On 03:12 pm, poal...@gmail.com wrote:
>
>I've still not been able to reproduce this on demand.. the least
>amount of request I've seen before getting the error is 6500 :/
>
>I've also seen this stack trace which I didn't notice before
>
>2013-02-08 10:07:28+0000 [HTTP11ClientProtocol,client] Unhandled Error
> Traceback (most recent call last):
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/application/app.py",
>line 323, in runReactorWithLogging
> reactor.run()
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/base.py",
>line 1169, in run
> self.mainLoop()
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/base.py",
>line 1181, in mainLoop
> self.doIteration(t)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/epollreactor.py",
>line 379, in doPoll
> log.callWithLogger(selectable, _drdw, selectable, fd, event)
> --- <exception caught here> ---
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-x86_64.egg/twisted/python/log.py",
>line 84, in callWithLogger
> return callWithContext({"system": lp}, func, *args, **kw)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-x86_64.egg/twisted/python/log.py",
>line 69, in callWithContext
> return context.call({ILogContext: newCtx}, func, *args,
>**kw)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/python/context.py",
>line 118, in callWithContext
> return self.currentContext().callWithContext(ctx, func,
>*args, **kw)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/python/context.py",
>line 81, in callWithContext
> return func(*args,**kw)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/posixbase.py",
>line 639, in _doReadOrWrite
> self._disconnectSelectable(selectable, why, inRead)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/posixbase.py",
>line 258, in _disconnectSelectable
> selectable.readConnectionLost(f)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/tcp.py",
>line 267, in readConnectionLost
> self.connectionLost(reason)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/tcp.py",
>line 473, in connectionLost
> self._commonConnection.connectionLost(self, reason)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/tcp.py",
>line 281, in connectionLost
>abstract.FileDescriptor.connectionLost(self, reason)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/abstract.py",
>line 182, in connectionLost self.producer.stopProducing()
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-x86_64.egg/twisted/web/client.py",
>line 760, in stopProducing self._task.stop()
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/task.py",
>line 460, in stop self._completeWith(TaskStopped(),
>Failure(TaskStopped()))
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/task.py",
>line 439, in _completeWith
>self._cooperator._removeTask(self)
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/task.py",
>line 578, in _removeTask self._delayedCall.cancel()
> File "/usr/local/lib/python2.7/dist-
>packages/Twisted-12.2.0-py2.7-linux-
>x86_64.egg/twisted/internet/base.py",
>line 89, in cancel
> raise error.AlreadyCalled
> twisted.internet.error.AlreadyCalled: Tried to cancel an
>already-called event.
>
>I'll keep trying to work out the issue, any suggestions on what I
>might try to reproduce it or guesses at causes?
Since it seems to be related to handling of lost connections, you may be
able to reproduce it more easily if you issue your requests to an HTTP
server which drops connections more often. Presumably the production
service you're issuing requests too tries pretty hard to properly serve
responses to every request. If you point `Agent` at a worse HTTP server
(eg, one you write using twisted.web and implement to close connections
prematurely at various points during the response) this may produce the
issue more quickly.
You could also try hooking `Agent` up to one of the in-memory
reactors/transports. The advantage of this is that it will be much
easier to "close" the connection at a specific point
(deterministically). The disadvantage is that the in-memory
reactor/transport may not exactly replicate the real reactor/transport
behavior and so fail to reproduce the issue entirely.
Jean-Paul
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