+ play: create and configure a default trace name generator for Play apps and closes #190

4 files changed, 31 insertions, 35 deletions

diff --git a/kamon-play/src/main/resources/reference.conf b/kamon-play/src/main/resources/reference.conf
index 7f6e651f..af43edec 100644
--- a/kamon-play/src/main/resources/reference.conf
+++ b/kamon-play/src/main/resources/reference.conf
@@ -17,7 +17,7 @@ kamon {
     #    in the request headers.
     automatic-trace-token-propagation = true
 
-    # Fully qualified name of the implementation of kamon.play.PlayNameGenerator that will be used for assigning names
+    # Fully qualified name of the implementation of kamon.play.NameGenerator that will be used for assigning names
     # to traces and client http segments.
     name-generator = kamon.play.DefaultNameGenerator
 
diff --git a/kamon-play/src/main/scala/kamon/play/Play.scala b/kamon-play/src/main/scala/kamon/play/Play.scala
index 072ea436..d9fdfea8 100644
--- a/kamon-play/src/main/scala/kamon/play/Play.scala
+++ b/kamon-play/src/main/scala/kamon/play/Play.scala
@@ -20,7 +20,6 @@ import akka.actor.{ ExtendedActorSystem, Extension, ExtensionId, ExtensionIdProv
 import akka.event.Logging
 import kamon.Kamon
 import kamon.http.HttpServerMetrics
-import kamon.metric.Entity
 import play.api.libs.ws.WSRequest
 import play.api.mvc.RequestHeader
 
@@ -54,6 +53,29 @@ trait NameGenerator {
 }
 
 class DefaultNameGenerator extends NameGenerator {
-  def generateTraceName(requestHeader: RequestHeader): String = s"${requestHeader.method}: ${requestHeader.uri}"
+  import scala.collection.concurrent.TrieMap
+  import play.api.Routes
+  import java.util.Locale
+  import kamon.util.TriemapAtomicGetOrElseUpdate.Syntax
+
+  private val cache = TrieMap.empty[String, String]
+  private val normalizePattern = """\$([^<]+)<[^>]+>""".r
+
+  def generateTraceName(requestHeader: RequestHeader): String = requestHeader.tags.get(Routes.ROUTE_VERB).map { verb ⇒
+    val path = requestHeader.tags(Routes.ROUTE_PATTERN)
+    cache.atomicGetOrElseUpdate(s"$verb$path", {
+      val traceName = {
+        // Convert paths of form GET /foo/bar/$paramname<regexp>/blah to foo.bar.paramname.blah.get
+        val p = normalizePattern.replaceAllIn(path, "$1").replace('/', '.').dropWhile(_ == '.')
+        val normalisedPath = {
+          if (p.lastOption.filter(_ != '.').isDefined) s"$p."
+          else p
+        }
+        s"$normalisedPath${verb.toLowerCase(Locale.ENGLISH)}"
+      }
+      traceName
+    })
+  } getOrElse s"${requestHeader.method}: ${requestHeader.uri}"
+
   def generateHttpClientSegmentName(request: WSRequest): String = request.url
 }
diff --git a/kamon-play/src/main/scala/kamon/play/instrumentation/RequestInstrumentation.scala b/kamon-play/src/main/scala/kamon/play/instrumentation/RequestInstrumentation.scala
index 200fe135..7dcb7913 100644
--- a/kamon-play/src/main/scala/kamon/play/instrumentation/RequestInstrumentation.scala
+++ b/kamon-play/src/main/scala/kamon/play/instrumentation/RequestInstrumentation.scala
@@ -1,5 +1,5 @@
 /* =========================================================================================
- * Copyright © 2013-2014 the kamon project <http://kamon.io/>
+ * Copyright © 2013-2015 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
@@ -17,12 +17,11 @@ package kamon.play.instrumentation
 
 import kamon.Kamon
 import kamon.play.Play
-import kamon.trace.TraceLocal.{ HttpContextKey, HttpContext }
+import kamon.trace.TraceLocal.{ HttpContext, HttpContextKey }
 import kamon.trace._
 import kamon.util.SameThreadExecutionContext
 import org.aspectj.lang.ProceedingJoinPoint
 import org.aspectj.lang.annotation._
-import play.api.Routes
 import play.api.mvc.Results._
 import play.api.mvc._
 
@@ -40,13 +39,11 @@ class RequestInstrumentation {
 
     val playExtension = Kamon(Play)
 
-    val defaultTraceName = playExtension.generateTraceName(requestHeader)
     val token = if (playExtension.includeTraceToken) {
-      requestHeader.headers.toSimpleMap.find(_._1 == playExtension.traceTokenHeaderName).map(_._2)
+      requestHeader.headers.get(playExtension.traceTokenHeaderName)
     } else None
 
-    val newContext = tracer.newContext(defaultTraceName, token)
-    Tracer.setCurrentContext(newContext)
+    Tracer.setCurrentContext(tracer.newContext("UnnamedTrace", token))
   }
 
   @Around("call(* play.api.GlobalSettings.doFilter(*)) && args(next)")
@@ -70,7 +67,7 @@ class RequestInstrumentation {
       storeDiagnosticData(requestHeader)
 
       //override the current trace name
-      normaliseTraceName(requestHeader).map(Tracer.currentContext.rename)
+      Tracer.currentContext.rename(playExtension.generateTraceName(requestHeader))
 
       // Invoke the action
       next(requestHeader).map(onResult)(SameThreadExecutionContext)
@@ -98,31 +95,7 @@ class RequestInstrumentation {
 }
 
 object RequestInstrumentation {
-  import kamon.util.TriemapAtomicGetOrElseUpdate.Syntax
-  import java.util.Locale
-  import scala.collection.concurrent.TrieMap
-
   val UserAgent = "User-Agent"
   val XForwardedFor = "X-Forwarded-For"
   val Unknown = "unknown"
-
-  private val cache = TrieMap.empty[String, String]
-
-  private val normalizePattern = """\$([^<]+)<[^>]+>""".r
-
-  def normaliseTraceName(requestHeader: RequestHeader): Option[String] = requestHeader.tags.get(Routes.ROUTE_VERB).map({ verb ⇒
-    val path = requestHeader.tags(Routes.ROUTE_PATTERN)
-    cache.atomicGetOrElseUpdate(s"$verb$path", {
-      val traceName = {
-        // Convert paths of form GET /foo/bar/$paramname<regexp>/blah to foo.bar.paramname.blah.get
-        val p = normalizePattern.replaceAllIn(path, "$1").replace('/', '.').dropWhile(_ == '.')
-        val normalisedPath = {
-          if (p.lastOption.filter(_ != '.').isDefined) s"$p."
-          else p
-        }
-        s"$normalisedPath${verb.toLowerCase(Locale.ENGLISH)}"
-      }
-      traceName
-    })
-  })
 }
diff --git a/kamon-play/src/test/resources/conf/application.conf b/kamon-play/src/test/resources/conf/application.conf
index b214edc0..b927087c 100644
--- a/kamon-play/src/test/resources/conf/application.conf
+++ b/kamon-play/src/test/resources/conf/application.conf
@@ -2,6 +2,7 @@ kamon {
     play {
       include-trace-token-header = true
       trace-token-header-name = "X-Trace-Token"
+      name-generator = kamon.play.DefaultNameGenerator
     }
 }