sdk-metrics: add SdkMeterProvider and SdkMeterBuilder

sdk/metrics/src/main/scala/org/typelevel/otel4s/sdk/metrics/SdkMeter.scala

@@ -29,7 +29,11 @@ import org.typelevel.otel4s.metrics.ObservableGauge
 import org.typelevel.otel4s.metrics.ObservableUpDownCounter
 import org.typelevel.otel4s.metrics.UpDownCounter
 import org.typelevel.otel4s.sdk.context.AskContext
+import org.typelevel.otel4s.sdk.metrics.data.MetricData
 import org.typelevel.otel4s.sdk.metrics.internal.MeterSharedState
+import org.typelevel.otel4s.sdk.metrics.internal.exporter.RegisteredReader
+
+import scala.concurrent.duration.FiniteDuration
 
 /** The meter is responsible for creating instruments.
   *
@@ -91,13 +95,21 @@ private class SdkMeter[F[_]: MonadCancelThrow: Clock: Console: AskContext](
   val batchCallback: BatchCallback[F] =
     new SdkBatchCallback[F](sharedState)
 
+  private[metrics] def collectAll(
+      reader: RegisteredReader[F],
+      collectTimestamp: FiniteDuration
+  ): F[Vector[MetricData]] =
+    sharedState.collectAll(reader, collectTimestamp)
+
+  override def toString: String =
+    s"SdkMeter{instrumentationScope=${sharedState.scope}}"
 }
 
-object SdkMeter {
+private object SdkMeter {
 
   // see https://opentelemetry.io/docs/specs/otel/metrics/api/#instrument-name-syntax
   private val InstrumentNamePattern =
-    "([A-Za-z]){1}([A-Za-z0-9\\_\\-\\./]){0,254}".r
+    "([A-Za-z]){1}([A-Za-z0-9_\\-./]){0,254}".r
 
   private def isValidName(name: String): Boolean =
     name != null && SdkMeter.InstrumentNamePattern.matches(name)

sdk/metrics/src/main/scala/org/typelevel/otel4s/sdk/metrics/SdkMeterBuilder.scala

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2024 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s.sdk.metrics
+
+import cats.Functor
+import cats.syntax.functor._
+import org.typelevel.otel4s.Attributes
+import org.typelevel.otel4s.metrics.Meter
+import org.typelevel.otel4s.metrics.MeterBuilder
+import org.typelevel.otel4s.sdk.internal.ComponentRegistry
+
+private final case class SdkMeterBuilder[F[_]: Functor](
+    componentRegistry: ComponentRegistry[F, SdkMeter[F]],
+    name: String,
+    version: Option[String] = None,
+    schemaUrl: Option[String] = None
+) extends MeterBuilder[F] {
+
+  def withVersion(version: String): MeterBuilder[F] =
+    copy(version = Option(version))
+
+  def withSchemaUrl(schemaUrl: String): MeterBuilder[F] =
+    copy(schemaUrl = Option(schemaUrl))
+
+  def get: F[Meter[F]] =
+    componentRegistry.get(name, version, schemaUrl, Attributes.empty).widen
+}

sdk/metrics/src/main/scala/org/typelevel/otel4s/sdk/metrics/SdkMeterProvider.scala

@@ -0,0 +1,280 @@
+/*
+ * Copyright 2024 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.typelevel.otel4s.sdk.metrics
+
+import cats.Applicative
+import cats.Monad
+import cats.data.NonEmptyVector
+import cats.effect.Clock
+import cats.effect.Temporal
+import cats.effect.std.Console
+import cats.effect.std.Random
+import cats.syntax.flatMap._
+import cats.syntax.foldable._
+import cats.syntax.functor._
+import cats.syntax.traverse._
+import org.typelevel.otel4s.metrics.MeterBuilder
+import org.typelevel.otel4s.metrics.MeterProvider
+import org.typelevel.otel4s.sdk.TelemetryResource
+import org.typelevel.otel4s.sdk.common.InstrumentationScope
+import org.typelevel.otel4s.sdk.context.AskContext
+import org.typelevel.otel4s.sdk.internal.ComponentRegistry
+import org.typelevel.otel4s.sdk.metrics.data.MetricData
+import org.typelevel.otel4s.sdk.metrics.exemplar.ExemplarFilter
+import org.typelevel.otel4s.sdk.metrics.exemplar.TraceContextLookup
+import org.typelevel.otel4s.sdk.metrics.exporter.MetricProducer
+import org.typelevel.otel4s.sdk.metrics.exporter.MetricReader
+import org.typelevel.otel4s.sdk.metrics.internal.MeterSharedState
+import org.typelevel.otel4s.sdk.metrics.internal.exporter.RegisteredReader
+import org.typelevel.otel4s.sdk.metrics.view.InstrumentSelector
+import org.typelevel.otel4s.sdk.metrics.view.RegisteredView
+import org.typelevel.otel4s.sdk.metrics.view.View
+import org.typelevel.otel4s.sdk.metrics.view.ViewRegistry
+
+import scala.concurrent.duration.FiniteDuration
+
+private final class SdkMeterProvider[F[_]: Applicative](
+    componentRegistry: ComponentRegistry[F, SdkMeter[F]],
+    resource: TelemetryResource,
+    views: Vector[RegisteredView],
+    readers: Vector[RegisteredReader[F]],
+    producers: Vector[MetricProducer[F]]
+) extends MeterProvider[F] {
+  import SdkMeterProvider.DefaultMeterName
+
+  def meter(name: String): MeterBuilder[F] =
+    if (readers.isEmpty) {
+      MeterBuilder.noop[F]
+    } else {
+      val meterName = if (name.trim.isEmpty) DefaultMeterName else name
+      SdkMeterBuilder(componentRegistry, meterName)
+    }
+
+  override def toString: String =
+    "SdkMeterProvider{" +
+      s"resource=$resource, " +
+      s"metricsReaders=${readers.map(_.reader).mkString("[", ", ", "]")}, " +
+      s"metricsProducers=${producers.mkString("[", ", ", "]")}, " +
+      s"views=${views.mkString("[", ", ", "]")}" +
+      "}"
+
+}
+
+object SdkMeterProvider {
+
+  private val DefaultMeterName = "unknown"
+
+  /** Builder for [[org.typelevel.otel4s.metrics.MeterProvider MeterProvider]].
+    */
+  sealed trait Builder[F[_]] {
+
+    /** Sets a [[TelemetryResource]] to be attached to all metrics created by
+      * [[org.typelevel.otel4s.metrics.Meter Meter]].
+      *
+      * @note
+      *   on multiple subsequent calls, the resource from the last call will be
+      *   retained.
+      *
+      * @param resource
+      *   the [[TelemetryResource]] to use
+      */
+    def withResource(resource: TelemetryResource): Builder[F]
+
+    /** Merges the given [[TelemetryResource]] with the current one.
+      *
+      * @note
+      *   if both resources have different non-empty `schemaUrl`, the merge will
+      *   fail.
+      *
+      * @see
+      *   [[TelemetryResource.mergeUnsafe]]
+      *
+      * @param resource
+      *   the [[TelemetryResource]] to merge the current one with
+      */
+    def addResource(resource: TelemetryResource): Builder[F]
+
+    /** Sets an [[ExemplarFilter]] to be used by all metrics.
+      *
+      * @param filter
+      *   the [[ExemplarFilter]] to register
+      */
+    def withExemplarFilter(filter: ExemplarFilter): Builder[F]
+
+    /** Sets a [[TraceContextLookup TraceContextLookup]] to be used by
+      * exemplars.
+      *
+      * @param lookup
+      *   the [[TraceContextLookup]] to use
+      */
+    def withTraceContextLookup(lookup: TraceContextLookup): Builder[F]
+
+    /** Registers a [[View]] for the given [[InstrumentSelector]].
+      *
+      * [[View]] affects aggregation and export of the instruments that match
+      * the given `selector`.
+      *
+      * @param selector
+      *   the [[InstrumentSelector]] to filter instruments with
+      *
+      * @param view
+      *   the [[View]] to register
+      */
+    def registerView(selector: InstrumentSelector, view: View): Builder[F]
+
+    /** Registers a
+      * [[org.typelevel.otel4s.sdk.metrics.exporter.MetricReader MetricReader]].
+      *
+      * @param reader
+      *   the
+      *   [[org.typelevel.otel4s.sdk.metrics.exporter.MetricReader MetricReader]]
+      *   to register
+      */
+    def registerMetricReader(reader: MetricReader[F]): Builder[F]
+
+    /** Registers a
+      * [[org.typelevel.otel4s.sdk.metrics.exporter.MetricProducer MetricProducer]].
+      *
+      * @param producer
+      *   the
+      *   [[org.typelevel.otel4s.sdk.metrics.exporter.MetricProducer MetricProducer]]
+      *   to register
+      */
+    def registerMetricProducer(producer: MetricProducer[F]): Builder[F]
+
+    /** Creates [[org.typelevel.otel4s.metrics.MeterProvider MeterProvider]]
+      * with the configuration of this builder.
+      */
+    def build: F[MeterProvider[F]]
+  }
+
+  /** Creates a new [[Builder]] with default configuration.
+    */
+  def builder[F[_]: Temporal: Random: Console: AskContext]: Builder[F] =
+    BuilderImpl(
+      resource = TelemetryResource.default,
+      exemplarFilter = None,
+      traceContextLookup = TraceContextLookup.noop,
+      registeredViews = Vector.empty,
+      metricReaders = Vector.empty,
+      metricProducers = Vector.empty
+    )
+
+  private final case class BuilderImpl[
+      F[_]: Temporal: Random: Console: AskContext
+  ](
+      resource: TelemetryResource,
+      exemplarFilter: Option[ExemplarFilter],
+      traceContextLookup: TraceContextLookup,
+      registeredViews: Vector[RegisteredView],
+      metricReaders: Vector[MetricReader[F]],
+      metricProducers: Vector[MetricProducer[F]]
+  ) extends Builder[F] {
+
+    def withResource(resource: TelemetryResource): Builder[F] =
+      copy(resource = resource)
+
+    def addResource(resource: TelemetryResource): Builder[F] =
+      copy(resource = this.resource.mergeUnsafe(resource))
+
+    def withExemplarFilter(filter: ExemplarFilter): Builder[F] =
+      copy(exemplarFilter = Some(filter))
+
+    def withTraceContextLookup(lookup: TraceContextLookup): Builder[F] =
+      copy(traceContextLookup = lookup)
+
+    def registerView(selector: InstrumentSelector, view: View): Builder[F] =
+      copy(registeredViews = registeredViews :+ RegisteredView(selector, view))
+
+    def registerMetricReader(reader: MetricReader[F]): Builder[F] =
+      copy(metricReaders = metricReaders :+ reader)
+
+    def registerMetricProducer(producer: MetricProducer[F]): Builder[F] =
+      copy(metricProducers = metricProducers :+ producer)
+
+    def build: F[MeterProvider[F]] =
+      if (metricReaders.isEmpty) Monad[F].pure(MeterProvider.noop)
+      else create
+
+    private def create: F[MeterProvider[F]] = {
+      def createMeter(
+          startTimestamp: FiniteDuration,
+          scope: InstrumentationScope,
+          readers: Vector[RegisteredReader[F]]
+      ): F[SdkMeter[F]] = {
+        val viewRegistry = ViewRegistry(registeredViews)
+
+        val filter = exemplarFilter.getOrElse(
+          ExemplarFilter.traceBased(traceContextLookup)
+        )
+
+        for {
+          state <- MeterSharedState.create(
+            resource,
+            scope,
+            startTimestamp,
+            filter,
+            traceContextLookup,
+            viewRegistry,
+            readers
+          )
+        } yield new SdkMeter[F](state)
+      }
+
+      def configureReader(
+          registry: ComponentRegistry[F, SdkMeter[F]],
+          reader: RegisteredReader[F]
+      ): F[Unit] = {
+        val sdkMetricProducer = new SdkMetricProducer[F](
+          registry,
+          reader
+        )
+
+        reader.reader.register(
+          NonEmptyVector(sdkMetricProducer, metricProducers)
+        )
+      }
+
+      for {
+        now <- Clock[F].realTime
+        readers <- metricReaders.traverse(r => RegisteredReader.create(now, r))
+        registry <- ComponentRegistry.create(s => createMeter(now, s, readers))
+        _ <- readers.traverse_(reader => configureReader(registry, reader))
+      } yield new SdkMeterProvider(
+        registry,
+        resource,
+        registeredViews,
+        readers,
+        metricProducers
+      )
+    }
+  }
+
+  private final class SdkMetricProducer[F[_]: Monad: Clock](
+      registry: ComponentRegistry[F, SdkMeter[F]],
+      reader: RegisteredReader[F]
+  ) extends MetricProducer[F] {
+    def produce: F[Vector[MetricData]] =
+      for {
+        meters <- registry.components
+        now <- Clock[F].realTime
+        result <- meters.flatTraverse(_.collectAll(reader, now))
+        _ <- reader.setLastCollectTimestamp(now)
+      } yield result
+  }
+
+}

sdk/metrics/src/main/scala/org/typelevel/otel4s/sdk/metrics/view/RegisteredView.scala

@@ -16,7 +16,35 @@
 
 package org.typelevel.otel4s.sdk.metrics.view
 
-private[metrics] final case class RegisteredView(
-    selector: InstrumentSelector,
-    view: View
-)
+import cats.Show
+
+private[metrics] sealed trait RegisteredView {
+
+  /** The selector associated with the view.
+    */
+  def selector: InstrumentSelector
+
+  /** The view.
+    */
+  def view: View
+
+  override final def toString: String =
+    Show[RegisteredView].show(this)
+}
+
+private[metrics] object RegisteredView {
+
+  def apply(selector: InstrumentSelector, view: View): RegisteredView =
+    Impl(selector, view)
+
+  implicit val registeredViewShow: Show[RegisteredView] =
+    Show.show { registeredView =>
+      s"RegisteredView{selector=${registeredView.selector}, view=${registeredView.view}}"
+    }
+
+  private final case class Impl(
+      selector: InstrumentSelector,
+      view: View
+  ) extends RegisteredView
+
+}