1 files changed, 88 insertions, 0 deletions
diff --git a/kamon-spray/src/main/scala/spray/can/client/ClientRequestTracing.scala b/kamon-spray/src/main/scala/spray/can/client/ClientRequestTracing.scala
new file mode 100644
index 00000000..b081bf00
--- /dev/null
+++ b/kamon-spray/src/main/scala/spray/can/client/ClientRequestTracing.scala
@@ -0,0 +1,88 @@
+/* ===================================================
+ * 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 spray.can.client
+
+import org.aspectj.lang.annotation._
+import org.aspectj.lang.ProceedingJoinPoint
+import spray.http.{HttpMessageEnd, HttpRequest}
+import spray.http.HttpHeaders.Host
+import kamon.trace.{TraceContext, Trace, Segments}
+import kamon.trace.Segments.{ContextAndSegmentCompletionAware, HttpClientRequest}
+import kamon.trace.Trace.SegmentCompletionHandle
+
+@Aspect
+class ClientRequestTracing {
+
+  @DeclareMixin("spray.can.client.HttpHostConnector.RequestContext")
+  def mixin: ContextAndSegmentCompletionAware = new ContextAndSegmentCompletionAware {
+    val traceContext: Option[TraceContext] = Trace.context()
+    var completionHandle: Option[SegmentCompletionHandle] = None
+  }
+
+
+  @Pointcut("execution(spray.can.client.HttpHostConnector.RequestContext.new(..)) && this(ctx) && args(request, *, *, *)")
+  def requestContextCreation(ctx: ContextAndSegmentCompletionAware, request: HttpRequest): Unit = {}
+
+  @After("requestContextCreation(ctx, request)")
+  def afterRequestContextCreation(ctx: ContextAndSegmentCompletionAware, request: HttpRequest): Unit = {
+    // The RequestContext will be copied when a request needs to be retried but we are only interested in creating the
+    // completion handle the first time we create one.
+
+    // The read to ctx.completionHandle should take care of initializing the aspect timely.
+    if(ctx.completionHandle.isEmpty) {
+      val requestAttributes = Map[String, String](
+        "host" -> request.header[Host].map(_.value).getOrElse("unknown"),
+        "path" -> request.uri.path.toString(),
+        "method" -> request.method.toString()
+      )
+      val completionHandle = Trace.startSegment(category = HttpClientRequest, attributes = requestAttributes)
+      ctx.completionHandle = Some(completionHandle)
+    }
+  }
+
+
+  @Pointcut("execution(* spray.can.client.HttpHostConnector.RequestContext.copy(..)) && this(old)")
+  def copyingRequestContext(old: ContextAndSegmentCompletionAware): Unit = {}
+
+  @Around("copyingRequestContext(old)")
+  def aroundCopyingRequestContext(pjp: ProceedingJoinPoint, old: ContextAndSegmentCompletionAware) = {
+    Trace.withContext(old.traceContext) {
+      pjp.proceed()
+    }
+  }
+
+
+  @Pointcut("execution(* spray.can.client.HttpHostConnectionSlot.dispatchToCommander(..)) && args(requestContext, message)")
+  def dispatchToCommander(requestContext: ContextAndSegmentCompletionAware, message: Any): Unit = {}
+
+  @Around("dispatchToCommander(requestContext, message)")
+  def aroundDispatchToCommander(pjp: ProceedingJoinPoint, requestContext: ContextAndSegmentCompletionAware, message: Any) = {
+    requestContext.traceContext match {
+      case ctx @ Some(_) =>
+        Trace.withContext(ctx) {
+          if(message.isInstanceOf[HttpMessageEnd])
+            requestContext.completionHandle.map(_.complete(Segments.End()))
+
+          pjp.proceed()
+        }
+
+      case None => pjp.proceed()
+    }
+  }
+
+
+}
+\ No newline at end of file