Merge branch 'master' into release-0.2

Conflicts:
	kamon-play/src/test/scala/kamon/play/WSInstrumentationSpec.scala
	kamon-statsd/src/main/scala/kamon/statsd/StatsD.scala
	project/Dependencies.scala
	project/Projects.scala
	version.sbt

2 files changed, 213 insertions, 0 deletions

diff --git a/kamon-datadog/src/main/scala/kamon/datadog/Datadog.scala b/kamon-datadog/src/main/scala/kamon/datadog/Datadog.scala
new file mode 100644
index 00000000..15d5d3fe
--- /dev/null
+++ b/kamon-datadog/src/main/scala/kamon/datadog/Datadog.scala
@@ -0,0 +1,82 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013-2014 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.datadog
+
+import akka.actor._
+import kamon.Kamon
+import kamon.metrics._
+import scala.concurrent.duration._
+import scala.collection.JavaConverters._
+import com.typesafe.config.Config
+import java.lang.management.ManagementFactory
+import akka.event.Logging
+import java.net.InetSocketAddress
+import java.util.concurrent.TimeUnit.MILLISECONDS
+
+object Datadog extends ExtensionId[DatadogExtension] with ExtensionIdProvider {
+  override def lookup(): ExtensionId[_ <: Extension] = Datadog
+  override def createExtension(system: ExtendedActorSystem): DatadogExtension = new DatadogExtension(system)
+
+  trait MetricKeyGenerator {
+    def generateKey(groupIdentity: MetricGroupIdentity, metricIdentity: MetricIdentity): String
+  }
+}
+
+class DatadogExtension(system: ExtendedActorSystem) extends Kamon.Extension {
+  val log = Logging(system, classOf[DatadogExtension])
+  log.info("Starting the Kamon(Datadog) extension")
+
+  private val datadogConfig = system.settings.config.getConfig("kamon.datadog")
+
+  val datadogHost = new InetSocketAddress(datadogConfig.getString("hostname"), datadogConfig.getInt("port"))
+  val flushInterval = datadogConfig.getDuration("flush-interval", MILLISECONDS)
+  val maxPacketSizeInBytes = datadogConfig.getBytes("max-packet-size")
+  val tickInterval = system.settings.config.getDuration("kamon.metrics.tick-interval", MILLISECONDS)
+
+  val datadogMetricsListener = buildMetricsListener(tickInterval, flushInterval)
+
+  // Subscribe to Actors
+  val includedActors = datadogConfig.getStringList("includes.actor").asScala
+  for (actorPathPattern ← includedActors) {
+    Kamon(Metrics)(system).subscribe(ActorMetrics, actorPathPattern, datadogMetricsListener, permanently = true)
+  }
+
+  // Subscribe to Traces
+  val includedTraces = datadogConfig.getStringList("includes.trace").asScala
+  for (tracePathPattern ← includedTraces) {
+    Kamon(Metrics)(system).subscribe(TraceMetrics, tracePathPattern, datadogMetricsListener, permanently = true)
+  }
+
+  // Subscribe to Dispatchers
+  val includedDispatchers = datadogConfig.getStringList("includes.dispatcher").asScala
+  for (dispatcherPathPattern ← includedDispatchers) {
+    Kamon(Metrics)(system).subscribe(DispatcherMetrics, dispatcherPathPattern, datadogMetricsListener, permanently = true)
+  }
+
+  def buildMetricsListener(tickInterval: Long, flushInterval: Long): ActorRef = {
+    assert(flushInterval >= tickInterval, "Datadog flush-interval needs to be equal or greater to the tick-interval")
+
+    val metricsTranslator = system.actorOf(DatadogMetricsSender.props(datadogHost, maxPacketSizeInBytes), "datadog-metrics-sender")
+    if (flushInterval == tickInterval) {
+      // No need to buffer the metrics, let's go straight to the metrics sender.
+      metricsTranslator
+    } else {
+      system.actorOf(TickMetricSnapshotBuffer.props(flushInterval.toInt.millis, metricsTranslator), "datadog-metrics-buffer")
+    }
+  }
+}
+
diff --git a/kamon-datadog/src/main/scala/kamon/datadog/DatadogMetricsSender.scala b/kamon-datadog/src/main/scala/kamon/datadog/DatadogMetricsSender.scala
new file mode 100644
index 00000000..028e9608
--- /dev/null
+++ b/kamon-datadog/src/main/scala/kamon/datadog/DatadogMetricsSender.scala
@@ -0,0 +1,131 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013-2014 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.datadog
+
+import akka.actor.{ ActorSystem, Props, ActorRef, Actor }
+import akka.io.{ Udp, IO }
+import java.net.InetSocketAddress
+import akka.util.ByteString
+import kamon.metrics.Subscriptions.TickMetricSnapshot
+import kamon.metrics.MetricSnapshot.Measurement
+import kamon.metrics.InstrumentTypes.{ Counter, Gauge, Histogram, InstrumentType }
+import java.text.{ DecimalFormatSymbols, DecimalFormat }
+import kamon.metrics.{ MetricIdentity, MetricGroupIdentity }
+import java.util.Locale
+
+class DatadogMetricsSender(remote: InetSocketAddress, maxPacketSizeInBytes: Long) extends Actor with UdpExtensionProvider {
+
+  import context.system
+
+  val appName = context.system.settings.config.getString("kamon.datadog.application-name")
+  val symbols = DecimalFormatSymbols.getInstance(Locale.US)
+  symbols.setDecimalSeparator('.') // Just in case there is some weird locale config we are not aware of.
+
+  // Absurdly high number of decimal digits, let the other end lose precision if it needs to.
+  val samplingRateFormat = new DecimalFormat("#.################################################################", symbols)
+
+  udpExtension ! Udp.SimpleSender
+
+  def receive = {
+    case Udp.SimpleSenderReady ⇒
+      context.become(ready(sender))
+  }
+
+  def ready(udpSender: ActorRef): Receive = {
+    case tick: TickMetricSnapshot ⇒ writeMetricsToRemote(tick, udpSender)
+  }
+
+  def writeMetricsToRemote(tick: TickMetricSnapshot, udpSender: ActorRef): Unit = {
+    val dataBuilder = new MetricDataPacketBuilder(maxPacketSizeInBytes, udpSender, remote)
+
+    for {
+      (groupIdentity, groupSnapshot) ← tick.metrics
+      (metricIdentity, metricSnapshot) ← groupSnapshot.metrics
+    } {
+
+      val key = buildMetricName(groupIdentity, metricIdentity)
+
+      for (measurement ← metricSnapshot.measurements) {
+        val measurementData = formatMeasurement(groupIdentity, metricIdentity, measurement, metricSnapshot.instrumentType)
+        dataBuilder.appendMeasurement(key, measurementData)
+      }
+    }
+    dataBuilder.flush()
+  }
+
+  def formatMeasurement(groupIdentity: MetricGroupIdentity, metricIdentity: MetricIdentity, measurement: Measurement,
+                        instrumentType: InstrumentType): String = {
+
+    StringBuilder.newBuilder.append(buildMeasurementData(measurement, instrumentType))
+      .append(buildIdentificationTag(groupIdentity, metricIdentity))
+      .result()
+  }
+
+  def buildMeasurementData(measurement: Measurement, instrumentType: InstrumentType): String = {
+    def dataDogDMetricFormat(value: String, metricType: String, samplingRate: Double = 1D): String =
+      s"$value|$metricType${(if (samplingRate != 1D) "|@" + samplingRateFormat.format(samplingRate) else "")}"
+
+    instrumentType match {
+      case Histogram ⇒ dataDogDMetricFormat(measurement.value.toString, "ms", (1D / measurement.count))
+      case Gauge     ⇒ dataDogDMetricFormat(measurement.value.toString, "g")
+      case Counter   ⇒ dataDogDMetricFormat(measurement.count.toString, "c")
+    }
+  }
+
+  def buildMetricName(groupIdentity: MetricGroupIdentity, metricIdentity: MetricIdentity): String =
+    s"$appName.${groupIdentity.category.name}.${metricIdentity.name}"
+
+  def buildIdentificationTag(groupIdentity: MetricGroupIdentity, metricIdentity: MetricIdentity): String =
+    s"|#${groupIdentity.category.name}:${groupIdentity.name}"
+}
+
+object DatadogMetricsSender {
+  def props(remote: InetSocketAddress, maxPacketSize: Long): Props = Props(new DatadogMetricsSender(remote, maxPacketSize))
+}
+
+trait UdpExtensionProvider {
+  def udpExtension(implicit system: ActorSystem): ActorRef = IO(Udp)
+}
+
+class MetricDataPacketBuilder(maxPacketSizeInBytes: Long, udpSender: ActorRef, remote: InetSocketAddress) {
+  val metricSeparator = "\n"
+  val measurementSeparator = ":"
+  var lastKey = ""
+  var buffer = new StringBuilder()
+
+  def appendMeasurement(key: String, measurementData: String): Unit = {
+    val data = key + measurementSeparator + measurementData
+
+    if (fitsOnBuffer(metricSeparator + data)) {
+      val mSeparator = if (buffer.length > 0) metricSeparator else ""
+      buffer.append(mSeparator).append(data)
+    } else {
+      flushToUDP(buffer.toString())
+      buffer.clear()
+      buffer.append(data)
+    }
+  }
+
+  def fitsOnBuffer(data: String): Boolean = (buffer.length + data.length) <= maxPacketSizeInBytes
+
+  private def flushToUDP(data: String): Unit = udpSender ! Udp.Send(ByteString(data), remote)
+
+  def flush(): Unit = {
+    flushToUDP(buffer.toString)
+    buffer.clear()
+  }
+}