[undertow-dev] http/2 server starts dying after rapid refresh
Michael Hixson
michael.hixson at gmail.com
Sat May 30 01:04:58 EDT 2015
Hi Jason,
I believe the close() call is coming from me declaring the writer in a
try-with-resources statement.
Here's a jstack from just now, where my CPU is sitting at 96%:
https://gist.github.com/michaelhixson/8a6f2ebf4b167fb1b67e
-Michael
On Fri, May 29, 2015 at 9:28 PM, Jason T. Greene
<jason.greene at redhat.com> wrote:
> 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
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