event.slf4j.Slf4jLogger.withMdc(..)) && args(logSource, logEvent, logStatement)")
+  def withMdcInvocation(logSource: String, logEvent: ContextAware, logStatement: () ⇒ _): Unit = {}
+
+  @Around("withMdcInvocation(logSource, logEvent, logStatement)")
+  def aroundWithMdcInvocation(pjp: ProceedingJoinPoint, logSource: String, logEvent: ContextAware, logStatement: () ⇒ _): Unit = {
+    Trace.withContext(logEvent.traceContext) {
+      pjp.proceed()
+    }
+  }
+}
diff --git a/kamon-core/src/main/scala/kamon/instrumentation/ExecutorServiceMetrics.scala b/kamon-core/src/main/scala/kamon/instrumentation/ExecutorServiceMetrics.scala
index a3da76f7..90d2b270 100644
--- a/kamon-core/src/main/scala/kamon/instrumentation/ExecutorServiceMetrics.scala
+++ b/kamon-core/src/main/scala/kamon/instrumentation/ExecutorServiceMetrics.scala
@@ -19,10 +19,8 @@ import org.aspectj.lang.annotation._
 import java.util.concurrent._
 import org.aspectj.lang.ProceedingJoinPoint
 import java.util
-import kamon.metric.{ DispatcherMetricCollector, Histogram, MetricDirectory, ExecutorServiceMetricCollector }
 import akka.dispatch.{ MonitorableThreadFactory, ExecutorServiceFactory }
 import com.typesafe.config.Config
-import kamon.Kamon
 import scala.concurrent.forkjoin.ForkJoinPool
 import akka.dispatch.ForkJoinExecutorConfigurator.AkkaForkJoinPool
 
@@ -41,8 +39,8 @@ class ActorSystemInstrumentation {
 
 @Aspect("perthis(forkJoinPoolInstantiation(int, scala.concurrent.forkjoin.ForkJoinPool.ForkJoinWorkerThreadFactory, java.lang.Thread.UncaughtExceptionHandler))")
 class ForkJoinPoolInstrumentation {
-  var activeThreadsHistogram: Histogram = _
-  var poolSizeHistogram: Histogram = _
+  /*  var activeThreadsHistogram: Histogram = _
+  var poolSizeHistogram: Histogram = _*/
 
   @Pointcut("execution(akka.dispatch.ForkJoinExecutorConfigurator.AkkaForkJoinPool.new(..)) && args(parallelism, threadFactory, exceptionHandler)")
   def forkJoinPoolInstantiation(parallelism: Int, threadFactory: ForkJoinPool.ForkJoinWorkerThreadFactory, exceptionHandler: Thread.UncaughtExceptionHandler) = {}
@@ -71,8 +69,8 @@ class ForkJoinPoolInstrumentation {
 
   @After("forkJoinScan(fjp)")
   def updateMetrics(fjp: AkkaForkJoinPool): Unit = {
-    activeThreadsHistogram.update(fjp.getActiveThreadCount)
-    poolSizeHistogram.update(fjp.getPoolSize)
+    /*activeThreadsHistogram.update(fjp.getActiveThreadCount)
+    poolSizeHistogram.update(fjp.getPoolSize)*/
   }
 
 }
@@ -90,6 +88,7 @@ trait WatchedExecutorService {
   def collector: ExecutorServiceCollector
 }
 
+/*
 trait ExecutorServiceMonitoring {
   def dispatcherMetrics: DispatcherMetricCollector
 }
@@ -97,6 +96,7 @@ trait ExecutorServiceMonitoring {
 class ExecutorServiceMonitoringImpl extends ExecutorServiceMonitoring {
   @volatile var dispatcherMetrics: DispatcherMetricCollector = _
 }
+*/
 
 case class NamedExecutorServiceFactoryDelegate(actorSystemName: String, dispatcherName: String, delegate: ExecutorServiceFactory) extends ExecutorServiceFactory {
   def createExecutorService: ExecutorService = delegate.createExecutorService
@@ -133,9 +133,9 @@ class NamedExecutorServiceFactoryDelegateInstrumentation {
   @Around("factoryMethodCall(namedFactory)")
   def enrichExecutorServiceWithMetricNameRoot(pjp: ProceedingJoinPoint, namedFactory: NamedExecutorServiceFactoryDelegate): ExecutorService = {
     val delegate = pjp.proceed().asInstanceOf[ExecutorService]
-    val executorFullName = MetricDirectory.nameForDispatcher(namedFactory.actorSystemName, namedFactory.dispatcherName)
+    val executorFullName = "" //MetricDirectory.nameForDispatcher(namedFactory.actorSystemName, namedFactory.dispatcherName)
 
-    ExecutorServiceMetricCollector.register(executorFullName, delegate)
+    //ExecutorServiceMetricCollector.register(executorFullName, delegate)
 
     new NamedExecutorServiceDelegate(executorFullName, delegate)
   }
@@ -143,7 +143,7 @@ class NamedExecutorServiceFactoryDelegateInstrumentation {
 
 case class NamedExecutorServiceDelegate(fullName: String, delegate: ExecutorService) extends ExecutorService {
   def shutdown() = {
-    ExecutorServiceMetricCollector.deregister(fullName)
+    //ExecutorServiceMetricCollector.deregister(fullName)
     delegate.shutdown()
   }
   def shutdownNow(): util.List[Runnable] = delegate.shutdownNow()
diff --git a/kamon-core/src/main/scala/kamon/instrumentation/FutureTracing.scala b/kamon-core/src/main/scala/kamon/instrumentation/FutureTracing.scala
new file mode 100644
index 00000000..5600d582
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/instrumentation/FutureTracing.scala
@@ -0,0 +1,47 @@
+/* ===================================================
+ * 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.instrumentation
+
+import org.aspectj.lang.annotation._
+import org.aspectj.lang.ProceedingJoinPoint
+import kamon.trace.{ ContextAware, TraceContext, Trace }
+
+@Aspect
+class FutureTracing {
+
+  @DeclareMixin("scala.concurrent.impl.CallbackRunnable || scala.concurrent.impl.Future.PromiseCompletingRunnable")
+  def mixin: ContextAware = ContextAware.default
+
+  @Pointcut("execution((scala.concurrent.impl.CallbackRunnable || scala.concurrent.impl.Future.PromiseCompletingRunnable).new(..)) && this(runnable)")
+  def futureRelatedRunnableCreation(runnable: ContextAware): Unit = {}
+
+  @After("futureRelatedRunnableCreation(runnable)")
+  def afterCreation(runnable: ContextAware): Unit = {
+    // Force traceContext initialization.
+    runnable.traceContext
+  }
+
+  @Pointcut("execution(* (scala.concurrent.impl.CallbackRunnable || scala.concurrent.impl.Future.PromiseCompletingRunnable).run()) && this(runnable)")
+  def futureRelatedRunnableExecution(runnable: ContextAware) = {}
+
+  @Around("futureRelatedRunnableExecution(runnable)")
+  def aroundExecution(pjp: ProceedingJoinPoint, runnable: ContextAware): Any = {
+    Trace.withContext(runnable.traceContext) {
+      pjp.proceed()
+    }
+  }
+
+}
\ No newline at end of file
diff --git a/kamon-core/src/main/scala/kamon/instrumentation/MessageQueueMetrics.scala b/kamon-core/src/main/scala/kamon/instrumentation/MessageQueueMetrics.scala
index da797fa1..44eb8c43 100644
--- a/kamon-core/src/main/scala/kamon/instrumentation/MessageQueueMetrics.scala
+++ b/kamon-core/src/main/scala/kamon/instrumentation/MessageQueueMetrics.scala
@@ -15,17 +15,16 @@
  * ========================================================== */
 package kamon.instrumentation
 
-import com.codahale.metrics.{ ExponentiallyDecayingReservoir, Histogram }
 import akka.dispatch.{ UnboundedMessageQueueSemantics, Envelope, MessageQueue }
 import org.aspectj.lang.annotation.{ Around, Pointcut, DeclareMixin, Aspect }
 import akka.actor.{ ActorSystem, ActorRef }
-import kamon.metric.{ Metrics, MetricDirectory }
 import org.aspectj.lang.ProceedingJoinPoint
 
 /**
  *  For Mailboxes we would like to track the queue size and message latency. Currently the latency
  *  will be gathered from the ActorCellMetrics.
  */
+/*
 
 @Aspect
 class MessageQueueInstrumentation {
@@ -74,4 +73,5 @@ class MonitoredMessageQueue(val delegate: MessageQueue, val queueSizeHistogram:
   def hasMessages: Boolean = delegate.hasMessages
   def cleanUp(owner: ActorRef, deadLetters: MessageQueue) = delegate.cleanUp(owner, deadLetters)
 }
+*/
 
diff --git a/kamon-core/src/main/scala/kamon/metric/ExecutorServiceMetricCollector.scala b/kamon-core/src/main/scala/kamon/metric/ExecutorServiceMetricCollector.scala
deleted file mode 100644
index 4c4b93e9..00000000
--- a/kamon-core/src/main/scala/kamon/metric/ExecutorServiceMetricCollector.scala
+++ /dev/null
@@ -1,74 +0,0 @@
-/* ===================================================
- * 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.metric
-
-import java.util.concurrent.{ ThreadPoolExecutor, ExecutorService }
-import scala.concurrent.forkjoin.ForkJoinPool
-import com.codahale.metrics.{ Metric, MetricFilter }
-
-object ExecutorServiceMetricCollector extends ForkJoinPoolMetricCollector with ThreadPoolExecutorMetricCollector {
-
-  def register(fullName: String, executorService: ExecutorService) = executorService match {
-    case fjp: ForkJoinPool       ⇒ registerForkJoinPool(fullName, fjp)
-    case tpe: ThreadPoolExecutor ⇒ registerThreadPoolExecutor(fullName, tpe)
-    case _                       ⇒ // If it is a unknown Executor then just do nothing.
-  }
-
-  def deregister(fullName: String) = {
-    Metrics.registry.removeMatching(new MetricFilter {
-      def matches(name: String, metric: Metric): Boolean = name.startsWith(fullName)
-    })
-  }
-}
-
-trait ForkJoinPoolMetricCollector {
-  import GaugeGenerator._
-  import BasicExecutorMetricNames._
-
-  def registerForkJoinPool(fullName: String, fjp: ForkJoinPool) = {
-    val forkJoinPoolGauge = newNumericGaugeFor(fjp) _
-
-    val allMetrics = Map(
-      fullName + queueSize -> forkJoinPoolGauge(_.getQueuedTaskCount.toInt),
-      fullName + poolSize -> forkJoinPoolGauge(_.getPoolSize),
-      fullName + activeThreads -> forkJoinPoolGauge(_.getActiveThreadCount))
-
-    allMetrics.foreach { case (name, metric) ⇒ Metrics.registry.register(name, metric) }
-  }
-}
-
-trait ThreadPoolExecutorMetricCollector {
-  import GaugeGenerator._
-  import BasicExecutorMetricNames._
-
-  def registerThreadPoolExecutor(fullName: String, tpe: ThreadPoolExecutor) = {
-    val tpeGauge = newNumericGaugeFor(tpe) _
-
-    val allMetrics = Map(
-      fullName + queueSize -> tpeGauge(_.getQueue.size()),
-      fullName + poolSize -> tpeGauge(_.getPoolSize),
-      fullName + activeThreads -> tpeGauge(_.getActiveCount))
-
-    allMetrics.foreach { case (name, metric) ⇒ Metrics.registry.register(name, metric) }
-  }
-}
-
-object BasicExecutorMetricNames {
-  val queueSize = "queueSize"
-  val poolSize = "threads/poolSize"
-  val activeThreads = "threads/activeThreads"
-}
-
diff --git a/kamon-core/src/main/scala/kamon/metric/Metrics.scala b/kamon-core/src/main/scala/kamon/metric/Metrics.scala
deleted file mode 100644
index b904ec56..00000000
--- a/kamon-core/src/main/scala/kamon/metric/Metrics.scala
+++ /dev/null
@@ -1,132 +0,0 @@
-/* ===================================================
- * 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.metric
-
-import java.util.concurrent.TimeUnit
-import akka.actor.ActorRef
-import com.codahale.metrics
-import com.codahale.metrics.{ MetricFilter, Metric, ConsoleReporter, MetricRegistry }
-import scala.collection.concurrent.TrieMap
-
-object Metrics {
-  val registry: MetricRegistry = new MetricRegistry
-
-  val consoleReporter = ConsoleReporter.forRegistry(registry).convertDurationsTo(TimeUnit.NANOSECONDS)
-  //consoleReporter.build().start(45, TimeUnit.SECONDS)
-
-  //val newrelicReporter = NewRelicReporter(registry)
-  //newrelicReporter.start(5, TimeUnit.SECONDS)
-
-  def include(name: String, metric: Metric) = {
-    //registry.register(name, metric)
-  }
-
-  def exclude(name: String) = {
-    registry.removeMatching(new MetricFilter {
-      def matches(name: String, metric: Metric): Boolean = name.startsWith(name)
-    })
-  }
-
-  def deregister(fullName: String) = {
-    registry.removeMatching(new MetricFilter {
-      def matches(name: String, metric: Metric): Boolean = name.startsWith(fullName)
-    })
-  }
-}
-
-object Watched {
-  case object Actor
-  case object Dispatcher
-}
-
-object MetricDirectory {
-  def nameForDispatcher(actorSystem: String, dispatcher: String) = s"/ActorSystem/${actorSystem}/Dispatcher/${dispatcher}/"
-
-  def nameForMailbox(actorSystem: String, actor: String) = s"/ActorSystem/$actorSystem/Actor/$actor/Mailbox"
-
-  def nameForActor(actorRef: ActorRef) = actorRef.path.elements.mkString("/")
-
-  def shouldInstrument(actorSystem: String): Boolean = !actorSystem.startsWith("kamon")
-
-  def shouldInstrumentActor(actorPath: String): Boolean = {
-    !(actorPath.isEmpty || actorPath.startsWith("system"))
-  }
-
-}
-
-case class DispatcherMetricCollector(activeThreadCount: Histogram, poolSize: Histogram, queueSize: Histogram)
-
-trait Histogram {
-  def update(value: Long): Unit
-  def snapshot: HistogramSnapshot
-}
-
-trait HistogramSnapshot {
-  def median: Double
-  def max: Double
-  def min: Double
-}
-
-case class ActorSystemMetrics(actorSystemName: String) {
-  val dispatchers = TrieMap.empty[String, DispatcherMetricCollector]
-
-  private[this] def createDispatcherCollector: DispatcherMetricCollector = DispatcherMetricCollector(CodahaleHistogram(), CodahaleHistogram(), CodahaleHistogram())
-
-  def registerDispatcher(dispatcherName: String): Option[DispatcherMetricCollector] = {
-    val stats = createDispatcherCollector
-    dispatchers.put(dispatcherName, stats)
-    Some(stats)
-  }
-
-}
-
-case class CodahaleHistogram() extends Histogram {
-  private[this] val histogram = new com.codahale.metrics.Histogram(new metrics.ExponentiallyDecayingReservoir())
-
-  def update(value: Long) = histogram.update(value)
-  def snapshot: HistogramSnapshot = {
-    val snapshot = histogram.getSnapshot
-
-    CodahaleHistogramSnapshot(snapshot.getMedian, snapshot.getMax, snapshot.getMin)
-  }
-}
-
-case class CodahaleHistogramSnapshot(median: Double, max: Double, min: Double) extends HistogramSnapshot
-
-/**
- *  Dispatcher Metrics that we care about currently with a histogram-like nature:
- *    - Work Queue Size
- *    - Total/Active Thread Count
- */
-
-import annotation.tailrec
-import java.util.concurrent.atomic.AtomicReference
-
-object Atomic {
-  def apply[T](obj: T) = new Atomic(new AtomicReference(obj))
-  implicit def toAtomic[T](ref: AtomicReference[T]): Atomic[T] = new Atomic(ref)
-}
-
-class Atomic[T](val atomic: AtomicReference[T]) {
-  @tailrec
-  final def update(f: T ⇒ T): T = {
-    val oldValue = atomic.get()
-    val newValue = f(oldValue)
-    if (atomic.compareAndSet(oldValue, newValue)) newValue else update(f)
-  }
-
-  def get() = atomic.get()
-}
\ No newline at end of file
diff --git a/kamon-core/src/main/scala/kamon/instrumentation/AspectJPimps.scala b/kamon-core/src/main/scala/kamon/metrics/ActorMetrics.scala
index 252e5220..72e473e8 100644
--- a/kamon-core/src/main/scala/kamon/instrumentation/AspectJPimps.scala
+++ b/kamon-core/src/main/scala/kamon/metrics/ActorMetrics.scala
@@ -13,26 +13,19 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  * ========================================================== */
-package kamon.instrumentation
 
-import org.aspectj.lang.ProceedingJoinPoint
+package kamon.metrics
 
-trait ProceedingJoinPointPimp {
-  import language.implicitConversions
+import akka.actor.{ Props, ExtendedActorSystem, ExtensionIdProvider, ExtensionId }
+import akka.actor
+import kamon.Kamon
 
-  implicit def pimpProceedingJointPoint(pjp: ProceedingJoinPoint) = RichProceedingJointPoint(pjp)
-}
-
-object ProceedingJoinPointPimp extends ProceedingJoinPointPimp
+object ActorMetrics extends ExtensionId[ActorMetricsExtension] with ExtensionIdProvider {
+  def lookup(): ExtensionId[_ <: actor.Extension] = ActorMetrics
+  def createExtension(system: ExtendedActorSystem): ActorMetricsExtension = new ActorMetricsExtension(system)
 
-case class RichProceedingJointPoint(pjp: ProceedingJoinPoint) {
-  def proceedWith(newUniqueArg: AnyRef) = {
-    val args = pjp.getArgs
-    args.update(0, newUniqueArg)
-    pjp.proceed(args)
-  }
+}
 
-  def proceedWithTarget(args: AnyRef*) = {
-    pjp.proceed(args.toArray)
-  }
+class ActorMetricsExtension(val system: ExtendedActorSystem) extends Kamon.Extension with ActorMetricsOps {
+  lazy val metricsDispatcher = system.actorOf(Props[ActorMetricsDispatcher], "kamon-actor-metrics")
 }
diff --git a/kamon-core/src/main/scala/kamon/metrics/ActorMetricsOps.scala b/kamon-core/src/main/scala/kamon/metrics/ActorMetricsOps.scala
new file mode 100644
index 00000000..dc4abde0
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/metrics/ActorMetricsOps.scala
@@ -0,0 +1,148 @@
+/*
+ * =========================================================================================
+ * 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 org.HdrHistogram.{ AbstractHistogram, AtomicHistogram }
+import kamon.util.GlobPathFilter
+import scala.collection.concurrent.TrieMap
+import scala.collection.JavaConversions.iterableAsScalaIterable
+import akka.actor._
+import kamon.metrics.ActorMetricsDispatcher.{ ActorMetricsSnapshot, FlushMetrics }
+import kamon.Kamon
+import scala.concurrent.duration._
+import java.util.concurrent.TimeUnit
+import kamon.metrics.ActorMetricsDispatcher.Subscribe
+
+trait ActorMetricsOps {
+  self: ActorMetricsExtension ⇒
+
+  val config = system.settings.config.getConfig("kamon.metrics.actors")
+  val actorMetrics = TrieMap[String, HdrActorMetricsRecorder]()
+
+  val trackedActors: Vector[GlobPathFilter] = config.getStringList("tracked").map(glob ⇒ new GlobPathFilter(glob)).toVector
+  val excludedActors: Vector[GlobPathFilter] = config.getStringList("excluded").map(glob ⇒ new GlobPathFilter(glob)).toVector
+
+  val actorMetricsFactory: () ⇒ HdrActorMetricsRecorder = {
+    val settings = config.getConfig("hdr-settings")
+    val processingTimeHdrConfig = HdrConfiguration.fromConfig(settings.getConfig("processing-time"))
+    val timeInMailboxHdrConfig = HdrConfiguration.fromConfig(settings.getConfig("time-in-mailbox"))
+    val mailboxSizeHdrConfig = HdrConfiguration.fromConfig(settings.getConfig("mailbox-size"))
+
+    () ⇒ new HdrActorMetricsRecorder(processingTimeHdrConfig, timeInMailboxHdrConfig, mailboxSizeHdrConfig)
+  }
+
+  import scala.concurrent.duration._
+  system.scheduler.schedule(0.seconds, 10.seconds)(
+    actorMetrics.collect {
+      case (name, recorder: HdrActorMetricsRecorder) ⇒
+        println(s"Actor: $name")
+        recorder.processingTimeHistogram.copy.getHistogramData.outputPercentileDistribution(System.out, 1000000D)
+    })(system.dispatcher)
+
+  def shouldTrackActor(path: String): Boolean =
+    trackedActors.exists(glob ⇒ glob.accept(path)) && !excludedActors.exists(glob ⇒ glob.accept(path))
+
+  def registerActor(path: String): HdrActorMetricsRecorder = actorMetrics.getOrElseUpdate(path, actorMetricsFactory())
+
+  def unregisterActor(path: String): Unit = actorMetrics.remove(path)
+}
+
+class HdrActorMetricsRecorder(processingTimeHdrConfig: HdrConfiguration, timeInMailboxHdrConfig: HdrConfiguration,
+                              mailboxSizeHdrConfig: HdrConfiguration) {
+
+  val processingTimeHistogram = new AtomicHistogram(processingTimeHdrConfig.highestTrackableValue, processingTimeHdrConfig.significantValueDigits)
+  val timeInMailboxHistogram = new AtomicHistogram(timeInMailboxHdrConfig.highestTrackableValue, timeInMailboxHdrConfig.significantValueDigits)
+  val mailboxSizeHistogram = new AtomicHistogram(mailboxSizeHdrConfig.highestTrackableValue, mailboxSizeHdrConfig.significantValueDigits)
+
+  def recordTimeInMailbox(waitTime: Long): Unit = timeInMailboxHistogram.recordValue(waitTime)
+
+  def recordProcessingTime(processingTime: Long): Unit = processingTimeHistogram.recordValue(processingTime)
+
+  def snapshot(): HdrActorMetricsSnapshot = {
+    HdrActorMetricsSnapshot(processingTimeHistogram.copy(), timeInMailboxHistogram.copy(), mailboxSizeHistogram.copy())
+  }
+
+  def reset(): Unit = {
+    processingTimeHistogram.reset()
+    timeInMailboxHistogram.reset()
+    mailboxSizeHistogram.reset()
+  }
+}
+
+case class HdrActorMetricsSnapshot(processingTimeHistogram: AbstractHistogram, timeInMailboxHistogram: AbstractHistogram,
+                                   mailboxSizeHistogram: AbstractHistogram)
+
+class ActorMetricsDispatcher extends Actor {
+  val tickInterval = Duration(context.system.settings.config.getNanoseconds("kamon.metrics.tick-interval"), TimeUnit.NANOSECONDS)
+  val flushMetricsSchedule = context.system.scheduler.schedule(tickInterval, tickInterval, self, FlushMetrics)(context.dispatcher)
+
+  var subscribedForever: Map[GlobPathFilter, List[ActorRef]] = Map.empty
+  var subscribedForOne: Map[GlobPathFilter, List[ActorRef]] = Map.empty
+  var lastTick = System.currentTimeMillis()
+
+  def receive = {
+    case Subscribe(path, true)  ⇒ subscribeForever(path, sender)
+    case Subscribe(path, false) ⇒ subscribeOneOff(path, sender)
+    case FlushMetrics           ⇒ flushMetrics()
+  }
+
+  def subscribeForever(path: String, receiver: ActorRef): Unit = subscribedForever = subscribe(receiver, path, subscribedForever)
+
+  def subscribeOneOff(path: String, receiver: ActorRef): Unit = subscribedForOne = subscribe(receiver, path, subscribedForOne)
+
+  def subscribe(receiver: ActorRef, path: String, target: Map[GlobPathFilter, List[ActorRef]]): Map[GlobPathFilter, List[ActorRef]] = {
+    val pathFilter = new GlobPathFilter(path)
+    val oldReceivers = target.get(pathFilter).getOrElse(Nil)
+    target.updated(pathFilter, receiver :: oldReceivers)
+  }
+
+  def flushMetrics(): Unit = {
+    val currentTick = System.currentTimeMillis()
+    val snapshots = Kamon(ActorMetrics)(context.system).actorMetrics.map {
+      case (path, metrics) ⇒
+        val snapshot = metrics.snapshot()
+        metrics.reset()
+
+        (path, snapshot)
+    }.toMap
+
+    dispatchMetricsTo(subscribedForOne, snapshots, currentTick)
+    dispatchMetricsTo(subscribedForever, snapshots, currentTick)
+
+    subscribedForOne = Map.empty
+    lastTick = currentTick
+  }
+
+  def dispatchMetricsTo(subscribers: Map[GlobPathFilter, List[ActorRef]], snapshots: Map[String, HdrActorMetricsSnapshot],
+                        currentTick: Long): Unit = {
+
+    for ((subscribedPath, receivers) ← subscribers) {
+      val metrics = snapshots.filterKeys(snapshotPath ⇒ subscribedPath.accept(snapshotPath))
+      val actorMetrics = ActorMetricsSnapshot(lastTick, currentTick, metrics)
+
+      receivers.foreach(ref ⇒ ref ! actorMetrics)
+    }
+  }
+}
+
+object ActorMetricsDispatcher {
+  case class Subscribe(path: String, forever: Boolean = false)
+  case class UnSubscribe(path: String)
+
+  case class ActorMetricsSnapshot(fromMillis: Long, toMillis: Long, metrics: Map[String, HdrActorMetricsSnapshot])
+  case object FlushMetrics
+}
diff --git a/kamon-core/src/main/scala/kamon/metrics/package.scala b/kamon-core/src/main/scala/kamon/metrics/package.scala
new file mode 100644
index 00000000..d6359ead
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/metrics/package.scala
@@ -0,0 +1,31 @@
+/*
+ * =========================================================================================
+ * 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
+
+import scala.concurrent.duration._
+import com.typesafe.config.Config
+
+package object metrics {
+  val OneHour = 1.hour.toNanos
+
+  case class HdrConfiguration(highestTrackableValue: Long, significantValueDigits: Int)
+  case object HdrConfiguration {
+    def fromConfig(config: Config): HdrConfiguration = {
+      HdrConfiguration(config.getLong("highest-trackable-value"), config.getInt("significant-value-digits"))
+    }
+  }
+}
diff --git a/kamon-core/src/main/scala/kamon/trace/Segments.scala b/kamon-core/src/main/scala/kamon/trace/Segments.scala
new file mode 100644
index 00000000..0bc68ee7
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/trace/Segments.scala
@@ -0,0 +1,38 @@
+/* ===================================================
+ * 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.trace
+
+import kamon.trace.Trace.SegmentCompletionHandle
+
+object Segments {
+
+  trait Category
+  case object HttpClientRequest extends Category
+
+  case class Start(category: Category, description: String = "",
+                   attributes: Map[String, String] = Map(), timestamp: Long = System.nanoTime())
+
+  case class End(attributes: Map[String, String] = Map(), timestamp: Long = System.nanoTime())
+
+  case class Segment(start: Start, end: End)
+
+  trait SegmentCompletionHandleAware {
+    var completionHandle: Option[SegmentCompletionHandle]
+  }
+
+  trait ContextAndSegmentCompletionAware extends ContextAware with SegmentCompletionHandleAware
+}
diff --git a/kamon-core/src/main/scala/kamon/trace/Trace.scala b/kamon-core/src/main/scala/kamon/trace/Trace.scala
new file mode 100644
index 00000000..31e8185a
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/trace/Trace.scala
@@ -0,0 +1,114 @@
+/* ===================================================
+ * 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.trace
+
+import kamon.Kamon
+import akka.actor._
+import scala.Some
+import kamon.trace.Trace.Register
+import scala.concurrent.duration._
+import java.util.concurrent.atomic.AtomicLong
+
+object Trace extends ExtensionId[TraceExtension] with ExtensionIdProvider {
+  def lookup(): ExtensionId[_ <: Extension] = Trace
+  def createExtension(system: ExtendedActorSystem): TraceExtension = new TraceExtension(system)
+
+  /*** Protocol */
+  case object Register
+
+  /** User API */
+  //private[trace] val traceContext = new DynamicVariable[Option[TraceContext]](None)
+  private[trace] val traceContext = new ThreadLocal[Option[TraceContext]] {
+    override def initialValue(): Option[TraceContext] = None
+  }
+  private[trace] val tranid = new AtomicLong()
+
+  def context() = traceContext.get
+  private def set(ctx: Option[TraceContext]) = traceContext.set(ctx)
+
+  def clear: Unit = traceContext.remove()
+  def start(name: String)(implicit system: ActorSystem): TraceContext = {
+    val ctx = newTraceContext(name)
+    ctx.start(name)
+    set(Some(ctx))
+
+    ctx
+  }
+
+  def withContext[T](ctx: Option[TraceContext])(thunk: ⇒ T): T = {
+    val oldval = context
+    set(ctx)
+
+    try thunk
+    finally set(oldval)
+  }
+
+  def transformContext(f: TraceContext ⇒ TraceContext): Unit = {
+    context.map(f).foreach(ctx ⇒ set(Some(ctx)))
+  }
+
+  def finish(): Option[TraceContext] = {
+    val ctx = context()
+    ctx.map(_.finish)
+    clear
+    ctx
+  }
+
+  // TODO: FIX
+  def newTraceContext(name: String)(implicit system: ActorSystem): TraceContext = TraceContext(Kamon(Trace).api, tranid.getAndIncrement, name)
+
+  def startSegment(category: Segments.Category, description: String = "", attributes: Map[String, String] = Map()): SegmentCompletionHandle = {
+    val start = Segments.Start(category, description, attributes)
+    SegmentCompletionHandle(start)
+  }
+
+  def startSegment(start: Segments.Start): SegmentCompletionHandle = SegmentCompletionHandle(start)
+
+  case class SegmentCompletionHandle(start: Segments.Start) {
+    def complete(): Unit = {
+      val end = Segments.End()
+      println(s"Completing the Segment: $start - $end")
+    }
+    def complete(end: Segments.End): Unit = {
+      println(s"Completing the Segment: $start - $end")
+    }
+  }
+}
+
+class TraceExtension(system: ExtendedActorSystem) extends Kamon.Extension {
+  val api: ActorRef = system.actorOf(Props[TraceManager], "kamon-trace")
+}
+
+class TraceManager extends Actor with ActorLogging {
+  var listeners: Seq[ActorRef] = Seq.empty
+
+  def receive = {
+    case Register ⇒
+      listeners = sender +: listeners
+      log.info("Registered [{}] as listener for Kamon traces", sender)
+
+    case segment: UowSegment ⇒
+      val tracerName = segment.id.toString
+      context.child(tracerName).getOrElse(newTracer(tracerName)) ! segment
+
+    case trace: UowTrace ⇒
+      listeners foreach (_ ! trace)
+  }
+
+  def newTracer(name: String): ActorRef = {
+    context.actorOf(UowTraceAggregator.props(self, 30 seconds), name)
+  }
+}
diff --git a/kamon-core/src/main/scala/kamon/trace/TraceContext.scala b/kamon-core/src/main/scala/kamon/trace/TraceContext.scala
new file mode 100644
index 00000000..3e68a816
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/trace/TraceContext.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.trace
+
+import java.util.UUID
+import akka.actor._
+import java.util.concurrent.atomic.AtomicLong
+import scala.concurrent.duration._
+import kamon.Kamon
+import kamon.trace.UowTracing.{ Finish, Start }
+
+// TODO: Decide if we need or not an ID, generating it takes time and it doesn't seem necessary.
+case class TraceContext(private val collector: ActorRef, id: Long, uow: String = "", userContext: Option[Any] = None) {
+
+  def start(name: String) = {
+    collector ! Start(id, name)
+  }
+
+  def finish: Unit = {
+    collector ! Finish(id)
+  }
+
+}
+
+trait ContextAware {
+  def traceContext: Option[TraceContext]
+}
+
+object ContextAware {
+  def default: ContextAware = new ContextAware {
+    val traceContext: Option[TraceContext] = Trace.context()
+  }
+}
+
+trait TimedContextAware {
+  def timestamp: Long
+  def traceContext: Option[TraceContext]
+}
diff --git a/kamon-core/src/main/scala/kamon/trace/UowTracing.scala b/kamon-core/src/main/scala/kamon/trace/UowTracing.scala
new file mode 100644
index 00000000..20cce830
--- /dev/null
+++ b/kamon-core/src/main/scala/kamon/trace/UowTracing.scala
@@ -0,0 +1,82 @@
+/* ===================================================
+ * 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.trace
+
+import akka.actor._
+import scala.concurrent.duration.Duration
+import kamon.trace.UowTracing._
+
+sealed trait UowSegment {
+  def id: Long
+  def timestamp: Long
+}
+
+trait AutoTimestamp extends UowSegment {
+  val timestamp = System.nanoTime
+}
+
+object UowTracing {
+  case class Start(id: Long, name: String) extends AutoTimestamp
+  case class Finish(id: Long) extends AutoTimestamp
+  case class Rename(id: Long, name: String) extends AutoTimestamp
+  case class WebExternalStart(id: Long, host: String) extends AutoTimestamp
+  case class WebExternalFinish(id: Long) extends AutoTimestamp
+  case class WebExternal(id: Long, start: Long, finish: Long, host: String) extends AutoTimestamp
+}
+
+case class UowTrace(name: String, uow: String, start: Long, end: Long, segments: Seq[UowSegment]) {
+  def elapsed: Long = end - start
+}
+
+class UowTraceAggregator(reporting: ActorRef, aggregationTimeout: Duration) extends Actor with ActorLogging {
+  context.setReceiveTimeout(aggregationTimeout)
+
+  var name: String = "UNKNOWN"
+  var segments: Seq[UowSegment] = Nil
+
+  var pendingExternal = List[WebExternalStart]()
+
+  var start = 0L
+  var end = 0L
+
+  def receive = {
+    case start: Start ⇒
+      this.start = start.timestamp
+      segments = segments :+ start
+      name = start.name
+    case finish: Finish ⇒
+      end = finish.timestamp
+      segments = segments :+ finish; finishTracing()
+    case wes: WebExternalStart ⇒ pendingExternal = pendingExternal :+ wes
+    case finish @ WebExternalFinish(id) ⇒ pendingExternal.find(_.id == id).map(start ⇒ {
+      segments = segments :+ WebExternal(finish.id, start.timestamp, finish.timestamp, start.host)
+    })
+    case Rename(id, newName) ⇒ name = newName
+    case segment: UowSegment ⇒ segments = segments :+ segment
+    case ReceiveTimeout ⇒
+      log.warning("Transaction {} did not complete properly, the recorded segments are: {}", name, segments)
+      context.stop(self)
+  }
+
+  def finishTracing(): Unit = {
+    reporting ! UowTrace(name, "", start, end, segments)
+    context.stop(self)
+  }
+}
+
+object UowTraceAggregator {
+  def props(reporting: ActorRef, aggregationTimeout: Duration) = Props(classOf[UowTraceAggregator], reporting, aggregationTimeout)
+}
diff --git a/kamon-core/src/main/scala/kamon/metric/GaugeGenerator.scala b/kamon-core/src/main/scala/kamon/trace/logging/LogbackUowConverter.scala
index 9eff2739..add47fdf 100644
--- a/kamon-core/src/main/scala/kamon/metric/GaugeGenerator.scala
+++ b/kamon-core/src/main/scala/kamon/trace/logging/LogbackUowConverter.scala
@@ -13,15 +13,12 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  * ========================================================== */
-package kamon.metric
+package kamon.trace.logging
 
-import com.codahale.metrics.Gauge
+import ch.qos.logback.classic.pattern.ClassicConverter
+import ch.qos.logback.classic.spi.ILoggingEvent
+import kamon.trace.Trace
 
-trait GaugeGenerator {
-
-  def newNumericGaugeFor[T, V >: AnyVal](target: T)(generator: T ⇒ V) = new Gauge[V] {
-    def getValue: V = generator(target)
-  }
+class LogbackUowConverter extends ClassicConverter {
+  def convert(event: ILoggingEvent): String = Trace.context().map(_.uow).getOrElse("undefined")
 }
-
-object GaugeGenerator extends GaugeGenerator