AVRO 模式更新的问题

Question

我有一个简单的案例类：

  case class User(id: String, login: String, key: String)

我正在添加字段“名称”

  case class User(id: String, login: String, name: String, key: String)

然后在 avro 架构 (user.avsc) 中添加此字段

{
  "namespace": "test",
  "type": "record",
  "name": "User",
  "fields": [
    { "name": "id", "type": "string" },
    { "name": "login", "type": "string" },
    { "name": "name", "type": "string" },
    { "name": "key", "type": "string" }
  ]
}

该类用于其他案例类：

case class AuthRequest(user: User, session: String)

化学（auth_request.avsc）

{
  "namespace": "test",
  "type": "record",
  "name": "AuthRequest",
  "fields": [
    { "name": "user", "type": "User" },
    { "name": "session", "type": "string" }
  ]
}

更改之后我的消费者开始抛出异常

Consumer.committableSource(consumerSettings, Subscriptions.topics("token_service_auth_request"))
    .map { msg =>
      Try {
        val in: ByteArrayInputStream = new ByteArrayInputStream(msg.record.value())
        val input: AvroBinaryInputStream[AuthRequest] = AvroInputStream.binary[AuthRequest](in)
        val result: AuthRequest = input.iterator.toSeq.head !!!! here is exception
        msg.committableOffset.commitScaladsl()

        (msg.record.value(), result, msg.record.key())
      } match {
        case Success((a: Array[Byte], value: AuthRequest, key: String)) =>
          log.info(s"listener got $msg -> $a -> $value")

          context.parent ! value

        case Failure(e) => e.printStackTrace()
      }
    }
    .runWith(Sink.ignore)

java.util.NoSuchElementException：空流的头在 scala.collection.immutable.Stream$Empty$.head(Stream.scala:1104) 在 scala.collection.immutable.Stream$Empty$.head(Stream.scala:1102) 在 test.consumers.AuthRequestListener.$anonfun$new$2(AuthRequestListener.scala:39) 在 scala.util.Try$.apply(Try.scala:209) 在 test.consumers.AuthRequestListener.$anonfun$new$1(AuthRequestListener.scala:36) 在 test.consumers.AuthRequestListener.$anonfun$new$1$adapted(AuthRequestListener.scala:35) 在 akka.stream.impl.fusing.Map$$anon$9.onPush(Ops.scala:51) 在 akka.stream.impl.fusing.GraphInterpreter.processPush(GraphInterpreter.scala:519) 在 akka.stream.impl.fusing.GraphInterpreter.processEvent(GraphInterpreter.scala:482) 在 akka.stream.impl.fusing.GraphInterpreter.execute(GraphInterpreter.scala:378) 在 akka.stream.impl.fusing.GraphInterpreterShell.runBatch(ActorGraphInterpreter.scala:588) 在 akka.stream.impl.fusing.GraphInterpreterShell$AsyncInput.execute(ActorGraphInterpreter.scala:472) 在 akka.stream.impl.fusing.GraphInterpreterShell.processEvent(ActorGraphInterpreter.scala:563) 在 akka.stream.impl.fusing.ActorGraphInterpreter.akka$stream$impl$fusing$ActorGraphInterpreter$$processEvent(ActorGraphInterpreter.scala:745) 在 akka.stream.impl.fusing.ActorGraphInterpreter$$anonfun$receive$1.applyOrElse(ActorGraphInterpreter.scala:760) 在 akka.actor.Actor.aroundReceive(Actor.scala:517) 在 akka.actor.Actor.aroundReceive$(Actor.scala:515) 在 akka.stream.impl.fusing.ActorGraphInterpreter.aroundReceive(ActorGraphInterpreter.scala:670) 在 akka.actor.ActorCell.receiveMessage(ActorCell.scala:588) 在 akka.actor.ActorCell.invoke(ActorCell.scala:557) 在 akka.dispatch.Mailbox.processMailbox(Mailbox.scala:258) 在 akka.dispatch.Mailbox.run(Mailbox.scala:225) 在 akka.dispatch.Mailbox.exec(Mailbox.scala:235) 在 akka.dispatch.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260) 在 akka.dispatch.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339) 在 akka.dispatch.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979) 在 akka.dispatch.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)

我试图清理构建并使缓存无效 - 我似乎在某些地方缓存了以前版本的架构 请帮忙！

Answer 1

您需要使您的更改向后兼容，使新字段可以为空并为其添加默认值。

{
  "namespace": "test",
  "type": "record",
  "name": "User",
  "fields": [
    { "name": "id", "type": "string" },
    { "name": "login", "type": "string" },
    { "name": "name", "type": ["null", "string"], "default": null },
    { "name": "key", "type": "string" }
  ]
}