/*
* =========================================================================================
* 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.statsd
import akka.actor.{ ActorSystem, Props, ActorRef, Actor }
import akka.io.{ Udp, IO }
import java.net.InetSocketAddress
import akka.util.ByteString
import kamon.Kamon
import kamon.metrics.Subscriptions.TickMetricSnapshot
import kamon.metrics.MetricSnapshot.Measurement
import kamon.metrics.InstrumentTypes.{ Counter, Gauge, Histogram, InstrumentType }
import java.text.DecimalFormat
class StatsDMetricsSender(remote: InetSocketAddress, maxPacketSize: Int) extends Actor with UdpExtensionProvider {
import context.system
val metricKeyGenerator = new SimpleMetricKeyGenerator(context.system.settings.config)
val samplingRateFormat = new DecimalFormat()
samplingRateFormat.setMaximumFractionDigits(128) // Absurdly high, let the other end loss precision if it needs to.
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(maxPacketSize, udpSender, remote)
for (
(groupIdentity, groupSnapshot) ← tick.metrics;
(metricIdentity, metricSnapshot) ← groupSnapshot.metrics
) {
val key = ByteString(metricKeyGenerator.generateKey(groupIdentity, metricIdentity))
for (measurement ← metricSnapshot.measurements) {
val measurementData = encodeMeasurement(measurement, metricSnapshot.instrumentType)
dataBuilder.appendMeasurement(key, measurementData)
}
}
dataBuilder.flush()
}
def encodeMeasurement(measurement: Measurement, instrumentType: InstrumentType): ByteString = {
def statsDMetricFormat(value: String, metricType: String, samplingRate: Double = 1D): ByteString =
ByteString(value + "|" + metricType + (if (samplingRate != 1D) "|@" + samplingRateFormat.format(samplingRate) else ""))
instrumentType match {
case Histogram ⇒ statsDMetricFormat(measurement.value.toString, "ms", (1D / measurement.count))
case Gauge ⇒ statsDMetricFormat(measurement.value.toString, "g")
case Counter ⇒ ByteString.empty // TODO: Need to decide how to report counters, when we have them!
}
}
}
object StatsDMetricsSender {
def props(remote: InetSocketAddress, maxPacketSize: Int): Props = Props(new StatsDMetricsSender(remote, maxPacketSize))
}
trait UdpExtensionProvider {
def udpExtension(implicit system: ActorSystem): ActorRef = IO(Udp)
}
class MetricDataPacketBuilder(maxPacketSize: Int, udpSender: ActorRef, remote: InetSocketAddress) {
val metricSeparator = ByteString("\n")
val measurementSeparator = ByteString(":")
var lastKey = ByteString.empty
var buffer = ByteString.empty
def appendMeasurement(key: ByteString, measurementData: ByteString): Unit = {
if (key == lastKey) {
val dataWithoutKey = measurementSeparator ++ measurementData
if (fitsOnBuffer(dataWithoutKey))
buffer = buffer ++ dataWithoutKey
else {
flushToUDP(buffer)
buffer = key ++ dataWithoutKey
}
} else {
lastKey = key
val dataWithoutSeparator = key ++ measurementSeparator ++ measurementData
if (fitsOnBuffer(metricSeparator ++ dataWithoutSeparator)) {
val mSeparator = if (buffer.length > 0) metricSeparator else ByteString.empty
buffer = buffer ++ mSeparator ++ dataWithoutSeparator
} else {
flushToUDP(buffer)
buffer = dataWithoutSeparator
}
}
}
def fitsOnBuffer(bs: ByteString): Boolean = (buffer.length + bs.length) <= maxPacketSize
private def flushToUDP(bytes: ByteString): Unit = udpSender ! Udp.Send(bytes, remote)
def flush(): Unit = {
flushToUDP(buffer)
buffer = ByteString.empty
}
}