[tahoe-lafs-trac-stream] [tahoe-lafs] #1664: webapi fails to handle all TCP disconnects: "Request.finish called on a request after its connection was lost; use Request.notifyFinish to keep track of this."

[tahoe-lafs]

#1664: webapi fails to handle all TCP disconnects: "Request.finish called on a
request after its connection was lost; use Request.notifyFinish to keep
track of this."
--------------------------+-----------------------
     Reporter:  nejucomo  |      Owner:  nobody
         Type:  defect    |     Status:  new
     Priority:  major     |  Milestone:  undecided
    Component:  unknown   |    Version:  1.9.0
   Resolution:            |   Keywords:
Launchpad Bug:            |
--------------------------+-----------------------
Description changed by nejucomo:

Old description:

> '''Symptoms''': While running a gateway which has haproxy as a webapi
> client which I frequently restart, I see exceptions like this:
>
> {{{
> 2012-01-21 14:35:15-0800 [-] Unhandled error in Deferred:
> 2012-01-21 14:35:15-0800 [-] Unhandled Error
>         Traceback (most recent call last):
>           File "/home/n/virtualenvs/default/lib/python2.7/site-
> packages/nevow/flat/twist.py", line 42, in cb
>             _drive(iterable, finished)
>           File "/home/n/virtualenvs/default/lib/python2.7/site-
> packages/nevow/flat/twist.py", line 26, in _drive
>             finished.callback('')
>           File "/home/n/virtualenvs/default/lib/python2.7/site-
> packages/twisted/internet/defer.py", line 362, in callback
>             self._startRunCallbacks(result)
>           File "/home/n/virtualenvs/default/lib/python2.7/site-
> packages/twisted/internet/defer.py", line 458, in _startRunCallbacks
>             self._runCallbacks()
>         --- <exception caught here> ---
>           File "/home/n/virtualenvs/default/lib/python2.7/site-
> packages/twisted/internet/defer.py", line 545, in _runCallbacks
>             current.result = callback(current.result, *args, **kw)
>           File "/home/n/virtualenvs/default/lib/python2.7/site-
> packages/nevow/appserver.py", line 181, in _cbFinishRender
>             self.finishRequest(  True )
>           File "/home/n/virtualenvs/default/lib/python2.7/site-
> packages/nevow/appserver.py", line 176, in finishRequest
>             server.Request.finish(self)
>           File "/home/n/virtualenvs/default/lib/python2.7/site-
> packages/twisted/web/http.py", line 866, in finish
>             "Request.finish called on a request after its connection was
> lost; "
>         exceptions.RuntimeError: Request.finish called on a request after
> its connection was lost; use Request.notifyFinish to keep track of this.
> }}}
>
> '''Resolution''': Handle early/exceptional TCP disconnects.
>
> '''Related Issues''':
> * It looks like a closed ticket purports to fix this issue, at least for
> some cases: https://tahoe-lafs.org/trac/tahoe-lafs/ticket/1366
> * haproxy may behave unlike browsers.  For instance, it may treat the
> connection to the gateway as Keep-Alive, even when the browser clients do
> not. I am using default configuration for this kind of behavior, and in
> generaly I expect haproxy to "play well" with many different http server
> implementations.

New description:

 '''Symptoms''': While running a gateway which has haproxy as a webapi
 client which I frequently restart, I see exceptions like this:

 {{{
 2012-01-21 14:35:15-0800 [-] Unhandled error in Deferred:
 2012-01-21 14:35:15-0800 [-] Unhandled Error
         Traceback (most recent call last):
           File "/home/n/virtualenvs/default/lib/python2.7/site-
 packages/nevow/flat/twist.py", line 42, in cb
             _drive(iterable, finished)
           File "/home/n/virtualenvs/default/lib/python2.7/site-
 packages/nevow/flat/twist.py", line 26, in _drive
             finished.callback('')
           File "/home/n/virtualenvs/default/lib/python2.7/site-
 packages/twisted/internet/defer.py", line 362, in callback
             self._startRunCallbacks(result)
           File "/home/n/virtualenvs/default/lib/python2.7/site-
 packages/twisted/internet/defer.py", line 458, in _startRunCallbacks
             self._runCallbacks()
         --- <exception caught here> ---
           File "/home/n/virtualenvs/default/lib/python2.7/site-
 packages/twisted/internet/defer.py", line 545, in _runCallbacks
             current.result = callback(current.result, *args, **kw)
           File "/home/n/virtualenvs/default/lib/python2.7/site-
 packages/nevow/appserver.py", line 181, in _cbFinishRender
             self.finishRequest(  True )
           File "/home/n/virtualenvs/default/lib/python2.7/site-
 packages/nevow/appserver.py", line 176, in finishRequest
             server.Request.finish(self)
           File "/home/n/virtualenvs/default/lib/python2.7/site-
 packages/twisted/web/http.py", line 866, in finish
             "Request.finish called on a request after its connection was
 lost; "
         exceptions.RuntimeError: Request.finish called on a request after
 its connection was lost; use Request.notifyFinish to keep track of this.
 }}}

 '''Resolution''': Handle early/exceptional TCP disconnects.

 '''Related Issues''':
 * It looks like a closed ticket purports to fix this issue, at least for
 some cases: #1366 -also see: #1278
 * haproxy may behave unlike browsers.  For instance, it may treat the
 connection to the gateway as Keep-Alive, even when the browser clients do
 not. I am using default configuration for this kind of behavior, and in
 generaly I expect haproxy to "play well" with many different http server
 implementations.

--

-- 
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/1664#comment:1>
tahoe-lafs <https://tahoe-lafs.org>
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