Hello,
Tomcat 8.5.55 (also tried with 8.5.37).
Similar to “Bug 62614 - Async servlet over HTTP/2 WriteListener does not work
because onWritePossible is never called back again” but using NIO connector:
<Connector port="80" protocol="org.apache.coyote.http11.Http11NioProtocol" />
I’m unable to create an example that reproduces this issue. So I will explain
what’s happening and I hope someone can give me some clue about what’s going on.
The case is simple: we connect to our servlet using http components setting a
response timeout of 10 seconds. Since our servlet takes less than 5 seconds to
get the response from the backend, it returns all the content to the client
(it’s about 180K).
The point is when we set a response timeout of, for instance, 2 seconds. In
this case the client closes the socket with the servlet before it can return
the response. In fact, in most situations, when we set the WriteListener to the
async response this socket is already closed. In this situation 2 different
things are randomly happening:
1. The expected, the WriteListener throws an IOException:
org.apache.catalina.connector.ClientAbortException: java.io.IOException: Broken
pipe, and the ‘onError’ method is called:
while (this.numIterations > 0 && this.os.isReady()) {
this.os.write(this.response, this.startIdx, this.endIdx -
this.startIdx); ← The error happens here.
( . . . )
}
2. The unexpected. The ‘onWritePossible’ method is called just once.
In this case ‘onWritePossible’ is called, this.os.isReady is true and the
execution enter into the cycle but the above ‘this.os.write’ does not throw any
exception, then ‘this.os.isReady’ becomes false so the execution exits the
cycle and the ‘onWritePossible’ method terminates. And it’s never called again
(neither the ‘onError’ method).
Here I leave a link to the interesting part of the WriteListener code and the 3
traces: the right one returning the document (trace_OK.txt), the right one
returning the error (trace_OK_with_broken_pipe.txt) and the wrong one calling
‘onWritePossible’ just once (trace_KO.txt) :
https://github.com/joanbalaguero/Tomcat.git
I tried to search a solution for this, no success. I developed a simple test
case, and it was impossible to reproduce the issue. I’m pretty sure it’s a lack
of knowledge about how this listener works in this case (sockets already
closed) but after reading tutorials and more tutorials I’m not able to find the
solution.
So any help would be very very appreciated.
Thanks for your time.
Joan.
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