+ core,spray: create and implement http server metrics for spray, related to #56

2 files changed, 17 insertions, 6 deletions

diff --git a/kamon-spray/src/main/scala/kamon/spray/Spray.scala b/kamon-spray/src/main/scala/kamon/spray/Spray.scala
index 9de1882a..76adb214 100644
--- a/kamon-spray/src/main/scala/kamon/spray/Spray.scala
+++ b/kamon-spray/src/main/scala/kamon/spray/Spray.scala
@@ -19,6 +19,8 @@ package kamon.spray
 import akka.actor.{ ExtendedActorSystem, ExtensionIdProvider, ExtensionId }
 import akka.actor
 import kamon.Kamon
+import kamon.http.HttpServerMetrics
+import kamon.metric.Metrics
 import spray.http.HttpRequest
 
 object Spray extends ExtensionId[SprayExtension] with ExtensionIdProvider {
@@ -38,6 +40,8 @@ class SprayExtension(private val system: ExtendedActorSystem) extends Kamon.Exte
 
   val includeTraceToken: Boolean = config.getBoolean("automatic-trace-token-propagation")
   val traceTokenHeaderName: String = config.getString("trace-token-header-name")
+  val httpServerMetrics = Kamon(Metrics)(system).register(HttpServerMetrics, HttpServerMetrics.Factory).get
+  // It's safe to assume that HttpServerMetrics will always exist because there is no particular filter for it.
 
   val clientSegmentCollectionStrategy: ClientSegmentCollectionStrategy.Strategy =
     config.getString("client.segment-collection-strategy") match {
diff --git a/kamon-spray/src/main/scala/spray/can/server/ServerRequestInstrumentation.scala b/kamon-spray/src/main/scala/spray/can/server/ServerRequestInstrumentation.scala
index 85782e22..69b0160e 100644
--- a/kamon-spray/src/main/scala/spray/can/server/ServerRequestInstrumentation.scala
+++ b/kamon-spray/src/main/scala/spray/can/server/ServerRequestInstrumentation.scala
@@ -22,7 +22,7 @@ import spray.http.{ HttpResponse, HttpMessagePartWrapper, HttpRequest }
 import akka.event.Logging.Warning
 import scala.Some
 import kamon.Kamon
-import kamon.spray.Spray
+import kamon.spray.{ SprayExtension, Spray }
 import org.aspectj.lang.ProceedingJoinPoint
 import spray.http.HttpHeaders.RawHeader
 
@@ -68,20 +68,21 @@ class ServerRequestInstrumentation {
     val storedContext = openRequest.traceContext
 
     verifyTraceContextConsistency(incomingContext, storedContext)
-    val proceedResult = incomingContext match {
+    incomingContext match {
       case None ⇒ pjp.proceed()
       case Some(traceContext) ⇒
         val sprayExtension = Kamon(Spray)(traceContext.system)
 
-        if (sprayExtension.includeTraceToken) {
+        val proceedResult = if (sprayExtension.includeTraceToken) {
           val responseWithHeader = includeTraceTokenIfPossible(response, sprayExtension.traceTokenHeaderName, traceContext.token)
           pjp.proceed(Array(openRequest, responseWithHeader))
 
         } else pjp.proceed
-    }
 
-    TraceRecorder.finish()
-    proceedResult
+        TraceRecorder.finish()
+        recordHttpServerMetrics(response, traceContext.name, sprayExtension)
+        proceedResult
+    }
   }
 
   def verifyTraceContextConsistency(incomingTraceContext: Option[TraceContext], storedTraceContext: Option[TraceContext]): Unit = {
@@ -102,6 +103,12 @@ class ServerRequestInstrumentation {
 
   }
 
+  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)