Pass ZIO Metrics histogram boundaries to OTEL (#864)

* Pass ZIO Metrics histogram boundaries to OTEL

* Pass ZIO Metrics histogram boundaries to OTEL

opentelemetry/src/main/scala/zio/telemetry/opentelemetry/metrics/internal/Instrument.scala

@@ -6,6 +6,8 @@ import zio._
 import zio.telemetry.opentelemetry.context.ContextStorage
 import zio.telemetry.opentelemetry.metrics.{Counter, Histogram, ObservableMeasurement, UpDownCounter}
 
+import scala.jdk.CollectionConverters._
+
 trait Instrument[-A] {
 
   def record0(
@@ -28,7 +30,12 @@ object Instrument {
       description: Option[String] = None
     ): UpDownCounter[Long]
 
-    def histogram(name: String, unit: Option[String] = None, description: Option[String] = None): Histogram[Double]
+    def histogram(
+      name: String,
+      unit: Option[String] = None,
+      description: Option[String] = None,
+      boundaries: Option[Chunk[Double]] = None
+    ): Histogram[Double]
 
     def observableCounter(
       name: String,
@@ -88,12 +95,14 @@ object Instrument {
           override def histogram(
             name: String,
             unit: Option[String] = None,
-            description: Option[String] = None
+            description: Option[String] = None,
+            boundaries: Option[Chunk[Double]] = None
           ): Histogram[Double] = {
             val builder = meter.histogramBuilder(name)
 
             unit.foreach(builder.setUnit)
             description.foreach(builder.setDescription)
+            boundaries.foreach(seq => builder.setExplicitBucketBoundariesAdvice(seq.map(Double.box).asJava))
 
             Histogram.double(builder.build(), ctxStorage, logAnnotated)
           }

opentelemetry/src/main/scala/zio/telemetry/opentelemetry/metrics/internal/InstrumentRegistry.scala

@@ -10,7 +10,7 @@ trait InstrumentRegistry {
 
   def getCounter(key: MetricKey.Counter): Counter[Long]
 
-  def getHistorgram(key: MetricKey.Histogram): Histogram[Double]
+  def getHistogram(key: MetricKey.Histogram): Histogram[Double]
 
   def getGauge(key: MetricKey.Gauge): AtomicDouble
 
@@ -33,8 +33,10 @@ private[opentelemetry] object InstrumentRegistry {
         def getCounter(key: MetricKey.Counter): Counter[Long] =
           getOrCreateInstrument[Counter, Long](key)(builder.counter(key.name, description = key.description))
 
-        def getHistorgram(key: MetricKey.Histogram): Histogram[Double] =
-          getOrCreateInstrument[Histogram, Double](key)(builder.histogram(key.name, description = key.description))
+        def getHistogram(key: MetricKey.Histogram): Histogram[Double] =
+          getOrCreateInstrument[Histogram, Double](key)(
+            builder.histogram(key.name, description = key.description, boundaries = Some(key.keyType.boundaries.values))
+          )
 
         def getGauge(key: MetricKey.Gauge): AtomicDouble =
           gauges.computeIfAbsent(

opentelemetry/src/main/scala/zio/telemetry/opentelemetry/metrics/internal/OtelMetricListener.scala

@@ -22,7 +22,7 @@ private[opentelemetry] object OtelMetricListener {
         override def updateHistogram(key: MetricKey[MetricKeyType.Histogram], value: Double)(implicit
           unsafe: Unsafe
         ): Unit =
-          registry.getHistorgram(key).record0(value, attributes(key.tags))
+          registry.getHistogram(key).record0(value, attributes(key.tags))
 
         override def updateCounter(key: MetricKey[MetricKeyType.Counter], value: Double)(implicit
           unsafe: Unsafe

opentelemetry/src/test/scala/zio/telemetry/opentelemetry/metrics/MeterTest.scala

@@ -3,6 +3,9 @@ package zio.telemetry.opentelemetry.metrics
 import io.opentelemetry.sdk.metrics.SdkMeterProvider
 import io.opentelemetry.sdk.testing.exporter.InMemoryMetricReader
 import zio._
+import zio.metrics.Metric
+import zio.metrics.MetricKeyType.Histogram.Boundaries
+import zio.telemetry.opentelemetry.OpenTelemetry
 import zio.telemetry.opentelemetry.common.{Attribute, Attributes}
 import zio.telemetry.opentelemetry.context.ContextStorage
 import zio.telemetry.opentelemetry.metrics.internal.Instrument
@@ -16,7 +19,9 @@ object MeterTest extends ZIOSpecDefault {
   val inMemoryMetricReaderLayer: ZLayer[Any, Nothing, InMemoryMetricReader] =
     ZLayer(ZIO.succeed(InMemoryMetricReader.create()))
 
-  def meterLayer(logAnnotated: Boolean = false): ZLayer[InMemoryMetricReader with ContextStorage, Nothing, Meter] = {
+  def meterLayer(
+    logAnnotated: Boolean = false
+  ): ZLayer[InMemoryMetricReader with ContextStorage, Nothing, Meter with Instrument.Builder] = {
     val jmeter  = ZLayer {
       for {
         metricReader  <- ZIO.service[InMemoryMetricReader]
@@ -26,7 +31,7 @@ object MeterTest extends ZIOSpecDefault {
     }
     val builder = jmeter >>> Instrument.Builder.live(logAnnotated)
 
-    builder >>> Meter.live
+    builder >+> Meter.live
   }
 
   val observableRefLayer: ULayer[Ref[Long]] =
@@ -45,7 +50,8 @@ object MeterTest extends ZIOSpecDefault {
       suite("Meter")(
         normalSpec,
         contextualSpec,
-        logAnnotatedSpec
+        logAnnotatedSpec,
+        zioMetricsSpec
       )
     )
 
@@ -216,4 +222,19 @@ object MeterTest extends ZIOSpecDefault {
       }
     ).provide(inMemoryMetricReaderLayer, meterLayer(logAnnotated = true), ContextStorage.fiberRef)
 
+  private val zioMetricsSpec =
+    suite("ZIO metrics integration")(
+      test("histogram boundaries should be passed to OTEL") {
+        val histogram = Metric.histogram("test_histogram", Boundaries(Chunk(1, 2, 3)))
+
+        for {
+          reader     <- ZIO.service[InMemoryMetricReader]
+          _          <- histogram.update(2.0)
+          metric      = reader.collectAllMetrics().asScala.find(_.getName == "test_histogram").get
+          metricPoint = metric.getHistogramData().getPoints().asScala.toList.head
+          boundaries  = metricPoint.getBoundaries.asScala.map(_.toDouble).toSeq
+        } yield assertTrue(boundaries == Seq(1.0, 2.0, 3.0))
+      }
+    ).provide(inMemoryMetricReaderLayer, meterLayer(), ContextStorage.fiberRef, OpenTelemetry.zioMetrics)
+
 }