Merge pull request #417 from fd4s/ce-3

Port to cats-effect 3.0

build.sbt

@@ -1,10 +1,10 @@
-val catsEffectVersion = "2.3.1"
+val catsEffectVersion = "3.0.0-RC2"
 
 val catsVersion = "2.4.1"
 
 val confluentVersion = "6.1.0"
 
-val fs2Version = "2.5.0"
+val fs2Version = "3.0.0-M8"
 
 val kafkaVersion = "2.7.0"
 
@@ -36,6 +36,7 @@ lazy val core = project
     name := moduleName.value,
     dependencySettings ++ Seq(
       libraryDependencies ++= Seq(
+        "org.typelevel" %% "cats-effect" % catsEffectVersion,
         "co.fs2" %% "fs2-core" % fs2Version,
         "org.apache.kafka" % "kafka-clients" % kafkaVersion
       )
@@ -87,6 +88,7 @@ lazy val dependencySettings = Seq(
       .withDottyCompat(scalaVersion.value),
     "org.typelevel" %% "discipline-scalatest" % "2.1.1",
     "org.typelevel" %% "cats-effect-laws" % catsEffectVersion,
+    "org.typelevel" %% "cats-effect-testkit" % catsEffectVersion,
     "org.typelevel" %% "cats-testkit-scalatest" % "2.1.1",
     "ch.qos.logback" % "logback-classic" % "1.2.3"
   ).map(_ % Test),
@@ -226,7 +228,7 @@ lazy val publishSettings =
   )
 
 lazy val mimaSettings = Seq(
-  // Restore this after releasing v2.0.0
+  // Restore this after releasing v3.0.0
   // mimaPreviousArtifacts := {
   //   if (publishArtifact.value) {
   //     Set(organization.value %% moduleName.value % (previousStableVersion in ThisBuild).value.get)

docs/src/main/mdoc/admin.md

@@ -28,8 +28,6 @@ def adminClientSettings[F[_]: Sync](bootstrapServers: String): AdminClientSettin
 
 There are several settings specific to the library.
 
-- `withBlocker` sets the `Blocker` on which blocking Java Kafka `AdminClient` functions are executed. Unless specified, a default fixed single-thread pool is created as part of admin client initialization, with the thread name using the `fs2-kafka-admin-client` prefix.
-
 - `withCloseTimeout` controls the timeout when waiting for admin client shutdown. Default is 20 seconds.
 
 - `withCreateAdminClient` changes how the underlying Java Kafka admin client is created. The default creates a Java `AdminClient` instance using set properties, but this function allows overriding the behaviour for e.g. testing purposes.
@@ -39,7 +37,7 @@ There are several settings specific to the library.
 Once settings are defined, we can use create an admin client in a `Stream`.
 
 ```scala mdoc:silent
-def kafkaAdminClientStream[F[_]: Concurrent: ContextShift](
+def kafkaAdminClientStream[F[_]: Async](
   bootstrapServers: String
 ): Stream[F, KafkaAdminClient[F]] =
   KafkaAdminClient.stream(adminClientSettings[F](bootstrapServers))
@@ -48,7 +46,7 @@ def kafkaAdminClientStream[F[_]: Concurrent: ContextShift](
 Alternatively, we can create an admin client in a `Resource` context.
 
 ```scala mdoc:silent
-def kafkaAdminClientResource[F[_]: Concurrent: ContextShift](
+def kafkaAdminClientResource[F[_]: Async](
   bootstrapServers: String
 ): Resource[F, KafkaAdminClient[F]] =
   KafkaAdminClient.resource(adminClientSettings[F](bootstrapServers))
@@ -61,7 +59,7 @@ There are functions available for describing, creating, and deleting topics.
 ```scala mdoc:silent
 import org.apache.kafka.clients.admin.{NewPartitions, NewTopic}
 
-def topicOperations[F[_]: Concurrent: ContextShift]: F[Unit] =
+def topicOperations[F[_]: Async]: F[Unit] =
   kafkaAdminClientResource[F]("localhost:9092").use { client =>
     for {
       topicNames <- client.listTopics.names
@@ -83,7 +81,7 @@ We can edit the configuration of different resources, like topics and nodes.
 import org.apache.kafka.common.config.ConfigResource
 import org.apache.kafka.clients.admin.{AlterConfigOp, ConfigEntry}
 
-def configOperations[F[_]: Concurrent: ContextShift]: F[Unit] =
+def configOperations[F[_]: Async]: F[Unit] =
   kafkaAdminClientResource[F]("localhost:9092").use { client =>
     val topic = new ConfigResource(ConfigResource.Type.TOPIC, "topic")
 
@@ -108,7 +106,7 @@ It's possible to retrieve metadata about the cluster nodes.
 ```scala mdoc:silent
 import org.apache.kafka.common.Node
 
-def clusterNodes[F[_]: Concurrent: ContextShift]: F[Set[Node]] =
+def clusterNodes[F[_]: Async]: F[Set[Node]] =
   kafkaAdminClientResource[F]("localhost:9092").use(_.describeCluster.nodes)
 ```
 
@@ -117,9 +115,7 @@ def clusterNodes[F[_]: Concurrent: ContextShift]: F[Set[Node]] =
 There are functions available for working with consumer groups.
 
 ```scala mdoc:silent
-import cats.Parallel
-
-def consumerGroupOperations[F[_]: Concurrent: ContextShift: Parallel]: F[Unit] =
+def consumerGroupOperations[F[_]: Async: cats.Parallel]: F[Unit] =
   kafkaAdminClientResource[F]("localhost:9092").use { client =>
     for {
       consumerGroupIds <- client.listConsumerGroups.groupIds
@@ -145,7 +141,7 @@ import org.apache.kafka.common.resource.{
   ResourceType
 }
 
-def aclOperations[F[_]: Concurrent: ContextShift]: F[Unit] =
+def aclOperations[F[_]: Async]: F[Unit] =
   kafkaAdminClientResource[F]("localhost:9092").use { client =>
     for {
       describedAcls <- client.describeAcls(AclBindingFilter.ANY)

docs/src/main/mdoc/consumers.md

@@ -144,8 +144,6 @@ In addition, there are several settings specific to the library.
 
 - `withCreateConsumer` changes how the underlying Java Kafka consumer is created. The default merely creates a Java `KafkaConsumer` instance using set properties, but this function allows overriding the behaviour for e.g. testing purposes.
 
-- `withBlocker` sets the `Blocker` on which blocking Java Kafka consumer functions are executed. Unless specified, a default fixed single-thread pool is created as part of consumer initialization, with the thread name using the `fs2-kafka-consumer` prefix.
-
 - `withMaxPrefetchBatches` adjusts the maximum number of record batches per topic-partition to prefetch before backpressure is applied. The default is 2, meaning there can be up to 2 record batches per topic-partition waiting to be processed.
 
 - `withPollInterval` alters how often consumer `poll` should take place. Default is 50 milliseconds.
@@ -344,7 +342,7 @@ To achieve this behavior we could use a `stopConsuming` method on a` KafkaConsum
 We could combine `stopConsuming` with the custom resource handling and implement a graceful shutdown. Let's try it:
 
 ```scala mdoc:silent
-import cats.effect.concurrent.{Deferred, Ref}
+import cats.effect.{Deferred, Ref}
 
 object WithGracefulShutdownExample extends IOApp {
   def run(args: List[String]): IO[ExitCode] = {
@@ -372,7 +370,7 @@ object WithGracefulShutdownExample extends IOApp {
           }.uncancelable // [7]
         } { case ((consumer, closeConsumer), exitCase) => // [8]
           (exitCase match {
-            case ExitCase.Error(e) => handleError(e) // [9]
+            case Outcome.Errored(e) => handleError(e) // [9]
             case _ => for {
               _ <- gracefulShutdownStartedRef.set(true) // [10]
               _ <- consumer.stopConsuming // [11]

docs/src/main/mdoc/producers.md

@@ -134,8 +134,6 @@ The following settings are specific to the library.
 
 - `withCreateProducer` changes how the underlying Java Kafka producer is created. The default merely creates a Java `KafkaProducer` instance using set properties, but this function allows overriding the behaviour for e.g. testing purposes.
 
-- `withBlocker` sets the `Blocker` on which blocking Java Kafka producer functions are executed. Unless specified, a default fixed single-thread pool is created as part of producer initialization, with the thread name using the `fs2-kafka-producer` prefix.
-
 ## Producer Creation
 
 Once [`ProducerSettings`][producersettings] is defined, use `KafkaProducer.stream` to create a [`KafkaProducer`][kafkaproducer] instance.

modules/core/src/main/scala/fs2/kafka/AdminClientSettings.scala

@@ -6,7 +6,7 @@
 
 package fs2.kafka
 
-import cats.effect.{Blocker, Sync}
+import cats.effect.Sync
 import cats.Show
 import fs2.kafka.internal.converters.collection._
 import org.apache.kafka.clients.admin.{AdminClient, AdminClientConfig}
@@ -27,19 +27,6 @@ import scala.concurrent.duration._
   */
 sealed abstract class AdminClientSettings[F[_]] {
 
-  /**
-    * The `Blocker` to use for blocking Kafka operations. If not
-    * explicitly provided, a default `Blocker` will be created
-    * when creating a `KafkaAdminClient` instance.
-    */
-  def blocker: Option[Blocker]
-
-  /**
-    * Returns a new [[AdminClientSettings]] instance with the
-    * specified [[blocker]] to use for blocking operations.
-    */
-  def withBlocker(blocker: Blocker): AdminClientSettings[F]
-
   /**
     * Properties which can be provided when creating a Java `KafkaAdminClient`
     * instance. Numerous functions in [[AdminClientSettings]] add properties
@@ -205,13 +192,10 @@ sealed abstract class AdminClientSettings[F[_]] {
 
 object AdminClientSettings {
   private[this] final case class AdminClientSettingsImpl[F[_]](
-    override val blocker: Option[Blocker],
     override val properties: Map[String, String],
     override val closeTimeout: FiniteDuration,
     val createAdminClientWith: Map[String, String] => F[AdminClient]
   ) extends AdminClientSettings[F] {
-    override def withBlocker(blocker: Blocker): AdminClientSettings[F] =
-      copy(blocker = Some(blocker))
 
     override def withBootstrapServers(bootstrapServers: String): AdminClientSettings[F] =
       withProperty(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers)
@@ -279,11 +263,10 @@ object AdminClientSettings {
 
   def apply[F[_]](implicit F: Sync[F]): AdminClientSettings[F] =
     AdminClientSettingsImpl(
-      blocker = None,
       properties = Map.empty,
       closeTimeout = 20.seconds,
       createAdminClientWith = properties =>
-        F.delay {
+        F.blocking {
           AdminClient.create {
             (properties: Map[String, AnyRef]).asJava
           }

modules/core/src/main/scala/fs2/kafka/CommitRecovery.scala

@@ -6,11 +6,11 @@
 
 package fs2.kafka
 
-import cats.effect.Timer
+import cats.effect.Temporal
 import cats.syntax.applicativeError._
 import cats.syntax.flatMap._
 import cats.syntax.functor._
-import cats.{Functor, MonadError}
+import cats.Functor
 import org.apache.kafka.clients.consumer.{OffsetAndMetadata, RetriableCommitFailedException}
 import org.apache.kafka.common.TopicPartition
 
@@ -44,9 +44,8 @@ abstract class CommitRecovery {
     offsets: Map[TopicPartition, OffsetAndMetadata],
     commit: F[Unit]
   )(
-    implicit F: MonadError[F, Throwable],
-    jitter: Jitter[F],
-    timer: Timer[F]
+    implicit F: Temporal[F],
+    jitter: Jitter[F]
   ): Throwable => F[Unit]
 }
 
@@ -89,15 +88,14 @@ object CommitRecovery {
         offsets: Map[TopicPartition, OffsetAndMetadata],
         commit: F[Unit]
       )(
-        implicit F: MonadError[F, Throwable],
-        jitter: Jitter[F],
-        timer: Timer[F]
+        implicit F: Temporal[F],
+        jitter: Jitter[F]
       ): Throwable => F[Unit] = {
         def retry(attempt: Int): Throwable => F[Unit] = {
           case retriable: RetriableCommitFailedException =>
             val commitWithRecovery = commit.handleErrorWith(retry(attempt + 1))
-            if (attempt <= 10) backoff(attempt).flatMap(timer.sleep) >> commitWithRecovery
-            else if (attempt <= 15) timer.sleep(10.seconds) >> commitWithRecovery
+            if (attempt <= 10) backoff(attempt).flatMap(F.sleep) >> commitWithRecovery
+            else if (attempt <= 15) F.sleep(10.seconds) >> commitWithRecovery
             else F.raiseError(CommitRecoveryException(attempt - 1, retriable, offsets))
 
           case nonRetriable: Throwable =>
@@ -120,9 +118,8 @@ object CommitRecovery {
         offsets: Map[TopicPartition, OffsetAndMetadata],
         commit: F[Unit]
       )(
-        implicit F: MonadError[F, Throwable],
-        jitter: Jitter[F],
-        timer: Timer[F]
+        implicit F: Temporal[F],
+        jitter: Jitter[F]
       ): Throwable => F[Unit] = F.raiseError
 
       override def toString: String =

modules/core/src/main/scala/fs2/kafka/ConsumerResource.scala

@@ -6,7 +6,7 @@
 
 package fs2.kafka
 
-import cats.effect.{ConcurrentEffect, ContextShift, Resource, Timer}
+import cats.effect.{Resource, Async}
 
 /**
   * [[ConsumerResource]] provides support for inferring the key and value
@@ -18,19 +18,18 @@ import cats.effect.{ConcurrentEffect, ContextShift, Resource, Timer}
   * }}}
   */
 final class ConsumerResource[F[_]] private[kafka] (
-  private val F: ConcurrentEffect[F]
+  private val F: Async[F]
 ) extends AnyVal {
 
   /**
     * Creates a new [[KafkaConsumer]] in the `Resource` context.
     * This is equivalent to using `KafkaConsumer.resource` directly,
     * except we're able to infer the key and value type.
     */
-  def using[K, V](settings: ConsumerSettings[F, K, V])(
-    implicit context: ContextShift[F],
-    timer: Timer[F]
+  def using[K, V](
+    settings: ConsumerSettings[F, K, V]
   ): Resource[F, KafkaConsumer[F, K, V]] =
-    KafkaConsumer.resource(settings)(F, context, timer)
+    KafkaConsumer.resource[F, K, V](settings)(F)
 
   override def toString: String =
     "ConsumerResource$" + System.identityHashCode(this)

modules/core/src/main/scala/fs2/kafka/ConsumerSettings.scala

@@ -6,7 +6,7 @@
 
 package fs2.kafka
 
-import cats.effect.{Blocker, Sync}
+import cats.effect.{Sync}
 import cats.Show
 import fs2.kafka.internal.converters.collection._
 import org.apache.kafka.clients.consumer.ConsumerConfig
@@ -47,19 +47,6 @@ sealed abstract class ConsumerSettings[F[_], K, V] {
     */
   def valueDeserializer: F[Deserializer[F, V]]
 
-  /**
-    * The `Blocker` to use for blocking Kafka operations. If not
-    * explicitly provided, a default `Blocker` will be created
-    * when creating a `KafkaConsumer` instance.
-    */
-  def blocker: Option[Blocker]
-
-  /**
-    * Returns a new [[ConsumerSettings]] instance with the
-    * specified [[blocker]] to use for blocking operations.
-    */
-  def withBlocker(blocker: Blocker): ConsumerSettings[F, K, V]
-
   /**
     * Properties which can be provided when creating a Java `KafkaConsumer`
     * instance. Numerous functions in [[ConsumerSettings]] add properties
@@ -403,7 +390,6 @@ object ConsumerSettings {
   private[this] final case class ConsumerSettingsImpl[F[_], K, V](
     override val keyDeserializer: F[Deserializer[F, K]],
     override val valueDeserializer: F[Deserializer[F, V]],
-    override val blocker: Option[Blocker],
     override val properties: Map[String, String],
     override val closeTimeout: FiniteDuration,
     override val commitTimeout: FiniteDuration,
@@ -414,8 +400,6 @@ object ConsumerSettings {
     override val maxPrefetchBatches: Int,
     val createConsumerWith: Map[String, String] => F[KafkaByteConsumer]
   ) extends ConsumerSettings[F, K, V] {
-    override def withBlocker(blocker: Blocker): ConsumerSettings[F, K, V] =
-      copy(blocker = Some(blocker))
 
     override def withBootstrapServers(bootstrapServers: String): ConsumerSettings[F, K, V] =
       withProperty(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers)
@@ -546,7 +530,6 @@ object ConsumerSettings {
     ConsumerSettingsImpl(
       keyDeserializer = keyDeserializer,
       valueDeserializer = valueDeserializer,
-      blocker = None,
       properties = Map(
         ConsumerConfig.AUTO_OFFSET_RESET_CONFIG -> "none",
         ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG -> "false"

modules/core/src/main/scala/fs2/kafka/ConsumerStream.scala

@@ -6,7 +6,7 @@
 
 package fs2.kafka
 
-import cats.effect.{ConcurrentEffect, ContextShift, Timer}
+import cats.effect.Async
 import fs2.Stream
 
 /**
@@ -19,19 +19,16 @@ import fs2.Stream
   * }}}
   */
 final class ConsumerStream[F[_]] private[kafka] (
-  private val F: ConcurrentEffect[F]
+  private val F: Async[F]
 ) extends AnyVal {
 
   /**
     * Creates a new [[KafkaConsumer]] in the `Stream` context.
     * This is equivalent to using `KafkaConsumer.stream` directly,
     * except we're able to infer the key and value type.
     */
-  def using[K, V](settings: ConsumerSettings[F, K, V])(
-    implicit context: ContextShift[F],
-    timer: Timer[F]
-  ): Stream[F, KafkaConsumer[F, K, V]] =
-    KafkaConsumer.stream(settings)(F, context, timer)
+  def using[K, V](settings: ConsumerSettings[F, K, V]): Stream[F, KafkaConsumer[F, K, V]] =
+    KafkaConsumer.stream[F, K, V](settings)(F)
 
   override def toString: String =
     "ConsumerStream$" + System.identityHashCode(this)

modules/core/src/main/scala/fs2/kafka/Deserializer.scala

@@ -166,7 +166,7 @@ object Deserializer {
 
       override def suspend: Deserializer[F, A] =
         Deserializer.instance { (topic, headers, bytes) =>
-          F.suspend(deserialize(topic, headers, bytes))
+          F.defer(deserialize(topic, headers, bytes))
         }
 
       override def toString: String =