statsd.scala

package com.lookout.borderpatrol.example

import java.net.InetSocketAddress
import java.nio.ByteBuffer

import com.twitter.finagle.stats.{Counter, Gauge, Stat, StatsReceiver}
import java.nio.channels.DatagramChannel

import com.twitter.io.Buf

class StatsdStatReceiver(port: Int) extends StatsReceiver {
  private[this] val addr = new InetSocketAddress((port))
  private[this] val channel = DatagramChannel.open()

  override val repr: AnyRef = this

  def format(names: Seq[String], value: Long, term: String): String =
    s"${names.mkString(".")}:$value|$term"

  def buf(utf8: String): Buf =
    Buf.Utf8(utf8)

  def byteBuf(buf: Buf): ByteBuffer =
    Buf.ByteBuffer.Owned.extract(buf)

  def serialize(names: Seq[String], value: Long, term: String): ByteBuffer =
    byteBuf(buf(format(names, value, term)))

  def send(bytes: ByteBuffer): Unit =
    channel.send(bytes, addr)

  override def counter(name: String*): Counter = new Counter {
    override def incr(delta: Int): Unit =
      send(serialize(name, delta.toLong, "c"))
  }

  override def addGauge(name: String*)(f: => Float): Gauge = new Gauge {
    override def remove(): Unit =
      send(serialize(name, f.toLong, "g"))
  }

  override def stat(name: String*): Stat = new Stat {
    override def add(value: Float): Unit =
      send(serialize(name, value.toLong, "h"))
  }
}

@trane Thanks. This looks great!. However, we will be shipping metric to datadog ONLY when counter/gauge is updated. We do not have any control over how to send it over periodically (say every 1 minute). Perhaps we should take this and store it in MetricsRegistry (like finagle-metrics do) and ship it to datadog using some reporter. Let me try cooking something up and send it for your review.

@maheshkelkar not sure what we gain by waiting to send metrics other than a potential for losing metrics. could you explain the benefit?