kafka stream. streams.allMetadata() get nothing back.

[Nan Xu]

hi,

   trying the following program and want to see the metadata for
test_store, and nothing get back, the  val metaIter =
streams.allMetadata().iterator() size is 0. I can see data in the store
though, but I need metadata so when I have multiple instance running. I can
find the right store.
is there any setting I missed?

Thanks,
Nan

   val storeName = "test_store"
  val streamProperties = new Properties()
  streamProperties.put(StreamsConfig.APPLICATION_ID_CONFIG,
"streams-store-test5")
  streamProperties.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG,
"localhost:9092")

  val streamBuilder = new StreamsBuilder()

  val inputStream = streamBuilder.stream[String, String]("test1")

  val kvStore = Stores.keyValueStoreBuilder(
    Stores.persistentKeyValueStore(storeName),
    serialization.Serdes.String(),
    serialization.Serdes.String(),
  ).withCachingDisabled()

  streamBuilder.addStateStore(kvStore)

  val transformer: TransformerSupplier[String, String, KeyValue[String,
String]]
  = () => new SimpleTransformer(storeName)

  inputStream.transform(transformer, storeName)

  val topology = streamBuilder.build()
  val streams = new KafkaStreams(topology, streamProperties)
  Runtime.getRuntime.addShutdownHook(new Thread { () => streams.close() })

  import scala.concurrent.ExecutionContext.Implicits.global

  streams.start()

  Thread.sleep(5000)
  Future {
    val metaIter = streams.allMetadata().iterator()
    while(metaIter.hasNext){
      println("===meta: " + metaIter.next())
    }
}