1 files changed, 27 insertions, 12 deletions
diff --git a/kamon-core/src/main/scala/kamon/trace/MetricsOnlyContext.scala b/kamon-core/src/main/scala/kamon/trace/MetricsOnlyContext.scala
index c45a49d7..7ef3ac14 100644
--- a/kamon-core/src/main/scala/kamon/trace/MetricsOnlyContext.scala
+++ b/kamon-core/src/main/scala/kamon/trace/MetricsOnlyContext.scala
@@ -20,12 +20,13 @@ import java.util.concurrent.ConcurrentLinkedQueue
 
 import akka.event.LoggingAdapter
 import kamon.Kamon
-import kamon.metric.{ SegmentMetrics, MetricsModule, TraceMetrics }
+import kamon.metric.{ SegmentMetrics, TraceMetrics }
 import kamon.util.{ NanoInterval, RelativeNanoTimestamp }
 
 import scala.annotation.tailrec
+import scala.collection.concurrent.TrieMap
 
-private[kamon] class MetricsOnlyContext(traceName: String, val token: String, tags: Map[String, String], izOpen: Boolean, val levelOfDetail: LevelOfDetail,
+private[kamon] class MetricsOnlyContext(traceName: String, val token: String, traceTags: Map[String, String], izOpen: Boolean, val levelOfDetail: LevelOfDetail,
   val startTimestamp: RelativeNanoTimestamp, log: LoggingAdapter)
     extends TraceContext {
 
@@ -35,6 +36,7 @@ private[kamon] class MetricsOnlyContext(traceName: String, val token: String, ta
 
   private val _finishedSegments = new ConcurrentLinkedQueue[SegmentLatencyData]()
   private val _traceLocalStorage = new TraceLocalStorage
+  private val _tags = TrieMap.empty[String, String] ++= traceTags
 
   def rename(newName: String): Unit =
     if (isOpen)
@@ -45,37 +47,44 @@ private[kamon] class MetricsOnlyContext(traceName: String, val token: String, ta
   def name: String = _name
   def isEmpty: Boolean = false
   def isOpen: Boolean = _isOpen
+
   def addMetadata(key: String, value: String): Unit = {}
 
+  def addTag(key: String, value: String): Unit = _tags.put(key, value)
+  def removeTag(key: String, value: String): Boolean = _tags.remove(key, value)
+
   def finish(): Unit = {
     _isOpen = false
     val traceElapsedTime = NanoInterval.since(startTimestamp)
     _elapsedTime = traceElapsedTime
 
     if (Kamon.metrics.shouldTrack(name, TraceMetrics.category))
-      Kamon.metrics.entity(TraceMetrics, name, tags).elapsedTime.record(traceElapsedTime.nanos)
+      Kamon.metrics.entity(TraceMetrics, name, _tags.toMap).elapsedTime.record(traceElapsedTime.nanos)
     drainFinishedSegments()
   }
 
   def startSegment(segmentName: String, category: String, library: String): Segment =
-    new MetricsOnlySegment(segmentName, category, library)
+    startSegment(segmentName, category, library, Map.empty[String, String])
+
+  def startSegment(segmentName: String, category: String, library: String, tags: Map[String, String]): Segment =
+    new MetricsOnlySegment(segmentName, category, library, tags)
 
   @tailrec private def drainFinishedSegments(): Unit = {
     val segment = _finishedSegments.poll()
     if (segment != null) {
-      val segmentTags = Map(
+      val deefaultTags = Map(
         "trace" -> name,
         "category" -> segment.category,
         "library" -> segment.library)
 
       if (Kamon.metrics.shouldTrack(segment.name, SegmentMetrics.category))
-        Kamon.metrics.entity(SegmentMetrics, segment.name, segmentTags).elapsedTime.record(segment.duration.nanos)
+        Kamon.metrics.entity(SegmentMetrics, segment.name, deefaultTags ++ segment.tags).elapsedTime.record(segment.duration.nanos)
       drainFinishedSegments()
     }
   }
 
-  protected def finishSegment(segmentName: String, category: String, library: String, duration: NanoInterval): Unit = {
-    _finishedSegments.add(SegmentLatencyData(segmentName, category, library, duration))
+  protected def finishSegment(segmentName: String, category: String, library: String, duration: NanoInterval, segmentTags: Map[String, String]): Unit = {
+    _finishedSegments.add(SegmentLatencyData(segmentName, category, library, duration, segmentTags))
 
     if (isClosed) {
       drainFinishedSegments()
@@ -89,17 +98,23 @@ private[kamon] class MetricsOnlyContext(traceName: String, val token: String, ta
   // will be returned.
   def elapsedTime: NanoInterval = _elapsedTime
 
-  class MetricsOnlySegment(segmentName: String, val category: String, val library: String) extends Segment {
+  class MetricsOnlySegment(segmentName: String, val category: String, val library: String, segmentTags: Map[String, String]) extends Segment {
     private val _startTimestamp = RelativeNanoTimestamp.now
+    protected val _tags = TrieMap.empty[String, String] ++= segmentTags
+
     @volatile private var _segmentName = segmentName
     @volatile private var _elapsedTime = NanoInterval.default
     @volatile private var _isOpen = true
 
     def name: String = _segmentName
     def isEmpty: Boolean = false
-    def addMetadata(key: String, value: String): Unit = {}
     def isOpen: Boolean = _isOpen
 
+    def addMetadata(key: String, value: String): Unit = {}
+
+    def addTag(key: String, value: String): Unit = _tags.put(key, value)
+    def removeTag(key: String, value: String): Boolean = _tags.remove(key, value)
+
     def rename(newName: String): Unit =
       if (isOpen)
         _segmentName = newName
@@ -111,7 +126,7 @@ private[kamon] class MetricsOnlyContext(traceName: String, val token: String, ta
       val segmentElapsedTime = NanoInterval.since(_startTimestamp)
       _elapsedTime = segmentElapsedTime
 
-      finishSegment(name, category, library, segmentElapsedTime)
+      finishSegment(name, category, library, segmentElapsedTime, _tags.toMap)
     }
 
     // Handle with care and make sure that the segment is closed before calling this method, otherwise
@@ -121,4 +136,4 @@ private[kamon] class MetricsOnlyContext(traceName: String, val token: String, ta
   }
 }
 
-case class SegmentLatencyData(name: String, category: String, library: String, duration: NanoInterval)
+case class SegmentLatencyData(name: String, category: String, library: String, duration: NanoInterval, tags: Map[String, String])