Can you post a minimal reproducer?

On Fri, Oct 7, 2016 at 9:02 PM, Eric Swenson <e...@swenson.org> wrote:

> I wrote a simple test for my CipherStage and it appears to work fine:
>
> "CipherStage" should "work" in {
>   val clearText = "0123456789abcdef"
>   val clearSource = Source.single(ByteString(clearText))
>
>   val encodedKey: String = "KCl02Tjzsid09VnDl6CDpDlnm4G4VUJr8l6PNg+MHkQ="
>   val decodedKey = Base64.getDecoder.decode(encodedKey)
>   val key = new SecretKeySpec(decodedKey, 0, decodedKey.length, "AES")
>
>   val encodedIv: String = "AAAAAAAAAAAAAAAAAAAAAA=="
>   val decodedIv = Base64.getDecoder.decode(encodedIv)
>   val iv = new IvParameterSpec(decodedIv)
>
>   val src = clearSource.via(new CipherStage(key, iv, Cipher.ENCRYPT_MODE))
>
>   implicit val system = ActorSystem("test")
>   implicit val materializer = ActorMaterializer()
>   src.runForeach(i => println(i))
>   println(src)
> }
>
> In other words, onUpstreamFinish is called and two AES blocks are emitted
> (by the println).  So it must have something to do with the graph I’m
> using.  It looks like:
>
> in ~> bcast ~> dgst ~> dgstOut
>       bcast ~> encryptor ~> blkOut
>
> Where in is a Source[ByteString,Any] (the payload), dgst is the
> DigestCalculator stage, encryptor is the CipherStage, and dgstOut and
> blkOut are the two Sink.head[ByteString] outputs of my graph.  bcast is a
> normal two-output Broadcast element.
>
> Why is it that in the flow in ~> bcast ~> dgst, the onStreamFinish of dgst
> is invoked correctly, but in the flow in ~> bcast ~> encryptor, it isn’t?
>
> — Eric
>
>
>
> On Oct 7, 2016, at 11:37, Eric Swenson <e...@swenson.org> wrote:
>
> I have a web service which accepts an inbound payload and runs it through
> an akka-streams pipeline that simulatenously computes the MD5 digest of the
> payload and encrypts that payload.  I’ve implemented a GraphStage that
> performs the crypto that looks like this:
>
> class CipherStage(key: SecretKey, iv: IvParameterSpec, mode: Int) extends 
> GraphStage[FlowShape[ByteString, ByteString]] {
>   val in = Inlet[ByteString]("Encryptor.in")
>   val out = Outlet[ByteString]("Encryptor.out")
>   override val shape = FlowShape.of(in, out)
>
>   override def createLogic(inheritedAttributes: Attributes): GraphStageLogic 
> = new GraphStageLogic(shape) {
>     val cipher: Cipher = Cipher.getInstance("AES/CBC/PKCS5Padding")
>     cipher.init(mode, key, iv)
>
>     setHandler(out, new OutHandler {
>       override def onPull(): Unit = {
>         pull(in)
>       }
>     })
>
>     setHandler(in, new InHandler {
>       override def onPush(): Unit = {
>         val chunk = grab(in)
>         emit(out, ByteString(cipher.update(chunk.toArray)))
>         pull(in)
>       }
>
>       override def onUpstreamFinish(): Unit = {
>         val chunk = cipher.doFinal()
>         emit(out, ByteString(chunk))
>         completeStage()
>       }
>
>       override def onUpstreamFailure(ex: Throwable): Unit = {
>         log.info(s”onUpstreamFailure: $ex")
>         failStage(ex)
>       }
>     })
>   }
> }
>
> I’m using it (and a similar digest-computing stage like this:
>
> def verifyAndStoreBlock(digest: String, byteStringSource: Source[ByteString, 
> Any], userUid: String, sender: ActorRef) = {
>   val digestOut = Sink.head[ByteString]
>   val blockOut = Sink.head[ByteString]
>
>   val graph: Graph[ClosedShape, (Future[ByteString], Future[ByteString])] = 
> GraphDSL.create(digestOut, blockOut)((_,_)) { implicit builder => (dgstOut, 
> blkOut) =>
>     import GraphDSL.Implicits._
>     val in: Source[ByteString,Any] = byteStringSource
>     val bcast = builder.add(Broadcast[ByteString](2))
>     val dgst = new DigestCalculator("MD5")
>     val encryptor = new CipherStage(blockEncryptionKey, 
> blockInitializationVector, Cipher.ENCRYPT_MODE)
>
>     in ~> bcast ~> dgst ~> dgstOut
>           bcast ~> encryptor ~> blkOut
>
>     ClosedShape
>   }
>
>   val rg = RunnableGraph.fromGraph[(Future[ByteString], 
> Future[ByteString])](graph)
>
>   implicit val materializer = ActorMaterializer()
>   val (dgstOutFuture, blkOutFuture) = rg.run()
>   implicit val ec = context.dispatcher
>   for {
>     dgst <- dgstOutFuture
>     blkOut <- blkOutFuture
>   } {
>     val verify = byteStringToHexString(dgst)
>     if (verify == digest) {
>       val dataStoreActor = context.actorOf(DataStoreActor.props(dataStore))
>       dataStoreActor ! DataStoreActor.Messages.SaveBlock(digest, blkOut)
>       blockStoreLogger.logEvent(PutBlockEvent(digest, userUid))
>       sender ! Right(())
>     } else {
>       log.warning(s"Invalid digest: supplied $digest, computed: $verify")
>       blockStoreLogger.logEvent(PutBlockFailedEvent(digest, userUid, "digest 
> invalid"))
>       sender ! Left(PutStatus.DigestInvalid)
>     }
>   }
> }
>
> When I get an inbound request, the digesting works correctly, and the
> encryption sort of works.  However, onUpstreamFinish is never called (in
> the CipherStage’s InHandler), and consequently the last AES block (with
> padding) is not emitted correctly.
>
> I modelled the above CipherStage on a similar DigestCalculator stage I
> found in the akka documentation.  In the DigestCalculator graph stage, the
> onUpstreamFinish handler is correctly called.  Why it not called for the
> CipherStage?
>
> — Eric
>
>
> --
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-- 
Cheers,
√

-- 
>>>>>>>>>>      Read the docs: http://akka.io/docs/
>>>>>>>>>>      Check the FAQ: 
>>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html
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