java.io.IOException: Broken pipe occurring on client calls with empty bodies

[ahjohannessen]

Seems like there is a bug in how empty body is handled. I have a repro here. The smithy spec show cases differences in payload. Details are found here.

[Baccata]

The fact that the body is empty is normal on requests/responses that transmit all their data through metadata. The fact that the client raises an exception is not.

[daddykotex]

This is interesting to look at. I guess other issues are coming into play here. If I keep the service modification that you've made @ahjohannessen in your repro but adjust the code to this:

package com.example

import smithy4s.hello._
import cats.effect._
import cats.effect.syntax.resource._
import cats.implicits._
import org.http4s.implicits._
import org.http4s.ember.server._
import org.http4s._
import com.comcast.ip4s._
import smithy4s.http4s.SimpleRestJsonBuilder
import org.http4s.ember.client.EmberClientBuilder
import org.http4s.client.Client

object HelloWorldImpl extends HelloWorldService[IO] {

  def hello(
      name: String,
      town: Option[String]
  ): IO[HelloOutput] =
    IO.pure { HelloOutput("hello") }

  def hello2(
      name: String,
      age: Option[Int],
      town: Option[String]
  ): IO[Hello2Output] =
    IO.pure { Hello2Output("hello2") }
}

object Routes {
  private val example: Resource[IO, HttpRoutes[IO]] =
    SimpleRestJsonBuilder.routes(HelloWorldImpl).resource

  private val docs: HttpRoutes[IO] =
    smithy4s.http4s.swagger.docs[IO](HelloWorldService)

  val all: Resource[IO, HttpRoutes[IO]] = example.map(_ <+> docs)
}

abstract class Setup extends IOApp.Simple {
  // client middleware
  val authMiddleware: org.http4s.client.Middleware[IO] = { client =>
    Client { req =>
      client.run(
        req.withHeaders(
          headers.Authorization(Credentials.Token(AuthScheme.Bearer, "TOKEN"))
        )
      )
    }
  }

  val client = EmberClientBuilder.default[IO].build.map { client =>
    SimpleRestJsonBuilder(HelloWorldService)
      .clientResource(
        authMiddleware(client),
        Uri.unsafeFromString("http://127.0.0.1:9000")
      )
  }

  val run = (client, Routes.all).tupled.flatMap { case (client, routes) =>
    for {
      hs <- client
      _ <- EmberServerBuilder
        .default[IO]
        .withPort(port"9000")
        .withHost(host"0.0.0.0")
        .withHttpApp(routes.orNotFound)
        .build
      _ <- clientOp(hs).toResource
    } yield ()
  }.use_

  def clientOp(hs: HelloWorldService[IO]): IO[Unit]
}

object FastServer extends Setup {
  def clientOp(hs: HelloWorldService[IO]): IO[Unit] = IO.unit
}

object Hello2 extends Setup {
  def clientOp(hs: HelloWorldService[IO]): IO[Unit] =
    hs.hello2("hey!").void
}

object Hello extends Setup {
  def clientOp(hs: HelloWorldService[IO]): IO[Unit] =
    hs.hello("hey!").void
}

object Broken extends Setup {
  def clientOp(hs: HelloWorldService[IO]): IO[Unit] =
    hs.hello("hey!") *> hs.hello2("hey 2!").void
}

Ran all 3 (Hello, Hello2 and Broken) with a script:

> ./benchmark.sh 

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
HTTP/1.1 POST http://127.0.0.1:9000/hello/hey! body=""
HTTP/1.1 200 OK body="{"message":"hello"}"
HelloOutput(hello)

real    0m7.283s
user    0m19.039s
sys     0m1.558s
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
HTTP/1.1 POST http://127.0.0.1:9000/hello2/hey! body="{}"
HTTP/1.1 200 OK body="{"message":"hello2"}"
Hello2Output(hello2)

real    *0m35.766s*
user    0m13.703s
sys     0m1.017s
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
HTTP/1.1 POST http://127.0.0.1:9000/hello/hey! body=""
HTTP/1.1 200 OK body="{"message":"hello"}"
HTTP/1.1 POST http://127.0.0.1:9000/hello2/hey%202! body=""
[error] java.io.IOException: Broken pipe
[error]         at java.base/sun.nio.ch.FileDispatcherImpl.write0(Native Method)
[error]         at java.base/sun.nio.ch.SocketDispatcher.write(SocketDispatcher.java:62)
[error]         at java.base/sun.nio.ch.IOUtil.writeFromNativeBuffer(IOUtil.java:132)
[error]         at java.base/sun.nio.ch.IOUtil.write(IOUtil.java:97)
[error]         at java.base/sun.nio.ch.IOUtil.write(IOUtil.java:60)
[error]         at java.base/sun.nio.ch.UnixAsynchronousSocketChannelImpl.finishWrite(UnixAsynchronousSocketChannelImpl.java:602)
[error]         at java.base/sun.nio.ch.UnixAsynchronousSocketChannelImpl.finish(UnixAsynchronousSocketChannelImpl.java:199)
[error]         at java.base/sun.nio.ch.UnixAsynchronousSocketChannelImpl.onEvent(UnixAsynchronousSocketChannelImpl.java:217)
[error]         at java.base/sun.nio.ch.KQueuePort$EventHandlerTask.run(KQueuePort.java:312)
[error]         at java.base/sun.nio.ch.AsynchronousChannelGroupImpl$1.run(AsynchronousChannelGroupImpl.java:113)
[error]         at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
[error]         at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
[error]         at java.base/java.lang.Thread.run(Thread.java:833)
[error]         at delay @ fs2.io.net.SocketCompanionPlatform$AsyncSocket.$anonfun$write$1(SocketPlatform.scala:137)
[error]         at async @ fs2.io.net.SocketCompanionPlatform$AsyncSocket.go$2(SocketPlatform.scala:131)
[error]         at flatMap @ fs2.io.net.SocketCompanionPlatform$AsyncSocket.go$2(SocketPlatform.scala:141)
[error]         at modify @ org.http4s.ember.server.internal.Shutdown$$anon$1.<init>(Shutdown.scala:83)
[error]         at flatten$extension @ org.http4s.ember.server.internal.Shutdown$$anon$1.<init>(Shutdown.scala:71)
[error]         at apply @ org.http4s.ember.server.EmberServerBuilder.$anonfun$build$2(EmberServerBuilder.scala:177)
[error] stack trace is suppressed; run 'last Compile / runMain' for the full output
[error] (Compile / runMain) java.io.IOException: Broken pipe

real    0m5.969s
user    0m13.843s
sys     0m0.969s

What's interesting is that

• calling hs.hello alone works
• calling hs.hello2 alone works but is super slow
• calling both in succession fail

I'm still looking into it

[daddykotex]

To be honest, it feels like it's an issue outside of smithy4s scope: fs2 or http4s related

Like if the the calls to the client, in succession, consumed (or not) a stream and we end up in an invalid state.

calling hs.hello then hs.hello2 fails, but calling hs.hello2 twice will not fail

[daddykotex]

but it could also be our usage of http4s and fs2 in the client that does this

[ahjohannessen]

@daddykotex What happens if you use http2 in ember server?

[daddykotex]

@daddykotex What happens if you use http2 in ember server?

it has no effect unfortunately

[ahjohannessen]

@daddykotex It might be related to this http4s/http4s#4935

[daddykotex]

Ok, this is definitely a bug in ember. Switching to blaze fixes the issue. I'm not sure if it's related to the one you referred too but it's good to know anyway.

[daddykotex]

Fixed in the 0.17.0 release