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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Hi all,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’ve been using Undertow embedded in an Akka application and it is working great apart from a small issue when running load tests.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I’ve reduced the problem down to a small little demo application which I’ve attached below. It is in Scala but I can create a Java version if required.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I fire one million POST requests at Undertow and almost all succeed, however some never receive a response. The number that fail varies from 1 to 10.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Increasing the concurrency on the client and server side together and independently increases the number of failures. I’ve not yet seen any failures with no concurrency on the server side.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>The HTTP handler callback is not invoked for the requests that fail. I’ve verified this by adding a counter before I call exchange.dispatch() and pass it on to the processing actor pool.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I don’t think I’m doing anything that is not thread-safe since Akka guarantees that actors do not execute concurrently. However the execution of the actor does move around a number of threads in the underlying Fork Join pool and I’m wondering if that would cause issues with Undertow?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Any suggestions for how I could debug this?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Michael<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Code to reproduce<o:p></o:p></p><p class=MsoNormal>==============<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>object UndertowTest {<o:p></o:p></p><p class=MsoNormal> def start(handler: HttpHandler) = Undertow.builder()<o:p></o:p></p><p class=MsoNormal> .addHttpListener(8888, "localhost")<o:p></o:p></p><p class=MsoNormal> .setHandler(handler)<o:p></o:p></p><p class=MsoNormal> .build()<o:p></o:p></p><p class=MsoNormal> .start()<o:p></o:p></p><p class=MsoNormal>}<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>class Responder extends HttpHandler {<o:p></o:p></p><p class=MsoNormal> override def handleRequest(exchange: HttpServerExchange): Unit = {<o:p></o:p></p><p class=MsoNormal> exchange.getResponseHeaders.put(io.undertow.util.Headers.CONTENT_TYPE, "text/plain")<o:p></o:p></p><p class=MsoNormal> exchange.getResponseSender.send("Hello world!")<o:p></o:p></p><p class=MsoNormal> }<o:p></o:p></p><p class=MsoNormal>}<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>class RequestHandler extends Actor with Loggable {<o:p></o:p></p><p class=MsoNormal> val handler = new Responder<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> override def receive = {<o:p></o:p></p><p class=MsoNormal> case exchange: HttpServerExchange =><o:p></o:p></p><p class=MsoNormal> handler.handeRequest(exchange)<o:p></o:p></p><p class=MsoNormal> }<o:p></o:p></p><p class=MsoNormal>}<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>object UndertowAkkaTest extends App {<o:p></o:p></p><p class=MsoNormal> val sys = ActorSystem()<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> // Changing the number here changes the number of actors handling incoming requests<o:p></o:p></p><p class=MsoNormal> val handlerPool = sys.actorOf(RoundRobinPool(4).props(Props(classOf[RequestHandler])))<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> UndertowTest.start(new HttpHandler {<o:p></o:p></p><p class=MsoNormal> override def handleRequest(exchange: HttpServerExchange): Unit = {<o:p></o:p></p><p class=MsoNormal> exchange.dispatch()<o:p></o:p></p><p class=MsoNormal> handlerPool ! exchange<o:p></o:p></p><p class=MsoNormal> }<o:p></o:p></p><p class=MsoNormal> })<o:p></o:p></p><p class=MsoNormal>}<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Apache Bench command to test<o:p></o:p></p><p class=MsoNormal>========================<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal># -c changes number of concurrent client side requests<o:p></o:p></p><p class=MsoNormal>ab -k -c 4 -n 100000 -p payload.json -T application/json <a href="http://localhost:8888/streams/demo/infrastructure/cpu">http://localhost:8888/streams/demo/infrastructure/cpu</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Data in payload.json<o:p></o:p></p><p class=MsoNormal>===============<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>{<o:p></o:p></p><p class=MsoNormal> "sampleTime": "2015-02-24T06:02:47",<o:p></o:p></p><p class=MsoNormal> "contributor": "3b8da322-ef8f-4f6b-93a3-a171dd794308",<o:p></o:p></p><p class=MsoNormal> "host": "some-host",<o:p></o:p></p><p class=MsoNormal> "process": "some-process",<o:p></o:p></p><p class=MsoNormal> "user": 35.7,<o:p></o:p></p><p class=MsoNormal> "kernel": 12.3<o:p></o:p></p><p class=MsoNormal>}<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p></div><br clear="both">
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