1 files changed, 136 insertions, 0 deletions
diff --git a/kamon-spray/src/main/scala/kamon/spray/instrumentation/ServerRequestInstrumentation.scala b/kamon-spray/src/main/scala/kamon/spray/instrumentation/ServerRequestInstrumentation.scala
new file mode 100644
index 00000000..73287132
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+++ b/kamon-spray/src/main/scala/kamon/spray/instrumentation/ServerRequestInstrumentation.scala
@@ -0,0 +1,136 @@
+/* ===================================================
+ * 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.server.instrumentation
+
+import kamon.trace.TraceLocal.{ HttpContext, HttpContextKey }
+import org.aspectj.lang.annotation._
+import kamon.trace._
+import akka.actor.ActorSystem
+import spray.can.server.OpenRequest
+import spray.http.{ HttpResponse, HttpMessagePartWrapper, HttpRequest }
+import kamon.Kamon
+import kamon.spray.{ SprayExtension, Spray }
+import org.aspectj.lang.ProceedingJoinPoint
+import spray.http.HttpHeaders.RawHeader
+
+@Aspect
+class ServerRequestInstrumentation {
+
+  import ServerRequestInstrumentation._
+
+  @DeclareMixin("spray.can.server.OpenRequestComponent.DefaultOpenRequest")
+  def mixinContextAwareToOpenRequest: TraceContextAware = TraceContextAware.default
+
+  @Pointcut("execution(spray.can.server.OpenRequestComponent$DefaultOpenRequest.new(..)) && this(openRequest) && args(*, request, *, *)")
+  def openRequestInit(openRequest: TraceContextAware, request: HttpRequest): Unit = {}
+
+  @After("openRequestInit(openRequest, request)")
+  def afterInit(openRequest: TraceContextAware, request: HttpRequest): Unit = {
+    val system: ActorSystem = openRequest.asInstanceOf[OpenRequest].context.actorContext.system
+    val tracer = Tracer.get(system)
+    val sprayExtension = Kamon(Spray)(system)
+
+    val defaultTraceName = sprayExtension.generateTraceName(request)
+    val token = if (sprayExtension.settings.includeTraceTokenHeader) {
+      request.headers.find(_.name == sprayExtension.settings.traceTokenHeaderName).map(_.value)
+    } else None
+
+    val newContext = token.map(customToken ⇒ tracer.newContext(defaultTraceName, customToken)) getOrElse (tracer.newContext(defaultTraceName))
+    TraceContext.setCurrentContext(newContext)
+
+    // Necessary to force initialization of traceContext when initiating the request.
+    openRequest.traceContext
+  }
+
+  @Pointcut("execution(* spray.can.server.ServerFrontend$$anon$2$$anon$1.spray$can$server$ServerFrontend$$anon$$anon$$openNewRequest(..))")
+  def openNewRequest(): Unit = {}
+
+  @After("openNewRequest()")
+  def afterOpenNewRequest(): Unit = {
+    TraceContext.clearCurrentContext
+  }
+
+  @Pointcut("execution(* spray.can.server.OpenRequestComponent$DefaultOpenRequest.handleResponseEndAndReturnNextOpenRequest(..)) && target(openRequest) && args(response)")
+  def openRequestCreation(openRequest: TraceContextAware, response: HttpMessagePartWrapper): Unit = {}
+
+  @Around("openRequestCreation(openRequest, response)")
+  def afterFinishingRequest(pjp: ProceedingJoinPoint, openRequest: TraceContextAware, response: HttpMessagePartWrapper): Any = {
+    val incomingContext = TraceContext.currentContext
+    val storedContext = openRequest.traceContext
+
+    // The stored context is always a DefaultTraceContext if the instrumentation is running
+    verifyTraceContextConsistency(incomingContext, storedContext)
+
+    if (incomingContext.isEmpty)
+      pjp.proceed()
+    else {
+      val sprayExtension = incomingContext.lookupExtension(Spray)
+
+      val proceedResult = if (sprayExtension.settings.includeTraceTokenHeader) {
+        val responseWithHeader = includeTraceTokenIfPossible(response, sprayExtension.settings.traceTokenHeaderName, incomingContext.token)
+        pjp.proceed(Array(openRequest, responseWithHeader))
+
+      } else pjp.proceed
+
+      TraceContext.currentContext.finish()
+
+      recordHttpServerMetrics(response, incomingContext.name, sprayExtension)
+
+      //store in TraceLocal useful data to diagnose errors
+      storeDiagnosticData(openRequest)
+
+      proceedResult
+    }
+  }
+
+  def verifyTraceContextConsistency(incomingTraceContext: TraceContext, storedTraceContext: TraceContext): Unit = {
+    def publishWarning(text: String): Unit =
+      storedTraceContext.lookupExtension(Spray).log.warning(text)
+
+    if (incomingTraceContext.nonEmpty) {
+      if (incomingTraceContext.token != storedTraceContext.token)
+        publishWarning(s"Different trace token found when trying to close a trace, original: [${storedTraceContext.token}] - incoming: [${incomingTraceContext.token}]")
+    } else
+      publishWarning(s"EmptyTraceContext present while closing the trace with token [${storedTraceContext.token}]")
+  }
+
+  def recordHttpServerMetrics(response: HttpMessagePartWrapper, traceName: String, sprayExtension: SprayExtension): Unit =
+    response match {
+      case httpResponse: HttpResponse ⇒ sprayExtension.httpServerMetrics.recordResponse(traceName, httpResponse.status.intValue.toString)
+      case other                      ⇒ // Nothing to do then.
+    }
+
+  def includeTraceTokenIfPossible(response: HttpMessagePartWrapper, traceTokenHeaderName: String, token: String): HttpMessagePartWrapper =
+    response match {
+      case response: HttpResponse ⇒ response.withHeaders(response.headers ::: RawHeader(traceTokenHeaderName, token) :: Nil)
+      case other                  ⇒ other
+    }
+
+  def storeDiagnosticData(currentContext: TraceContextAware): Unit = {
+    val request = currentContext.asInstanceOf[OpenRequest].request
+    val headers = request.headers.map(header ⇒ header.name -> header.value).toMap
+    val agent = headers.getOrElse(UserAgent, Unknown)
+    val forwarded = headers.getOrElse(XForwardedFor, Unknown)
+
+    TraceLocal.store(HttpContextKey)(HttpContext(agent, request.uri.toRelative.toString(), forwarded))
+  }
+}
+
+object ServerRequestInstrumentation {
+  val UserAgent = "User-Agent"
+  val XForwardedFor = "X-Forwarded-For"
+  val Unknown = "unknown"
+}