1 files changed, 81 insertions, 0 deletions
diff --git a/kamon-newrelic/src/main/scala/kamon/newrelic/WebTransactionMetricExtractor.scala b/kamon-newrelic/src/main/scala/kamon/newrelic/WebTransactionMetricExtractor.scala
new file mode 100644
index 00000000..cfb0e721
--- /dev/null
+++ b/kamon-newrelic/src/main/scala/kamon/newrelic/WebTransactionMetricExtractor.scala
@@ -0,0 +1,81 @@
+/*
+ * =========================================================================================
+ * 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 kamon.newrelic
+
+import kamon.metric._
+import kamon.metric.TraceMetrics.ElapsedTime
+import kamon.metric.instrument.Histogram
+import kamon.trace.SegmentMetricIdentityLabel.HttpClient
+import kamon.trace.SegmentMetricIdentity
+
+object WebTransactionMetricExtractor extends MetricExtractor {
+
+  def extract(settings: Agent.Settings, collectionContext: CollectionContext, metrics: Map[MetricGroupIdentity, MetricGroupSnapshot]): Map[MetricID, MetricData] = {
+    val apdexBuilder = new ApdexBuilder("Apdex", None, settings.apdexT)
+
+    // Trace metrics are recorded in nanoseconds.
+    var accumulatedHttpDispatcher: Histogram.Snapshot = Histogram.Snapshot.empty(Scale.Nano)
+    var accumulatedExternalServices: Histogram.Snapshot = Histogram.Snapshot.empty(Scale.Nano)
+
+    val transactionMetrics = metrics.collect {
+      case (TraceMetrics(name), groupSnapshot) ⇒
+
+        groupSnapshot.metrics collect {
+          // Extract WebTransaction metrics and accumulate HttpDispatcher
+          case (ElapsedTime, snapshot: Histogram.Snapshot) ⇒
+            accumulatedHttpDispatcher = accumulatedHttpDispatcher.merge(snapshot, collectionContext)
+            snapshot.recordsIterator.foreach { record ⇒
+              apdexBuilder.record(Scale.convert(snapshot.scale, Scale.Unit, record.level), record.count)
+            }
+
+            Metric.fromKamonMetricSnapshot(snapshot, s"WebTransaction/Custom/$name", None, Scale.Unit)
+
+          // Extract all external services.
+          case (SegmentMetricIdentity(segmentName, label), snapshot: Histogram.Snapshot) if label.equals(HttpClient)⇒
+            accumulatedExternalServices = accumulatedExternalServices.merge(snapshot, collectionContext)
+
+            Metric.fromKamonMetricSnapshot(snapshot, s"External/$segmentName/all", None, Scale.Unit)
+        }
+    }
+
+    val httpDispatcher = Metric.fromKamonMetricSnapshot(accumulatedHttpDispatcher, "HttpDispatcher", None, Scale.Unit)
+    val webTransaction = Metric.fromKamonMetricSnapshot(accumulatedHttpDispatcher, "WebTransaction", None, Scale.Unit)
+    val external = Metric.fromKamonMetricSnapshot(accumulatedExternalServices, "External", None, Scale.Unit)
+    val externalAllWeb = Metric.fromKamonMetricSnapshot(accumulatedExternalServices, "External/allWeb", None, Scale.Unit)
+
+    Map(httpDispatcher, webTransaction, external, externalAllWeb, apdexBuilder.build) ++ transactionMetrics.flatten.toMap
+  }
+}
+
+class ApdexBuilder(name: String, scope: Option[String], apdexT: Double) {
+  val frustratingThreshold = 4 * apdexT
+
+  var satisfying = 0L
+  var tolerating = 0L
+  var frustrating = 0L
+
+  def record(duration: Double, count: Long): Unit =
+    if (duration <= apdexT)
+      satisfying += count
+    else if (duration <= frustratingThreshold)
+      tolerating += count
+    else
+      frustrating += count
+
+  // NewRelic reuses the same metric structure for recording the Apdex.. weird, but that's how it works.
+  def build: Metric = (MetricID(name, scope), MetricData(satisfying, tolerating, frustrating, apdexT, apdexT, 0))
+}