+ statsd: allow users to provide their own MetricKeyGenerator.

4 files changed, 20 insertions, 14 deletions

diff --git a/kamon-statsd/src/main/resources/reference.conf b/kamon-statsd/src/main/resources/reference.conf
index bd713f65..a10ac735 100644
--- a/kamon-statsd/src/main/resources/reference.conf
+++ b/kamon-statsd/src/main/resources/reference.conf
@@ -4,6 +4,7 @@
 
 kamon {
   statsd {
+
     # Hostname and port in which your StatsD is running. Remember that StatsD packets are sent using UDP and
     # setting unreachable hosts and/or not open ports wont be warned by the Kamon, your data wont go anywhere.
     hostname = "127.0.0.1"
@@ -29,6 +30,10 @@ kamon {
     # In order to not get a ClassNotFoundException, we must register the kamon-sytem-metrics module
     report-system-metrics = false
 
+    # FQCN of the implementation of `kamon.statsd.MetricKeyGenerator` to be instantiated and used for assigning
+    # metric names. The implementation must have a single parameter constructor accepting a `com.typesafe.config.Config`.
+    metric-key-generator = kamon.statsd.SimpleMetricKeyGenerator
+
     simple-metric-key-generator {
 
       # Application prefix for all metrics pushed to StatsD. The default namespacing scheme for metrics follows
diff --git a/kamon-statsd/src/main/scala/kamon/statsd/SimpleMetricKeyGenerator.scala b/kamon-statsd/src/main/scala/kamon/statsd/SimpleMetricKeyGenerator.scala
index f0bc6d64..28354423 100644
--- a/kamon-statsd/src/main/scala/kamon/statsd/SimpleMetricKeyGenerator.scala
+++ b/kamon-statsd/src/main/scala/kamon/statsd/SimpleMetricKeyGenerator.scala
@@ -6,7 +6,11 @@ import com.typesafe.config.Config
 import kamon.metric.UserMetrics.UserMetricGroup
 import kamon.metric.{ MetricIdentity, MetricGroupIdentity }
 
-class SimpleMetricKeyGenerator(config: Config) extends StatsD.MetricKeyGenerator {
+trait MetricKeyGenerator {
+  def generateKey(groupIdentity: MetricGroupIdentity, metricIdentity: MetricIdentity): String
+}
+
+class SimpleMetricKeyGenerator(config: Config) extends MetricKeyGenerator {
   type Normalizer = String ⇒ String
 
   val configSettings = config.getConfig("kamon.statsd.simple-metric-key-generator")
diff --git a/kamon-statsd/src/main/scala/kamon/statsd/StatsD.scala b/kamon-statsd/src/main/scala/kamon/statsd/StatsD.scala
index c8f647a8..e92cb546 100644
--- a/kamon-statsd/src/main/scala/kamon/statsd/StatsD.scala
+++ b/kamon-statsd/src/main/scala/kamon/statsd/StatsD.scala
@@ -24,7 +24,6 @@ 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
@@ -32,24 +31,22 @@ import java.util.concurrent.TimeUnit.MILLISECONDS
 object StatsD extends ExtensionId[StatsDExtension] with ExtensionIdProvider {
   override def lookup(): ExtensionId[_ <: Extension] = StatsD
   override def createExtension(system: ExtendedActorSystem): StatsDExtension = new StatsDExtension(system)
-
-  trait MetricKeyGenerator {
-    def generateKey(groupIdentity: MetricGroupIdentity, metricIdentity: MetricIdentity): String
-  }
 }
 
 class StatsDExtension(system: ExtendedActorSystem) extends Kamon.Extension {
   val log = Logging(system, classOf[StatsDExtension])
   log.info("Starting the Kamon(StatsD) extension")
 
-  private val statsDConfig = system.settings.config.getConfig("kamon.statsd")
+  private val config = system.settings.config
+  private val statsDConfig = config.getConfig("kamon.statsd")
 
+  val tickInterval = config.getDuration("kamon.metrics.tick-interval", MILLISECONDS)
   val statsDHost = new InetSocketAddress(statsDConfig.getString("hostname"), statsDConfig.getInt("port"))
   val flushInterval = statsDConfig.getDuration("flush-interval", MILLISECONDS)
   val maxPacketSizeInBytes = statsDConfig.getBytes("max-packet-size")
-  val tickInterval = system.settings.config.getDuration("kamon.metrics.tick-interval", MILLISECONDS)
+  val keyGeneratorFQCN = statsDConfig.getString("metric-key-generator")
 
-  val statsDMetricsListener = buildMetricsListener(tickInterval, flushInterval)
+  val statsDMetricsListener = buildMetricsListener(tickInterval, flushInterval, keyGeneratorFQCN, config)
 
   // Subscribe to all user metrics
   Kamon(Metrics)(system).subscribe(UserHistograms, "*", statsDMetricsListener, permanently = true)
@@ -89,14 +86,14 @@ class StatsDExtension(system: ExtendedActorSystem) extends Kamon.Extension {
     }
   }
 
-  def buildMetricsListener(tickInterval: Long, flushInterval: Long): ActorRef = {
+  def buildMetricsListener(tickInterval: Long, flushInterval: Long, keyGeneratorFQCN: String, config: Config): ActorRef = {
     assert(flushInterval >= tickInterval, "StatsD flush-interval needs to be equal or greater to the tick-interval")
-    val defaultMetricKeyGenerator = new SimpleMetricKeyGenerator(system.settings.config)
+    val keyGenerator = system.dynamicAccess.createInstanceFor[MetricKeyGenerator](keyGeneratorFQCN, (classOf[Config], config) :: Nil).get
 
     val metricsSender = system.actorOf(StatsDMetricsSender.props(
       statsDHost,
       maxPacketSizeInBytes,
-      defaultMetricKeyGenerator), "statsd-metrics-sender")
+      keyGenerator), "statsd-metrics-sender")
 
     if (flushInterval == tickInterval) {
       // No need to buffer the metrics, let's go straight to the metrics sender.
diff --git a/kamon-statsd/src/main/scala/kamon/statsd/StatsDMetricsSender.scala b/kamon-statsd/src/main/scala/kamon/statsd/StatsDMetricsSender.scala
index 8fbf4fee..2aac3a52 100644
--- a/kamon-statsd/src/main/scala/kamon/statsd/StatsDMetricsSender.scala
+++ b/kamon-statsd/src/main/scala/kamon/statsd/StatsDMetricsSender.scala
@@ -26,7 +26,7 @@ import java.util.Locale
 
 import kamon.metric.instrument.{ Counter, Histogram }
 
-class StatsDMetricsSender(remote: InetSocketAddress, maxPacketSizeInBytes: Long, metricKeyGenerator: StatsD.MetricKeyGenerator)
+class StatsDMetricsSender(remote: InetSocketAddress, maxPacketSizeInBytes: Long, metricKeyGenerator: MetricKeyGenerator)
     extends Actor with UdpExtensionProvider {
   import context.system
 
@@ -80,7 +80,7 @@ class StatsDMetricsSender(remote: InetSocketAddress, maxPacketSizeInBytes: Long,
 }
 
 object StatsDMetricsSender {
-  def props(remote: InetSocketAddress, maxPacketSize: Long, metricKeyGenerator: StatsD.MetricKeyGenerator): Props =
+  def props(remote: InetSocketAddress, maxPacketSize: Long, metricKeyGenerator: MetricKeyGenerator): Props =
     Props(new StatsDMetricsSender(remote, maxPacketSize, metricKeyGenerator))
 }