address some review comments

Author: hughsimpson

reporters/kamon-opentelemetry/src/main/scala/kamon/otel/MetricsConverter.scala

@@ -21,8 +21,6 @@ import io.opentelemetry.sdk.metrics.internal.data._
 import io.opentelemetry.sdk.resources.Resource
 import kamon.metric.Instrument.Snapshot
 import kamon.metric.{Distribution, MeasurementUnit, MetricSnapshot, PeriodSnapshot}
-import kamon.tag.Lookups
-import kamon.trace.Span.TagKeys
 
 import java.lang.{Double => JDouble, Long => JLong}
 import java.time.Instant
@@ -34,16 +32,14 @@ class WithResourceMetricsConverter(resource: Resource, kamonVersion: String, fro
   private val fromNs = from.toEpochMilli * 1000000
   private val toNs = to.toEpochMilli * 1000000
 
-  private def instrumentationScopeInfo(snapshot: MetricSnapshot[_, _]): InstrumentationScopeInfo = {
-    // logic for looking up the component doesn't really seem to make sense - to be compliant we should probably be grouping the metrics by component before calling this
-    InstrumentationScopeInfo.create(snapshot.instruments.headOption.flatMap(_.tags.get(Lookups.option(TagKeys.Component))) getOrElse "kamon-instrumentation", kamonVersion, null)
-  }
+  private def instrumentationScopeInfo(snapshot: MetricSnapshot[_, _]): InstrumentationScopeInfo =
+    InstrumentationScopeInfo.create("kamon-metrics", kamonVersion, null)
 
   private def toString(unit: MeasurementUnit): String = unit.magnitude.name
 
-  def toGaugeDatum(g: Snapshot[Double]): DoublePointData = ImmutableDoublePointData.create(fromNs, toNs, SpanConverter.toAttributes(g.tags), g.value)
+  private def toGaugeDatum(g: Snapshot[Double]): DoublePointData = ImmutableDoublePointData.create(fromNs, toNs, SpanConverter.toAttributes(g.tags), g.value)
 
-  def toGaugeData(g: Seq[Snapshot[Double]]): GaugeData[DoublePointData] = ImmutableGaugeData.create(g.map(toGaugeDatum).asJava)
+  private def toGaugeData(g: Seq[Snapshot[Double]]): GaugeData[DoublePointData] = ImmutableGaugeData.create(g.map(toGaugeDatum).asJava)
 
   def convertGauge(gauge: MetricSnapshot.Values[Double]): MetricData =
     ImmutableMetricData.createDoubleGauge(
@@ -54,7 +50,7 @@ class WithResourceMetricsConverter(resource: Resource, kamonVersion: String, fro
       toString(gauge.settings.unit),
       toGaugeData(gauge.instruments))
 
-  def toHistogramDatum(s: Snapshot[Distribution]): HistogramPointData = {
+  private def toHistogramDatum(s: Snapshot[Distribution]): HistogramPointData = {
     val boundaries = ArrayBuffer.newBuilder[JDouble]
     val counts = ArrayBuffer.newBuilder[JLong]
     for (el <- s.value.bucketsIterator) {
@@ -73,10 +69,10 @@ class WithResourceMetricsConverter(resource: Resource, kamonVersion: String, fro
     )
   }
 
-  def toHistogramData(distributions: Seq[Snapshot[Distribution]]): Option[HistogramData] =
+  private def toHistogramData(distributions: Seq[Snapshot[Distribution]]): Option[HistogramData] =
     distributions.filter(_.value.buckets.nonEmpty) match {
       case Nil => None
-      case nonEmpty => Some(ImmutableHistogramData.create(AggregationTemporality.CUMULATIVE, nonEmpty.map(toHistogramDatum).asJava))
+      case nonEmpty => Some(ImmutableHistogramData.create(AggregationTemporality.DELTA, nonEmpty.map(toHistogramDatum).asJava))
     }
 
   def convertHistogram(histogram: MetricSnapshot.Distributions): Option[MetricData] =
@@ -89,11 +85,11 @@ class WithResourceMetricsConverter(resource: Resource, kamonVersion: String, fro
         toString(histogram.settings.unit),
         d))
 
-  def toCounterDatum(g: Snapshot[Long]): LongPointData =
+  private def toCounterDatum(g: Snapshot[Long]): LongPointData =
     ImmutableLongPointData.create(fromNs, toNs, SpanConverter.toAttributes(g.tags), g.value)
 
-  def toCounterData(g: Seq[Snapshot[Long]]): SumData[LongPointData] =
-    ImmutableSumData.create(false, AggregationTemporality.CUMULATIVE, g.map(toCounterDatum).asJava)
+  private def toCounterData(g: Seq[Snapshot[Long]]): SumData[LongPointData] =
+    ImmutableSumData.create(false, AggregationTemporality.DELTA, g.map(toCounterDatum).asJava)
 
   def convertCounter(counter: MetricSnapshot.Values[Long]): MetricData =
     ImmutableMetricData.createLongSum(