instrument akka testkit to correctly propagate TraceContexts when replying from a test probe

2 files changed, 67 insertions, 0 deletions

diff --git a/kamon-testkit/src/main/resources/META-INF/aop.xml b/kamon-testkit/src/main/resources/META-INF/aop.xml
new file mode 100644
index 00000000..8c5cfe42
--- /dev/null
+++ b/kamon-testkit/src/main/resources/META-INF/aop.xml
@@ -0,0 +1,13 @@
+<!DOCTYPE aspectj PUBLIC "-//AspectJ//DTD//EN" "http://www.eclipse.org/aspectj/dtd/aspectj.dtd">
+
+<aspectj>
+    <aspects>
+        <!-- TestKit -->
+        <aspect name="akka.testkit.TestProbeInstrumentation"/>
+    </aspects>
+
+    <weaver options="-verbose -showWeaveInfo">
+        <include within="akka..*"/>
+    </weaver>
+
+</aspectj>
\ No newline at end of file
diff --git a/kamon-testkit/src/main/scala/testkit/TestProbeInstrumentation.scala b/kamon-testkit/src/main/scala/testkit/TestProbeInstrumentation.scala
new file mode 100644
index 00000000..de867035
--- /dev/null
+++ b/kamon-testkit/src/main/scala/testkit/TestProbeInstrumentation.scala
@@ -0,0 +1,54 @@
+/*
+ * =========================================================================================
+ * Copyright © 2013 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 akka.testkit
+
+import org.aspectj.lang.annotation._
+import kamon.trace.{ TraceContextAware, TraceRecorder }
+import org.aspectj.lang.ProceedingJoinPoint
+import akka.testkit.TestActor.RealMessage
+
+@Aspect
+class TestProbeInstrumentation {
+
+  @DeclareMixin("akka.testkit.TestActor.RealMessage")
+  def mixin: TraceContextAware = TraceContextAware.default
+
+  @Pointcut("execution(akka.testkit.TestActor.RealMessage.new(..)) && this(ctx)")
+  def realMessageCreation(ctx: TraceContextAware): Unit = {}
+
+  @After("realMessageCreation(ctx)")
+  def afterRealMessageCreation(ctx: TraceContextAware): Unit = {
+    // Necessary to force the initialization of ContextAware at the moment of creation.
+    ctx.traceContext
+  }
+
+  @Pointcut("execution(* akka.testkit.TestProbe.reply(..)) && this(testProbe)")
+  def testProbeReply(testProbe: TestProbe): Unit = {}
+
+  @Around("testProbeReply(testProbe)")
+  def aroundTestProbeReply(pjp: ProceedingJoinPoint, testProbe: TestProbe): Any = {
+    val traceContext = testProbe.lastMessage match {
+      case msg: RealMessage ⇒ msg.asInstanceOf[TraceContextAware].traceContext
+      case _                ⇒ None
+    }
+
+    TraceRecorder.withTraceContext(traceContext) {
+      pjp.proceed
+    }
+  }
+
+}