WS Streams loads the response in memory instead of streaming

[mohittt8]

Play Version

2.8.19

API

WS.stream() ( https://www.playframework.com/documentation/2.8.x/ScalaWS#Processing-large-responses )

Scala

Operating System

Mac OS

JDK

openjdk version "11.0.18" 2023-01-17 LTS
OpenJDK Runtime Environment Corretto-11.0.18.10.1 (build 11.0.18+10-LTS)
OpenJDK 64-Bit Server VM Corretto-11.0.18.10.1 (build 11.0.18+10-LTS, mixed mode)

Library Dependencies

WS

Code to reproduce the issue -

def test = Action.async { implicit request =>
    val res = ws.url("").stream()
    println("after request " + LocalDateTime.now())
    res.map {
      f =>
        println("Inside future " + LocalDateTime.now())
        Ok.chunked(f.bodyAsSource)
    }
  }

Expected behaviour -
The code execution inside the res future as soon as first bytes are received.

Actual behaviour -
The code execution inside future does not start till the file is downloaded.

after request 2023-05-19T23:30:43.941997
Inside future 2023-05-19T23:31:05.353642

Roughly 20 seconds have passed when the code execution reaches inside the res future. It is the same amount of time to download 150MB of image on my network.

I get the same effect if I use .get() instead of .stream()

[guillaumebadin]

It seems we have performance problème since play 2.8.19 with Play Streams (Akka Streams ?).

        success =>
          success.warnings foreach { w => logger.warn(s"$context Warning: <<<${w.value}>>>") }
          val a: Source[ByteString, Unit] = StreamConverters.fromInputStream(() => success.inputStream).mapMaterializedValue(_.onComplete(_ => success.inputStream.close()))
          Ok.streamed(
            a, None, false,
            Some(s"${resultId.value}_-_${
              success.metadata.oneMatch.hprimFileS3Key
            }_-_${
              success.metadata.oneMatch.attachmentFileNameInHprim
            }")
            ).as(applicationPdf)

We have a crazy leaks since this version.

[guillaumebadin]

@mohittt8 did you fix your issue by downgrading play or Akka version ?

[mohittt8]

@guillaumebadin - We have started using Akka Http.

[mkurz]

Can you please tell exactly from which version you upgraded to what version?