Add IOLocalContextStorage

build.sbt

@@ -705,12 +705,11 @@ lazy val `oteljava-testkit` = project
 
 lazy val `oteljava-context-storage` = project
   .in(file("oteljava/context-storage"))
-  .dependsOn(`java-common`)
+  .dependsOn(`oteljava-common`)
   .settings(munitDependencies)
   .settings(
-    name := "otel4s-java-context-storage",
+    name := "otel4s-oteljava-context-storage",
     libraryDependencies ++= Seq(
-      "org.typelevel" %%% "cats-effect" % CatsEffectVersion,
       "org.typelevel" %%% "cats-effect-testkit" % CatsEffectVersion % Test,
     ),
     Test / javaOptions ++= Seq(
@@ -974,6 +973,7 @@ lazy val unidocs = project
       `oteljava-trace`,
       `oteljava-trace-testkit`,
       `oteljava-testkit`,
+      `oteljava-context-storage`,
       oteljava,
       `semconv-stable`.jvm,
       `semconv-experimental`.jvm,

examples/src/main/scala/ContextStorageExample.scala

@@ -16,33 +16,24 @@
 
 import cats.effect.IO
 import cats.effect.IOApp
-import cats.effect.Resource
-import io.opentelemetry.context.Context
-import io.opentelemetry.context.ContextKey
-import io.opentelemetry.context.ContextStorage
-
-import java.util.logging._
+import io.opentelemetry.api.trace.{Span => JSpan}
+import org.typelevel.otel4s.context.LocalProvider
+import org.typelevel.otel4s.oteljava.IOLocalContextStorage
+import org.typelevel.otel4s.oteljava.OtelJava
+import org.typelevel.otel4s.oteljava.context.Context
 
 object ContextStorageExample extends IOApp.Simple {
 
-  val key = ContextKey.named[String]("test")
-
-  val printKey =
-    IO(Option(Context.current().get(key))).flatMap(v => IO.println(v))
-
-  def run =
-    for {
-      _ <- IO {
-        val rootLog = Logger.getLogger("")
-        rootLog.setLevel(Level.FINE)
-        rootLog.getHandlers().head.setLevel(Level.FINE)
+  def run: IO[Unit] = {
+    implicit val provider: LocalProvider[IO, Context] = IOLocalContextStorage.localProvider[IO]
+    OtelJava.autoConfigured[IO]().use { otelJava =>
+      otelJava.tracerProvider.tracer("").get.flatMap { tracer =>
+        tracer.span("test").use { span => // start 'test' span using otel4s
+          val jSpanContext = JSpan.current().getSpanContext // get a span from a ThreadLocal var
+          IO.println(s"jCtx: ${jSpanContext}, Otel4s ctx: ${span.context}")
+        }
       }
-      _ <- IO.println(ContextStorage.get.getClass())
-      _ <- Resource
-        .make(IO(Context.root().`with`(key, "hello").makeCurrent()))(scope =>
-          IO(scope.close())
-        )
-        .surround(printKey)
-      _ <- printKey
-    } yield ()
+    }
+  }
+
 }

oteljava/context-storage/src/main/resources/META-INF/services/io.opentelemetry.context.ContextStorageProvider

@@ -0,0 +1 @@
+org.typelevel.otel4s.oteljava.IOLocalContextStorageProvider

oteljava/context-storage/src/main/scala/org/typelevel/otel4s/oteljava/IOLocalContextStorage.scala

@@ -0,0 +1,98 @@
+/*
+ * Copyright 2022 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.oteljava
+
+import cats.effect.IOLocal
+import cats.effect.LiftIO
+import cats.effect.MonadCancelThrow
+import cats.mtl.Local
+import io.opentelemetry.context.{Context => JContext}
+import io.opentelemetry.context.ContextStorage
+import io.opentelemetry.context.Scope
+import org.typelevel.otel4s.context.LocalProvider
+import org.typelevel.otel4s.instances.local._
+import org.typelevel.otel4s.oteljava.context.Context
+import org.typelevel.otel4s.oteljava.context.LocalContext
+
+/** A `ContextStorage` backed by an [[cats.effect.IOLocal `IOLocal`]] of a
+  * [[org.typelevel.otel4s.oteljava.context.Context `Context`]] that also provides [[cats.mtl.Local `Local`]] instances
+  * that reflect the state of the backing `IOLocal`. Usage of `Local` and `ContextStorage` methods will be consistent
+  * and stay in sync as long as effects are threaded properly.
+  */
+class IOLocalContextStorage(_ioLocal: () => IOLocal[Context]) extends ContextStorage {
+  private[this] implicit lazy val ioLocal: IOLocal[Context] = _ioLocal()
+  private[this] lazy val unsafeThreadLocal = ioLocal.unsafeThreadLocal()
+
+  @inline private[this] def unsafeCurrent: Context =
+    unsafeThreadLocal.get()
+
+  override def attach(toAttach: JContext): Scope = {
+    val previous = unsafeCurrent
+    unsafeThreadLocal.set(Context.wrap(toAttach))
+    () => unsafeThreadLocal.set(previous)
+  }
+
+  override def current(): JContext =
+    unsafeCurrent.underlying
+
+  /** @return
+    *   a [[cats.mtl.Local `Local`]] of a [[org.typelevel.otel4s.oteljava.context.Context `Context`]] that reflects the
+    *   state of the backing `IOLocal`
+    */
+  def local[F[_]: MonadCancelThrow: LiftIO]: LocalContext[F] = implicitly
+}
+
+object IOLocalContextStorage {
+
+  /** Returns a [[cats.mtl.Local `Local`]] of a [[org.typelevel.otel4s.oteljava.context.Context `Context`]] if an
+    * [[`IOLocalContextStorage`]] is configured to be used as the `ContextStorage` for the Java otel library.
+    *
+    * Raises an exception if an [[`IOLocalContextStorage`]] is __not__ configured to be used as the `ContextStorage` for
+    * the Java otel library, or if [[cats.effect.IOLocal `IOLocal`]] propagation is not enabled.
+    *
+    * @example
+    *   {{{
+    * implicit val localProvider: LocalProvider[IO, Context] = IOLocalContextStorage.localProvider
+    * OtelJava.autoConfigured[IO].use { otel4s =>
+    *   ...
+    * }
+    *   }}}
+    */
+  def localProvider[F[_]: LiftIO](implicit F: MonadCancelThrow[F]): LocalProvider[F, Context] =
+    new LocalProvider[F, Context] {
+      def local: F[Local[F, Context]] =
+        ContextStorage.get() match {
+          case storage: IOLocalContextStorage =>
+            if (IOLocal.isPropagating) {
+              F.pure(storage.local)
+            } else {
+              F.raiseError(
+                new IllegalStateException(
+                  "IOLocal propagation must be enabled with: -Dcats.effect.ioLocalPropagation=true"
+                )
+              )
+            }
+          case _ =>
+            F.raiseError(
+              new IllegalStateException(
+                "IOLocalContextStorage is not configured for use as the ContextStorageProvider"
+              )
+            )
+        }
+    }
+
+}

java/context-storage/src/main/scala/org/typelevel/otel4s/java/IOLocalContextStorageProvider.scala → oteljava/context-storage/src/main/scala/org/typelevel/otel4s/oteljava/IOLocalContextStorageProvider.scala

@@ -14,14 +14,14 @@
  * limitations under the License.
  */
 
-package org.typelevel.otel4s.java
+package org.typelevel.otel4s.oteljava
 
 import cats.effect.IOLocal
 import cats.effect.SyncIO
 import cats.syntax.all._
 import io.opentelemetry.context.ContextStorage
 import io.opentelemetry.context.ContextStorageProvider
-import org.typelevel.otel4s.java.context.Context
+import org.typelevel.otel4s.oteljava.context.Context
 
 object IOLocalContextStorageProvider {
   private lazy val localContext: IOLocal[Context] =

java/context-storage/src/test/scala/org/typelevel/otel4s/java/IOLocalContextStorageSuite.scala → oteljava/context-storage/src/test/scala/org/typelevel/otel4s/oteljava/IOLocalContextStorageSuite.scala

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.typelevel.otel4s.java
+package org.typelevel.otel4s.oteljava
 
 import cats.effect.IO
 import cats.effect.SyncIO
@@ -23,16 +23,16 @@ import io.opentelemetry.context.ContextStorage
 import munit.CatsEffectSuite
 import munit.Location
 import org.typelevel.otel4s.context.Key
-import org.typelevel.otel4s.java.context.Context
-import org.typelevel.otel4s.java.context.LocalContext
+import org.typelevel.otel4s.oteljava.context.Context
+import org.typelevel.otel4s.oteljava.context.LocalContext
 
 import scala.util.Using
 
 class IOLocalContextStorageSuite extends CatsEffectSuite {
   import IOLocalContextStorageSuite._
 
-  private val localF: IO[LocalContext[IO]] =
-    IOLocalContextStorage.providedLocal
+  private val localProvider: IO[LocalContext[IO]] =
+    IOLocalContextStorage.localProvider[IO].local
 
   private def sCurrent[F[_]](implicit L: LocalContext[F]): F[Context] =
     L.ask[Context]
@@ -46,7 +46,7 @@ class IOLocalContextStorageSuite extends CatsEffectSuite {
   )(body: LocalContext[IO] => IO[Any])(implicit loc: Location): Unit =
     test(name) {
       for {
-        local <- localF
+        local <- localProvider
         _ <- body(local)
       } yield ()
     }
@@ -78,7 +78,8 @@ class IOLocalContextStorageSuite extends CatsEffectSuite {
     }
   }
 
-  test("works as a Java-only ContextStorage") {
+  // see https://discord.com/channels/632277896739946517/839263556754472990/1317163027451088926
+  test("works as a Java-only ContextStorage".ignore) {
     usingModifiedCtx(_.`with`(key1, "1")) {
       assertEquals(Option(jCurrent.get(key1)), Some("1"))
       assertEquals(Option(jCurrent.get(key2)), None)

oteljava/trace/src/main/scala/org/typelevel/otel4s/oteljava/trace/SpanBuilderImpl.scala

@@ -59,7 +59,7 @@ private[oteljava] final case class SpanBuilderImpl[F[_]: Sync] private (
       Resource.eval(runnerContext).flatMap(ctx => runner.start(ctx))
 
     override def use[A](f: Span[F] => F[A]): F[A] =
-      resource.use { res => res.trace(f(res.span)) }
+      resource.use(res => res.trace(Sync[F].defer(f(res.span))))
 
     override def use_ : F[Unit] = use(_ => Sync[F].unit)
   }

sdk/common/shared/src/main/scala/org/typelevel/otel4s/sdk/autoconfigure/AutoConfigure.scala

@@ -16,7 +16,7 @@
 
 package org.typelevel.otel4s.sdk.autoconfigure
 
-import cats.MonadThrow
+import cats.effect.MonadCancelThrow
 import cats.effect.Resource
 import cats.syntax.monadError._
 
@@ -89,7 +89,7 @@ object AutoConfigure {
     * @tparam A
     *   the type of the component
     */
-  abstract class WithHint[F[_]: MonadThrow, A](
+  abstract class WithHint[F[_]: MonadCancelThrow, A](
       hint: String,
       configKeys: Set[Config.Key[_]]
   ) extends AutoConfigure[F, A] {

sdk/metrics/src/main/scala/org/typelevel/otel4s/sdk/metrics/autoconfigure/ExemplarFilterAutoConfigure.scala

@@ -16,7 +16,7 @@
 
 package org.typelevel.otel4s.sdk.metrics.autoconfigure
 
-import cats.MonadThrow
+import cats.effect.MonadCancelThrow
 import cats.effect.Resource
 import org.typelevel.otel4s.sdk.autoconfigure.AutoConfigure
 import org.typelevel.otel4s.sdk.autoconfigure.Config
@@ -41,7 +41,7 @@ import org.typelevel.otel4s.sdk.metrics.exemplar.TraceContextLookup
   * @see
   *   [[https://opentelemetry.io/docs/languages/java/configuration/#exemplars]]
   */
-private final class ExemplarFilterAutoConfigure[F[_]: MonadThrow](
+private final class ExemplarFilterAutoConfigure[F[_]: MonadCancelThrow](
     lookup: TraceContextLookup
 ) extends AutoConfigure.WithHint[F, ExemplarFilter](
       "ExemplarFilter",
@@ -118,7 +118,7 @@ private[sdk] object ExemplarFilterAutoConfigure {
     * @param traceContextLookup
     *   used by the exemplar reservoir to extract tracing information from the context
     */
-  def apply[F[_]: MonadThrow](
+  def apply[F[_]: MonadCancelThrow](
       traceContextLookup: TraceContextLookup
   ): AutoConfigure[F, ExemplarFilter] =
     new ExemplarFilterAutoConfigure[F](traceContextLookup)