! statsd,datadog: reformat metric names to get a better display of automatically named traces, closes #35

After a bit of testing it seems like instead of  generating more friendly names by default, we need to do
changes that are specific to each module (StatsD and Datadog) in order to make it work properly. Here is
a list of the introduced changes:
  - StatsD
    - Change dots (.) to underscores (_) on the host name string.
    - Change ': ' to single underscore and spaced to underscore. Userful for automatically generated http
      trace names.
    - Change '/' to underscore. Ideally the dashboard could replace '_' with '/' to display it like a path.

  - Datadog
    - Change ': ' to ':'. Userful for automatically generated http trace names.

3 files changed, 21 insertions, 7 deletions

diff --git a/kamon-datadog/src/main/scala/kamon/datadog/Datadog.scala b/kamon-datadog/src/main/scala/kamon/datadog/Datadog.scala
index b4358ce7..1ae493f7 100644
--- a/kamon-datadog/src/main/scala/kamon/datadog/Datadog.scala
+++ b/kamon-datadog/src/main/scala/kamon/datadog/Datadog.scala
@@ -70,12 +70,12 @@ class DatadogExtension(system: ExtendedActorSystem) extends Kamon.Extension {
   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")
+    val metricsSender = 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
+      metricsSender
     } else {
-      system.actorOf(TickMetricSnapshotBuffer.props(flushInterval.toInt.millis, metricsTranslator), "datadog-metrics-buffer")
+      system.actorOf(TickMetricSnapshotBuffer.props(flushInterval.toInt.millis, metricsSender), "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
index 17e19d0b..0f67cc34 100644
--- a/kamon-datadog/src/main/scala/kamon/datadog/DatadogMetricsSender.scala
+++ b/kamon-datadog/src/main/scala/kamon/datadog/DatadogMetricsSender.scala
@@ -90,8 +90,11 @@ class DatadogMetricsSender(remote: InetSocketAddress, maxPacketSizeInBytes: Long
   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}"
+  def buildIdentificationTag(groupIdentity: MetricGroupIdentity, metricIdentity: MetricIdentity): String = {
+    // Make the automatic HTTP trace names a bit more friendly
+    val normalizedEntityName = groupIdentity.name.replace(": ", ":")
+    s"|#${groupIdentity.category.name}:${normalizedEntityName}"
+  }
 }
 
 object DatadogMetricsSender {
diff --git a/kamon-datadog/src/test/scala/kamon/datadog/DatadogMetricSenderSpec.scala b/kamon-datadog/src/test/scala/kamon/datadog/DatadogMetricSenderSpec.scala
index 91b503e2..713db30d 100644
--- a/kamon-datadog/src/test/scala/kamon/datadog/DatadogMetricSenderSpec.scala
+++ b/kamon-datadog/src/test/scala/kamon/datadog/DatadogMetricSenderSpec.scala
@@ -30,8 +30,19 @@ import java.net.InetSocketAddress
 import com.typesafe.config.ConfigFactory
 
 class DatadogMetricSenderSpec extends TestKitBase with WordSpecLike with Matchers {
-  implicit lazy val system = ActorSystem("datadog-metric-sender-spec",
-    ConfigFactory.parseString("kamon.datadog.max-packet-size = 256 bytes"))
+  implicit lazy val system: ActorSystem = ActorSystem("datadog-metric-sender-spec", ConfigFactory.parseString(
+    """
+      |kamon {
+      |  metrics {
+      |    disable-aspectj-weaver-missing-error = true
+      |  }
+      |
+      |  datadog {
+      |    max-packet-size = 256 bytes
+      |  }
+      |}
+      |
+    """.stripMargin))
 
   val collectionContext = Kamon(Metrics).buildDefaultCollectionContext