[undertow-dev] http/2 server starts dying after rapid refresh

Sat May 30 00:28:14 EDT 2015

Hi Michael,

That stack trace seems to show a close() call to the writer in your handler, but I don't see that call in the code?

Note that getting I/o exceptions during write and close calls is normal after a client abnormally terminates. You typically just drop the exception (perhaps trace logging).

Could you get a jstack output under the scenario where you see high CPU load?

> On May 28, 2015, at 6:19 PM, Michael Hixson <michael.hixson at gmail.com> wrote:
> 
> Hello,
> 
> I'm trying out HTTP/2 with undertow-core in my application, and I see
> that I'm able to get the server into a bad state pretty reliably by
> refreshing quickly in my browser.  It stops responding to requests and
> the CPU usage of the Java process starts to climb towards 100%.
> 
> I was able to replicate this in the HTTP/2 example in the latest from
> the master branch, by changing the main HttpHandler.  This is what I
> put in Http2Server#main(String[]):
> 
>  Undertow server = Undertow.builder()
>        .setServerOption(UndertowOptions.ENABLE_HTTP2, true)
>        .setServerOption(UndertowOptions.ENABLE_SPDY, true)
>        .addHttpListener(8080, bindAddress)
>        .addHttpsListener(8443, bindAddress, sslContext)
>        .setHandler(new HttpHandler() {
>          @Override
>          public void handleRequest(HttpServerExchange exchange) {
>            if (exchange.isInIoThread()) {
>              exchange.dispatch(this);
>              return;
>            }
>            exchange.startBlocking();
>            exchange.getResponseHeaders().put(
>                new HttpString("Content-Type"), "text/html");
>            try (BufferedWriter writer = new BufferedWriter(
>                new OutputStreamWriter(
>                    exchange.getOutputStream(),
>                    StandardCharsets.UTF_8))) {
>              writer.append("<!DOCTYPE html><html>\n");
>              for (int i = 0; i < 100; i++) {
>                writer.append(
>                    "<link rel=\"stylesheet\" href=\"/" + i + ".css\">\n");
>              }
>              writer.append("hello");
>            } catch (IOException e) {
>              e.printStackTrace();
>              throw new RuntimeException(e);
>            }
>          }
>        }).build();
> 
> Then I go to https://localhost:8443/ in a browser and hold down F5 for
> a bit.  I start seeing errors like this:
> 
>  java.nio.channels.ClosedChannelException
>        at io.undertow.server.protocol.framed.AbstractFramedStreamSinkChannel.write(AbstractFramedStreamSinkChannel.java:396)
>        at org.xnio.channels.Channels.writeFinalBasic(Channels.java:961)
>        at io.undertow.server.protocol.framed.AbstractFramedStreamSinkChannel.writeFinal(AbstractFramedStreamSinkChannel.java:420)
>        at org.xnio.conduits.StreamSinkChannelWrappingConduit.writeFinal(StreamSinkChannelWrappingConduit.java:66)
>        at org.xnio.conduits.ConduitStreamSinkChannel.writeFinal(ConduitStreamSinkChannel.java:104)
>        at io.undertow.channels.DetachableStreamSinkChannel.writeFinal(DetachableStreamSinkChannel.java:195)
>        at io.undertow.server.HttpServerExchange$WriteDispatchChannel.writeFinal(HttpServerExchange.java:1882)
>        at io.undertow.io.UndertowOutputStream.writeBufferBlocking(UndertowOutputStream.java:288)
>        at io.undertow.io.UndertowOutputStream.close(UndertowOutputStream.java:331)
>        at sun.nio.cs.StreamEncoder.implClose(StreamEncoder.java:320)
>        at sun.nio.cs.StreamEncoder.close(StreamEncoder.java:149)
>        at java.io.OutputStreamWriter.close(OutputStreamWriter.java:233)
>        at java.io.BufferedWriter.close(BufferedWriter.java:266)
>        at io.undertow.examples.http2.Http2Server$1.handleRequest(Http2Server.java:94)
>        at io.undertow.server.Connectors.executeRootHandler(Connectors.java:199)
>        at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:774)
>        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
>        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
>        at java.lang.Thread.run(Thread.java:745)
> 
> In case it helps, I saw a different error in my real (not undertow
> example) application when I started seeing the same effects visibly
> (site down and CPU climbing to 100%).  Maybe it is the same root cause
> but just being caught/logged differently:
> 
>  ERROR [2015-05-28 14:23:59,804] org.xnio.nio: XNIO000011: Task
> io.undertow.server.protocol.framed.AbstractFramedChannel$2 at 308b5f1f
> failed with an exception
>  java.lang.IllegalStateException: null
>  at io.undertow.server.protocol.framed.AbstractFramedStreamSinkChannel.getBuffer(AbstractFramedStreamSinkChannel.java:523)
> ~[undertow-core-1.3.0.Beta1-SNAPSHOT.jar:1.3.0.Beta1-SNAPSHOT]
>  at io.undertow.server.protocol.framed.AbstractFramedChannel.flushSenders(AbstractFramedChannel.java:496)
> ~[undertow-core-1.3.0.Beta1-SNAPSHOT.jar:1.3.0.Beta1-SNAPSHOT]
>  at io.undertow.server.protocol.framed.AbstractFramedChannel$2.run(AbstractFramedChannel.java:581)
> ~[undertow-core-1.3.0.Beta1-SNAPSHOT.jar:1.3.0.Beta1-SNAPSHOT]
>  at org.xnio.nio.WorkerThread.safeRun(WorkerThread.java:560)
> ~[xnio-nio-3.3.1.Final.jar:3.3.1.Final]
>  at org.xnio.nio.WorkerThread.run(WorkerThread.java:462)
> ~[xnio-nio-3.3.1.Final.jar:3.3.1.Final]
> 
> I see the same behavior in my real application with both undertow-core
> 1.2.6.Final and 1.3.0.Beta1-SNAPSHOT (the latter installed locally
> from source).  I only tried the Http2Server example in the latest
> version though.
> 
> -Michael
> _______________________________________________
> undertow-dev mailing list
> undertow-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/undertow-dev