從 Chill 0.6.0 (Kryo 2.21) 遷移到 0.9.5 (Kryo 4.0.2) 並反序列化舊消息

Question

我們正在使用 Chill-bijection 來序列化/反序列化與 Kryo 的 Kafka 之間的消息。 Older version of our application is using Chill 0.6.0 which depends on com.esotericsoftware.kryo.kryo-2.21.jar and new version of our application uses Chill 0.9.5 which depends on com.esotericsoftware.kryo-shaded-4.0.2.jar 。

為了最大限度地減少停機時間，我們的新版本應用程序需要能夠讀取舊版本應用程序寫入的消息，但它失敗並出現錯誤：

org.apache.kafka.common.errors.SerializationException: Error deserializing key/value for partition prod_2x02_external_entity_updates-0 at offset 8764198. If needed, please seek past the record to continue consumption.
Caused by: com.twitter.bijection.InversionFailure: Failed to invert: [B@14122f45
    at com.twitter.bijection.InversionFailure$$anonfun$partialFailure$1.applyOrElse(InversionFailure.scala:43)
    at com.twitter.bijection.InversionFailure$$anonfun$partialFailure$1.applyOrElse(InversionFailure.scala:42)
    at scala.runtime.AbstractPartialFunction.apply(AbstractPartialFunction.scala:38)
    at scala.util.Failure.recoverWith(Try.scala:236)
    at com.twitter.bijection.Inversion$.attempt(Inversion.scala:32)
    at com.X.backend.serialization.CustomKafkaKryoDeserializer.deserialize(KafkaKryoSerialization.scala:38)
    at org.apache.kafka.common.serialization.Deserializer.deserialize(Deserializer.java:60)
    at org.apache.kafka.clients.consumer.internals.Fetcher.parseRecord(Fetcher.java:1310)
    at org.apache.kafka.clients.consumer.internals.Fetcher.access$3500(Fetcher.java:128)
    at org.apache.kafka.clients.consumer.internals.Fetcher$CompletedFetch.fetchRecords(Fetcher.java:1541)
    at org.apache.kafka.clients.consumer.internals.Fetcher$CompletedFetch.access$1700(Fetcher.java:1377)
    at org.apache.kafka.clients.consumer.internals.Fetcher.fetchRecords(Fetcher.java:677)
    at org.apache.kafka.clients.consumer.internals.Fetcher.fetchedRecords(Fetcher.java:632)
    at org.apache.kafka.clients.consumer.KafkaConsumer.pollForFetches(KafkaConsumer.java:1315)
    at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1248)
    at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1216)
    at com.X.common.kafka.KafkaSubscriber$$anonfun$brokerFound$1.applyOrElse(KafkaSubscriber.scala:163)
    at akka.actor.Actor.aroundReceive(Actor.scala:535)
    at akka.actor.Actor.aroundReceive$(Actor.scala:533)
    at com.X.common.kafka.KafkaSubscriber.aroundReceive(KafkaSubscriber.scala:29)
    at akka.actor.ActorCell.receiveMessage(ActorCell.scala:577)
    at akka.actor.ActorCell.invoke(ActorCell.scala:547)
    at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:270)
    at akka.dispatch.Mailbox.run(Mailbox.scala:231)
    at akka.dispatch.Mailbox.exec(Mailbox.scala:243)
    at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
    at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
    at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692)
    at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:175)
Caused by: com.esotericsoftware.kryo.KryoException: Unable to find class: com.X.backend.DashboardExternalEntities$ExtMessage
Serialization trace:
entity (com.X.backend.QueueMessageProtocol$ExternalEntityUpdated)
    at com.esotericsoftware.kryo.util.DefaultClassResolver.readName(DefaultClassResolver.java:160)
    at com.esotericsoftware.kryo.util.DefaultClassResolver.readClass(DefaultClassResolver.java:133)
    at com.esotericsoftware.kryo.Kryo.readClass(Kryo.java:693)
    at com.esotericsoftware.kryo.serializers.ObjectField.read(ObjectField.java:118)
    at com.esotericsoftware.kryo.serializers.FieldSerializer.read(FieldSerializer.java:543)
    at com.esotericsoftware.kryo.Kryo.readClassAndObject(Kryo.java:813)
    at com.twitter.chill.SerDeState.readClassAndObject(SerDeState.java:61)
    at com.twitter.chill.KryoPool.fromBytes(KryoPool.java:94)
    at com.X.backend.serialization.CustomKafkaKryoDeserializer.$anonfun$deserialize$1(KafkaKryoSerialization.scala:38)
    at com.twitter.bijection.Inversion$.$anonfun$attempt$1(Inversion.scala:32)
    at scala.util.Try$.apply(Try.scala:213)
    ... 25 common frames omitted
Caused by: java.lang.ClassNotFoundException: com.X.backend.DashboardExternalEntities$ExtMessage
    at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at com.esotericsoftware.kryo.util.DefaultClassResolver.readName(DefaultClassResolver.java:154)
    ... 35 common frames omitted

基於此： https://github.com/EsotericSoftware/kryo/releases/tag/kryo-parent-4.0.0我實現了一個自定義ScalaKryoInstantiator和相應的類來添加setOptimizedGenerics(true) ：

class CustomKafkaKryoDeserializer[M <: AnyRef] extends KafkaDeserializer[M] {
  override def configure(configs: util.Map[String, _], isKey: Boolean): Unit = ()

  override def close(): Unit = ()

  override def deserialize(topic: String, data: Array[Byte]): M = {
    Inversion.attempt(data) {
      CustomKryoInstantiator.defaultPool.fromBytes(_)
    }.get.asInstanceOf[M]
  }
}

object CustomKryoInstantiator extends ScalaKryoInstantiator {
  private val mutex = new AnyRef with Serializable // some serializable object
  @transient private var kpool: Option[KryoPool] = None

  def defaultPool: KryoPool = mutex.synchronized {
    if (kpool.isEmpty) {
      kpool = Some(KryoPool.withByteArrayOutputStream(guessThreads, new CustomKryoInstantiator))
    }
    kpool.get
  }

  private def guessThreads: Int = {
    val cores = Runtime.getRuntime.availableProcessors
    val GUESS_THREADS_PER_CORE = 4
    GUESS_THREADS_PER_CORE * cores
  }
}

class CustomKryoInstantiator extends EmptyScalaKryoInstantiator {
  override def newKryo: KryoBase = {
    val k = super.newKryo
    k.getFieldSerializerConfig.setOptimizedGenerics(true)
    val reg = new AllScalaRegistrar
    reg(k)
    k
  }
}

但我仍然得到同樣的錯誤。 有沒有辦法用 Kryo 4.0.2 讀取由 Kryo 2.21 序列化的消息？ 消息類本身沒有改變。

Answer 1

事實證明，消息包被重命名，因此 Kryo 無法找到正確的類。

盡管如此，即使 package 重命名被恢復，Kryo 4.0.2 和 3.0.3 也無法反序列化使用 Kryo 2.21 序列化的消息。

總之，我們決定用 Protobuf 替換 Kryo，並編寫一個MirrorMakerMessageHandler將 Kafka 消息從 Chill-bijection 0.6.0 (Kryo 2.21) 轉換為 Protobuf。