Splitting an Akka stream

Akka Libraries
1

Is there a way to split an Akka stream? My use case is downloading a file from a http URL on GET request and then streaming it to the client as as well as a local file.

2

Hi,

You would need to create a graph as described in https://doc.akka.io/docs/akka/current/stream/stream-graphs.html, similar to this:

val g = RunnableGraph.fromGraph(GraphDSL.create() { implicit builder: GraphDSL.Builder[NotUsed] =>
  import GraphDSL.Implicits._
  val in = Source(1 to 10)
  val out = Sink.ignore

  val bcast = builder.add(Broadcast[Int](2))
  val merge = builder.add(Merge[Int](2))

  val f1, f2, f3, f4 = Flow[Int].map(_ + 10)

  in ~> f1 ~> bcast ~> f2 ~> merge ~> f3 ~> out
  bcast ~> f4 ~> merge
  ClosedShape
})

Idea would be broadcast your incoming file into two ports, instead of merge you can use two sinks to consume elements.

Regards,

Syed Farhan Ali