AVRO 模式更新的问题

Question

我有一个简单的案例class:

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

我正在添加字段"name"

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

然后在 avro 架构中添加此字段 (user.avsc)

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

这个class用于其他情况class：

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

架构 (auth_request.avsc)

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

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

我尝试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

您需要使更改向后兼容，使新字段可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" }
  ]
}

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