From 501f8e103f96b5544b65f20201fbdc95ba044c78 Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Thu, 9 Jun 2022 15:06:38 +0300
Subject: [PATCH 01/19] Measure metrics using `otel4s`

---
 build.sbt                                     |  10 +
 .../typelevel/keypool/PoolMetricsSpec.scala   | 258 ++++++++++++++++++
 .../scala/org/typelevel/keypool/KeyPool.scala |  94 ++++---
 .../typelevel/keypool/KeyPoolBuilder.scala    |  12 +-
 .../scala/org/typelevel/keypool/Pool.scala    |  20 +-
 .../typelevel/keypool/internal/Metrics.scala  | 120 ++++++++
 6 files changed, 467 insertions(+), 47 deletions(-)
 create mode 100644 core/.jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
 create mode 100644 core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala

diff --git a/build.sbt b/build.sbt
index 6cab399a..58032cf7 100644
--- a/build.sbt
+++ b/build.sbt
@@ -23,6 +23,13 @@ lazy val core = crossProject(JVMPlatform, JSPlatform)
   .jsSettings(
     tlVersionIntroduced := List("2.12", "2.13", "3").map(_ -> "0.4.6").toMap
   )
+  .jvmSettings(
+    libraryDependencies ++= Seq(
+      "org.typelevel"   %% "otel4s-java"               % otel4sV  % Test,
+      "io.opentelemetry" % "opentelemetry-sdk"         % "1.14.0" % Test,
+      "io.opentelemetry" % "opentelemetry-sdk-testing" % "1.14.0" % Test
+    )
+  )
   .settings(
     mimaBinaryIssueFilters ++= Seq(
       ProblemFilters.exclude[DirectMissingMethodProblem]("org.typelevel.keypool.KeyPool.destroy"),
@@ -48,6 +55,8 @@ lazy val docs = project
 val catsV = "2.7.0"
 val catsEffectV = "3.3.12"
 
+val otel4sV = "0.0-c25617c-20220609T070516Z-SNAPSHOT"
+
 val munitV = "0.7.29"
 val munitCatsEffectV = "1.0.7"
 
@@ -60,6 +69,7 @@ lazy val commonSettings = Seq(
   libraryDependencies ++= Seq(
     "org.typelevel" %%% "cats-core"           % catsV,
     "org.typelevel" %%% "cats-effect-kernel"  % catsEffectV,
+    "org.typelevel" %%% "otel4s-core"         % otel4sV,
     "org.typelevel" %%% "cats-effect-std"     % catsEffectV      % Test,
     "org.scalameta" %%% "munit"               % munitV           % Test,
     "org.typelevel" %%% "munit-cats-effect-3" % munitCatsEffectV % Test
diff --git a/core/.jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/core/.jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
new file mode 100644
index 00000000..ce09818b
--- /dev/null
+++ b/core/.jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -0,0 +1,258 @@
+package org.typelevel.keypool
+
+import java.util.concurrent.TimeUnit
+
+import cats.syntax.all._
+import cats.effect._
+import io.opentelemetry.sdk.OpenTelemetrySdk
+import io.opentelemetry.sdk.metrics.{
+  Aggregation,
+  InstrumentSelector,
+  InstrumentType,
+  SdkMeterProvider,
+  View
+}
+import io.opentelemetry.sdk.testing.exporter.InMemoryMetricReader
+import munit.CatsEffectSuite
+import org.typelevel.otel4s.{MeterProvider, Otel4s}
+import org.typelevel.otel4s.java.OtelJava
+import scala.concurrent.duration._
+import scala.jdk.CollectionConverters._
+import scala.util.control.NoStackTrace
+
+class PoolMetricsSpec extends CatsEffectSuite {
+
+  test("Metrics should be empty for unused pool") {
+    val expectedSnapshot = MetricsSnapshot(0, 0, Nil, 0, Nil)
+
+    for {
+      snapshot <- setupSdk.use(sdk => mkPool(sdk.otel.meterProvider).use(_ => sdk.snapshot))
+    } yield assertEquals(snapshot, expectedSnapshot)
+  }
+
+  test("In use: increment on acquire and decrement on release") {
+    poolTest() { (sdk, pool) =>
+      for {
+        inUse <- pool.take.use(_ => sdk.snapshot)
+        afterUse <- sdk.snapshot
+      } yield {
+        assertEquals(inUse.inUse, 1L)
+        assertEquals(afterUse.inUse, 0L)
+      }
+    }
+  }
+
+  test("In use: increment on acquire and decrement on release (failure)") {
+    val exception = new RuntimeException("Something went wrong") with NoStackTrace
+
+    poolTest() { (sdk, pool) =>
+      for {
+        deferred <- IO.deferred[MetricsSnapshot]
+        _ <- pool.take
+          .use(_ => sdk.snapshot.flatMap(deferred.complete) >> IO.raiseError(exception))
+          .attempt
+        inUse <- deferred.get
+        afterUse <- sdk.snapshot
+      } yield {
+        assertEquals(inUse.inUse, 1L)
+        assertEquals(afterUse.inUse, 0L)
+      }
+    }
+  }
+
+  test("Idle: keep 0 when `maxIdle` is 0") {
+    // todo replace with `withMaxIdle` once https://github.com/typelevel/keypool/pull/394 gets merged
+    poolTest(_.withMaxTotal(-1)) { (sdk, pool) =>
+      for {
+        inUse <- pool.take.use(_ => sdk.snapshot)
+        afterUse <- sdk.snapshot
+      } yield {
+        assertEquals(inUse.idle, 0L)
+        assertEquals(afterUse.idle, 0L)
+      }
+    }
+  }
+
+  test("Idle: keep 1 when `maxIdle` is 1") {
+    // todo replace with `withMaxIdle` once https://github.com/typelevel/keypool/pull/394 gets merged
+    poolTest(_.withMaxTotal(1)) { (sdk, pool) =>
+      for {
+        inUse <- pool.take.use(_ => sdk.snapshot)
+        afterUse <- sdk.snapshot
+      } yield {
+        assertEquals(inUse.idle, 0L)
+        assertEquals(afterUse.idle, 1L)
+      }
+    }
+  }
+
+  test("Idle: decrement on reaper cleanup") {
+    // todo replace with `withMaxIdle` once https://github.com/typelevel/keypool/pull/394 gets merged
+    poolTest(_.withMaxTotal(1).withIdleTimeAllowedInPool(1.second)) { (sdk, pool) =>
+      for {
+        inUse <- pool.take.use(_ => sdk.snapshot)
+        afterUse <- sdk.snapshot
+        afterSleep <- sdk.snapshot.delayBy(6.seconds)
+      } yield {
+        assertEquals(inUse.idle, 0L)
+        assertEquals(afterUse.idle, 1L)
+        assertEquals(afterSleep.idle, 0L)
+      }
+    }
+  }
+
+  test("Generate valid metric snapshots") {
+    setupSdk.use { sdk =>
+      mkPool(sdk.otel.meterProvider)
+        .use(pool => pool.take.use(_ => sdk.snapshot.delayBy(500.millis)).product(sdk.snapshot))
+        .map { case (inUse, afterUse) =>
+          val acquireDuration =
+            List(HistogramSnapshot(0, 1, HistogramBuckets, List(1, 0, 0, 0, 0)))
+
+          val expectedInUse = MetricsSnapshot(
+            idle = 0,
+            inUse = 1,
+            inUseDuration = Nil,
+            acquiredTotal = 1,
+            acquireDuration = acquireDuration
+          )
+
+          val expectedAfterUser = MetricsSnapshot(
+            idle = 1,
+            inUse = 0,
+            inUseDuration = List(HistogramSnapshot(0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))),
+            acquiredTotal = 1,
+            acquireDuration = acquireDuration
+          )
+
+          assertEquals(inUse, expectedInUse)
+          assertEquals(
+            afterUse.copy(inUseDuration = afterUse.inUseDuration.map(_.copy(sum = 0))),
+            expectedAfterUser
+          )
+          assert(afterUse.inUseDuration.forall(r => r.sum >= 500 && r.sum <= 700))
+        }
+    }
+  }
+
+  private def poolTest(
+      customize: Pool.Builder[IO, Ref[IO, Int]] => Pool.Builder[IO, Ref[IO, Int]] = identity
+  )(scenario: (OtelSdk[IO], Pool[IO, Ref[IO, Int]]) => IO[Unit]): IO[Unit] =
+    setupSdk.use { sdk =>
+      val builder =
+        Pool.Builder(Ref.of[IO, Int](1), nothing).withMeterProvider(sdk.otel.meterProvider)
+
+      customize(builder).build.use(pool => scenario(sdk, pool))
+    }
+
+  private def mkPool(meterProvider: MeterProvider[IO]) =
+    Pool
+      .Builder(
+        Ref.of[IO, Int](1),
+        nothing
+      )
+      .withMeterProvider(meterProvider)
+      .withMaxTotal(10)
+      .build
+
+  private def setupSdk: Resource[IO, OtelSdk[IO]] = {
+    val acquire = IO.delay {
+      val mr = InMemoryMetricReader.create()
+
+      val mp = SdkMeterProvider
+        .builder()
+        .registerMetricReader(mr)
+        .registerView(
+          InstrumentSelector.builder().setType(InstrumentType.HISTOGRAM).build(),
+          View
+            .builder()
+            .setAggregation(
+              Aggregation.explicitBucketHistogram(HistogramBuckets.map(Double.box).asJava)
+            )
+            .build()
+        )
+        .build()
+
+      val sdk = OpenTelemetrySdk
+        .builder()
+        .setMeterProvider(mp)
+        .build()
+
+      new OtelSdk[IO] {
+        def metricReader: InMemoryMetricReader = mr
+        def otel: Otel4s[IO] = OtelJava.forSync[IO](sdk)
+        def flush: IO[Unit] = IO.blocking(mp.forceFlush().join(5, TimeUnit.SECONDS))
+
+        def snapshot: IO[MetricsSnapshot] = {
+          IO.delay {
+            val items = metricReader.collectAllMetrics().asScala.toList
+
+            def counterValue(name: String): Long =
+              items
+                .find(_.getName === name)
+                .flatMap(_.getLongSumData.getPoints.asScala.headOption.map(_.getValue))
+                .getOrElse(0L)
+
+            def histogramSnapshot(name: String): List[HistogramSnapshot] =
+              items
+                .find(_.getName === name)
+                .map { metric =>
+                  val points = metric.getHistogramData.getPoints.asScala.toList
+
+                  points.map { hdp =>
+                    HistogramSnapshot(
+                      hdp.getSum,
+                      hdp.getCount,
+                      hdp.getBoundaries.asScala.toList.map(Double.unbox),
+                      hdp.getCounts.asScala.toList.map(Long.unbox)
+                    )
+                  }
+                }
+                .getOrElse(Nil)
+
+            MetricsSnapshot(
+              counterValue("idle"),
+              counterValue("in_use"),
+              histogramSnapshot("in_use_duration"),
+              counterValue("acquired_total"),
+              histogramSnapshot("acquire_duration")
+            )
+          }
+        }
+      }
+    }
+
+    def release(sdk: OtelSdk[IO]) = sdk.flush
+
+    Resource.make(acquire)(release)
+  }
+
+  final case class MetricsSnapshot(
+      idle: Long,
+      inUse: Long,
+      inUseDuration: List[HistogramSnapshot],
+      acquiredTotal: Long,
+      acquireDuration: List[HistogramSnapshot]
+  )
+
+  final case class HistogramSnapshot(
+      sum: Double,
+      count: Double,
+      boundaries: List[Double],
+      counts: List[Long]
+  )
+
+  private trait OtelSdk[F[_]] {
+    def metricReader: InMemoryMetricReader
+    def otel: Otel4s[F]
+    def flush: F[Unit]
+    def snapshot: F[MetricsSnapshot]
+  }
+
+  private val HistogramBuckets: List[Double] =
+    List(0.01, 1, 100, 1000)
+
+  private def nothing(ref: Ref[IO, Int]): IO[Unit] =
+    ref.get.void
+
+}
diff --git a/core/src/main/scala/org/typelevel/keypool/KeyPool.scala b/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
index 261cfefd..3200ce29 100644
--- a/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
+++ b/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
@@ -23,9 +23,11 @@ package org.typelevel.keypool
 
 import cats._
 import cats.effect.kernel._
+import cats.effect.syntax.spawn._
 import cats.syntax.all._
 import scala.concurrent.duration._
 import org.typelevel.keypool.internal._
+import org.typelevel.otel4s.{MeterProvider}
 
 /**
  * This pools internal guarantees are that the max number of values are in the pool at any time, not
@@ -64,7 +66,8 @@ object KeyPool {
       private[keypool] val kpDefaultReuseState: Reusable,
       private[keypool] val kpMaxPerKey: A => Int,
       private[keypool] val kpMaxTotal: Int,
-      private[keypool] val kpVar: Ref[F, PoolMap[A, (B, F[Unit])]]
+      private[keypool] val kpVar: Ref[F, PoolMap[A, (B, F[Unit])]],
+      private[keypool] val kpMetrics: Metrics[F]
   ) extends KeyPool[F, A, B] {
 
     def take(k: A): Resource[F, Managed[F, B]] =
@@ -133,6 +136,7 @@ object KeyPool {
   private[keypool] def reap[F[_], A, B](
       idleTimeAllowedInPoolNanos: FiniteDuration,
       kpVar: Ref[F, PoolMap[A, (B, F[Unit])]],
+      metrics: Metrics[F],
       onReaperException: Throwable => F[Unit]
   )(implicit F: Temporal[F]): F[Unit] = {
     // We are going to do non-referentially tranpsarent things as we may be waiting for our modification to go through
@@ -194,7 +198,7 @@ object KeyPool {
               val (m_, toDestroy) = findStale(now, idleCount, m)
               (
                 m_,
-                toDestroy.traverse_(_._2._2).attempt.flatMap {
+                toDestroy.traverse_(r => metrics.decIdle >> r._2._2).attempt.flatMap {
                   case Left(t) => onReaperException(t)
                   // .handleErrorWith(t => F.delay(t.printStackTrace())) // CHEATING?
                   case Right(()) => F.unit
@@ -214,25 +218,26 @@ object KeyPool {
   private[keypool] def state[F[_]: Functor, A, B](
       kpVar: Ref[F, PoolMap[A, (B, F[Unit])]]
   ): F[(Int, Map[A, Int])] =
-    kpVar.get.map(pm =>
-      pm match {
-        case PoolClosed() => (0, Map.empty)
-        case PoolOpen(idleCount, m) =>
-          val modified = m.map { case (k, pl) =>
-            pl match {
-              case One(_, _) => (k, 1)
-              case Cons(_, length, _, _) => (k, length)
-            }
-          }.toMap
-          (idleCount, modified)
-      }
-    )
+    kpVar.get.map {
+      case PoolClosed() =>
+        (0, Map.empty)
+
+      case PoolOpen(idleCount, m) =>
+        val modified = m.map { case (k, pl) =>
+          pl match {
+            case One(_, _) => (k, 1)
+            case Cons(_, length, _, _) => (k, length)
+          }
+        }
+        (idleCount, modified)
+    }
 
   private[keypool] def put[F[_]: Temporal, A, B](
       kp: KeyPoolConcrete[F, A, B],
       k: A,
       r: B,
-      destroy: F[Unit]
+      destroy: F[Unit],
+      isFromPool: Boolean
   ): F[Unit] = {
     def addToList[Z](
         now: FiniteDuration,
@@ -249,22 +254,25 @@ object KeyPool {
             else (l, Some(x))
         }
       }
+
+    def decIdle = kp.kpMetrics.decIdle.whenA(isFromPool)
+
     def go(now: FiniteDuration, pc: PoolMap[A, (B, F[Unit])]): (PoolMap[A, (B, F[Unit])], F[Unit]) =
       pc match {
-        case p @ PoolClosed() => (p, destroy)
+        case p @ PoolClosed() => (p, decIdle >> destroy)
         case p @ PoolOpen(idleCount, m) =>
-          if (idleCount > kp.kpMaxTotal) (p, destroy)
+          if (idleCount > kp.kpMaxTotal) (p, decIdle >> destroy)
           else
             m.get(k) match {
               case None =>
                 val cnt_ = idleCount + 1
                 val m_ = PoolMap.open(cnt_, m + (k -> One((r, destroy), now)))
-                (m_, Applicative[F].pure(()))
+                (m_, kp.kpMetrics.incIdle)
               case Some(l) =>
                 val (l_, mx) = addToList(now, kp.kpMaxPerKey(k), (r, destroy), l)
                 val cnt_ = idleCount + mx.fold(1)(_ => 0)
                 val m_ = PoolMap.open(cnt_, m + (k -> l_))
-                (m_, mx.fold(Applicative[F].unit)(_ => destroy))
+                (m_, mx.fold(kp.kpMetrics.incIdle)(_ => decIdle >> destroy))
             }
       }
 
@@ -293,16 +301,20 @@ object KeyPool {
     for {
       optR <- Resource.eval(kp.kpVar.modify(go))
       releasedState <- Resource.eval(Ref[F].of[Reusable](kp.kpDefaultReuseState))
-      resource <- Resource.make(optR.fold(kp.kpRes(k).allocated)(r => Applicative[F].pure(r))) {
-        resource =>
-          for {
-            reusable <- releasedState.get
-            out <- reusable match {
-              case Reusable.Reuse => put(kp, k, resource._1, resource._2).attempt.void
-              case Reusable.DontReuse => resource._2.attempt.void
-            }
-          } yield out
+      resource <- Resource.make(
+        optR.fold(kp.kpMetrics.recordAcquireDuration(kp.kpRes(k)))(r => Applicative[F].pure(r))
+      ) { resource =>
+        for {
+          reusable <- releasedState.get
+          out <- reusable match {
+            case Reusable.Reuse => put(kp, k, resource._1, resource._2, optR.nonEmpty).attempt.void
+            case Reusable.DontReuse => resource._2.attempt.void
+          }
+        } yield out
       }
+      _ <- Resource.eval(kp.kpMetrics.acquiredTotal.add(1).whenA(optR.isEmpty))
+      _ <- Resource.make(kp.kpMetrics.incInUse)(_ => kp.kpMetrics.decInUse)
+      _ <- kp.kpMetrics.recordInUseDuration
     } yield new Managed(resource._1, optR.isDefined, releasedState)
   }
 
@@ -312,7 +324,8 @@ object KeyPool {
       val idleTimeAllowedInPool: Duration,
       val kpMaxPerKey: A => Int,
       val kpMaxTotal: Int,
-      val onReaperException: Throwable => F[Unit]
+      val onReaperException: Throwable => F[Unit],
+      val meterProvider: MeterProvider[F]
   ) {
     private def copy(
         kpRes: A => Resource[F, B] = this.kpRes,
@@ -320,14 +333,16 @@ object KeyPool {
         idleTimeAllowedInPool: Duration = this.idleTimeAllowedInPool,
         kpMaxPerKey: A => Int = this.kpMaxPerKey,
         kpMaxTotal: Int = this.kpMaxTotal,
-        onReaperException: Throwable => F[Unit] = this.onReaperException
+        onReaperException: Throwable => F[Unit] = this.onReaperException,
+        meterProvider: MeterProvider[F] = this.meterProvider
     ): Builder[F, A, B] = new Builder[F, A, B](
       kpRes,
       kpDefaultReuseState,
       idleTimeAllowedInPool,
       kpMaxPerKey,
       kpMaxTotal,
-      onReaperException
+      onReaperException,
+      meterProvider
     )
 
     def doOnCreate(f: B => F[Unit]): Builder[F, A, B] =
@@ -353,6 +368,9 @@ object KeyPool {
     def withOnReaperException(f: Throwable => F[Unit]): Builder[F, A, B] =
       copy(onReaperException = f)
 
+    def withMeterProvider(meterProvider: MeterProvider[F]): Builder[F, A, B] =
+      copy(meterProvider = meterProvider)
+
     def build: Resource[F, KeyPool[F, A, B]] = {
       def keepRunning[Z](fa: F[Z]): F[Z] =
         fa.onError { case e => onReaperException(e) }.attempt >> keepRunning(fa)
@@ -360,12 +378,11 @@ object KeyPool {
         kpVar <- Resource.make(
           Ref[F].of[PoolMap[A, (B, F[Unit])]](PoolMap.open(0, Map.empty[A, PoolList[(B, F[Unit])]]))
         )(kpVar => KeyPool.destroy(kpVar))
+        kpMetrics <- Resource.eval(Metrics.fromMeterProvider(meterProvider))
         _ <- idleTimeAllowedInPool match {
           case fd: FiniteDuration =>
             val nanos = 0.seconds.max(fd)
-            Resource.make(
-              Concurrent[F].start(keepRunning(KeyPool.reap(nanos, kpVar, onReaperException)))
-            )(_.cancel)
+            keepRunning(KeyPool.reap(nanos, kpVar, kpMetrics, onReaperException)).background.void
           case _ =>
             Applicative[Resource[F, *]].unit
         }
@@ -374,7 +391,8 @@ object KeyPool {
         kpDefaultReuseState,
         kpMaxPerKey,
         kpMaxTotal,
-        kpVar
+        kpVar,
+        kpMetrics
       )
     }
 
@@ -389,7 +407,8 @@ object KeyPool {
       Defaults.idleTimeAllowedInPool,
       Defaults.maxPerKey,
       Defaults.maxTotal,
-      Defaults.onReaperException[F]
+      Defaults.onReaperException[F],
+      Defaults.meterProvider
     )
 
     def apply[F[_]: Temporal, A, B](
@@ -406,6 +425,7 @@ object KeyPool {
       def onReaperException[F[_]: Applicative] = { (t: Throwable) =>
         Function.const(Applicative[F].unit)(t)
       }
+      def meterProvider[F[_]: Applicative]: MeterProvider[F] = MeterProvider.noop
     }
   }
 }
diff --git a/core/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala b/core/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
index 8f914203..3170da45 100644
--- a/core/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
+++ b/core/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
@@ -21,10 +21,12 @@
 
 package org.typelevel.keypool
 
-import internal.{PoolList, PoolMap}
+import internal.{Metrics, PoolList, PoolMap}
 import cats._
 import cats.syntax.all._
 import cats.effect.kernel._
+import cats.effect.syntax.spawn._
+import org.typelevel.otel4s.MeterProvider
 import scala.concurrent.duration._
 
 @deprecated("use KeyPool.Builder", "0.4.7")
@@ -83,12 +85,11 @@ final class KeyPoolBuilder[F[_]: Temporal, A, B] private (
       kpVar <- Resource.make(
         Ref[F].of[PoolMap[A, (B, F[Unit])]](PoolMap.open(0, Map.empty[A, PoolList[(B, F[Unit])]]))
       )(kpVar => KeyPool.destroy(kpVar))
+      kpMetrics <- Resource.eval(Metrics.fromMeterProvider(MeterProvider.noop))
       _ <- idleTimeAllowedInPool match {
         case fd: FiniteDuration =>
           val nanos = 0.seconds.max(fd)
-          Resource.make(
-            Concurrent[F].start(keepRunning(KeyPool.reap(nanos, kpVar, onReaperException)))
-          )(_.cancel)
+          keepRunning(KeyPool.reap(nanos, kpVar, kpMetrics, onReaperException)).background.void
         case _ =>
           Applicative[Resource[F, *]].unit
       }
@@ -97,7 +98,8 @@ final class KeyPoolBuilder[F[_]: Temporal, A, B] private (
       kpDefaultReuseState,
       kpMaxPerKey,
       kpMaxTotal,
-      kpVar
+      kpVar,
+      kpMetrics
     )
   }
 
diff --git a/core/src/main/scala/org/typelevel/keypool/Pool.scala b/core/src/main/scala/org/typelevel/keypool/Pool.scala
index 3d275ffd..36f857dc 100644
--- a/core/src/main/scala/org/typelevel/keypool/Pool.scala
+++ b/core/src/main/scala/org/typelevel/keypool/Pool.scala
@@ -24,6 +24,7 @@ package org.typelevel.keypool
 import cats._
 import cats.effect.kernel._
 import cats.syntax.all._
+import org.typelevel.otel4s.MeterProvider
 import scala.concurrent.duration._
 
 /**
@@ -75,20 +76,23 @@ object Pool {
       val kpDefaultReuseState: Reusable,
       val idleTimeAllowedInPool: Duration,
       val kpMaxTotal: Int,
-      val onReaperException: Throwable => F[Unit]
+      val onReaperException: Throwable => F[Unit],
+      val meterProvider: MeterProvider[F]
   ) {
     private def copy(
         kpRes: Resource[F, B] = this.kpRes,
         kpDefaultReuseState: Reusable = this.kpDefaultReuseState,
         idleTimeAllowedInPool: Duration = this.idleTimeAllowedInPool,
         kpMaxTotal: Int = this.kpMaxTotal,
-        onReaperException: Throwable => F[Unit] = this.onReaperException
+        onReaperException: Throwable => F[Unit] = this.onReaperException,
+        meterProvider: MeterProvider[F] = this.meterProvider
     ): Builder[F, B] = new Builder[F, B](
       kpRes,
       kpDefaultReuseState,
       idleTimeAllowedInPool,
       kpMaxTotal,
-      onReaperException
+      onReaperException,
+      meterProvider
     )
 
     def doOnCreate(f: B => F[Unit]): Builder[F, B] =
@@ -111,6 +115,9 @@ object Pool {
     def withOnReaperException(f: Throwable => F[Unit]): Builder[F, B] =
       copy(onReaperException = f)
 
+    def withMeterProvider(meterProvider: MeterProvider[F]): Builder[F, B] =
+      copy(meterProvider = meterProvider)
+
     private def toKeyPoolBuilder: KeyPool.Builder[F, Unit, B] =
       new KeyPool.Builder(
         kpRes = _ => kpRes,
@@ -118,7 +125,8 @@ object Pool {
         idleTimeAllowedInPool = idleTimeAllowedInPool,
         kpMaxPerKey = _ => kpMaxTotal,
         kpMaxTotal = kpMaxTotal,
-        onReaperException = onReaperException
+        onReaperException = onReaperException,
+        meterProvider = meterProvider
       )
 
     def build: Resource[F, Pool[F, B]] = {
@@ -139,7 +147,8 @@ object Pool {
       Defaults.defaultReuseState,
       Defaults.idleTimeAllowedInPool,
       Defaults.maxTotal,
-      Defaults.onReaperException[F]
+      Defaults.onReaperException[F],
+      Defaults.meterProvider
     )
 
     def apply[F[_]: Temporal, B](
@@ -155,6 +164,7 @@ object Pool {
       def onReaperException[F[_]: Applicative] = { (t: Throwable) =>
         Function.const(Applicative[F].unit)(t)
       }
+      def meterProvider[F[_]: Applicative]: MeterProvider[F] = MeterProvider.noop
     }
   }
 }
diff --git a/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala b/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
new file mode 100644
index 00000000..43ed53bd
--- /dev/null
+++ b/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
@@ -0,0 +1,120 @@
+package org.typelevel.keypool.internal
+
+import cats.Monad
+import cats.effect.{Resource, Temporal}
+import cats.syntax.functor._
+import cats.syntax.flatMap._
+import org.typelevel.otel4s._
+
+private[keypool] trait Metrics[F[_]] {
+
+  /**
+   * The '''current''' number of the '''idle''' resources
+   */
+  def idle: UpDownCounter[F, Long]
+
+  /**
+   * The '''current''' number of the '''borrowed (in use)''' resources
+   */
+  def inUse: UpDownCounter[F, Long]
+
+  def inUseDuration: Histogram[F, Double]
+
+  /**
+   * The '''total''' number of the '''acquired''' resources.
+   *
+   * The value can be only incremented.
+   */
+  def acquiredTotal: Counter[F, Long]
+
+  def acquireDuration: Histogram[F, Double]
+
+  private[keypool] final def incIdle: F[Unit] = idle.add(1L)
+  private[keypool] final def decIdle: F[Unit] = idle.add(-1L)
+  private[keypool] final def incInUse: F[Unit] = inUse.add(1L)
+  private[keypool] final def decInUse: F[Unit] = inUse.add(-1L)
+
+  private[keypool] final def recordInUseDuration(implicit F: Temporal[F]): Resource[F, Unit] =
+    Metrics.recordInUseDuration(this)
+
+  private[keypool] final def recordAcquireDuration[A](
+      resource: Resource[F, A]
+  )(implicit F: Temporal[F]): F[(A, F[Unit])] =
+    Metrics.recordAcquireDuration(this, resource)
+
+}
+
+private[keypool] object Metrics {
+
+  private val CauseKey: AttributeKey[String] = AttributeKey.string("cause")
+
+  def fromMeterProvider[F[_]: Monad](meterProvider: MeterProvider[F]): F[Metrics[F]] = {
+    for {
+      meter <- meterProvider.get("org.typelevel.keypool")
+
+      idleCounter <- meter
+        .upDownCounter("idle")
+        .withDescription("A current number of idle resources")
+        .create
+
+      inUseCounter <- meter
+        .upDownCounter("in_use")
+        .withDescription("A current number of resources in use")
+        .create
+
+      inUseDurationHistogram <- meter
+        .histogram("in_use_duration")
+        .withUnit("ms")
+        .withDescription("For how long a resource is in use")
+        .create
+
+      acquiredCounter <- meter
+        .counter("acquired_total")
+        .withDescription("A total number of acquired resources")
+        .create
+
+      acquireDurationHistogram <- meter
+        .histogram("acquire_duration")
+        .withUnit("ms")
+        .withDescription("How long does it take to acquire a resource")
+        .create
+
+    } yield new Metrics[F] {
+      def idle: UpDownCounter[F, Long] = idleCounter
+      def inUse: UpDownCounter[F, Long] = inUseCounter
+      def inUseDuration: Histogram[F, Double] = inUseDurationHistogram
+      def acquiredTotal: Counter[F, Long] = acquiredCounter
+      def acquireDuration: Histogram[F, Double] = acquireDurationHistogram
+    }
+  }
+
+  private def recordInUseDuration[F[_]](
+      metrics: Metrics[F]
+  )(implicit F: Temporal[F]): Resource[F, Unit] =
+    Resource
+      .makeCase(Temporal[F].monotonic) { case (start, ec) =>
+        for {
+          end <- Temporal[F].monotonic
+          _ <- metrics.inUseDuration.record((end - start).toMillis, causeAttributes(ec): _*)
+        } yield ()
+      }
+      .void
+
+  private def recordAcquireDuration[F[_], A](
+      metrics: Metrics[F],
+      resource: Resource[F, A]
+  )(implicit F: Temporal[F]): F[(A, F[Unit])] =
+    Temporal[F]
+      .timed(resource.allocated)
+      .flatMap { case (acquireTime, r) =>
+        metrics.acquireDuration.record(acquireTime.toMillis).as(r)
+      }
+
+  private def causeAttributes(ec: Resource.ExitCase): List[Attribute[String]] =
+    ec match {
+      case Resource.ExitCase.Succeeded => Nil
+      case Resource.ExitCase.Errored(e) => List(Attribute(CauseKey, e.getClass.getName))
+      case Resource.ExitCase.Canceled => List(Attribute(CauseKey, "canceled"))
+    }
+
+}

From 0a99a7b114cf91e8fe578179769daa005465c05a Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Mon, 13 Jun 2022 10:32:03 +0300
Subject: [PATCH 02/19] Update otel4s

---
 build.sbt                                     |  4 +-
 .../typelevel/keypool/PoolMetricsSpec.scala   | 67 +++++++++++--------
 .../scala/org/typelevel/keypool/KeyPool.scala | 26 ++++---
 .../typelevel/keypool/internal/Metrics.scala  | 45 -------------
 4 files changed, 56 insertions(+), 86 deletions(-)

diff --git a/build.sbt b/build.sbt
index 49e1a3fa..741c048c 100644
--- a/build.sbt
+++ b/build.sbt
@@ -13,7 +13,7 @@ ThisBuild / tlSiteApiUrl := Some(url("https://www.javadoc.io/doc/org.typelevel/k
 lazy val root = tlCrossRootProject.aggregate(core)
 
 lazy val core = crossProject(JVMPlatform, JSPlatform)
-  .crossType(CrossType.Full)
+  .crossType(CrossType.Pure)
   .in(file("core"))
   .settings(commonSettings)
   .settings(
@@ -59,7 +59,7 @@ lazy val docs = project
 val catsV = "2.7.0"
 val catsEffectV = "3.3.12"
 
-val otel4sV = "0.0-d3796fb-20220613T071000Z-SNAPSHOT"
+val otel4sV = "0.0-7f89139-20220613T071957Z-SNAPSHOT"
 
 val munitV = "0.7.29"
 val munitCatsEffectV = "1.0.7"
diff --git a/core/.jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/core/.jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index ce09818b..1e785f4f 100644
--- a/core/.jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/core/.jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -21,6 +21,7 @@ import scala.jdk.CollectionConverters._
 import scala.util.control.NoStackTrace
 
 class PoolMetricsSpec extends CatsEffectSuite {
+  import PoolMetricsSpec._
 
   test("Metrics should be empty for unused pool") {
     val expectedSnapshot = MetricsSnapshot(0, 0, Nil, 0, Nil)
@@ -61,8 +62,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
   }
 
   test("Idle: keep 0 when `maxIdle` is 0") {
-    // todo replace with `withMaxIdle` once https://github.com/typelevel/keypool/pull/394 gets merged
-    poolTest(_.withMaxTotal(-1)) { (sdk, pool) =>
+    poolTest(_.withMaxIdle(0)) { (sdk, pool) =>
       for {
         inUse <- pool.take.use(_ => sdk.snapshot)
         afterUse <- sdk.snapshot
@@ -74,8 +74,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
   }
 
   test("Idle: keep 1 when `maxIdle` is 1") {
-    // todo replace with `withMaxIdle` once https://github.com/typelevel/keypool/pull/394 gets merged
-    poolTest(_.withMaxTotal(1)) { (sdk, pool) =>
+    poolTest(_.withMaxIdle(1)) { (sdk, pool) =>
       for {
         inUse <- pool.take.use(_ => sdk.snapshot)
         afterUse <- sdk.snapshot
@@ -87,8 +86,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
   }
 
   test("Idle: decrement on reaper cleanup") {
-    // todo replace with `withMaxIdle` once https://github.com/typelevel/keypool/pull/394 gets merged
-    poolTest(_.withMaxTotal(1).withIdleTimeAllowedInPool(1.second)) { (sdk, pool) =>
+    poolTest(_.withMaxIdle(1).withIdleTimeAllowedInPool(1.second)) { (sdk, pool) =>
       for {
         inUse <- pool.take.use(_ => sdk.snapshot)
         afterUse <- sdk.snapshot
@@ -107,7 +105,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
         .use(pool => pool.take.use(_ => sdk.snapshot.delayBy(500.millis)).product(sdk.snapshot))
         .map { case (inUse, afterUse) =>
           val acquireDuration =
-            List(HistogramSnapshot(0, 1, HistogramBuckets, List(1, 0, 0, 0, 0)))
+            List(HistogramSnapshot(0, 1, HistogramBuckets, List(0, 1, 0, 0, 0)))
 
           val expectedInUse = MetricsSnapshot(
             idle = 0,
@@ -125,11 +123,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
             acquireDuration = acquireDuration
           )
 
-          assertEquals(inUse, expectedInUse)
-          assertEquals(
-            afterUse.copy(inUseDuration = afterUse.inUseDuration.map(_.copy(sum = 0))),
-            expectedAfterUser
-          )
+          assertEquals(inUse.zeroSumHistogram, expectedInUse)
+          assertEquals(afterUse.zeroSumHistogram, expectedAfterUser)
           assert(afterUse.inUseDuration.forall(r => r.sum >= 500 && r.sum <= 700))
         }
     }
@@ -181,7 +176,10 @@ class PoolMetricsSpec extends CatsEffectSuite {
       new OtelSdk[IO] {
         def metricReader: InMemoryMetricReader = mr
         def otel: Otel4s[IO] = OtelJava.forSync[IO](sdk)
-        def flush: IO[Unit] = IO.blocking(mp.forceFlush().join(5, TimeUnit.SECONDS))
+        def flush: IO[Unit] = IO.blocking {
+          val _ = mp.forceFlush().join(5, TimeUnit.SECONDS)
+          ()
+        }
 
         def snapshot: IO[MetricsSnapshot] = {
           IO.delay {
@@ -227,32 +225,45 @@ class PoolMetricsSpec extends CatsEffectSuite {
     Resource.make(acquire)(release)
   }
 
+  private val HistogramBuckets: List[Double] =
+    List(0.01, 1, 100, 1000)
+
+  private def nothing(ref: Ref[IO, Int]): IO[Unit] =
+    ref.get.void
+
+}
+
+object PoolMetricsSpec {
+
+  trait OtelSdk[F[_]] {
+    def metricReader: InMemoryMetricReader
+    def otel: Otel4s[F]
+    def flush: F[Unit]
+    def snapshot: F[MetricsSnapshot]
+  }
+
   final case class MetricsSnapshot(
       idle: Long,
       inUse: Long,
       inUseDuration: List[HistogramSnapshot],
       acquiredTotal: Long,
       acquireDuration: List[HistogramSnapshot]
-  )
+  ) {
+    // use 0 for `histogram#sum` to simplify the comparison
+    def zeroSumHistogram: MetricsSnapshot =
+      copy(
+        inUseDuration = inUseDuration.map(_.zeroSum),
+        acquireDuration = acquireDuration.map(_.zeroSum)
+      )
+  }
 
   final case class HistogramSnapshot(
       sum: Double,
-      count: Double,
+      count: Long,
       boundaries: List[Double],
       counts: List[Long]
-  )
-
-  private trait OtelSdk[F[_]] {
-    def metricReader: InMemoryMetricReader
-    def otel: Otel4s[F]
-    def flush: F[Unit]
-    def snapshot: F[MetricsSnapshot]
+  ) {
+    def zeroSum: HistogramSnapshot = copy(sum = 0)
   }
 
-  private val HistogramBuckets: List[Double] =
-    List(0.01, 1, 100, 1000)
-
-  private def nothing(ref: Ref[IO, Int]): IO[Unit] =
-    ref.get.void
-
 }
diff --git a/core/src/main/scala/org/typelevel/keypool/KeyPool.scala b/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
index b4d011a6..e903e4e0 100644
--- a/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
+++ b/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
@@ -21,6 +21,7 @@
 
 package org.typelevel.keypool
 
+import java.util.concurrent.TimeUnit
 import cats._
 import cats.effect.kernel._
 import cats.effect.kernel.syntax.spawn._
@@ -202,7 +203,7 @@ object KeyPool {
               val (m_, toDestroy) = findStale(now, idleCount, m)
               (
                 m_,
-                toDestroy.traverse_(r => metrics.decIdle >> r._2._2).attempt.flatMap {
+                toDestroy.traverse_(r => metrics.idle.dec() >> r._2._2).attempt.flatMap {
                   case Left(t) => onReaperException(t)
                   // .handleErrorWith(t => F.delay(t.printStackTrace())) // CHEATING?
                   case Right(()) => F.unit
@@ -259,24 +260,24 @@ object KeyPool {
         }
       }
 
-    def decIdle = kp.kpMetrics.decIdle.whenA(isFromPool)
+    def decIdle = kp.kpMetrics.idle.dec().whenA(isFromPool)
 
     def go(now: FiniteDuration, pc: PoolMap[A, (B, F[Unit])]): (PoolMap[A, (B, F[Unit])], F[Unit]) =
       pc match {
         case p @ PoolClosed() => (p, decIdle >> destroy)
         case p @ PoolOpen(idleCount, m) =>
-          if (idleCount > kp.kpMaxIdle) (p, decIdle >> destroy)
+          if (kp.kpMaxIdle == 0 || idleCount > kp.kpMaxIdle) (p, decIdle >> destroy)
           else
             m.get(k) match {
               case None =>
                 val cnt_ = idleCount + 1
                 val m_ = PoolMap.open(cnt_, m + (k -> One((r, destroy), now)))
-                (m_, kp.kpMetrics.incIdle)
+                (m_, kp.kpMetrics.idle.inc())
               case Some(l) =>
                 val (l_, mx) = addToList(now, kp.kpMaxPerKey(k), (r, destroy), l)
                 val cnt_ = idleCount + mx.fold(1)(_ => 0)
                 val m_ = PoolMap.open(cnt_, m + (k -> l_))
-                (m_, mx.fold(kp.kpMetrics.incIdle)(_ => decIdle >> destroy))
+                (m_, mx.fold(kp.kpMetrics.idle.inc())(_ => decIdle >> destroy))
             }
       }
 
@@ -302,13 +303,16 @@ object KeyPool {
           }
       }
 
+    def allocateNew: F[(B, F[Unit])] =
+      kp.kpMetrics.acquireDuration
+        .recordDuration(TimeUnit.MILLISECONDS)
+        .use(_ => kp.kpRes(k).allocated)
+
     for {
       _ <- kp.kpMaxTotalSem.permit
       optR <- Resource.eval(kp.kpVar.modify(go))
       releasedState <- Resource.eval(Ref[F].of[Reusable](kp.kpDefaultReuseState))
-      resource <- Resource.make(
-        optR.fold(kp.kpMetrics.recordAcquireDuration(kp.kpRes(k)))(r => Applicative[F].pure(r))
-      ) { resource =>
+      resource <- Resource.make(optR.fold(allocateNew)(r => Applicative[F].pure(r))) { resource =>
         for {
           reusable <- releasedState.get
           out <- reusable match {
@@ -317,9 +321,9 @@ object KeyPool {
           }
         } yield out
       }
-      _ <- Resource.eval(kp.kpMetrics.acquiredTotal.add(1).whenA(optR.isEmpty))
-      _ <- Resource.make(kp.kpMetrics.incInUse)(_ => kp.kpMetrics.decInUse)
-      _ <- kp.kpMetrics.recordInUseDuration
+      _ <- Resource.eval(kp.kpMetrics.acquiredTotal.inc().whenA(optR.isEmpty))
+      _ <- Resource.make(kp.kpMetrics.inUse.inc())(_ => kp.kpMetrics.inUse.dec())
+      _ <- kp.kpMetrics.inUseDuration.recordDuration(TimeUnit.MILLISECONDS)
     } yield new Managed(resource._1, optR.isDefined, releasedState)
   }
 
diff --git a/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala b/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
index 43ed53bd..b00a6d0f 100644
--- a/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
+++ b/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
@@ -1,7 +1,6 @@
 package org.typelevel.keypool.internal
 
 import cats.Monad
-import cats.effect.{Resource, Temporal}
 import cats.syntax.functor._
 import cats.syntax.flatMap._
 import org.typelevel.otel4s._
@@ -29,25 +28,10 @@ private[keypool] trait Metrics[F[_]] {
 
   def acquireDuration: Histogram[F, Double]
 
-  private[keypool] final def incIdle: F[Unit] = idle.add(1L)
-  private[keypool] final def decIdle: F[Unit] = idle.add(-1L)
-  private[keypool] final def incInUse: F[Unit] = inUse.add(1L)
-  private[keypool] final def decInUse: F[Unit] = inUse.add(-1L)
-
-  private[keypool] final def recordInUseDuration(implicit F: Temporal[F]): Resource[F, Unit] =
-    Metrics.recordInUseDuration(this)
-
-  private[keypool] final def recordAcquireDuration[A](
-      resource: Resource[F, A]
-  )(implicit F: Temporal[F]): F[(A, F[Unit])] =
-    Metrics.recordAcquireDuration(this, resource)
-
 }
 
 private[keypool] object Metrics {
 
-  private val CauseKey: AttributeKey[String] = AttributeKey.string("cause")
-
   def fromMeterProvider[F[_]: Monad](meterProvider: MeterProvider[F]): F[Metrics[F]] = {
     for {
       meter <- meterProvider.get("org.typelevel.keypool")
@@ -88,33 +72,4 @@ private[keypool] object Metrics {
     }
   }
 
-  private def recordInUseDuration[F[_]](
-      metrics: Metrics[F]
-  )(implicit F: Temporal[F]): Resource[F, Unit] =
-    Resource
-      .makeCase(Temporal[F].monotonic) { case (start, ec) =>
-        for {
-          end <- Temporal[F].monotonic
-          _ <- metrics.inUseDuration.record((end - start).toMillis, causeAttributes(ec): _*)
-        } yield ()
-      }
-      .void
-
-  private def recordAcquireDuration[F[_], A](
-      metrics: Metrics[F],
-      resource: Resource[F, A]
-  )(implicit F: Temporal[F]): F[(A, F[Unit])] =
-    Temporal[F]
-      .timed(resource.allocated)
-      .flatMap { case (acquireTime, r) =>
-        metrics.acquireDuration.record(acquireTime.toMillis).as(r)
-      }
-
-  private def causeAttributes(ec: Resource.ExitCase): List[Attribute[String]] =
-    ec match {
-      case Resource.ExitCase.Succeeded => Nil
-      case Resource.ExitCase.Errored(e) => List(Attribute(CauseKey, e.getClass.getName))
-      case Resource.ExitCase.Canceled => List(Attribute(CauseKey, "canceled"))
-    }
-
 }

From 734fedf1f7c717ac531aaf670cd58838e8baa310 Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Mon, 13 Jun 2022 10:53:16 +0300
Subject: [PATCH 03/19] Use `CrossType.Full`

---
 build.sbt                                                       | 2 +-
 .../src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala  | 0
 .../src/main/scala/org/typelevel/keypool/KeyPool.scala          | 0
 .../src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala   | 0
 .../src/main/scala/org/typelevel/keypool/Managed.scala          | 0
 .../src/main/scala/org/typelevel/keypool/Pool.scala             | 0
 .../src/main/scala/org/typelevel/keypool/PoolStats.scala        | 0
 .../src/main/scala/org/typelevel/keypool/Reusable.scala         | 0
 .../src/main/scala/org/typelevel/keypool/internal/Metrics.scala | 0
 .../main/scala/org/typelevel/keypool/internal/PoolList.scala    | 0
 .../src/main/scala/org/typelevel/keypool/internal/PoolMap.scala | 0
 .../src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala      | 2 +-
 .../src/test/scala/org/typelevel/keypool/PoolSpec.scala         | 0
 13 files changed, 2 insertions(+), 2 deletions(-)
 rename core/{.jvm => jvm}/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala (100%)
 rename core/{ => shared}/src/main/scala/org/typelevel/keypool/KeyPool.scala (100%)
 rename core/{ => shared}/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala (100%)
 rename core/{ => shared}/src/main/scala/org/typelevel/keypool/Managed.scala (100%)
 rename core/{ => shared}/src/main/scala/org/typelevel/keypool/Pool.scala (100%)
 rename core/{ => shared}/src/main/scala/org/typelevel/keypool/PoolStats.scala (100%)
 rename core/{ => shared}/src/main/scala/org/typelevel/keypool/Reusable.scala (100%)
 rename core/{ => shared}/src/main/scala/org/typelevel/keypool/internal/Metrics.scala (100%)
 rename core/{ => shared}/src/main/scala/org/typelevel/keypool/internal/PoolList.scala (100%)
 rename core/{ => shared}/src/main/scala/org/typelevel/keypool/internal/PoolMap.scala (100%)
 rename core/{ => shared}/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala (99%)
 rename core/{ => shared}/src/test/scala/org/typelevel/keypool/PoolSpec.scala (100%)

diff --git a/build.sbt b/build.sbt
index 741c048c..425bab03 100644
--- a/build.sbt
+++ b/build.sbt
@@ -13,7 +13,7 @@ ThisBuild / tlSiteApiUrl := Some(url("https://www.javadoc.io/doc/org.typelevel/k
 lazy val root = tlCrossRootProject.aggregate(core)
 
 lazy val core = crossProject(JVMPlatform, JSPlatform)
-  .crossType(CrossType.Pure)
+  .crossType(CrossType.Full)
   .in(file("core"))
   .settings(commonSettings)
   .settings(
diff --git a/core/.jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
similarity index 100%
rename from core/.jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
rename to core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
diff --git a/core/src/main/scala/org/typelevel/keypool/KeyPool.scala b/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/keypool/KeyPool.scala
rename to core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala
diff --git a/core/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala b/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
rename to core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
diff --git a/core/src/main/scala/org/typelevel/keypool/Managed.scala b/core/shared/src/main/scala/org/typelevel/keypool/Managed.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/keypool/Managed.scala
rename to core/shared/src/main/scala/org/typelevel/keypool/Managed.scala
diff --git a/core/src/main/scala/org/typelevel/keypool/Pool.scala b/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/keypool/Pool.scala
rename to core/shared/src/main/scala/org/typelevel/keypool/Pool.scala
diff --git a/core/src/main/scala/org/typelevel/keypool/PoolStats.scala b/core/shared/src/main/scala/org/typelevel/keypool/PoolStats.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/keypool/PoolStats.scala
rename to core/shared/src/main/scala/org/typelevel/keypool/PoolStats.scala
diff --git a/core/src/main/scala/org/typelevel/keypool/Reusable.scala b/core/shared/src/main/scala/org/typelevel/keypool/Reusable.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/keypool/Reusable.scala
rename to core/shared/src/main/scala/org/typelevel/keypool/Reusable.scala
diff --git a/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala b/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
rename to core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
diff --git a/core/src/main/scala/org/typelevel/keypool/internal/PoolList.scala b/core/shared/src/main/scala/org/typelevel/keypool/internal/PoolList.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/keypool/internal/PoolList.scala
rename to core/shared/src/main/scala/org/typelevel/keypool/internal/PoolList.scala
diff --git a/core/src/main/scala/org/typelevel/keypool/internal/PoolMap.scala b/core/shared/src/main/scala/org/typelevel/keypool/internal/PoolMap.scala
similarity index 100%
rename from core/src/main/scala/org/typelevel/keypool/internal/PoolMap.scala
rename to core/shared/src/main/scala/org/typelevel/keypool/internal/PoolMap.scala
diff --git a/core/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala b/core/shared/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala
similarity index 99%
rename from core/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala
rename to core/shared/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala
index 8eb60997..d5527133 100644
--- a/core/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala
+++ b/core/shared/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala
@@ -27,7 +27,7 @@ import cats.effect.std.CountDownLatch
 import scala.concurrent.duration._
 import munit.CatsEffectSuite
 
-class KeypoolSpec extends CatsEffectSuite {
+class KeyPoolSpec extends CatsEffectSuite {
 
   test("Keep Resources marked to be kept") {
     KeyPool
diff --git a/core/src/test/scala/org/typelevel/keypool/PoolSpec.scala b/core/shared/src/test/scala/org/typelevel/keypool/PoolSpec.scala
similarity index 100%
rename from core/src/test/scala/org/typelevel/keypool/PoolSpec.scala
rename to core/shared/src/test/scala/org/typelevel/keypool/PoolSpec.scala

From 4a178e8654937270ddcef813fc82d752f2c3b981 Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Sat, 18 Jun 2022 17:14:31 +0300
Subject: [PATCH 04/19] Use `otel4s-testkit`

---
 build.sbt                                     |   7 +-
 .../typelevel/keypool/PoolMetricsSpec.scala   | 224 ++++++++----------
 2 files changed, 97 insertions(+), 134 deletions(-)

diff --git a/build.sbt b/build.sbt
index 425bab03..dd0bd098 100644
--- a/build.sbt
+++ b/build.sbt
@@ -25,9 +25,8 @@ lazy val core = crossProject(JVMPlatform, JSPlatform)
   )
   .jvmSettings(
     libraryDependencies ++= Seq(
-      "org.typelevel"   %% "otel4s-java"               % otel4sV  % Test,
-      "io.opentelemetry" % "opentelemetry-sdk"         % "1.15.0" % Test,
-      "io.opentelemetry" % "opentelemetry-sdk-testing" % "1.15.0" % Test
+      "org.typelevel" %% "otel4s-java"    % otel4sV % Test,
+      "org.typelevel" %% "otel4s-testkit" % otel4sV % Test
     )
   )
   .settings(
@@ -59,7 +58,7 @@ lazy val docs = project
 val catsV = "2.7.0"
 val catsEffectV = "3.3.12"
 
-val otel4sV = "0.0-7f89139-20220613T071957Z-SNAPSHOT"
+val otel4sV = "0.0-e63fe8a-20220618T140401Z-SNAPSHOT"
 
 val munitV = "0.7.29"
 val munitCatsEffectV = "1.0.7"
diff --git a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index 1e785f4f..d0bab851 100644
--- a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -1,21 +1,17 @@
 package org.typelevel.keypool
 
-import java.util.concurrent.TimeUnit
-
-import cats.syntax.all._
 import cats.effect._
-import io.opentelemetry.sdk.OpenTelemetrySdk
 import io.opentelemetry.sdk.metrics.{
   Aggregation,
   InstrumentSelector,
   InstrumentType,
-  SdkMeterProvider,
+  SdkMeterProviderBuilder,
   View
 }
-import io.opentelemetry.sdk.testing.exporter.InMemoryMetricReader
 import munit.CatsEffectSuite
 import org.typelevel.otel4s.{MeterProvider, Otel4s}
 import org.typelevel.otel4s.java.OtelJava
+import org.typelevel.otel4s.testkit.{HistogramPointData, Metric, MetricData, Sdk}
 import scala.concurrent.duration._
 import scala.jdk.CollectionConverters._
 import scala.util.control.NoStackTrace
@@ -24,10 +20,12 @@ class PoolMetricsSpec extends CatsEffectSuite {
   import PoolMetricsSpec._
 
   test("Metrics should be empty for unused pool") {
-    val expectedSnapshot = MetricsSnapshot(0, 0, Nil, 0, Nil)
+    val sdk = createSdk
+    val expectedSnapshot =
+      MetricsSnapshot(Nil, Nil, Nil, Nil, Nil)
 
     for {
-      snapshot <- setupSdk.use(sdk => mkPool(sdk.otel.meterProvider).use(_ => sdk.snapshot))
+      snapshot <- mkPool(sdk.otel.meterProvider).use(_ => sdk.snapshot)
     } yield assertEquals(snapshot, expectedSnapshot)
   }
 
@@ -37,8 +35,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
         inUse <- pool.take.use(_ => sdk.snapshot)
         afterUse <- sdk.snapshot
       } yield {
-        assertEquals(inUse.inUse, 1L)
-        assertEquals(afterUse.inUse, 0L)
+        assertEquals(inUse.inUse, List(1L))
+        assertEquals(afterUse.inUse, List(0L))
       }
     }
   }
@@ -55,8 +53,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
         inUse <- deferred.get
         afterUse <- sdk.snapshot
       } yield {
-        assertEquals(inUse.inUse, 1L)
-        assertEquals(afterUse.inUse, 0L)
+        assertEquals(inUse.inUse, List(1L))
+        assertEquals(afterUse.inUse, List(0L))
       }
     }
   }
@@ -67,8 +65,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
         inUse <- pool.take.use(_ => sdk.snapshot)
         afterUse <- sdk.snapshot
       } yield {
-        assertEquals(inUse.idle, 0L)
-        assertEquals(afterUse.idle, 0L)
+        assertEquals(inUse.idle, Nil)
+        assertEquals(afterUse.idle, Nil)
       }
     }
   }
@@ -79,8 +77,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
         inUse <- pool.take.use(_ => sdk.snapshot)
         afterUse <- sdk.snapshot
       } yield {
-        assertEquals(inUse.idle, 0L)
-        assertEquals(afterUse.idle, 1L)
+        assertEquals(inUse.idle, Nil)
+        assertEquals(afterUse.idle, List(1L))
       }
     }
   }
@@ -92,53 +90,54 @@ class PoolMetricsSpec extends CatsEffectSuite {
         afterUse <- sdk.snapshot
         afterSleep <- sdk.snapshot.delayBy(6.seconds)
       } yield {
-        assertEquals(inUse.idle, 0L)
-        assertEquals(afterUse.idle, 1L)
-        assertEquals(afterSleep.idle, 0L)
+        assertEquals(inUse.idle, Nil)
+        assertEquals(afterUse.idle, List(1L))
+        assertEquals(afterSleep.idle, List(0L))
       }
     }
   }
 
   test("Generate valid metric snapshots") {
-    setupSdk.use { sdk =>
-      mkPool(sdk.otel.meterProvider)
-        .use(pool => pool.take.use(_ => sdk.snapshot.delayBy(500.millis)).product(sdk.snapshot))
-        .map { case (inUse, afterUse) =>
-          val acquireDuration =
-            List(HistogramSnapshot(0, 1, HistogramBuckets, List(0, 1, 0, 0, 0)))
-
-          val expectedInUse = MetricsSnapshot(
-            idle = 0,
-            inUse = 1,
-            inUseDuration = Nil,
-            acquiredTotal = 1,
-            acquireDuration = acquireDuration
-          )
+    val sdk = createSdk
+
+    mkPool(sdk.otel.meterProvider)
+      .use(pool => pool.take.use(_ => sdk.snapshot.delayBy(500.millis)).product(sdk.snapshot))
+      .map { case (inUse, afterUse) =>
+        val acquireDuration =
+          List(HistogramPointData(0, 1, HistogramBuckets, List(0, 1, 0, 0, 0)))
+
+        val expectedInUse = MetricsSnapshot(
+          idle = Nil,
+          inUse = List(1),
+          inUseDuration = Nil,
+          acquiredTotal = List(1),
+          acquireDuration = acquireDuration
+        )
 
-          val expectedAfterUser = MetricsSnapshot(
-            idle = 1,
-            inUse = 0,
-            inUseDuration = List(HistogramSnapshot(0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))),
-            acquiredTotal = 1,
-            acquireDuration = acquireDuration
-          )
+        val expectedAfterUser = MetricsSnapshot(
+          idle = List(1),
+          inUse = List(0),
+          inUseDuration = List(HistogramPointData(0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))),
+          acquiredTotal = List(1),
+          acquireDuration = acquireDuration
+        )
 
-          assertEquals(inUse.zeroSumHistogram, expectedInUse)
-          assertEquals(afterUse.zeroSumHistogram, expectedAfterUser)
-          assert(afterUse.inUseDuration.forall(r => r.sum >= 500 && r.sum <= 700))
-        }
-    }
+        assertEquals(inUse.zeroSumHistogram, expectedInUse)
+        assertEquals(afterUse.zeroSumHistogram, expectedAfterUser)
+        assert(afterUse.inUseDuration.forall(r => r.sum >= 500 && r.sum <= 700))
+      }
   }
 
   private def poolTest(
       customize: Pool.Builder[IO, Ref[IO, Int]] => Pool.Builder[IO, Ref[IO, Int]] = identity
-  )(scenario: (OtelSdk[IO], Pool[IO, Ref[IO, Int]]) => IO[Unit]): IO[Unit] =
-    setupSdk.use { sdk =>
-      val builder =
-        Pool.Builder(Ref.of[IO, Int](1), nothing).withMeterProvider(sdk.otel.meterProvider)
+  )(scenario: (OtelSdk[IO], Pool[IO, Ref[IO, Int]]) => IO[Unit]): IO[Unit] = {
+    val sdk = createSdk
 
-      customize(builder).build.use(pool => scenario(sdk, pool))
-    }
+    val builder =
+      Pool.Builder(Ref.of[IO, Int](1), nothing).withMeterProvider(sdk.otel.meterProvider)
+
+    customize(builder).build.use(pool => scenario(sdk, pool))
+  }
 
   private def mkPool(meterProvider: MeterProvider[IO]) =
     Pool
@@ -150,13 +149,9 @@ class PoolMetricsSpec extends CatsEffectSuite {
       .withMaxTotal(10)
       .build
 
-  private def setupSdk: Resource[IO, OtelSdk[IO]] = {
-    val acquire = IO.delay {
-      val mr = InMemoryMetricReader.create()
-
-      val mp = SdkMeterProvider
-        .builder()
-        .registerMetricReader(mr)
+  private def createSdk: OtelSdk[IO] = {
+    def customize(builder: SdkMeterProviderBuilder) =
+      builder
         .registerView(
           InstrumentSelector.builder().setType(InstrumentType.HISTOGRAM).build(),
           View
@@ -166,63 +161,43 @@ class PoolMetricsSpec extends CatsEffectSuite {
             )
             .build()
         )
-        .build()
-
-      val sdk = OpenTelemetrySdk
-        .builder()
-        .setMeterProvider(mp)
-        .build()
-
-      new OtelSdk[IO] {
-        def metricReader: InMemoryMetricReader = mr
-        def otel: Otel4s[IO] = OtelJava.forSync[IO](sdk)
-        def flush: IO[Unit] = IO.blocking {
-          val _ = mp.forceFlush().join(5, TimeUnit.SECONDS)
-          ()
-        }
 
-        def snapshot: IO[MetricsSnapshot] = {
-          IO.delay {
-            val items = metricReader.collectAllMetrics().asScala.toList
-
-            def counterValue(name: String): Long =
-              items
-                .find(_.getName === name)
-                .flatMap(_.getLongSumData.getPoints.asScala.headOption.map(_.getValue))
-                .getOrElse(0L)
-
-            def histogramSnapshot(name: String): List[HistogramSnapshot] =
-              items
-                .find(_.getName === name)
-                .map { metric =>
-                  val points = metric.getHistogramData.getPoints.asScala.toList
-
-                  points.map { hdp =>
-                    HistogramSnapshot(
-                      hdp.getSum,
-                      hdp.getCount,
-                      hdp.getBoundaries.asScala.toList.map(Double.unbox),
-                      hdp.getCounts.asScala.toList.map(Long.unbox)
-                    )
-                  }
-                }
-                .getOrElse(Nil)
-
-            MetricsSnapshot(
-              counterValue("idle"),
-              counterValue("in_use"),
-              histogramSnapshot("in_use_duration"),
-              counterValue("acquired_total"),
-              histogramSnapshot("acquire_duration")
-            )
-          }
+    val sdk = Sdk.create[IO](customize)
+
+    new OtelSdk[IO] {
+      val otel: Otel4s[IO] = OtelJava.forSync[IO](sdk.sdk)
+
+      def snapshot: IO[MetricsSnapshot] =
+        for {
+          metrics <- sdk.metrics
+        } yield {
+          def counterValue(name: String): List[Long] =
+            metrics
+              .collectFirst {
+                case Metric(metricName, _, _, _, _, MetricData.LongSum(points))
+                    if metricName == name =>
+                  points.map(_.value)
+              }
+              .getOrElse(Nil)
+
+          def histogramSnapshot(name: String): List[HistogramPointData] =
+            metrics
+              .collectFirst {
+                case Metric(metricName, _, _, _, _, h: MetricData.Histogram)
+                    if metricName == name =>
+                  h.points.map(_.value)
+              }
+              .getOrElse(Nil)
+
+          MetricsSnapshot(
+            counterValue("idle"),
+            counterValue("in_use"),
+            histogramSnapshot("in_use_duration"),
+            counterValue("acquired_total"),
+            histogramSnapshot("acquire_duration")
+          )
         }
-      }
     }
-
-    def release(sdk: OtelSdk[IO]) = sdk.flush
-
-    Resource.make(acquire)(release)
   }
 
   private val HistogramBuckets: List[Double] =
@@ -236,34 +211,23 @@ class PoolMetricsSpec extends CatsEffectSuite {
 object PoolMetricsSpec {
 
   trait OtelSdk[F[_]] {
-    def metricReader: InMemoryMetricReader
     def otel: Otel4s[F]
-    def flush: F[Unit]
     def snapshot: F[MetricsSnapshot]
   }
 
   final case class MetricsSnapshot(
-      idle: Long,
-      inUse: Long,
-      inUseDuration: List[HistogramSnapshot],
-      acquiredTotal: Long,
-      acquireDuration: List[HistogramSnapshot]
+      idle: List[Long],
+      inUse: List[Long],
+      inUseDuration: List[HistogramPointData],
+      acquiredTotal: List[Long],
+      acquireDuration: List[HistogramPointData]
   ) {
     // use 0 for `histogram#sum` to simplify the comparison
     def zeroSumHistogram: MetricsSnapshot =
       copy(
-        inUseDuration = inUseDuration.map(_.zeroSum),
-        acquireDuration = acquireDuration.map(_.zeroSum)
+        inUseDuration = inUseDuration.map(_.copy(sum = 0)),
+        acquireDuration = acquireDuration.map(_.copy(sum = 0))
       )
   }
 
-  final case class HistogramSnapshot(
-      sum: Double,
-      count: Long,
-      boundaries: List[Double],
-      counts: List[Long]
-  ) {
-    def zeroSum: HistogramSnapshot = copy(sum = 0)
-  }
-
 }

From a3b253d49fa46bca95a6a4227668dac8660015b5 Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Sun, 3 Jul 2022 10:38:57 +0300
Subject: [PATCH 05/19] Update `otel4s-testkit`

---
 build.sbt                                     |  2 +-
 .../typelevel/keypool/PoolMetricsSpec.scala   | 86 ++++++++++---------
 .../scala/org/typelevel/keypool/KeyPool.scala |  2 +-
 .../typelevel/keypool/KeyPoolBuilder.scala    |  2 +-
 .../scala/org/typelevel/keypool/Pool.scala    |  2 +-
 .../typelevel/keypool/internal/Metrics.scala  |  2 +-
 6 files changed, 49 insertions(+), 47 deletions(-)

diff --git a/build.sbt b/build.sbt
index eadec3ed..4838427b 100644
--- a/build.sbt
+++ b/build.sbt
@@ -58,7 +58,7 @@ lazy val docs = project
 val catsV = "2.7.0"
 val catsEffectV = "3.3.13"
 
-val otel4sV = "0.0-e63fe8a-20220618T140401Z-SNAPSHOT"
+val otel4sV = "0.0-53d0a08-20220703T071423Z-SNAPSHOT"
 
 val munitV = "0.7.29"
 val munitCatsEffectV = "1.0.7"
diff --git a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index d0bab851..46cf3593 100644
--- a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -1,6 +1,7 @@
 package org.typelevel.keypool
 
 import cats.effect._
+import cats.effect.testkit._
 import io.opentelemetry.sdk.metrics.{
   Aggregation,
   InstrumentSelector,
@@ -9,8 +10,9 @@ import io.opentelemetry.sdk.metrics.{
   View
 }
 import munit.CatsEffectSuite
-import org.typelevel.otel4s.{MeterProvider, Otel4s}
+import org.typelevel.otel4s.Otel4s
 import org.typelevel.otel4s.java.OtelJava
+import org.typelevel.otel4s.metrics.MeterProvider
 import org.typelevel.otel4s.testkit.{HistogramPointData, Metric, MetricData, Sdk}
 import scala.concurrent.duration._
 import scala.jdk.CollectionConverters._
@@ -84,15 +86,17 @@ class PoolMetricsSpec extends CatsEffectSuite {
   }
 
   test("Idle: decrement on reaper cleanup") {
-    poolTest(_.withMaxIdle(1).withIdleTimeAllowedInPool(1.second)) { (sdk, pool) =>
-      for {
-        inUse <- pool.take.use(_ => sdk.snapshot)
-        afterUse <- sdk.snapshot
-        afterSleep <- sdk.snapshot.delayBy(6.seconds)
-      } yield {
-        assertEquals(inUse.idle, Nil)
-        assertEquals(afterUse.idle, List(1L))
-        assertEquals(afterSleep.idle, List(0L))
+    TestControl.executeEmbed {
+      poolTest(_.withMaxIdle(1).withIdleTimeAllowedInPool(1.second)) { (sdk, pool) =>
+        for {
+          inUse <- pool.take.use(_ => sdk.snapshot)
+          afterUse <- sdk.snapshot
+          afterSleep <- sdk.snapshot.delayBy(6.seconds)
+        } yield {
+          assertEquals(inUse.idle, Nil)
+          assertEquals(afterUse.idle, List(1L))
+          assertEquals(afterSleep.idle, List(0L))
+        }
       }
     }
   }
@@ -100,32 +104,37 @@ class PoolMetricsSpec extends CatsEffectSuite {
   test("Generate valid metric snapshots") {
     val sdk = createSdk
 
-    mkPool(sdk.otel.meterProvider)
-      .use(pool => pool.take.use(_ => sdk.snapshot.delayBy(500.millis)).product(sdk.snapshot))
-      .map { case (inUse, afterUse) =>
-        val acquireDuration =
-          List(HistogramPointData(0, 1, HistogramBuckets, List(0, 1, 0, 0, 0)))
-
-        val expectedInUse = MetricsSnapshot(
-          idle = Nil,
-          inUse = List(1),
-          inUseDuration = Nil,
-          acquiredTotal = List(1),
-          acquireDuration = acquireDuration
-        )
+    TestControl.executeEmbed {
+      mkPool(sdk.otel.meterProvider)
+        .use(pool => pool.take.use(_ => sdk.snapshot.delayBy(500.millis)).product(sdk.snapshot))
+        .map { case (inUse, afterUse) =>
+          val acquireDuration =
+            List(
+              HistogramPointData(0, 1, HistogramBuckets, List(1, 0, 0, 0, 0))
+            )
 
-        val expectedAfterUser = MetricsSnapshot(
-          idle = List(1),
-          inUse = List(0),
-          inUseDuration = List(HistogramPointData(0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))),
-          acquiredTotal = List(1),
-          acquireDuration = acquireDuration
-        )
+          val expectedInUse = MetricsSnapshot(
+            idle = Nil,
+            inUse = List(1),
+            inUseDuration = Nil,
+            acquiredTotal = List(1),
+            acquireDuration = acquireDuration
+          )
 
-        assertEquals(inUse.zeroSumHistogram, expectedInUse)
-        assertEquals(afterUse.zeroSumHistogram, expectedAfterUser)
-        assert(afterUse.inUseDuration.forall(r => r.sum >= 500 && r.sum <= 700))
-      }
+          val expectedAfterUser = MetricsSnapshot(
+            idle = List(1),
+            inUse = List(0),
+            inUseDuration = List(
+              HistogramPointData(500.0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))
+            ),
+            acquiredTotal = List(1),
+            acquireDuration = acquireDuration
+          )
+
+          assertEquals(inUse, expectedInUse)
+          assertEquals(afterUse, expectedAfterUser)
+        }
+    }
   }
 
   private def poolTest(
@@ -221,13 +230,6 @@ object PoolMetricsSpec {
       inUseDuration: List[HistogramPointData],
       acquiredTotal: List[Long],
       acquireDuration: List[HistogramPointData]
-  ) {
-    // use 0 for `histogram#sum` to simplify the comparison
-    def zeroSumHistogram: MetricsSnapshot =
-      copy(
-        inUseDuration = inUseDuration.map(_.copy(sum = 0)),
-        acquireDuration = acquireDuration.map(_.copy(sum = 0))
-      )
-  }
+  )
 
 }
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala b/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala
index e903e4e0..9e220f5d 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala
+++ b/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala
@@ -29,7 +29,7 @@ import cats.effect.std.Semaphore
 import cats.syntax.all._
 import scala.concurrent.duration._
 import org.typelevel.keypool.internal._
-import org.typelevel.otel4s.MeterProvider
+import org.typelevel.otel4s.metrics.MeterProvider
 
 /**
  * This pools internal guarantees are that the max number of values are in the pool at any time, not
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala b/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
index ba4e8b80..ebb97c06 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
+++ b/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
@@ -27,7 +27,7 @@ import cats.syntax.all._
 import cats.effect.kernel._
 import cats.effect.kernel.syntax.spawn._
 import cats.effect.std.Semaphore
-import org.typelevel.otel4s.MeterProvider
+import org.typelevel.otel4s.metrics.MeterProvider
 import scala.concurrent.duration._
 
 @deprecated("use KeyPool.Builder", "0.4.7")
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala b/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala
index e2233f46..e33469af 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala
+++ b/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala
@@ -24,7 +24,7 @@ package org.typelevel.keypool
 import cats._
 import cats.effect.kernel._
 import cats.syntax.all._
-import org.typelevel.otel4s.MeterProvider
+import org.typelevel.otel4s.metrics.MeterProvider
 import scala.concurrent.duration._
 
 /**
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala b/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
index b00a6d0f..cae523d6 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
+++ b/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
@@ -3,7 +3,7 @@ package org.typelevel.keypool.internal
 import cats.Monad
 import cats.syntax.functor._
 import cats.syntax.flatMap._
-import org.typelevel.otel4s._
+import org.typelevel.otel4s.metrics._
 
 private[keypool] trait Metrics[F[_]] {
 

From 1e16c635a59302684b99a03a345349bde5f74ae1 Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Sun, 3 Jul 2022 10:41:04 +0300
Subject: [PATCH 06/19] Generate headers, update `ci.yml`

---
 .github/workflows/ci.yml                      |  4 ++--
 .../typelevel/keypool/PoolMetricsSpec.scala   | 21 +++++++++++++++++++
 .../typelevel/keypool/internal/Metrics.scala  | 21 +++++++++++++++++++
 3 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fa7cfaaa..5923c37d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -90,11 +90,11 @@ jobs:
 
       - name: Make target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: mkdir -p target .js/target site/target core/.js/target core/.jvm/target .jvm/target .native/target project/target
+        run: mkdir -p target .js/target site/target core/js/target core/jvm/target .jvm/target .native/target project/target
 
       - name: Compress target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: tar cf targets.tar target .js/target site/target core/.js/target core/.jvm/target .jvm/target .native/target project/target
+        run: tar cf targets.tar target .js/target site/target core/js/target core/jvm/target .jvm/target .native/target project/target
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
diff --git a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index 46cf3593..3ce17de7 100644
--- a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -1,3 +1,24 @@
+/*
+ * Copyright (c) 2019 Typelevel
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
 package org.typelevel.keypool
 
 import cats.effect._
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala b/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
index cae523d6..22b16141 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
+++ b/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
@@ -1,3 +1,24 @@
+/*
+ * Copyright (c) 2019 Typelevel
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
 package org.typelevel.keypool.internal
 
 import cats.Monad

From 7f172fbbd5971819b68717c9093a5079dcab59f7 Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Wed, 3 Aug 2022 12:53:37 +0300
Subject: [PATCH 07/19] Use snapshot version of `otel4s`

---
 build.sbt                                     |  5 +++--
 .../typelevel/keypool/PoolMetricsSpec.scala   | 22 +++++++++----------
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/build.sbt b/build.sbt
index 4838427b..38d3d9ff 100644
--- a/build.sbt
+++ b/build.sbt
@@ -3,7 +3,7 @@ import com.typesafe.tools.mima.core._
 val Scala213 = "2.13.8"
 
 ThisBuild / tlBaseVersion := "0.4"
-ThisBuild / crossScalaVersions := Seq("2.12.16", Scala213, "3.0.2")
+ThisBuild / crossScalaVersions := Seq("2.12.16", Scala213, "3.1.2")
 ThisBuild / tlVersionIntroduced := Map("3" -> "0.4.3")
 ThisBuild / developers += tlGitHubDev("ChristopherDavenport", "Christopher Davenport")
 ThisBuild / startYear := Some(2019)
@@ -58,7 +58,7 @@ lazy val docs = project
 val catsV = "2.7.0"
 val catsEffectV = "3.3.13"
 
-val otel4sV = "0.0-53d0a08-20220703T071423Z-SNAPSHOT"
+val otel4sV = "0.0-2daac91-SNAPSHOT"
 
 val munitV = "0.7.29"
 val munitCatsEffectV = "1.0.7"
@@ -69,6 +69,7 @@ val betterMonadicForV = "0.3.1"
 // General Settings
 lazy val commonSettings = Seq(
   Test / parallelExecution := false,
+  resolvers += "Sonatype OSS Snapshots" at "https://s01.oss.sonatype.org/content/repositories/snapshots",
   libraryDependencies ++= Seq(
     "org.typelevel" %%% "cats-core"           % catsV,
     "org.typelevel" %%% "cats-effect-std"     % catsEffectV,
diff --git a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index 3ce17de7..294a1cef 100644
--- a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -34,7 +34,7 @@ import munit.CatsEffectSuite
 import org.typelevel.otel4s.Otel4s
 import org.typelevel.otel4s.java.OtelJava
 import org.typelevel.otel4s.metrics.MeterProvider
-import org.typelevel.otel4s.testkit.{HistogramPointData, Metric, MetricData, Sdk}
+import org.typelevel.otel4s.testkit.{HistogramPointData, MetricData, Sdk}
 import scala.concurrent.duration._
 import scala.jdk.CollectionConverters._
 import scala.util.control.NoStackTrace
@@ -131,7 +131,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
         .map { case (inUse, afterUse) =>
           val acquireDuration =
             List(
-              HistogramPointData(0, 1, HistogramBuckets, List(1, 0, 0, 0, 0))
+              new HistogramPointData(0, 1, HistogramBuckets, List(1, 0, 0, 0, 0))
             )
 
           val expectedInUse = MetricsSnapshot(
@@ -146,7 +146,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
             idle = List(1),
             inUse = List(0),
             inUseDuration = List(
-              HistogramPointData(500.0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))
+              new HistogramPointData(500.0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))
             ),
             acquiredTotal = List(1),
             acquireDuration = acquireDuration
@@ -203,19 +203,19 @@ class PoolMetricsSpec extends CatsEffectSuite {
         } yield {
           def counterValue(name: String): List[Long] =
             metrics
-              .collectFirst {
-                case Metric(metricName, _, _, _, _, MetricData.LongSum(points))
-                    if metricName == name =>
-                  points.map(_.value)
+              .find(_.name == name)
+              .map(_.data)
+              .collectFirst { case MetricData.LongSum(points) =>
+                points.map(_.value)
               }
               .getOrElse(Nil)
 
           def histogramSnapshot(name: String): List[HistogramPointData] =
             metrics
-              .collectFirst {
-                case Metric(metricName, _, _, _, _, h: MetricData.Histogram)
-                    if metricName == name =>
-                  h.points.map(_.value)
+              .find(_.name == name)
+              .map(_.data)
+              .collectFirst { case MetricData.Histogram(points) =>
+                points.map(_.value)
               }
               .getOrElse(Nil)
 

From 016178bd8fa35e9dcec83b0a8ce45df854944d03 Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Wed, 3 Aug 2022 13:02:18 +0300
Subject: [PATCH 08/19] Use `Resolver.sonatypeOssRepos`

---
 build.sbt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/build.sbt b/build.sbt
index 74691012..689b51bb 100644
--- a/build.sbt
+++ b/build.sbt
@@ -69,7 +69,7 @@ val betterMonadicForV = "0.3.1"
 // General Settings
 lazy val commonSettings = Seq(
   Test / parallelExecution := false,
-  resolvers += "Sonatype OSS Snapshots" at "https://s01.oss.sonatype.org/content/repositories/snapshots",
+  resolvers ++= Resolver.sonatypeOssRepos("snapshots"),
   libraryDependencies ++= Seq(
     "org.typelevel" %%% "cats-core"           % catsV,
     "org.typelevel" %%% "cats-effect-std"     % catsEffectV,

From 831588c858fcf7c6d729390f4e44c201f10d631a Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Wed, 25 Jan 2023 09:37:25 +0200
Subject: [PATCH 09/19] Use `otel4s` snapshot

---
 .github/workflows/ci.yml                      |   4 +-
 .../typelevel/keypool/PoolMetricsSpec.scala   | 144 +++++++++---------
 2 files changed, 75 insertions(+), 73 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 31e2f4e8..0f269705 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -94,11 +94,11 @@ jobs:
 
       - name: Make target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: mkdir -p target .js/target core/.native/target site/target core/.js/target core/.jvm/target .jvm/target .native/target project/target
+        run: mkdir -p target .js/target core/native/target site/target core/js/target core/jvm/target .jvm/target .native/target project/target
 
       - name: Compress target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: tar cf targets.tar target .js/target core/.native/target site/target core/.js/target core/.jvm/target .jvm/target .native/target project/target
+        run: tar cf targets.tar target .js/target core/native/target site/target core/js/target core/jvm/target .jvm/target .native/target project/target
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
diff --git a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index 294a1cef..d1ec1452 100644
--- a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -34,7 +34,7 @@ import munit.CatsEffectSuite
 import org.typelevel.otel4s.Otel4s
 import org.typelevel.otel4s.java.OtelJava
 import org.typelevel.otel4s.metrics.MeterProvider
-import org.typelevel.otel4s.testkit.{HistogramPointData, MetricData, Sdk}
+import org.typelevel.otel4s.testkit.metrics.{HistogramPointData, MetricData, MetricsSdk}
 import scala.concurrent.duration._
 import scala.jdk.CollectionConverters._
 import scala.util.control.NoStackTrace
@@ -43,11 +43,11 @@ class PoolMetricsSpec extends CatsEffectSuite {
   import PoolMetricsSpec._
 
   test("Metrics should be empty for unused pool") {
-    val sdk = createSdk
     val expectedSnapshot =
       MetricsSnapshot(Nil, Nil, Nil, Nil, Nil)
 
     for {
+      sdk <- createSdk
       snapshot <- mkPool(sdk.otel.meterProvider).use(_ => sdk.snapshot)
     } yield assertEquals(snapshot, expectedSnapshot)
   }
@@ -123,50 +123,50 @@ class PoolMetricsSpec extends CatsEffectSuite {
   }
 
   test("Generate valid metric snapshots") {
-    val sdk = createSdk
-
     TestControl.executeEmbed {
-      mkPool(sdk.otel.meterProvider)
-        .use(pool => pool.take.use(_ => sdk.snapshot.delayBy(500.millis)).product(sdk.snapshot))
-        .map { case (inUse, afterUse) =>
-          val acquireDuration =
-            List(
-              new HistogramPointData(0, 1, HistogramBuckets, List(1, 0, 0, 0, 0))
+      createSdk.flatMap { sdk =>
+        mkPool(sdk.otel.meterProvider)
+          .use(pool => pool.take.use(_ => sdk.snapshot.delayBy(500.millis)).product(sdk.snapshot))
+          .map { case (inUse, afterUse) =>
+            val acquireDuration =
+              List(
+                new HistogramPointData(0, 1, HistogramBuckets, List(1, 0, 0, 0, 0))
+              )
+
+            val expectedInUse = MetricsSnapshot(
+              idle = Nil,
+              inUse = List(1),
+              inUseDuration = Nil,
+              acquiredTotal = List(1),
+              acquireDuration = acquireDuration
             )
 
-          val expectedInUse = MetricsSnapshot(
-            idle = Nil,
-            inUse = List(1),
-            inUseDuration = Nil,
-            acquiredTotal = List(1),
-            acquireDuration = acquireDuration
-          )
-
-          val expectedAfterUser = MetricsSnapshot(
-            idle = List(1),
-            inUse = List(0),
-            inUseDuration = List(
-              new HistogramPointData(500.0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))
-            ),
-            acquiredTotal = List(1),
-            acquireDuration = acquireDuration
-          )
+            val expectedAfterUser = MetricsSnapshot(
+              idle = List(1),
+              inUse = List(0),
+              inUseDuration = List(
+                new HistogramPointData(500.0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))
+              ),
+              acquiredTotal = List(1),
+              acquireDuration = acquireDuration
+            )
 
-          assertEquals(inUse, expectedInUse)
-          assertEquals(afterUse, expectedAfterUser)
-        }
+            assertEquals(inUse, expectedInUse)
+            assertEquals(afterUse, expectedAfterUser)
+          }
+      }
     }
   }
 
   private def poolTest(
       customize: Pool.Builder[IO, Ref[IO, Int]] => Pool.Builder[IO, Ref[IO, Int]] = identity
   )(scenario: (OtelSdk[IO], Pool[IO, Ref[IO, Int]]) => IO[Unit]): IO[Unit] = {
-    val sdk = createSdk
-
-    val builder =
-      Pool.Builder(Ref.of[IO, Int](1), nothing).withMeterProvider(sdk.otel.meterProvider)
+    createSdk.flatMap { sdk =>
+      val builder =
+        Pool.Builder(Ref.of[IO, Int](1), nothing).withMeterProvider(sdk.otel.meterProvider)
 
-    customize(builder).build.use(pool => scenario(sdk, pool))
+      customize(builder).build.use(pool => scenario(sdk, pool))
+    }
   }
 
   private def mkPool(meterProvider: MeterProvider[IO]) =
@@ -179,7 +179,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
       .withMaxTotal(10)
       .build
 
-  private def createSdk: OtelSdk[IO] = {
+  private def createSdk: IO[OtelSdk[IO]] = {
     def customize(builder: SdkMeterProviderBuilder) =
       builder
         .registerView(
@@ -192,41 +192,43 @@ class PoolMetricsSpec extends CatsEffectSuite {
             .build()
         )
 
-    val sdk = Sdk.create[IO](customize)
-
-    new OtelSdk[IO] {
-      val otel: Otel4s[IO] = OtelJava.forSync[IO](sdk.sdk)
-
-      def snapshot: IO[MetricsSnapshot] =
-        for {
-          metrics <- sdk.metrics
-        } yield {
-          def counterValue(name: String): List[Long] =
-            metrics
-              .find(_.name == name)
-              .map(_.data)
-              .collectFirst { case MetricData.LongSum(points) =>
-                points.map(_.value)
-              }
-              .getOrElse(Nil)
-
-          def histogramSnapshot(name: String): List[HistogramPointData] =
-            metrics
-              .find(_.name == name)
-              .map(_.data)
-              .collectFirst { case MetricData.Histogram(points) =>
-                points.map(_.value)
-              }
-              .getOrElse(Nil)
-
-          MetricsSnapshot(
-            counterValue("idle"),
-            counterValue("in_use"),
-            histogramSnapshot("in_use_duration"),
-            counterValue("acquired_total"),
-            histogramSnapshot("acquire_duration")
-          )
-        }
+    val sdk = MetricsSdk.create[IO](customize)
+
+    OtelJava.forSync[IO](sdk.sdk).map { otel4s =>
+      new OtelSdk[IO] {
+        val otel: Otel4s[IO] = otel4s
+
+        def snapshot: IO[MetricsSnapshot] =
+          for {
+            metrics <- sdk.metrics
+          } yield {
+            def counterValue(name: String): List[Long] =
+              metrics
+                .find(_.name == name)
+                .map(_.data)
+                .collectFirst { case MetricData.LongSum(points) =>
+                  points.map(_.value)
+                }
+                .getOrElse(Nil)
+
+            def histogramSnapshot(name: String): List[HistogramPointData] =
+              metrics
+                .find(_.name == name)
+                .map(_.data)
+                .collectFirst { case MetricData.Histogram(points) =>
+                  points.map(_.value)
+                }
+                .getOrElse(Nil)
+
+            MetricsSnapshot(
+              counterValue("idle"),
+              counterValue("in_use"),
+              histogramSnapshot("in_use_duration"),
+              counterValue("acquired_total"),
+              histogramSnapshot("acquire_duration")
+            )
+          }
+      }
     }
   }
 

From 369482eb8b7078ce6b2af40aa9eac1de69854e2d Mon Sep 17 00:00:00 2001
From: Maksim Ochenashko <maxochenashko@gmail.com>
Date: Wed, 8 Feb 2023 15:51:51 +0200
Subject: [PATCH 10/19] Use `0.1.0` of `otel4s`

---
 build.sbt | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/build.sbt b/build.sbt
index 73511815..195087c1 100644
--- a/build.sbt
+++ b/build.sbt
@@ -62,7 +62,7 @@ lazy val docs = project
 val catsV = "2.9.0"
 val catsEffectV = "3.4.6"
 
-val otel4sV = "0.0-9193d5a-SNAPSHOT"
+val otel4sV = "0.1.0"
 
 val munitV = "1.0.0-M7"
 val munitCatsEffectV = "2.0.0-M3"
@@ -73,7 +73,6 @@ val betterMonadicForV = "0.3.1"
 // General Settings
 lazy val commonSettings = Seq(
   Test / parallelExecution := false,
-  resolvers ++= Resolver.sonatypeOssRepos("snapshots"),
   libraryDependencies ++= Seq(
     "org.typelevel" %%% "cats-core"           % catsV,
     "org.typelevel" %%% "cats-effect-std"     % catsEffectV,

From 8792c343c278b0cb653a9bc369875ea4354b41c4 Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Sat, 30 Mar 2024 19:09:38 +0200
Subject: [PATCH 11/19] Update otel4s to `0.5.0`

---
 build.sbt                                     |  1 -
 .../typelevel/keypool/PoolMetricsSpec.scala   | 63 +++++++-------
 .../scala/org/typelevel/keypool/KeyPool.scala | 31 ++++---
 .../typelevel/keypool/KeyPoolBuilder.scala    |  7 +-
 .../scala/org/typelevel/keypool/Pool.scala    |  9 ++
 .../typelevel/keypool/internal/Metrics.scala  | 84 ++++++++++++-------
 6 files changed, 117 insertions(+), 78 deletions(-)

diff --git a/build.sbt b/build.sbt
index 0ed5f4b6..210e5a91 100644
--- a/build.sbt
+++ b/build.sbt
@@ -26,7 +26,6 @@ lazy val core = crossProject(JVMPlatform, JSPlatform, NativePlatform)
   )
   .jvmSettings(
     libraryDependencies ++= Seq(
-      "org.typelevel" %% "otel4s-oteljava"         % otel4sV % Test,
       "org.typelevel" %% "otel4s-oteljava-testkit" % otel4sV % Test
     )
   )
diff --git a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index d1ec1452..8cc3cafd 100644
--- a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -23,18 +23,12 @@ package org.typelevel.keypool
 
 import cats.effect._
 import cats.effect.testkit._
-import io.opentelemetry.sdk.metrics.{
-  Aggregation,
-  InstrumentSelector,
-  InstrumentType,
-  SdkMeterProviderBuilder,
-  View
-}
+import io.opentelemetry.sdk.metrics.{Aggregation, InstrumentSelector, InstrumentType, SdkMeterProviderBuilder, View}
 import munit.CatsEffectSuite
-import org.typelevel.otel4s.Otel4s
-import org.typelevel.otel4s.java.OtelJava
 import org.typelevel.otel4s.metrics.MeterProvider
-import org.typelevel.otel4s.testkit.metrics.{HistogramPointData, MetricData, MetricsSdk}
+import org.typelevel.otel4s.oteljava.testkit.metrics.MetricsTestkit
+import org.typelevel.otel4s.oteljava.testkit.metrics.data.{HistogramPointData, Metric, MetricData}
+
 import scala.concurrent.duration._
 import scala.jdk.CollectionConverters._
 import scala.util.control.NoStackTrace
@@ -46,10 +40,11 @@ class PoolMetricsSpec extends CatsEffectSuite {
     val expectedSnapshot =
       MetricsSnapshot(Nil, Nil, Nil, Nil, Nil)
 
-    for {
-      sdk <- createSdk
-      snapshot <- mkPool(sdk.otel.meterProvider).use(_ => sdk.snapshot)
-    } yield assertEquals(snapshot, expectedSnapshot)
+    createTestkit.use { testkit =>
+      for {
+        snapshot <- mkPool(testkit.metrics.meterProvider).use(_ => testkit.snapshot)
+      } yield assertEquals(snapshot, expectedSnapshot)
+    }
   }
 
   test("In use: increment on acquire and decrement on release") {
@@ -124,13 +119,13 @@ class PoolMetricsSpec extends CatsEffectSuite {
 
   test("Generate valid metric snapshots") {
     TestControl.executeEmbed {
-      createSdk.flatMap { sdk =>
-        mkPool(sdk.otel.meterProvider)
+      createTestkit.use { sdk =>
+        mkPool(sdk.metrics.meterProvider)
           .use(pool => pool.take.use(_ => sdk.snapshot.delayBy(500.millis)).product(sdk.snapshot))
           .map { case (inUse, afterUse) =>
             val acquireDuration =
               List(
-                new HistogramPointData(0, 1, HistogramBuckets, List(1, 0, 0, 0, 0))
+                HistogramPointData(0, 1, HistogramBuckets, List(1, 0, 0, 0, 0))
               )
 
             val expectedInUse = MetricsSnapshot(
@@ -145,7 +140,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
               idle = List(1),
               inUse = List(0),
               inUseDuration = List(
-                new HistogramPointData(500.0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))
+                HistogramPointData(500.0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))
               ),
               acquiredTotal = List(1),
               acquireDuration = acquireDuration
@@ -160,10 +155,10 @@ class PoolMetricsSpec extends CatsEffectSuite {
 
   private def poolTest(
       customize: Pool.Builder[IO, Ref[IO, Int]] => Pool.Builder[IO, Ref[IO, Int]] = identity
-  )(scenario: (OtelSdk[IO], Pool[IO, Ref[IO, Int]]) => IO[Unit]): IO[Unit] = {
-    createSdk.flatMap { sdk =>
+  )(scenario: (OtelTestkit[IO], Pool[IO, Ref[IO, Int]]) => IO[Unit]): IO[Unit] = {
+    createTestkit.use { sdk =>
       val builder =
-        Pool.Builder(Ref.of[IO, Int](1), nothing).withMeterProvider(sdk.otel.meterProvider)
+        Pool.Builder(Ref.of[IO, Int](1), nothing).withMeterProvider(sdk.metrics.meterProvider)
 
       customize(builder).build.use(pool => scenario(sdk, pool))
     }
@@ -179,7 +174,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
       .withMaxTotal(10)
       .build
 
-  private def createSdk: IO[OtelSdk[IO]] = {
+  private def createTestkit: Resource[IO, OtelTestkit[IO]] = {
     def customize(builder: SdkMeterProviderBuilder) =
       builder
         .registerView(
@@ -192,15 +187,13 @@ class PoolMetricsSpec extends CatsEffectSuite {
             .build()
         )
 
-    val sdk = MetricsSdk.create[IO](customize)
-
-    OtelJava.forSync[IO](sdk.sdk).map { otel4s =>
-      new OtelSdk[IO] {
-        val otel: Otel4s[IO] = otel4s
+    MetricsTestkit.inMemory[IO](customize).map { testkit =>
+      new OtelTestkit[IO] {
+        val metrics: MetricsTestkit[IO] = testkit
 
         def snapshot: IO[MetricsSnapshot] =
           for {
-            metrics <- sdk.metrics
+            metrics <- testkit.collectMetrics[Metric]
           } yield {
             def counterValue(name: String): List[Long] =
               metrics
@@ -221,11 +214,11 @@ class PoolMetricsSpec extends CatsEffectSuite {
                 .getOrElse(Nil)
 
             MetricsSnapshot(
-              counterValue("idle"),
-              counterValue("in_use"),
-              histogramSnapshot("in_use_duration"),
-              counterValue("acquired_total"),
-              histogramSnapshot("acquire_duration")
+              counterValue("idle.current"),
+              counterValue("in_use.current"),
+              histogramSnapshot("in_use.duration"),
+              counterValue("acquired.total"),
+              histogramSnapshot("acquire.duration")
             )
           }
       }
@@ -242,8 +235,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
 
 object PoolMetricsSpec {
 
-  trait OtelSdk[F[_]] {
-    def otel: Otel4s[F]
+  trait OtelTestkit[F[_]] {
+    def metrics: MetricsTestkit[F]
     def snapshot: F[MetricsSnapshot]
   }
 
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala b/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala
index 13f93658..9e5906a0 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala
+++ b/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala
@@ -21,7 +21,6 @@
 
 package org.typelevel.keypool
 
-import java.util.concurrent.TimeUnit
 import cats._
 import cats.effect.kernel._
 import cats.effect.kernel.syntax.spawn._
@@ -203,7 +202,7 @@ object KeyPool {
               val (m_, toDestroy) = findStale(now, idleCount, m)
               (
                 m_,
-                toDestroy.traverse_(r => metrics.idle.dec() >> r._2._2).attempt.flatMap {
+                toDestroy.traverse_(r => metrics.idleDec >> r._2._2).attempt.flatMap {
                   case Left(t) => onReaperException(t)
                   // .handleErrorWith(t => F.delay(t.printStackTrace())) // CHEATING?
                   case Right(()) => F.unit
@@ -260,7 +259,7 @@ object KeyPool {
         }
       }
 
-    def decIdle = kp.kpMetrics.idle.dec().whenA(isFromPool)
+    def decIdle = kp.kpMetrics.idleDec.whenA(isFromPool)
 
     def go(now: FiniteDuration, pc: PoolMap[A, (B, F[Unit])]): (PoolMap[A, (B, F[Unit])], F[Unit]) =
       pc match {
@@ -272,12 +271,12 @@ object KeyPool {
               case None =>
                 val cnt_ = idleCount + 1
                 val m_ = PoolMap.open(cnt_, m + (k -> One((r, destroy), now)))
-                (m_, kp.kpMetrics.idle.inc())
+                (m_, kp.kpMetrics.idleInc)
               case Some(l) =>
                 val (l_, mx) = addToList(now, kp.kpMaxPerKey(k), (r, destroy), l)
                 val cnt_ = idleCount + mx.fold(1)(_ => 0)
                 val m_ = PoolMap.open(cnt_, m + (k -> l_))
-                (m_, mx.fold(kp.kpMetrics.idle.inc())(_ => decIdle >> destroy))
+                (m_, mx.fold(kp.kpMetrics.idleInc)(_ => decIdle >> destroy))
             }
       }
 
@@ -304,9 +303,7 @@ object KeyPool {
       }
 
     def allocateNew: F[(B, F[Unit])] =
-      kp.kpMetrics.acquireDuration
-        .recordDuration(TimeUnit.MILLISECONDS)
-        .use(_ => kp.kpRes(k).allocated)
+      kp.kpMetrics.acquireRecordDuration.use(_ => kp.kpRes(k).allocated)
 
     for {
       _ <- kp.kpMaxTotalSem.permit
@@ -323,14 +320,15 @@ object KeyPool {
           }
         } yield out
       }
-      _ <- Resource.eval(kp.kpMetrics.acquiredTotal.inc().whenA(optR.isEmpty))
-      _ <- Resource.make(kp.kpMetrics.inUse.inc())(_ => kp.kpMetrics.inUse.dec())
-      _ <- kp.kpMetrics.inUseDuration.recordDuration(TimeUnit.MILLISECONDS)
+      _ <- Resource.eval(kp.kpMetrics.acquiredTotalInc.whenA(optR.isEmpty))
+      _ <- kp.kpMetrics.inUseCount
+      _ <- kp.kpMetrics.inUseRecordDuration
     } yield new Managed(resource._1, optR.isDefined, releasedState)
   }
 
   final class Builder[F[_]: Temporal, A, B] private[keypool] (
       val kpRes: A => Resource[F, B],
+      val name: String,
       val kpDefaultReuseState: Reusable,
       val idleTimeAllowedInPool: Duration,
       val kpMaxPerKey: A => Int,
@@ -347,9 +345,11 @@ object KeyPool {
         kpMaxIdle: Int = this.kpMaxIdle,
         kpMaxTotal: Int = this.kpMaxTotal,
         onReaperException: Throwable => F[Unit] = this.onReaperException,
-        meterProvider: MeterProvider[F] = this.meterProvider
+        meterProvider: MeterProvider[F] = this.meterProvider,
+        name: String = this.name
     ): Builder[F, A, B] = new Builder[F, A, B](
       kpRes,
+      name,
       kpDefaultReuseState,
       idleTimeAllowedInPool,
       kpMaxPerKey,
@@ -388,6 +388,9 @@ object KeyPool {
     def withMeterProvider(meterProvider: MeterProvider[F]): Builder[F, A, B] =
       copy(meterProvider = meterProvider)
 
+    def withName(name: String): Builder[F, A, B] =
+      copy(name = name)
+
     def build: Resource[F, KeyPool[F, A, B]] = {
       def keepRunning[Z](fa: F[Z]): F[Z] =
         fa.onError { case e => onReaperException(e) }.attempt >> keepRunning(fa)
@@ -396,7 +399,7 @@ object KeyPool {
           Ref[F].of[PoolMap[A, (B, F[Unit])]](PoolMap.open(0, Map.empty[A, PoolList[(B, F[Unit])]]))
         )(kpVar => KeyPool.destroy(kpVar))
         kpMaxTotalSem <- Resource.eval(Semaphore[F](kpMaxTotal.toLong))
-        kpMetrics <- Resource.eval(Metrics.fromMeterProvider(meterProvider))
+        kpMetrics <- Resource.eval(Metrics.fromMeterProvider(meterProvider, name))
         _ <- idleTimeAllowedInPool match {
           case fd: FiniteDuration =>
             val nanos = 0.seconds.max(fd)
@@ -423,6 +426,7 @@ object KeyPool {
         res: A => Resource[F, B]
     ): Builder[F, A, B] = new Builder[F, A, B](
       res,
+      Defaults.name,
       Defaults.defaultReuseState,
       Defaults.idleTimeAllowedInPool,
       Defaults.maxPerKey,
@@ -444,6 +448,7 @@ object KeyPool {
       def maxPerKey[K](k: K): Int = Function.const(100)(k)
       val maxIdle = 100
       val maxTotal = 100
+      val name = "unknown"
       def onReaperException[F[_]: Applicative] = { (t: Throwable) =>
         Function.const(Applicative[F].unit)(t)
       }
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala b/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
index ebb97c06..7856c56e 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
+++ b/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
@@ -32,6 +32,7 @@ import scala.concurrent.duration._
 
 @deprecated("use KeyPool.Builder", "0.4.7")
 final class KeyPoolBuilder[F[_]: Temporal, A, B] private (
+    val name: String,
     val kpCreate: A => F[B],
     val kpDestroy: B => F[Unit],
     val kpDefaultReuseState: Reusable,
@@ -42,6 +43,7 @@ final class KeyPoolBuilder[F[_]: Temporal, A, B] private (
     val onReaperException: Throwable => F[Unit]
 ) {
   private def copy(
+      name: String = this.name,
       kpCreate: A => F[B] = this.kpCreate,
       kpDestroy: B => F[Unit] = this.kpDestroy,
       kpDefaultReuseState: Reusable = this.kpDefaultReuseState,
@@ -51,6 +53,7 @@ final class KeyPoolBuilder[F[_]: Temporal, A, B] private (
       kpMaxTotal: Int = this.kpMaxTotal,
       onReaperException: Throwable => F[Unit] = this.onReaperException
   ): KeyPoolBuilder[F, A, B] = new KeyPoolBuilder[F, A, B](
+    name,
     kpCreate,
     kpDestroy,
     kpDefaultReuseState,
@@ -93,7 +96,7 @@ final class KeyPoolBuilder[F[_]: Temporal, A, B] private (
         Ref[F].of[PoolMap[A, (B, F[Unit])]](PoolMap.open(0, Map.empty[A, PoolList[(B, F[Unit])]]))
       )(kpVar => KeyPool.destroy(kpVar))
       kpMaxTotalSem <- Resource.eval(Semaphore[F](kpMaxTotal.toLong))
-      kpMetrics <- Resource.eval(Metrics.fromMeterProvider(MeterProvider.noop))
+      kpMetrics <- Resource.eval(Metrics.fromMeterProvider(MeterProvider.noop, name))
       _ <- idleTimeAllowedInPool match {
         case fd: FiniteDuration =>
           val nanos = 0.seconds.max(fd)
@@ -121,6 +124,7 @@ object KeyPoolBuilder {
       create: A => F[B],
       destroy: B => F[Unit]
   ): KeyPoolBuilder[F, A, B] = new KeyPoolBuilder[F, A, B](
+    Defaults.name,
     create,
     destroy,
     Defaults.defaultReuseState,
@@ -137,6 +141,7 @@ object KeyPoolBuilder {
     def maxPerKey[K](k: K): Int = Function.const(100)(k)
     val maxIdle = 100
     val maxTotal = 100
+    val name = "unknown"
     def onReaperException[F[_]: Applicative] = { (t: Throwable) =>
       Function.const(Applicative[F].unit)(t)
     }
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala b/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala
index e33469af..b960e5d2 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala
+++ b/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala
@@ -73,6 +73,7 @@ object Pool {
 
   final class Builder[F[_]: Temporal, B] private (
       val kpRes: Resource[F, B],
+      val name: String,
       val kpDefaultReuseState: Reusable,
       val idleTimeAllowedInPool: Duration,
       val kpMaxIdle: Int,
@@ -82,6 +83,7 @@ object Pool {
   ) {
     private def copy(
         kpRes: Resource[F, B] = this.kpRes,
+        name: String = this.name,
         kpDefaultReuseState: Reusable = this.kpDefaultReuseState,
         idleTimeAllowedInPool: Duration = this.idleTimeAllowedInPool,
         kpMaxIdle: Int = this.kpMaxIdle,
@@ -90,6 +92,7 @@ object Pool {
         meterProvider: MeterProvider[F] = this.meterProvider
     ): Builder[F, B] = new Builder[F, B](
       kpRes,
+      name = name,
       kpDefaultReuseState,
       idleTimeAllowedInPool,
       kpMaxIdle,
@@ -124,9 +127,13 @@ object Pool {
     def withMeterProvider(meterProvider: MeterProvider[F]): Builder[F, B] =
       copy(meterProvider = meterProvider)
 
+    def withName(name: String): Builder[F, B] =
+      copy(name = name)
+
     private def toKeyPoolBuilder: KeyPool.Builder[F, Unit, B] =
       new KeyPool.Builder(
         kpRes = _ => kpRes,
+        name = name,
         kpDefaultReuseState = kpDefaultReuseState,
         idleTimeAllowedInPool = idleTimeAllowedInPool,
         kpMaxPerKey = _ => kpMaxTotal,
@@ -151,6 +158,7 @@ object Pool {
         res: Resource[F, B]
     ): Builder[F, B] = new Builder[F, B](
       res,
+      Defaults.name,
       Defaults.defaultReuseState,
       Defaults.idleTimeAllowedInPool,
       Defaults.maxIdle,
@@ -170,6 +178,7 @@ object Pool {
       val idleTimeAllowedInPool = 30.seconds
       val maxIdle = 100
       val maxTotal = 100
+      val name = "unknown"
       def onReaperException[F[_]: Applicative] = { (t: Throwable) =>
         Function.const(Applicative[F].unit)(t)
       }
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala b/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
index 22b16141..346df04f 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
+++ b/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
@@ -21,76 +21,104 @@
 
 package org.typelevel.keypool.internal
 
+import java.util.concurrent.TimeUnit
+
 import cats.Monad
+import cats.effect.kernel.Resource
 import cats.syntax.functor._
 import cats.syntax.flatMap._
+import org.typelevel.otel4s.Attribute
 import org.typelevel.otel4s.metrics._
 
 private[keypool] trait Metrics[F[_]] {
 
   /**
-   * The '''current''' number of the '''idle''' resources
+   * Increments the number of idle resources.
+   */
+  def idleInc: F[Unit]
+
+  /**
+   * Decrements the number of idle resources.
    */
-  def idle: UpDownCounter[F, Long]
+  def idleDec: F[Unit]
 
   /**
-   * The '''current''' number of the '''borrowed (in use)''' resources
+   * Records the number of in-use resources.
    */
-  def inUse: UpDownCounter[F, Long]
+  def inUseCount: Resource[F, Unit]
 
-  def inUseDuration: Histogram[F, Double]
+  /**
+   * Records for how long the resource has been in use.
+   */
+  def inUseRecordDuration: Resource[F, Unit]
 
   /**
-   * The '''total''' number of the '''acquired''' resources.
-   *
-   * The value can be only incremented.
+   * Increments the number of acquired resources.
    */
-  def acquiredTotal: Counter[F, Long]
+  def acquiredTotalInc: F[Unit]
 
-  def acquireDuration: Histogram[F, Double]
+  /**
+   * Records how long does it take to acquire a resource.
+   */
+  def acquireRecordDuration: Resource[F, Unit]
 
 }
 
 private[keypool] object Metrics {
 
-  def fromMeterProvider[F[_]: Monad](meterProvider: MeterProvider[F]): F[Metrics[F]] = {
+  def fromMeterProvider[F[_]: Monad](meterProvider: MeterProvider[F], name: String): F[Metrics[F]] =
     for {
       meter <- meterProvider.get("org.typelevel.keypool")
 
-      idleCounter <- meter
-        .upDownCounter("idle")
+      idle <- meter
+        .upDownCounter[Long]("idle.current")
+        .withUnit("{resource}")
         .withDescription("A current number of idle resources")
         .create
 
-      inUseCounter <- meter
-        .upDownCounter("in_use")
+      inUse <- meter
+        .upDownCounter[Long]("in_use.current")
+        .withUnit("{resource}")
         .withDescription("A current number of resources in use")
         .create
 
-      inUseDurationHistogram <- meter
-        .histogram("in_use_duration")
+      inUseDuration <- meter
+        .histogram[Long]("in_use.duration")
         .withUnit("ms")
         .withDescription("For how long a resource is in use")
         .create
 
-      acquiredCounter <- meter
-        .counter("acquired_total")
+      acquiredTotal <- meter
+        .counter[Long]("acquired.total")
+        .withUnit("{resource}")
         .withDescription("A total number of acquired resources")
         .create
 
-      acquireDurationHistogram <- meter
-        .histogram("acquire_duration")
+      acquireDuration <- meter
+        .histogram[Long]("acquire.duration")
         .withUnit("ms")
         .withDescription("How long does it take to acquire a resource")
         .create
-
     } yield new Metrics[F] {
-      def idle: UpDownCounter[F, Long] = idleCounter
-      def inUse: UpDownCounter[F, Long] = inUseCounter
-      def inUseDuration: Histogram[F, Double] = inUseDurationHistogram
-      def acquiredTotal: Counter[F, Long] = acquiredCounter
-      def acquireDuration: Histogram[F, Double] = acquireDurationHistogram
+      private val nameAttribute = Attribute("pool.name", name)
+
+      def idleInc: F[Unit] =
+        idle.inc(nameAttribute)
+
+      def idleDec: F[Unit] =
+        idle.dec(nameAttribute)
+
+      def inUseCount: Resource[F, Unit] =
+        Resource.make(inUse.inc(nameAttribute))(_ => inUse.dec(nameAttribute))
+
+      def inUseRecordDuration: Resource[F, Unit] =
+        inUseDuration.recordDuration(TimeUnit.MILLISECONDS, nameAttribute)
+
+      def acquiredTotalInc: F[Unit] =
+        acquiredTotal.inc(nameAttribute)
+
+      def acquireRecordDuration: Resource[F, Unit] =
+        acquireDuration.recordDuration(TimeUnit.MILLISECONDS, nameAttribute)
     }
-  }
 
 }

From 8afd3222eca75da2c2c94d808602987fc35b4fe4 Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Sun, 31 Mar 2024 13:45:41 +0300
Subject: [PATCH 12/19] Move otel4s integration to a separate module

---
 build.sbt                                     |  27 ++--
 .../typelevel/keypool/internal/Metrics.scala  | 124 ------------------
 .../scala/org/typelevel/keypool/KeyPool.scala |  25 ++--
 .../typelevel/keypool/KeyPoolBuilder.scala    |   8 +-
 .../scala/org/typelevel/keypool/Managed.scala |   0
 .../scala/org/typelevel/keypool/Pool.scala    |  27 ++--
 .../org/typelevel/keypool/PoolStats.scala     |   0
 .../org/typelevel/keypool/Reusable.scala      |   0
 .../typelevel/keypool/internal/Metrics.scala  |  84 ++++++++++++
 .../typelevel/keypool/internal/PoolList.scala |   0
 .../typelevel/keypool/internal/PoolMap.scala  |   0
 .../org/typelevel/keypool/KeyPoolSpec.scala   |   0
 .../org/typelevel/keypool/PoolSpec.scala      |   0
 .../typelevel/keypool/PoolMetricsSpec.scala   |  12 +-
 .../org/typelevel/keypool/Otel4sMetrics.scala |  96 ++++++++++++++
 15 files changed, 224 insertions(+), 179 deletions(-)
 delete mode 100644 core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
 rename core/{shared => }/src/main/scala/org/typelevel/keypool/KeyPool.scala (95%)
 rename core/{shared => }/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala (95%)
 rename core/{shared => }/src/main/scala/org/typelevel/keypool/Managed.scala (100%)
 rename core/{shared => }/src/main/scala/org/typelevel/keypool/Pool.scala (89%)
 rename core/{shared => }/src/main/scala/org/typelevel/keypool/PoolStats.scala (100%)
 rename core/{shared => }/src/main/scala/org/typelevel/keypool/Reusable.scala (100%)
 create mode 100644 core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
 rename core/{shared => }/src/main/scala/org/typelevel/keypool/internal/PoolList.scala (100%)
 rename core/{shared => }/src/main/scala/org/typelevel/keypool/internal/PoolMap.scala (100%)
 rename core/{shared => }/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala (100%)
 rename core/{shared => }/src/test/scala/org/typelevel/keypool/PoolSpec.scala (100%)
 rename {core => otel4s}/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala (96%)
 create mode 100644 otel4s/shared/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala

diff --git a/build.sbt b/build.sbt
index 210e5a91..1e4806a8 100644
--- a/build.sbt
+++ b/build.sbt
@@ -11,10 +11,10 @@ ThisBuild / startYear := Some(2019)
 ThisBuild / licenses := Seq(License.MIT)
 ThisBuild / tlSiteApiUrl := Some(url("https://www.javadoc.io/doc/org.typelevel/keypool_2.12"))
 
-lazy val root = tlCrossRootProject.aggregate(core)
+lazy val root = tlCrossRootProject.aggregate(core, otel4s)
 
 lazy val core = crossProject(JVMPlatform, JSPlatform, NativePlatform)
-  .crossType(CrossType.Full)
+  .crossType(CrossType.Pure)
   .in(file("core"))
   .settings(commonSettings)
   .settings(
@@ -24,11 +24,6 @@ lazy val core = crossProject(JVMPlatform, JSPlatform, NativePlatform)
   .jsSettings(
     tlVersionIntroduced := List("2.12", "2.13", "3").map(_ -> "0.4.6").toMap
   )
-  .jvmSettings(
-    libraryDependencies ++= Seq(
-      "org.typelevel" %% "otel4s-oteljava-testkit" % otel4sV % Test
-    )
-  )
   .nativeSettings(
     tlVersionIntroduced := List("2.12", "2.13", "3").map(_ -> "0.4.8").toMap
   )
@@ -52,10 +47,25 @@ lazy val core = crossProject(JVMPlatform, JSPlatform, NativePlatform)
     )
   )
 
+lazy val otel4s = crossProject(JVMPlatform, JSPlatform, NativePlatform)
+  .crossType(CrossType.Full)
+  .in(file("otel4s"))
+  .dependsOn(core)
+  .settings(commonSettings)
+  .settings(
+    name := "keypool-otel4s",
+    startYear := Some(2024),
+    crossScalaVersions := Seq(Scala213, Scala3),
+    libraryDependencies += "org.typelevel" %%% "otel4s-core" % otel4sV
+  )
+  .jvmSettings(
+    libraryDependencies += "org.typelevel" %% "otel4s-oteljava-testkit" % otel4sV % Test
+  )
+
 lazy val docs = project
   .in(file("site"))
   .settings(commonSettings)
-  .dependsOn(core.jvm)
+  .dependsOn(core.jvm, otel4s.jvm)
   .enablePlugins(TypelevelSitePlugin)
 
 val catsV = "2.10.0"
@@ -75,7 +85,6 @@ lazy val commonSettings = Seq(
   libraryDependencies ++= Seq(
     "org.typelevel" %%% "cats-core"           % catsV,
     "org.typelevel" %%% "cats-effect-std"     % catsEffectV,
-    "org.typelevel" %%% "otel4s-core"         % otel4sV,
     "org.typelevel" %%% "cats-effect-testkit" % catsEffectV      % Test,
     "org.scalameta" %%% "munit"               % munitV           % Test,
     "org.typelevel" %%% "munit-cats-effect"   % munitCatsEffectV % Test
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala b/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
deleted file mode 100644
index 346df04f..00000000
--- a/core/shared/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
+++ /dev/null
@@ -1,124 +0,0 @@
-/*
- * Copyright (c) 2019 Typelevel
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy of
- * this software and associated documentation files (the "Software"), to deal in
- * the Software without restriction, including without limitation the rights to
- * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
- * the Software, and to permit persons to whom the Software is furnished to do so,
- * subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
- * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
- * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
- * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
- * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- */
-
-package org.typelevel.keypool.internal
-
-import java.util.concurrent.TimeUnit
-
-import cats.Monad
-import cats.effect.kernel.Resource
-import cats.syntax.functor._
-import cats.syntax.flatMap._
-import org.typelevel.otel4s.Attribute
-import org.typelevel.otel4s.metrics._
-
-private[keypool] trait Metrics[F[_]] {
-
-  /**
-   * Increments the number of idle resources.
-   */
-  def idleInc: F[Unit]
-
-  /**
-   * Decrements the number of idle resources.
-   */
-  def idleDec: F[Unit]
-
-  /**
-   * Records the number of in-use resources.
-   */
-  def inUseCount: Resource[F, Unit]
-
-  /**
-   * Records for how long the resource has been in use.
-   */
-  def inUseRecordDuration: Resource[F, Unit]
-
-  /**
-   * Increments the number of acquired resources.
-   */
-  def acquiredTotalInc: F[Unit]
-
-  /**
-   * Records how long does it take to acquire a resource.
-   */
-  def acquireRecordDuration: Resource[F, Unit]
-
-}
-
-private[keypool] object Metrics {
-
-  def fromMeterProvider[F[_]: Monad](meterProvider: MeterProvider[F], name: String): F[Metrics[F]] =
-    for {
-      meter <- meterProvider.get("org.typelevel.keypool")
-
-      idle <- meter
-        .upDownCounter[Long]("idle.current")
-        .withUnit("{resource}")
-        .withDescription("A current number of idle resources")
-        .create
-
-      inUse <- meter
-        .upDownCounter[Long]("in_use.current")
-        .withUnit("{resource}")
-        .withDescription("A current number of resources in use")
-        .create
-
-      inUseDuration <- meter
-        .histogram[Long]("in_use.duration")
-        .withUnit("ms")
-        .withDescription("For how long a resource is in use")
-        .create
-
-      acquiredTotal <- meter
-        .counter[Long]("acquired.total")
-        .withUnit("{resource}")
-        .withDescription("A total number of acquired resources")
-        .create
-
-      acquireDuration <- meter
-        .histogram[Long]("acquire.duration")
-        .withUnit("ms")
-        .withDescription("How long does it take to acquire a resource")
-        .create
-    } yield new Metrics[F] {
-      private val nameAttribute = Attribute("pool.name", name)
-
-      def idleInc: F[Unit] =
-        idle.inc(nameAttribute)
-
-      def idleDec: F[Unit] =
-        idle.dec(nameAttribute)
-
-      def inUseCount: Resource[F, Unit] =
-        Resource.make(inUse.inc(nameAttribute))(_ => inUse.dec(nameAttribute))
-
-      def inUseRecordDuration: Resource[F, Unit] =
-        inUseDuration.recordDuration(TimeUnit.MILLISECONDS, nameAttribute)
-
-      def acquiredTotalInc: F[Unit] =
-        acquiredTotal.inc(nameAttribute)
-
-      def acquireRecordDuration: Resource[F, Unit] =
-        acquireDuration.recordDuration(TimeUnit.MILLISECONDS, nameAttribute)
-    }
-
-}
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala b/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
similarity index 95%
rename from core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala
rename to core/src/main/scala/org/typelevel/keypool/KeyPool.scala
index 9e5906a0..fe5a1019 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/KeyPool.scala
+++ b/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
@@ -28,7 +28,6 @@ import cats.effect.std.Semaphore
 import cats.syntax.all._
 import scala.concurrent.duration._
 import org.typelevel.keypool.internal._
-import org.typelevel.otel4s.metrics.MeterProvider
 
 /**
  * This pools internal guarantees are that the max number of values are in the pool at any time, not
@@ -328,14 +327,13 @@ object KeyPool {
 
   final class Builder[F[_]: Temporal, A, B] private[keypool] (
       val kpRes: A => Resource[F, B],
-      val name: String,
       val kpDefaultReuseState: Reusable,
       val idleTimeAllowedInPool: Duration,
       val kpMaxPerKey: A => Int,
       val kpMaxIdle: Int,
       val kpMaxTotal: Int,
       val onReaperException: Throwable => F[Unit],
-      val meterProvider: MeterProvider[F]
+      val metricsProvider: Metrics.Provider[F]
   ) {
     private def copy(
         kpRes: A => Resource[F, B] = this.kpRes,
@@ -345,18 +343,16 @@ object KeyPool {
         kpMaxIdle: Int = this.kpMaxIdle,
         kpMaxTotal: Int = this.kpMaxTotal,
         onReaperException: Throwable => F[Unit] = this.onReaperException,
-        meterProvider: MeterProvider[F] = this.meterProvider,
-        name: String = this.name
+        metricsProvider: Metrics.Provider[F] = this.metricsProvider
     ): Builder[F, A, B] = new Builder[F, A, B](
       kpRes,
-      name,
       kpDefaultReuseState,
       idleTimeAllowedInPool,
       kpMaxPerKey,
       kpMaxIdle,
       kpMaxTotal,
       onReaperException,
-      meterProvider
+      metricsProvider
     )
 
     def doOnCreate(f: B => F[Unit]): Builder[F, A, B] =
@@ -385,11 +381,8 @@ object KeyPool {
     def withOnReaperException(f: Throwable => F[Unit]): Builder[F, A, B] =
       copy(onReaperException = f)
 
-    def withMeterProvider(meterProvider: MeterProvider[F]): Builder[F, A, B] =
-      copy(meterProvider = meterProvider)
-
-    def withName(name: String): Builder[F, A, B] =
-      copy(name = name)
+    def withMetricsProvider(metricsProvider: Metrics.Provider[F]): Builder[F, A, B] =
+      copy(metricsProvider = metricsProvider)
 
     def build: Resource[F, KeyPool[F, A, B]] = {
       def keepRunning[Z](fa: F[Z]): F[Z] =
@@ -399,7 +392,7 @@ object KeyPool {
           Ref[F].of[PoolMap[A, (B, F[Unit])]](PoolMap.open(0, Map.empty[A, PoolList[(B, F[Unit])]]))
         )(kpVar => KeyPool.destroy(kpVar))
         kpMaxTotalSem <- Resource.eval(Semaphore[F](kpMaxTotal.toLong))
-        kpMetrics <- Resource.eval(Metrics.fromMeterProvider(meterProvider, name))
+        kpMetrics <- Resource.eval(metricsProvider.get)
         _ <- idleTimeAllowedInPool match {
           case fd: FiniteDuration =>
             val nanos = 0.seconds.max(fd)
@@ -426,14 +419,13 @@ object KeyPool {
         res: A => Resource[F, B]
     ): Builder[F, A, B] = new Builder[F, A, B](
       res,
-      Defaults.name,
       Defaults.defaultReuseState,
       Defaults.idleTimeAllowedInPool,
       Defaults.maxPerKey,
       Defaults.maxIdle,
       Defaults.maxTotal,
       Defaults.onReaperException[F],
-      Defaults.meterProvider
+      Defaults.metricsProvider
     )
 
     def apply[F[_]: Temporal, A, B](
@@ -448,11 +440,10 @@ object KeyPool {
       def maxPerKey[K](k: K): Int = Function.const(100)(k)
       val maxIdle = 100
       val maxTotal = 100
-      val name = "unknown"
       def onReaperException[F[_]: Applicative] = { (t: Throwable) =>
         Function.const(Applicative[F].unit)(t)
       }
-      def meterProvider[F[_]: Applicative]: MeterProvider[F] = MeterProvider.noop
+      def metricsProvider[F[_]: Applicative]: Metrics.Provider[F] = Metrics.Provider.noop
     }
   }
 }
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala b/core/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
similarity index 95%
rename from core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
rename to core/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
index 7856c56e..681738fd 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
+++ b/core/src/main/scala/org/typelevel/keypool/KeyPoolBuilder.scala
@@ -27,12 +27,10 @@ import cats.syntax.all._
 import cats.effect.kernel._
 import cats.effect.kernel.syntax.spawn._
 import cats.effect.std.Semaphore
-import org.typelevel.otel4s.metrics.MeterProvider
 import scala.concurrent.duration._
 
 @deprecated("use KeyPool.Builder", "0.4.7")
 final class KeyPoolBuilder[F[_]: Temporal, A, B] private (
-    val name: String,
     val kpCreate: A => F[B],
     val kpDestroy: B => F[Unit],
     val kpDefaultReuseState: Reusable,
@@ -43,7 +41,6 @@ final class KeyPoolBuilder[F[_]: Temporal, A, B] private (
     val onReaperException: Throwable => F[Unit]
 ) {
   private def copy(
-      name: String = this.name,
       kpCreate: A => F[B] = this.kpCreate,
       kpDestroy: B => F[Unit] = this.kpDestroy,
       kpDefaultReuseState: Reusable = this.kpDefaultReuseState,
@@ -53,7 +50,6 @@ final class KeyPoolBuilder[F[_]: Temporal, A, B] private (
       kpMaxTotal: Int = this.kpMaxTotal,
       onReaperException: Throwable => F[Unit] = this.onReaperException
   ): KeyPoolBuilder[F, A, B] = new KeyPoolBuilder[F, A, B](
-    name,
     kpCreate,
     kpDestroy,
     kpDefaultReuseState,
@@ -96,7 +92,7 @@ final class KeyPoolBuilder[F[_]: Temporal, A, B] private (
         Ref[F].of[PoolMap[A, (B, F[Unit])]](PoolMap.open(0, Map.empty[A, PoolList[(B, F[Unit])]]))
       )(kpVar => KeyPool.destroy(kpVar))
       kpMaxTotalSem <- Resource.eval(Semaphore[F](kpMaxTotal.toLong))
-      kpMetrics <- Resource.eval(Metrics.fromMeterProvider(MeterProvider.noop, name))
+      kpMetrics <- Resource.pure(Metrics.noop)
       _ <- idleTimeAllowedInPool match {
         case fd: FiniteDuration =>
           val nanos = 0.seconds.max(fd)
@@ -124,7 +120,6 @@ object KeyPoolBuilder {
       create: A => F[B],
       destroy: B => F[Unit]
   ): KeyPoolBuilder[F, A, B] = new KeyPoolBuilder[F, A, B](
-    Defaults.name,
     create,
     destroy,
     Defaults.defaultReuseState,
@@ -141,7 +136,6 @@ object KeyPoolBuilder {
     def maxPerKey[K](k: K): Int = Function.const(100)(k)
     val maxIdle = 100
     val maxTotal = 100
-    val name = "unknown"
     def onReaperException[F[_]: Applicative] = { (t: Throwable) =>
       Function.const(Applicative[F].unit)(t)
     }
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/Managed.scala b/core/src/main/scala/org/typelevel/keypool/Managed.scala
similarity index 100%
rename from core/shared/src/main/scala/org/typelevel/keypool/Managed.scala
rename to core/src/main/scala/org/typelevel/keypool/Managed.scala
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala b/core/src/main/scala/org/typelevel/keypool/Pool.scala
similarity index 89%
rename from core/shared/src/main/scala/org/typelevel/keypool/Pool.scala
rename to core/src/main/scala/org/typelevel/keypool/Pool.scala
index b960e5d2..635f76a3 100644
--- a/core/shared/src/main/scala/org/typelevel/keypool/Pool.scala
+++ b/core/src/main/scala/org/typelevel/keypool/Pool.scala
@@ -24,7 +24,7 @@ package org.typelevel.keypool
 import cats._
 import cats.effect.kernel._
 import cats.syntax.all._
-import org.typelevel.otel4s.metrics.MeterProvider
+import org.typelevel.keypool.internal.Metrics
 import scala.concurrent.duration._
 
 /**
@@ -73,32 +73,29 @@ object Pool {
 
   final class Builder[F[_]: Temporal, B] private (
       val kpRes: Resource[F, B],
-      val name: String,
       val kpDefaultReuseState: Reusable,
       val idleTimeAllowedInPool: Duration,
       val kpMaxIdle: Int,
       val kpMaxTotal: Int,
       val onReaperException: Throwable => F[Unit],
-      val meterProvider: MeterProvider[F]
+      val metricsProvider: Metrics.Provider[F]
   ) {
     private def copy(
         kpRes: Resource[F, B] = this.kpRes,
-        name: String = this.name,
         kpDefaultReuseState: Reusable = this.kpDefaultReuseState,
         idleTimeAllowedInPool: Duration = this.idleTimeAllowedInPool,
         kpMaxIdle: Int = this.kpMaxIdle,
         kpMaxTotal: Int = this.kpMaxTotal,
         onReaperException: Throwable => F[Unit] = this.onReaperException,
-        meterProvider: MeterProvider[F] = this.meterProvider
+        metricsProvider: Metrics.Provider[F] = this.metricsProvider
     ): Builder[F, B] = new Builder[F, B](
       kpRes,
-      name = name,
       kpDefaultReuseState,
       idleTimeAllowedInPool,
       kpMaxIdle,
       kpMaxTotal,
       onReaperException,
-      meterProvider
+      metricsProvider
     )
 
     def doOnCreate(f: B => F[Unit]): Builder[F, B] =
@@ -124,23 +121,19 @@ object Pool {
     def withOnReaperException(f: Throwable => F[Unit]): Builder[F, B] =
       copy(onReaperException = f)
 
-    def withMeterProvider(meterProvider: MeterProvider[F]): Builder[F, B] =
-      copy(meterProvider = meterProvider)
-
-    def withName(name: String): Builder[F, B] =
-      copy(name = name)
+    def withMetricsProvider(metricsProvider: Metrics.Provider[F]): Builder[F, B] =
+      copy(metricsProvider = metricsProvider)
 
     private def toKeyPoolBuilder: KeyPool.Builder[F, Unit, B] =
       new KeyPool.Builder(
         kpRes = _ => kpRes,
-        name = name,
         kpDefaultReuseState = kpDefaultReuseState,
         idleTimeAllowedInPool = idleTimeAllowedInPool,
         kpMaxPerKey = _ => kpMaxTotal,
         kpMaxIdle = kpMaxIdle,
         kpMaxTotal = kpMaxTotal,
         onReaperException = onReaperException,
-        meterProvider = meterProvider
+        metricsProvider = metricsProvider
       )
 
     def build: Resource[F, Pool[F, B]] = {
@@ -158,13 +151,12 @@ object Pool {
         res: Resource[F, B]
     ): Builder[F, B] = new Builder[F, B](
       res,
-      Defaults.name,
       Defaults.defaultReuseState,
       Defaults.idleTimeAllowedInPool,
       Defaults.maxIdle,
       Defaults.maxTotal,
       Defaults.onReaperException[F],
-      Defaults.meterProvider
+      Defaults.metricsProvider
     )
 
     def apply[F[_]: Temporal, B](
@@ -178,11 +170,10 @@ object Pool {
       val idleTimeAllowedInPool = 30.seconds
       val maxIdle = 100
       val maxTotal = 100
-      val name = "unknown"
       def onReaperException[F[_]: Applicative] = { (t: Throwable) =>
         Function.const(Applicative[F].unit)(t)
       }
-      def meterProvider[F[_]: Applicative]: MeterProvider[F] = MeterProvider.noop
+      def metricsProvider[F[_]: Applicative]: Metrics.Provider[F] = Metrics.Provider.noop
     }
   }
 }
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/PoolStats.scala b/core/src/main/scala/org/typelevel/keypool/PoolStats.scala
similarity index 100%
rename from core/shared/src/main/scala/org/typelevel/keypool/PoolStats.scala
rename to core/src/main/scala/org/typelevel/keypool/PoolStats.scala
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/Reusable.scala b/core/src/main/scala/org/typelevel/keypool/Reusable.scala
similarity index 100%
rename from core/shared/src/main/scala/org/typelevel/keypool/Reusable.scala
rename to core/src/main/scala/org/typelevel/keypool/Reusable.scala
diff --git a/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala b/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
new file mode 100644
index 00000000..a66df167
--- /dev/null
+++ b/core/src/main/scala/org/typelevel/keypool/internal/Metrics.scala
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2019 Typelevel
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package org.typelevel.keypool.internal
+
+import cats.Applicative
+import cats.effect.kernel.Resource
+
+private[keypool] trait Metrics[F[_]] {
+
+  /**
+   * Increments the number of idle resources.
+   */
+  def idleInc: F[Unit]
+
+  /**
+   * Decrements the number of idle resources.
+   */
+  def idleDec: F[Unit]
+
+  /**
+   * Records the number of in-use resources.
+   */
+  def inUseCount: Resource[F, Unit]
+
+  /**
+   * Records for how long the resource has been in use.
+   */
+  def inUseRecordDuration: Resource[F, Unit]
+
+  /**
+   * Increments the number of acquired resources.
+   */
+  def acquiredTotalInc: F[Unit]
+
+  /**
+   * Records how long does it take to acquire a resource.
+   */
+  def acquireRecordDuration: Resource[F, Unit]
+
+}
+
+private[keypool] object Metrics {
+
+  trait Provider[F[_]] {
+    def get: F[Metrics[F]]
+  }
+
+  object Provider {
+    def noop[F[_]: Applicative]: Provider[F] =
+      new Provider[F] {
+        def get: F[Metrics[F]] = Applicative[F].pure(Metrics.noop)
+      }
+  }
+
+  def noop[F[_]: Applicative]: Metrics[F] =
+    new Metrics[F] {
+      def idleInc: F[Unit] = Applicative[F].unit
+      def idleDec: F[Unit] = Applicative[F].unit
+      def inUseCount: Resource[F, Unit] = Resource.unit
+      def inUseRecordDuration: Resource[F, Unit] = Resource.unit
+      def acquiredTotalInc: F[Unit] = Applicative[F].unit
+      def acquireRecordDuration: Resource[F, Unit] = Resource.unit
+    }
+
+}
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/internal/PoolList.scala b/core/src/main/scala/org/typelevel/keypool/internal/PoolList.scala
similarity index 100%
rename from core/shared/src/main/scala/org/typelevel/keypool/internal/PoolList.scala
rename to core/src/main/scala/org/typelevel/keypool/internal/PoolList.scala
diff --git a/core/shared/src/main/scala/org/typelevel/keypool/internal/PoolMap.scala b/core/src/main/scala/org/typelevel/keypool/internal/PoolMap.scala
similarity index 100%
rename from core/shared/src/main/scala/org/typelevel/keypool/internal/PoolMap.scala
rename to core/src/main/scala/org/typelevel/keypool/internal/PoolMap.scala
diff --git a/core/shared/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala b/core/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala
similarity index 100%
rename from core/shared/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala
rename to core/src/test/scala/org/typelevel/keypool/KeyPoolSpec.scala
diff --git a/core/shared/src/test/scala/org/typelevel/keypool/PoolSpec.scala b/core/src/test/scala/org/typelevel/keypool/PoolSpec.scala
similarity index 100%
rename from core/shared/src/test/scala/org/typelevel/keypool/PoolSpec.scala
rename to core/src/test/scala/org/typelevel/keypool/PoolSpec.scala
diff --git a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
similarity index 96%
rename from core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
rename to otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index 8cc3cafd..1931b686 100644
--- a/core/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019 Typelevel
+ * Copyright (c) 2024 Typelevel
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy of
  * this software and associated documentation files (the "Software"), to deal in
@@ -23,7 +23,7 @@ package org.typelevel.keypool
 
 import cats.effect._
 import cats.effect.testkit._
-import io.opentelemetry.sdk.metrics.{Aggregation, InstrumentSelector, InstrumentType, SdkMeterProviderBuilder, View}
+import io.opentelemetry.sdk.metrics._
 import munit.CatsEffectSuite
 import org.typelevel.otel4s.metrics.MeterProvider
 import org.typelevel.otel4s.oteljava.testkit.metrics.MetricsTestkit
@@ -158,7 +158,11 @@ class PoolMetricsSpec extends CatsEffectSuite {
   )(scenario: (OtelTestkit[IO], Pool[IO, Ref[IO, Int]]) => IO[Unit]): IO[Unit] = {
     createTestkit.use { sdk =>
       val builder =
-        Pool.Builder(Ref.of[IO, Int](1), nothing).withMeterProvider(sdk.metrics.meterProvider)
+        Pool
+          .Builder(Ref.of[IO, Int](1), nothing)
+          .withMetricsProvider(
+            Otel4sMetrics.provider(sdk.metrics.meterProvider, "test")
+          )
 
       customize(builder).build.use(pool => scenario(sdk, pool))
     }
@@ -170,7 +174,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
         Ref.of[IO, Int](1),
         nothing
       )
-      .withMeterProvider(meterProvider)
+      .withMetricsProvider(Otel4sMetrics.provider(meterProvider, "test"))
       .withMaxTotal(10)
       .build
 
diff --git a/otel4s/shared/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala b/otel4s/shared/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala
new file mode 100644
index 00000000..1e78a306
--- /dev/null
+++ b/otel4s/shared/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2024 Typelevel
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+package org.typelevel.keypool
+
+import java.util.concurrent.TimeUnit
+
+import cats.Monad
+import cats.effect.kernel.Resource
+import cats.syntax.functor._
+import cats.syntax.flatMap._
+import org.typelevel.keypool.internal.Metrics
+import org.typelevel.otel4s.Attribute
+import org.typelevel.otel4s.metrics.MeterProvider
+
+object Otel4sMetrics {
+
+  def provider[F[_]: Monad](
+      meterProvider: MeterProvider[F],
+      poolName: String
+  ): Metrics.Provider[F] =
+    new Metrics.Provider[F] {
+      def get: F[Metrics[F]] =
+        for {
+          meter <- meterProvider.get("org.typelevel.keypool")
+
+          idle <- meter
+            .upDownCounter[Long]("idle.current")
+            .withUnit("{resource}")
+            .withDescription("A current number of idle resources")
+            .create
+
+          inUse <- meter
+            .upDownCounter[Long]("in_use.current")
+            .withUnit("{resource}")
+            .withDescription("A current number of resources in use")
+            .create
+
+          inUseDuration <- meter
+            .histogram[Long]("in_use.duration")
+            .withUnit("ms")
+            .withDescription("For how long a resource is in use")
+            .create
+
+          acquiredTotal <- meter
+            .counter[Long]("acquired.total")
+            .withUnit("{resource}")
+            .withDescription("A total number of acquired resources")
+            .create
+
+          acquireDuration <- meter
+            .histogram[Long]("acquire.duration")
+            .withUnit("ms")
+            .withDescription("How long does it take to acquire a resource")
+            .create
+        } yield new Metrics[F] {
+          private val nameAttribute = Attribute("pool.name", poolName)
+
+          def idleInc: F[Unit] =
+            idle.inc(nameAttribute)
+
+          def idleDec: F[Unit] =
+            idle.dec(nameAttribute)
+
+          def inUseCount: Resource[F, Unit] =
+            Resource.make(inUse.inc(nameAttribute))(_ => inUse.dec(nameAttribute))
+
+          def inUseRecordDuration: Resource[F, Unit] =
+            inUseDuration.recordDuration(TimeUnit.MILLISECONDS, nameAttribute)
+
+          def acquiredTotalInc: F[Unit] =
+            acquiredTotal.inc(nameAttribute)
+
+          def acquireRecordDuration: Resource[F, Unit] =
+            acquireDuration.recordDuration(TimeUnit.MILLISECONDS, nameAttribute)
+        }
+    }
+}

From 00e75eef109e6f7216bd50229fd559574d461871 Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Sun, 31 Mar 2024 13:49:20 +0300
Subject: [PATCH 13/19] generate CI workflow

---
 .github/workflows/ci.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e7c4538a..f8cfe828 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -80,11 +80,11 @@ jobs:
 
       - name: Make target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: mkdir -p core/.native/target core/.js/target core/.jvm/target project/target
+        run: mkdir -p otel4s/native/target core/.native/target otel4s/js/target otel4s/jvm/target core/.js/target core/.jvm/target project/target
 
       - name: Compress target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: tar cf targets.tar core/.native/target core/.js/target core/.jvm/target project/target
+        run: tar cf targets.tar otel4s/native/target core/.native/target otel4s/js/target otel4s/jvm/target core/.js/target core/.jvm/target project/target
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')

From 8212c5bed59a5f701f78e14eb0b21308f48dbfcb Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Tue, 16 Apr 2024 19:39:18 +0300
Subject: [PATCH 14/19] Update build.sbt

---
 .github/workflows/ci.yml | 123 ++++++++++++++++++++++++++++++---------
 build.sbt                |  11 ++++
 2 files changed, 106 insertions(+), 28 deletions(-)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f8cfe828..d7e995b4 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -30,7 +30,14 @@ jobs:
         os: [ubuntu-latest]
         scala: [2.12, 2.13, 3]
         java: [temurin@8]
-        project: [rootJS, rootJVM, rootNative]
+        project: [coreJVM, coreJS, coreNative, otel4sJVM, otel4sJS, otel4sNative]
+        exclude:
+          - project: otel4sJVM
+            scala: 2.12
+          - project: otel4sJS
+            scala: 2.12
+          - project: otel4sNative
+            scala: 2.12
     runs-on: ${{ matrix.os }}
     timeout-minutes: 60
     steps:
@@ -121,92 +128,152 @@ jobs:
         if: matrix.java == 'temurin@8' && steps.setup-java-temurin-8.outputs.cache-hit == 'false'
         run: sbt +update
 
-      - name: Download target directories (2.12, rootJS)
+      - name: Download target directories (2.12, coreJVM)
         uses: actions/download-artifact@v4
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.12-rootJS
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.12-coreJVM
 
-      - name: Inflate target directories (2.12, rootJS)
+      - name: Inflate target directories (2.12, coreJVM)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (2.12, rootJVM)
+      - name: Download target directories (2.12, coreJS)
         uses: actions/download-artifact@v4
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.12-rootJVM
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.12-coreJS
 
-      - name: Inflate target directories (2.12, rootJVM)
+      - name: Inflate target directories (2.12, coreJS)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (2.12, rootNative)
+      - name: Download target directories (2.12, coreNative)
         uses: actions/download-artifact@v4
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.12-rootNative
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.12-coreNative
 
-      - name: Inflate target directories (2.12, rootNative)
+      - name: Inflate target directories (2.12, coreNative)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (2.13, rootJS)
+      - name: Download target directories (2.13, coreJVM)
         uses: actions/download-artifact@v4
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-rootJS
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-coreJVM
 
-      - name: Inflate target directories (2.13, rootJS)
+      - name: Inflate target directories (2.13, coreJVM)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (2.13, rootJVM)
+      - name: Download target directories (2.13, coreJS)
         uses: actions/download-artifact@v4
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-rootJVM
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-coreJS
 
-      - name: Inflate target directories (2.13, rootJVM)
+      - name: Inflate target directories (2.13, coreJS)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (2.13, rootNative)
+      - name: Download target directories (2.13, coreNative)
         uses: actions/download-artifact@v4
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-rootNative
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-coreNative
 
-      - name: Inflate target directories (2.13, rootNative)
+      - name: Inflate target directories (2.13, coreNative)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (3, rootJS)
+      - name: Download target directories (2.13, otel4sJVM)
         uses: actions/download-artifact@v4
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-3-rootJS
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-otel4sJVM
 
-      - name: Inflate target directories (3, rootJS)
+      - name: Inflate target directories (2.13, otel4sJVM)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (3, rootJVM)
+      - name: Download target directories (2.13, otel4sJS)
         uses: actions/download-artifact@v4
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-3-rootJVM
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-otel4sJS
 
-      - name: Inflate target directories (3, rootJVM)
+      - name: Inflate target directories (2.13, otel4sJS)
         run: |
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (3, rootNative)
+      - name: Download target directories (2.13, otel4sNative)
         uses: actions/download-artifact@v4
         with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-3-rootNative
+          name: target-${{ matrix.os }}-${{ matrix.java }}-2.13-otel4sNative
 
-      - name: Inflate target directories (3, rootNative)
+      - name: Inflate target directories (2.13, otel4sNative)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
+      - name: Download target directories (3, coreJVM)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-${{ matrix.java }}-3-coreJVM
+
+      - name: Inflate target directories (3, coreJVM)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
+      - name: Download target directories (3, coreJS)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-${{ matrix.java }}-3-coreJS
+
+      - name: Inflate target directories (3, coreJS)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
+      - name: Download target directories (3, coreNative)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-${{ matrix.java }}-3-coreNative
+
+      - name: Inflate target directories (3, coreNative)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
+      - name: Download target directories (3, otel4sJVM)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-${{ matrix.java }}-3-otel4sJVM
+
+      - name: Inflate target directories (3, otel4sJVM)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
+      - name: Download target directories (3, otel4sJS)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-${{ matrix.java }}-3-otel4sJS
+
+      - name: Inflate target directories (3, otel4sJS)
+        run: |
+          tar xf targets.tar
+          rm targets.tar
+
+      - name: Download target directories (3, otel4sNative)
+        uses: actions/download-artifact@v4
+        with:
+          name: target-${{ matrix.os }}-${{ matrix.java }}-3-otel4sNative
+
+      - name: Inflate target directories (3, otel4sNative)
         run: |
           tar xf targets.tar
           rm targets.tar
diff --git a/build.sbt b/build.sbt
index 1e4806a8..a39dec6b 100644
--- a/build.sbt
+++ b/build.sbt
@@ -13,6 +13,17 @@ ThisBuild / tlSiteApiUrl := Some(url("https://www.javadoc.io/doc/org.typelevel/k
 
 lazy val root = tlCrossRootProject.aggregate(core, otel4s)
 
+ThisBuild / githubWorkflowBuildMatrixAdditions := {
+  val projects = core.componentProjects ++ otel4s.componentProjects
+
+  Map("project" -> projects.map(_.id).toList)
+}
+
+ThisBuild / githubWorkflowBuildMatrixExclusions ++= {
+  val projects = otel4s.componentProjects.map(_.id)
+  projects.map(project => MatrixExclude(Map("project" -> project, "scala" -> "2.12"))).toSeq
+}
+
 lazy val core = crossProject(JVMPlatform, JSPlatform, NativePlatform)
   .crossType(CrossType.Pure)
   .in(file("core"))

From 8e1252692919464448d02ae6521e0e53af1f04ef Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Tue, 16 Apr 2024 20:47:56 +0300
Subject: [PATCH 15/19] build.sbt: update previous mima artifacts for otel4s

---
 build.sbt | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/build.sbt b/build.sbt
index a39dec6b..56d5b0b8 100644
--- a/build.sbt
+++ b/build.sbt
@@ -21,7 +21,7 @@ ThisBuild / githubWorkflowBuildMatrixAdditions := {
 
 ThisBuild / githubWorkflowBuildMatrixExclusions ++= {
   val projects = otel4s.componentProjects.map(_.id)
-  projects.map(project => MatrixExclude(Map("project" -> project, "scala" -> "2.12"))).toSeq
+  projects.map(project => MatrixExclude(Map("project" -> project, "scala" -> "2.12")))
 }
 
 lazy val core = crossProject(JVMPlatform, JSPlatform, NativePlatform)
@@ -67,7 +67,8 @@ lazy val otel4s = crossProject(JVMPlatform, JSPlatform, NativePlatform)
     name := "keypool-otel4s",
     startYear := Some(2024),
     crossScalaVersions := Seq(Scala213, Scala3),
-    libraryDependencies += "org.typelevel" %%% "otel4s-core" % otel4sV
+    libraryDependencies += "org.typelevel" %%% "otel4s-core" % otel4sV,
+    mimaPreviousArtifacts ~= { _.filterNot(_.revision.startsWith("0.4")) }
   )
   .jvmSettings(
     libraryDependencies += "org.typelevel" %% "otel4s-oteljava-testkit" % otel4sV % Test
@@ -82,7 +83,7 @@ lazy val docs = project
 val catsV = "2.10.0"
 val catsEffectV = "3.5.4"
 
-val otel4sV = "0.5.0"
+val otel4sV = "0.6.0"
 
 val munitV = "1.0.0-M11"
 val munitCatsEffectV = "2.0.0-M4"

From 98da94df2829ebc5e61d1d8c906c61a59f611ba8 Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Tue, 16 Apr 2024 20:48:12 +0300
Subject: [PATCH 16/19] add scaladocs, update tests

---
 .../scala/org/typelevel/keypool/KeyPool.scala |  2 +-
 .../typelevel/keypool/PoolMetricsSpec.scala   | 83 ++++++++---------
 .../org/typelevel/keypool/Otel4sMetrics.scala | 91 ++++++++++++-------
 3 files changed, 100 insertions(+), 76 deletions(-)

diff --git a/core/src/main/scala/org/typelevel/keypool/KeyPool.scala b/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
index fe5a1019..ed26948b 100644
--- a/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
+++ b/core/src/main/scala/org/typelevel/keypool/KeyPool.scala
@@ -302,7 +302,7 @@ object KeyPool {
       }
 
     def allocateNew: F[(B, F[Unit])] =
-      kp.kpMetrics.acquireRecordDuration.use(_ => kp.kpRes(k).allocated)
+      kp.kpMetrics.acquireRecordDuration.surround(kp.kpRes(k).allocated)
 
     for {
       _ <- kp.kpMaxTotalSem.permit
diff --git a/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index 1931b686..ab120f23 100644
--- a/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -23,9 +23,10 @@ package org.typelevel.keypool
 
 import cats.effect._
 import cats.effect.testkit._
-import io.opentelemetry.sdk.metrics._
 import munit.CatsEffectSuite
-import org.typelevel.otel4s.metrics.MeterProvider
+import org.typelevel.keypool.internal.Metrics
+import org.typelevel.otel4s.{Attribute, Attributes}
+import org.typelevel.otel4s.metrics.{BucketBoundaries, Meter, MeterProvider}
 import org.typelevel.otel4s.oteljava.testkit.metrics.MetricsTestkit
 import org.typelevel.otel4s.oteljava.testkit.metrics.data.{HistogramPointData, Metric, MetricData}
 
@@ -42,7 +43,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
 
     createTestkit.use { testkit =>
       for {
-        snapshot <- mkPool(testkit.metrics.meterProvider).use(_ => testkit.snapshot)
+        snapshot <- mkPool(testkit.metrics.meterProvider).surround(testkit.snapshot)
       } yield assertEquals(snapshot, expectedSnapshot)
     }
   }
@@ -50,7 +51,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
   test("In use: increment on acquire and decrement on release") {
     poolTest() { (sdk, pool) =>
       for {
-        inUse <- pool.take.use(_ => sdk.snapshot)
+        inUse <- pool.take.surround(sdk.snapshot)
         afterUse <- sdk.snapshot
       } yield {
         assertEquals(inUse.inUse, List(1L))
@@ -66,7 +67,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
       for {
         deferred <- IO.deferred[MetricsSnapshot]
         _ <- pool.take
-          .use(_ => sdk.snapshot.flatMap(deferred.complete) >> IO.raiseError(exception))
+          .surround(sdk.snapshot.flatMap(deferred.complete) >> IO.raiseError(exception))
           .attempt
         inUse <- deferred.get
         afterUse <- sdk.snapshot
@@ -80,7 +81,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
   test("Idle: keep 0 when `maxIdle` is 0") {
     poolTest(_.withMaxIdle(0)) { (sdk, pool) =>
       for {
-        inUse <- pool.take.use(_ => sdk.snapshot)
+        inUse <- pool.take.surround(sdk.snapshot)
         afterUse <- sdk.snapshot
       } yield {
         assertEquals(inUse.idle, Nil)
@@ -92,7 +93,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
   test("Idle: keep 1 when `maxIdle` is 1") {
     poolTest(_.withMaxIdle(1)) { (sdk, pool) =>
       for {
-        inUse <- pool.take.use(_ => sdk.snapshot)
+        inUse <- pool.take.surround(sdk.snapshot)
         afterUse <- sdk.snapshot
       } yield {
         assertEquals(inUse.idle, Nil)
@@ -105,7 +106,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
     TestControl.executeEmbed {
       poolTest(_.withMaxIdle(1).withIdleTimeAllowedInPool(1.second)) { (sdk, pool) =>
         for {
-          inUse <- pool.take.use(_ => sdk.snapshot)
+          inUse <- pool.take.surround(sdk.snapshot)
           afterUse <- sdk.snapshot
           afterSleep <- sdk.snapshot.delayBy(6.seconds)
         } yield {
@@ -121,7 +122,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
     TestControl.executeEmbed {
       createTestkit.use { sdk =>
         mkPool(sdk.metrics.meterProvider)
-          .use(pool => pool.take.use(_ => sdk.snapshot.delayBy(500.millis)).product(sdk.snapshot))
+          .use(pool => pool.take.surround(sdk.snapshot.delayBy(1.second)).product(sdk.snapshot))
           .map { case (inUse, afterUse) =>
             val acquireDuration =
               List(
@@ -140,7 +141,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
               idle = List(1),
               inUse = List(0),
               inUseDuration = List(
-                HistogramPointData(500.0, 1, HistogramBuckets, List(0, 0, 0, 1, 0))
+                HistogramPointData(1.0, 1, HistogramBuckets, List(0, 1, 0, 0, 0))
               ),
               acquiredTotal = List(1),
               acquireDuration = acquireDuration
@@ -157,41 +158,38 @@ class PoolMetricsSpec extends CatsEffectSuite {
       customize: Pool.Builder[IO, Ref[IO, Int]] => Pool.Builder[IO, Ref[IO, Int]] = identity
   )(scenario: (OtelTestkit[IO], Pool[IO, Ref[IO, Int]]) => IO[Unit]): IO[Unit] = {
     createTestkit.use { sdk =>
-      val builder =
-        Pool
+      sdk.metrics.meterProvider.get("org.typelevel.keypool").flatMap { implicit M: Meter[IO] =>
+        val builder = Pool
           .Builder(Ref.of[IO, Int](1), nothing)
-          .withMetricsProvider(
-            Otel4sMetrics.provider(sdk.metrics.meterProvider, "test")
-          )
+          .withMetricsProvider(metricsProvider)
 
-      customize(builder).build.use(pool => scenario(sdk, pool))
+        customize(builder).build.use(pool => scenario(sdk, pool))
+      }
     }
   }
 
   private def mkPool(meterProvider: MeterProvider[IO]) =
-    Pool
-      .Builder(
-        Ref.of[IO, Int](1),
-        nothing
-      )
-      .withMetricsProvider(Otel4sMetrics.provider(meterProvider, "test"))
-      .withMaxTotal(10)
-      .build
-
-  private def createTestkit: Resource[IO, OtelTestkit[IO]] = {
-    def customize(builder: SdkMeterProviderBuilder) =
-      builder
-        .registerView(
-          InstrumentSelector.builder().setType(InstrumentType.HISTOGRAM).build(),
-          View
-            .builder()
-            .setAggregation(
-              Aggregation.explicitBucketHistogram(HistogramBuckets.map(Double.box).asJava)
-            )
-            .build()
+    Resource.eval(meterProvider.get("org.typelevel.keypool")).flatMap { implicit M: Meter[IO] =>
+      Pool
+        .Builder(
+          Ref.of[IO, Int](1),
+          nothing
         )
+        .withMetricsProvider(metricsProvider)
+        .withMaxTotal(10)
+        .build
+    }
 
-    MetricsTestkit.inMemory[IO](customize).map { testkit =>
+  private def metricsProvider(implicit M: Meter[IO]): Metrics.Provider[IO] =
+    Otel4sMetrics.provider[IO](
+      "keypool",
+      Attributes(Attribute("pool.name", "test")),
+      BucketBoundaries(HistogramBuckets.toVector),
+      BucketBoundaries(HistogramBuckets.toVector)
+    )
+
+  private def createTestkit: Resource[IO, OtelTestkit[IO]] =
+    MetricsTestkit.inMemory[IO]().map { testkit =>
       new OtelTestkit[IO] {
         val metrics: MetricsTestkit[IO] = testkit
 
@@ -218,16 +216,15 @@ class PoolMetricsSpec extends CatsEffectSuite {
                 .getOrElse(Nil)
 
             MetricsSnapshot(
-              counterValue("idle.current"),
-              counterValue("in_use.current"),
-              histogramSnapshot("in_use.duration"),
-              counterValue("acquired.total"),
-              histogramSnapshot("acquire.duration")
+              counterValue("keypool.idle.current"),
+              counterValue("keypool.in_use.current"),
+              histogramSnapshot("keypool.in_use.duration"),
+              counterValue("keypool.acquired.total"),
+              histogramSnapshot("keypool.acquire.duration")
             )
           }
       }
     }
-  }
 
   private val HistogramBuckets: List[Double] =
     List(0.01, 1, 100, 1000)
diff --git a/otel4s/shared/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala b/otel4s/shared/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala
index 1e78a306..61beb883 100644
--- a/otel4s/shared/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala
+++ b/otel4s/shared/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala
@@ -28,69 +28,96 @@ import cats.effect.kernel.Resource
 import cats.syntax.functor._
 import cats.syntax.flatMap._
 import org.typelevel.keypool.internal.Metrics
-import org.typelevel.otel4s.Attribute
-import org.typelevel.otel4s.metrics.MeterProvider
+import org.typelevel.otel4s.Attributes
+import org.typelevel.otel4s.metrics.{BucketBoundaries, Meter}
 
 object Otel4sMetrics {
 
-  def provider[F[_]: Monad](
-      meterProvider: MeterProvider[F],
-      poolName: String
+  private val DefaultHistogramBuckets: BucketBoundaries =
+    BucketBoundaries(Vector(.005, .01, .025, .05, .075, .1, .25, .5, .75, 1, 2.5, 5, 7.5, 10))
+
+  /**
+   * Creates metrics provider using otel4s `Meter` under the hood.
+   *
+   * Use `attributes` to customize the metrics.
+   *
+   * @example
+   *   {{{
+   * val attributes = Attributes(Attribute("pool.name", "db-pool"))
+   *
+   * Otel4sMetrics.provider[IO](attributes = attributes)
+   *   }}}
+   *
+   * @param prefix
+   *   the prefix to prepend to the metrics
+   *
+   * @param attributes
+   *   the attributes to attach to the measurements
+   *
+   * @param inUseDurationSecondsHistogramBuckets
+   *   the histogram buckets for the 'in_use.duration' histogram
+   *
+   * @param acquireDurationSecondsHistogramBuckets
+   *   the histogram buckets for 'acquire.duration' histogram
+   */
+  def provider[F[_]: Monad: Meter](
+      prefix: String = "keypool",
+      attributes: Attributes = Attributes.empty,
+      inUseDurationSecondsHistogramBuckets: BucketBoundaries = DefaultHistogramBuckets,
+      acquireDurationSecondsHistogramBuckets: BucketBoundaries = DefaultHistogramBuckets
   ): Metrics.Provider[F] =
     new Metrics.Provider[F] {
       def get: F[Metrics[F]] =
         for {
-          meter <- meterProvider.get("org.typelevel.keypool")
-
-          idle <- meter
-            .upDownCounter[Long]("idle.current")
+          idle <- Meter[F]
+            .upDownCounter[Long](s"$prefix.idle.current")
             .withUnit("{resource}")
-            .withDescription("A current number of idle resources")
+            .withDescription("A current number of idle resources.")
             .create
 
-          inUse <- meter
-            .upDownCounter[Long]("in_use.current")
+          inUse <- Meter[F]
+            .upDownCounter[Long](s"$prefix.in_use.current")
             .withUnit("{resource}")
-            .withDescription("A current number of resources in use")
+            .withDescription("A current number of resources in use.")
             .create
 
-          inUseDuration <- meter
-            .histogram[Long]("in_use.duration")
-            .withUnit("ms")
-            .withDescription("For how long a resource is in use")
+          inUseDuration <- Meter[F]
+            .histogram[Long](s"$prefix.in_use.duration")
+            .withUnit("s")
+            .withDescription("For how long a resource is in use.")
+            .withExplicitBucketBoundaries(inUseDurationSecondsHistogramBuckets)
             .create
 
-          acquiredTotal <- meter
-            .counter[Long]("acquired.total")
+          acquiredTotal <- Meter[F]
+            .counter[Long](s"$prefix.acquired.total")
             .withUnit("{resource}")
-            .withDescription("A total number of acquired resources")
+            .withDescription("A total number of acquired resources.")
             .create
 
-          acquireDuration <- meter
-            .histogram[Long]("acquire.duration")
-            .withUnit("ms")
-            .withDescription("How long does it take to acquire a resource")
+          acquireDuration <- Meter[F]
+            .histogram[Long](s"$prefix.acquire.duration")
+            .withUnit("s")
+            .withDescription("How long does it take to acquire a resource.")
+            .withExplicitBucketBoundaries(acquireDurationSecondsHistogramBuckets)
             .create
         } yield new Metrics[F] {
-          private val nameAttribute = Attribute("pool.name", poolName)
-
           def idleInc: F[Unit] =
-            idle.inc(nameAttribute)
+            idle.inc(attributes)
 
           def idleDec: F[Unit] =
-            idle.dec(nameAttribute)
+            idle.dec(attributes)
 
           def inUseCount: Resource[F, Unit] =
-            Resource.make(inUse.inc(nameAttribute))(_ => inUse.dec(nameAttribute))
+            Resource.make(inUse.inc(attributes))(_ => inUse.dec(attributes))
 
           def inUseRecordDuration: Resource[F, Unit] =
-            inUseDuration.recordDuration(TimeUnit.MILLISECONDS, nameAttribute)
+            inUseDuration.recordDuration(TimeUnit.SECONDS, attributes)
 
           def acquiredTotalInc: F[Unit] =
-            acquiredTotal.inc(nameAttribute)
+            acquiredTotal.inc(attributes)
 
           def acquireRecordDuration: Resource[F, Unit] =
-            acquireDuration.recordDuration(TimeUnit.MILLISECONDS, nameAttribute)
+            acquireDuration.recordDuration(TimeUnit.SECONDS, attributes)
         }
     }
 }

From f7a16b7c5b5ab16269e668ac88fe3c0641ec57d9 Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Tue, 16 Apr 2024 20:51:15 +0300
Subject: [PATCH 17/19] fix compilation issue

---
 .../src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala   | 1 -
 1 file changed, 1 deletion(-)

diff --git a/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index ab120f23..6fede521 100644
--- a/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -31,7 +31,6 @@ import org.typelevel.otel4s.oteljava.testkit.metrics.MetricsTestkit
 import org.typelevel.otel4s.oteljava.testkit.metrics.data.{HistogramPointData, Metric, MetricData}
 
 import scala.concurrent.duration._
-import scala.jdk.CollectionConverters._
 import scala.util.control.NoStackTrace
 
 class PoolMetricsSpec extends CatsEffectSuite {

From 041bd8112741486d3afe8e72e0ea4b691d5d0830 Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Tue, 16 Apr 2024 20:56:55 +0300
Subject: [PATCH 18/19] make mima happy

---
 build.sbt | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/build.sbt b/build.sbt
index 56d5b0b8..e1708f3f 100644
--- a/build.sbt
+++ b/build.sbt
@@ -54,7 +54,8 @@ lazy val core = crossProject(JVMPlatform, JSPlatform, NativePlatform)
       ProblemFilters
         .exclude[DirectMissingMethodProblem]("org.typelevel.keypool.KeyPoolBuilder.this"),
       ProblemFilters
-        .exclude[DirectMissingMethodProblem]("org.typelevel.keypool.KeyPool#Builder.this")
+        .exclude[DirectMissingMethodProblem]("org.typelevel.keypool.KeyPool#Builder.this"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("org.typelevel.keypool.Pool#Builder.this")
     )
   )
 

From 6bfb5572a21b9b0255a7b76ab7650d6d1d8b6d3c Mon Sep 17 00:00:00 2001
From: Maksym Ochenashko <maxochenashko@gmail.com>
Date: Sun, 5 May 2024 11:59:59 +0300
Subject: [PATCH 19/19] Use otel4s `0.7.0`

---
 .github/workflows/ci.yml                      |   4 +-
 build.sbt                                     |  16 +-
 .../org/typelevel/keypool/Otel4sMetrics.scala |   0
 .../typelevel/keypool/PoolMetricsSpec.scala   | 170 ++++++++++--------
 4 files changed, 102 insertions(+), 88 deletions(-)
 rename otel4s/{shared => }/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala (100%)
 rename otel4s/{jvm => }/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala (57%)

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d7e995b4..b0a52b52 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -87,11 +87,11 @@ jobs:
 
       - name: Make target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: mkdir -p otel4s/native/target core/.native/target otel4s/js/target otel4s/jvm/target core/.js/target core/.jvm/target project/target
+        run: mkdir -p otel4s/.native/target core/.native/target otel4s/.js/target otel4s/.jvm/target core/.js/target core/.jvm/target project/target
 
       - name: Compress target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
-        run: tar cf targets.tar otel4s/native/target core/.native/target otel4s/js/target otel4s/jvm/target core/.js/target core/.jvm/target project/target
+        run: tar cf targets.tar otel4s/.native/target core/.native/target otel4s/.js/target otel4s/.jvm/target core/.js/target core/.jvm/target project/target
 
       - name: Upload target directories
         if: github.event_name != 'pull_request' && (startsWith(github.ref, 'refs/tags/v') || github.ref == 'refs/heads/main')
diff --git a/build.sbt b/build.sbt
index e1708f3f..b510774e 100644
--- a/build.sbt
+++ b/build.sbt
@@ -60,7 +60,7 @@ lazy val core = crossProject(JVMPlatform, JSPlatform, NativePlatform)
   )
 
 lazy val otel4s = crossProject(JVMPlatform, JSPlatform, NativePlatform)
-  .crossType(CrossType.Full)
+  .crossType(CrossType.Pure)
   .in(file("otel4s"))
   .dependsOn(core)
   .settings(commonSettings)
@@ -68,12 +68,12 @@ lazy val otel4s = crossProject(JVMPlatform, JSPlatform, NativePlatform)
     name := "keypool-otel4s",
     startYear := Some(2024),
     crossScalaVersions := Seq(Scala213, Scala3),
-    libraryDependencies += "org.typelevel" %%% "otel4s-core" % otel4sV,
+    libraryDependencies ++= Seq(
+      "org.typelevel" %%% "otel4s-core-metrics"        % otel4sV,
+      "org.typelevel" %%% "otel4s-sdk-metrics-testkit" % otel4sV % Test
+    ),
     mimaPreviousArtifacts ~= { _.filterNot(_.revision.startsWith("0.4")) }
   )
-  .jvmSettings(
-    libraryDependencies += "org.typelevel" %% "otel4s-oteljava-testkit" % otel4sV % Test
-  )
 
 lazy val docs = project
   .in(file("site"))
@@ -84,10 +84,10 @@ lazy val docs = project
 val catsV = "2.10.0"
 val catsEffectV = "3.5.4"
 
-val otel4sV = "0.6.0"
+val otel4sV = "0.7.0"
 
-val munitV = "1.0.0-M11"
-val munitCatsEffectV = "2.0.0-M4"
+val munitV = "1.0.0-RC1"
+val munitCatsEffectV = "2.0.0-M5"
 
 val kindProjectorV = "0.13.3"
 val betterMonadicForV = "0.3.1"
diff --git a/otel4s/shared/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala b/otel4s/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala
similarity index 100%
rename from otel4s/shared/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala
rename to otel4s/src/main/scala/org/typelevel/keypool/Otel4sMetrics.scala
diff --git a/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala b/otel4s/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
similarity index 57%
rename from otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
rename to otel4s/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
index 6fede521..e03bee84 100644
--- a/otel4s/jvm/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
+++ b/otel4s/src/test/scala/org/typelevel/keypool/PoolMetricsSpec.scala
@@ -27,8 +27,8 @@ import munit.CatsEffectSuite
 import org.typelevel.keypool.internal.Metrics
 import org.typelevel.otel4s.{Attribute, Attributes}
 import org.typelevel.otel4s.metrics.{BucketBoundaries, Meter, MeterProvider}
-import org.typelevel.otel4s.oteljava.testkit.metrics.MetricsTestkit
-import org.typelevel.otel4s.oteljava.testkit.metrics.data.{HistogramPointData, Metric, MetricData}
+import org.typelevel.otel4s.sdk.metrics.data.{MetricPoints, PointData, TimeWindow}
+import org.typelevel.otel4s.sdk.testkit.metrics.MetricsTestkit
 
 import scala.concurrent.duration._
 import scala.util.control.NoStackTrace
@@ -38,7 +38,7 @@ class PoolMetricsSpec extends CatsEffectSuite {
 
   test("Metrics should be empty for unused pool") {
     val expectedSnapshot =
-      MetricsSnapshot(Nil, Nil, Nil, Nil, Nil)
+      MetricsSnapshot(Vector.empty, Vector.empty, Vector.empty, Vector.empty, Vector.empty)
 
     createTestkit.use { testkit =>
       for {
@@ -53,8 +53,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
         inUse <- pool.take.surround(sdk.snapshot)
         afterUse <- sdk.snapshot
       } yield {
-        assertEquals(inUse.inUse, List(1L))
-        assertEquals(afterUse.inUse, List(0L))
+        assertEquals(inUse.inUse, Vector(1L))
+        assertEquals(afterUse.inUse, Vector(0L))
       }
     }
   }
@@ -71,8 +71,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
         inUse <- deferred.get
         afterUse <- sdk.snapshot
       } yield {
-        assertEquals(inUse.inUse, List(1L))
-        assertEquals(afterUse.inUse, List(0L))
+        assertEquals(inUse.inUse, Vector(1L))
+        assertEquals(afterUse.inUse, Vector(0L))
       }
     }
   }
@@ -83,8 +83,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
         inUse <- pool.take.surround(sdk.snapshot)
         afterUse <- sdk.snapshot
       } yield {
-        assertEquals(inUse.idle, Nil)
-        assertEquals(afterUse.idle, Nil)
+        assertEquals(inUse.idle, Vector.empty)
+        assertEquals(afterUse.idle, Vector.empty)
       }
     }
   }
@@ -95,77 +95,89 @@ class PoolMetricsSpec extends CatsEffectSuite {
         inUse <- pool.take.surround(sdk.snapshot)
         afterUse <- sdk.snapshot
       } yield {
-        assertEquals(inUse.idle, Nil)
-        assertEquals(afterUse.idle, List(1L))
+        assertEquals(inUse.idle, Vector.empty)
+        assertEquals(afterUse.idle, Vector(1L))
       }
     }
   }
 
   test("Idle: decrement on reaper cleanup") {
-    TestControl.executeEmbed {
-      poolTest(_.withMaxIdle(1).withIdleTimeAllowedInPool(1.second)) { (sdk, pool) =>
-        for {
-          inUse <- pool.take.surround(sdk.snapshot)
-          afterUse <- sdk.snapshot
-          afterSleep <- sdk.snapshot.delayBy(6.seconds)
-        } yield {
-          assertEquals(inUse.idle, Nil)
-          assertEquals(afterUse.idle, List(1L))
-          assertEquals(afterSleep.idle, List(0L))
-        }
+    poolTest(_.withMaxIdle(1).withIdleTimeAllowedInPool(1.second)) { (sdk, pool) =>
+      for {
+        inUse <- pool.take.surround(sdk.snapshot)
+        afterUse <- sdk.snapshot
+        afterSleep <- sdk.snapshot.delayBy(6.seconds)
+      } yield {
+        assertEquals(inUse.idle, Vector.empty)
+        assertEquals(afterUse.idle, Vector(1L))
+        assertEquals(afterSleep.idle, Vector(0L))
       }
     }
+
   }
 
   test("Generate valid metric snapshots") {
-    TestControl.executeEmbed {
-      createTestkit.use { sdk =>
-        mkPool(sdk.metrics.meterProvider)
-          .use(pool => pool.take.surround(sdk.snapshot.delayBy(1.second)).product(sdk.snapshot))
-          .map { case (inUse, afterUse) =>
-            val acquireDuration =
-              List(
-                HistogramPointData(0, 1, HistogramBuckets, List(1, 0, 0, 0, 0))
-              )
-
-            val expectedInUse = MetricsSnapshot(
-              idle = Nil,
-              inUse = List(1),
-              inUseDuration = Nil,
-              acquiredTotal = List(1),
-              acquireDuration = acquireDuration
+    poolTest() { (sdk, pool) =>
+      pool.take
+        .surround(sdk.snapshot.delayBy(1.second))
+        .product(sdk.snapshot)
+        .map { case (inUse, afterUse) =>
+          val acquireDuration = Vector(
+            PointData.histogram(
+              TimeWindow(Duration.Zero, 1.second),
+              Attributes(Attribute("pool.name", "test")),
+              Vector.empty,
+              Some(PointData.Histogram.Stats(0.0, 0.0, 0.0, 1)),
+              HistogramBuckets,
+              Vector(1, 0, 0, 0, 0)
             )
+          )
 
-            val expectedAfterUser = MetricsSnapshot(
-              idle = List(1),
-              inUse = List(0),
-              inUseDuration = List(
-                HistogramPointData(1.0, 1, HistogramBuckets, List(0, 1, 0, 0, 0))
-              ),
-              acquiredTotal = List(1),
-              acquireDuration = acquireDuration
-            )
+          val expectedInUse = MetricsSnapshot(
+            idle = Vector.empty,
+            inUse = Vector(1L),
+            inUseDuration = Vector.empty,
+            acquiredTotal = Vector(1L),
+            acquireDuration = acquireDuration
+          )
 
-            assertEquals(inUse, expectedInUse)
-            assertEquals(afterUse, expectedAfterUser)
-          }
-      }
+          val expectedAfterUser = MetricsSnapshot(
+            idle = Vector(1L),
+            inUse = Vector(0L),
+            inUseDuration = Vector(
+              PointData.histogram(
+                TimeWindow(Duration.Zero, 1.second),
+                Attributes(Attribute("pool.name", "test")),
+                Vector.empty,
+                Some(PointData.Histogram.Stats(1.0, 1.0, 1.0, 1)),
+                HistogramBuckets,
+                Vector(0, 1, 0, 0, 0)
+              )
+            ),
+            acquiredTotal = Vector(1L),
+            acquireDuration = acquireDuration
+          )
+
+          assertEquals(inUse, expectedInUse)
+          assertEquals(afterUse, expectedAfterUser)
+        }
     }
   }
 
   private def poolTest(
       customize: Pool.Builder[IO, Ref[IO, Int]] => Pool.Builder[IO, Ref[IO, Int]] = identity
-  )(scenario: (OtelTestkit[IO], Pool[IO, Ref[IO, Int]]) => IO[Unit]): IO[Unit] = {
-    createTestkit.use { sdk =>
-      sdk.metrics.meterProvider.get("org.typelevel.keypool").flatMap { implicit M: Meter[IO] =>
-        val builder = Pool
-          .Builder(Ref.of[IO, Int](1), nothing)
-          .withMetricsProvider(metricsProvider)
-
-        customize(builder).build.use(pool => scenario(sdk, pool))
+  )(scenario: (OtelTestkit[IO], Pool[IO, Ref[IO, Int]]) => IO[Unit]): IO[Unit] =
+    TestControl.executeEmbed {
+      createTestkit.use { sdk =>
+        sdk.metrics.meterProvider.get("org.typelevel.keypool").flatMap { implicit M: Meter[IO] =>
+          val builder = Pool
+            .Builder(Ref.of[IO, Int](1), nothing)
+            .withMetricsProvider(metricsProvider)
+
+          customize(builder).build.use(pool => scenario(sdk, pool))
+        }
       }
     }
-  }
 
   private def mkPool(meterProvider: MeterProvider[IO]) =
     Resource.eval(meterProvider.get("org.typelevel.keypool")).flatMap { implicit M: Meter[IO] =>
@@ -183,8 +195,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
     Otel4sMetrics.provider[IO](
       "keypool",
       Attributes(Attribute("pool.name", "test")),
-      BucketBoundaries(HistogramBuckets.toVector),
-      BucketBoundaries(HistogramBuckets.toVector)
+      HistogramBuckets,
+      HistogramBuckets
     )
 
   private def createTestkit: Resource[IO, OtelTestkit[IO]] =
@@ -194,25 +206,27 @@ class PoolMetricsSpec extends CatsEffectSuite {
 
         def snapshot: IO[MetricsSnapshot] =
           for {
-            metrics <- testkit.collectMetrics[Metric]
+            metrics <- testkit.collectMetrics
           } yield {
-            def counterValue(name: String): List[Long] =
+            def counterValue(name: String): Vector[Long] =
               metrics
                 .find(_.name == name)
                 .map(_.data)
-                .collectFirst { case MetricData.LongSum(points) =>
-                  points.map(_.value)
+                .collectFirst { case sum: MetricPoints.Sum =>
+                  sum.points.toVector.collect { case long: PointData.LongNumber =>
+                    long.value
+                  }
                 }
-                .getOrElse(Nil)
+                .getOrElse(Vector.empty)
 
-            def histogramSnapshot(name: String): List[HistogramPointData] =
+            def histogramSnapshot(name: String): Vector[PointData.Histogram] =
               metrics
                 .find(_.name == name)
                 .map(_.data)
-                .collectFirst { case MetricData.Histogram(points) =>
-                  points.map(_.value)
+                .collectFirst { case histogram: MetricPoints.Histogram =>
+                  histogram.points.toVector
                 }
-                .getOrElse(Nil)
+                .getOrElse(Vector.empty)
 
             MetricsSnapshot(
               counterValue("keypool.idle.current"),
@@ -225,8 +239,8 @@ class PoolMetricsSpec extends CatsEffectSuite {
       }
     }
 
-  private val HistogramBuckets: List[Double] =
-    List(0.01, 1, 100, 1000)
+  private val HistogramBuckets: BucketBoundaries =
+    BucketBoundaries(Vector(0.01, 1.0, 100.0, 1000.0))
 
   private def nothing(ref: Ref[IO, Int]): IO[Unit] =
     ref.get.void
@@ -241,11 +255,11 @@ object PoolMetricsSpec {
   }
 
   final case class MetricsSnapshot(
-      idle: List[Long],
-      inUse: List[Long],
-      inUseDuration: List[HistogramPointData],
-      acquiredTotal: List[Long],
-      acquireDuration: List[HistogramPointData]
+      idle: Vector[Long],
+      inUse: Vector[Long],
+      inUseDuration: Vector[PointData.Histogram],
+      acquiredTotal: Vector[Long],
+      acquireDuration: Vector[PointData.Histogram]
   )
 
 }