WIP: added tests to play requests instrumentation

2 files changed, 97 insertions, 1 deletions

diff --git a/kamon-play/src/main/scala/kamon/play/Play.scala b/kamon-play/src/main/scala/kamon/play/Play.scala
index da8622c0..2e1f789f 100644
--- a/kamon-play/src/main/scala/kamon/play/Play.scala
+++ b/kamon-play/src/main/scala/kamon/play/Play.scala
@@ -25,6 +25,11 @@ object Play extends ExtensionId[PlayExtension] with ExtensionIdProvider {
 }
 
 class PlayExtension(private val system: ExtendedActorSystem) extends Kamon.Extension {
-  println("Play extension loaded")
+  publishInfoMessage(system, "Play Extension Loaded!!")
+
   private val config = system.settings.config.getConfig("kamon.play")
+
+  val includeTraceToken: Boolean = config.getBoolean("include-trace-token-header")
+  val traceTokenHeaderName: String = config.getString("trace-token-header-name")
 }
+
diff --git a/kamon-play/src/main/scala/kamon/play/instrumentation/RequestInstrumentation.scala b/kamon-play/src/main/scala/kamon/play/instrumentation/RequestInstrumentation.scala
new file mode 100644
index 00000000..a983cc17
--- /dev/null
+++ b/kamon-play/src/main/scala/kamon/play/instrumentation/RequestInstrumentation.scala
@@ -0,0 +1,91 @@
+/* ===================================================
+ * 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.play.instrumentation
+
+import org.aspectj.lang.annotation._
+import play.api.mvc._
+import kamon.trace.{ TraceRecorder, TraceContextAware }
+import kamon.Kamon
+import kamon.play.Play
+import akka.actor.ActorSystem
+import play.libs.Akka
+import scala.Some
+import org.aspectj.lang.ProceedingJoinPoint
+
+@Aspect
+class RequestInstrumentation {
+
+  @DeclareMixin("play.api.mvc.Request || play.api.mvc.WrappedRequest || play.api.test.FakeRequest")
+  def mixinContextAwareNewRequest: TraceContextAware = TraceContextAware.default
+
+  @Pointcut("execution(* play.api.GlobalSettings+.onStart(*)) && args(application)")
+  def onStart(application: play.api.Application): Unit = {}
+
+  @After("onStart(application)")
+  def afterApplicationStart(application: play.api.Application): Unit = {
+    Kamon(Play)(Akka.system())
+  }
+
+  @Pointcut("execution(* play.api.GlobalSettings+.onRouteRequest(*)) && args(request)")
+  def onRouteRequest(request: TraceContextAware): Unit = {}
+
+  @After("onRouteRequest(request)")
+  def afterRouteRequest(request: TraceContextAware): Unit = {
+    val system: ActorSystem = Akka.system()
+    val playExtension = Kamon(Play)(system)
+
+    val requestHeader: RequestHeader = request.asInstanceOf[RequestHeader]
+    val defaultTraceName: String = requestHeader.method + ": " + requestHeader.uri
+    val token = if (playExtension.includeTraceToken) {
+      requestHeader.headers.toSimpleMap.find(_._1 == playExtension.traceTokenHeaderName).map(_._2)
+    } else None
+
+    TraceRecorder.start(defaultTraceName, token)(system)
+
+    //Necessary to force initialization of traceContext when initiating the request.
+    request.traceContext
+  }
+
+  @Pointcut("execution(* play.api.GlobalSettings+.doFilter(*)) && args(next)")
+  def doFilter(next: EssentialAction): Unit = {}
+
+  @Around("doFilter(next)")
+  def afterDoFilter(pjp: ProceedingJoinPoint, next: EssentialAction): Any = {
+    Filters(pjp.proceed(Array(next)).asInstanceOf[EssentialAction], kamonRequestFilter)
+  }
+
+  private[this] val kamonRequestFilter = Filter { (nextFilter, requestHeader) ⇒
+    import scala.concurrent.ExecutionContext.Implicits.global
+
+    val incomingContext = TraceRecorder.currentContext
+
+    nextFilter(requestHeader).map { result ⇒
+      TraceRecorder.finish()
+
+      val simpleResult = incomingContext match {
+        case None ⇒ result
+        case Some(traceContext) ⇒ {
+          val playExtension = Kamon(Play)(traceContext.system)
+          if (playExtension.includeTraceToken) {
+            result.withHeaders(playExtension.traceTokenHeaderName -> traceContext.token)
+          } else result
+        }
+      }
+      simpleResult
+    }
+  }
+}