scala - 图表创建错误 : requirement failed: The inlets [] and outlets [] must correspond to the inlets [in] and outlets [out]

Question

我正在使用 akka Streams graphDSL 创建一个可运行的图。流组件的入口/导出不存在编译时错误。运行时抛出以下错误:

有什么想法我应该验证什么才能使其运行吗？

requirement failed: The inlets [] and outlets [] must correspond to the inlets [in] and outlets [out]
at scala.Predef$.require(Predef.scala:219)
at akka.stream.Shape.requireSamePortsAs(Shape.scala:168)
at akka.stream.impl.StreamLayout$CompositeModule.replaceShape(StreamLayout.scala:390)
at akka.stream.scaladsl.GraphApply$class.create(GraphApply.scala:18)
at akka.stream.scaladsl.GraphDSL$.create(Graph.scala:813)
at com.flipkart.connekt.busybees.streams.Topology$.bootstrap(Topology.scala:109)
at com.flipkart.connekt.busybees.BusyBeesBoot$.start(BusyBeesBoot.scala:65)
at com.flipkart.connekt.boot.Boot$.delayedEndpoint$com$flipkart$connekt$boot$Boot$1(Boot.scala:39)
at com.flipkart.connekt.boot.Boot$delayedInit$body.apply(Boot.scala:13)

图表结构:

source ~> flowRate ~> render ~> platformPartition.in
platformPartition.out(0) ~> formatIOS ~> apnsDispatcher ~> apnsEventCreator ~> merger.in(0)
platformPartition.out(1) ~> formatAndroid ~> httpDispatcher ~> gcmPoolFlow ~> rHandlerGCM ~> merger.in(1)
merger.out ~> evtCreator ~> Sink.ignore

Answer 1

您有一个未使用的入口或导出(您的一个流或某些东西未在所有侧面连接)。以下是一些示例:

这有效:

val workingFlow =
  Flow.fromGraph(GraphDSL.create() { implicit b =>
    import GraphDSL.Implicits._
    val intFlow = b.add(Flow[Int])
    FlowShape(intFlow.in, intFlow.out)
  })

以下代码会产生与您类似的错误，因为它具有整个未使用的流程:

val buggyFlow =
  Flow.fromGraph(GraphDSL.create() { implicit b =>
    import GraphDSL.Implicits._
    val intFlow = b.add(Flow[Int])
    val unusedFlow = b.add(Flow[Int]) // ERROR: This flow is unused
    FlowShape(intFlow.in, intFlow.out)
  })

一个稍微复杂的例子:这里没有整个未使用的流，只有一个未使用的导出。它会产生相同的错误:

val buggyFlow =
  Flow.fromGraph(GraphDSL.create() { implicit b =>
    import GraphDSL.Implicits._

    val broadcast = b.add(Broadcast[Int](2))
    val intFlow = b.add(Flow[Int])
    val unusedFlow = b.add(Flow[Int]) // ERROR: This flow's outlet isn't used

    broadcast ~> intFlow
    broadcast ~> unusedFlow

    FlowShape(broadcast.in, intFlow.out)
  })