Re: 'premature end of script headers' error

Bernhard,

Oops, I forgot the import for logging. Here is the hg diff for client.py

$ hg diff client.py
diff -r 740402e61479 roundup/cgi/client.py
--- a/roundup/cgi/client.py     Tue May 21 12:53:20 2013 -0700
+++ b/roundup/cgi/client.py     Fri Dec 13 13:58:52 2013 -0800
@@ -6,6 +6,7 @@
  import quopri, random, re, rfc822, stat, sys, time
  import socket, errno
  from traceback import format_exc
+import logging

  try:
      from OpenSSL.SSL import SysCallError
@@ -486,10 +487,14 @@
                  self.serve_file(designator)
              except SendStaticFile, file:
                  self.serve_static_file(str(file))
-            except IOError:
+            except IOError as e:
                  # IOErrors here are due to the client disconnecting before
                  # receiving the reply.
-                pass
+                # They can also be caused by detector errors.
+                import traceback
+                tb = traceback.format_exc()
+                lg = logging.getLogger('roundup')
+                lg.debug('Caught exception %s: %s\n%s' % (str(type(e)), e, tb))
              except SysCallError:
                  # OpenSSL.SSL.SysCallError is similar to IOError above
                  pass

Tom Ekberg
Senior Computer Specialist, Lab Medicine
University of Washington Medical Center
1959 NE Pacific St, MS 357110
Seattle WA 98195
cell: (253) 561-2509
email: [email protected]

On Thu, 12 Dec 2013, Bernhard Reiter wrote:

> Tom,
>
> On Wednesday 11 December 2013 at 23:08:52, Tom Ekberg wrote:
>> Thank you for your response. I can find no traceback. None in the log file,
>> nor the apache ssl_error_log which is where I have seen stack traces
>> before. I peppered my systems tracker's roundup.cgi with more log messages
>> - there is no python error at that level.  I made sure to catch any
>> exception.
>
> hmmm, yes this is strange, but it was important to check.
>
>> I wrote a wrapper class (snarfed most of the code from
>> http://code.activestate.com/recipes/577555-object-wrapper-class/) to have
>> HTML text go to the log file as well as to sys.stdout. When I'm displaying
>> the issue detail (issue.item.html) I see lots of HMTL in the log file. When
>> I change a simple attribute and press the 'submit' button I see the SQL
>> statements that I saw before, but no HTML text. This is why apache is
>> complaining about the script headers - there aren't any. I'll have to dig
>> deeper in the roundup/cgi/* code to determine where the error is. I'm
>> thinking that something like this happens:
>>
>>    create DB transaction
>>    do a lot of selects
>>    perform update and inserts
>>    some unknown error happens
>>    transaction is aborted
>
> Yes, this seems to be a good starting hypothesis.
> You could try to verify it maybe by the database side,
> if there is more diagnostics, it may tell you if the transaction was actually
> aborted.
>
>> I'm pretty certain the database itself isn't the problem. I modified the
>> same issue's attribute with roundup-admin and it works fine. I also did the
>> UPDATE cut/pasted from the log using psql (the postgres command line) while
>> logged as the user I'm using in the tracker. That also works fine.
>
> It still could be the database because of timing or so, but I also would try
> to falsify other hypothesis first.
>
>> If you think I'm going down the wrong path (digging into the roundup/cgi/*
>> code) I'd appreciate your input.
>
> The result probably comes out of the db layer, maybe that is another place
> where you can try to detect and track the infection (bad behaviour
> propagating).
>
> Let us know about your progress. ;)
> Bernhard
>
> -- 
> www.intevation.de/~bernhard (CEO)    www.fsfe.org (Founding GA Member)
> Intevation GmbH, Osnabrück, Germany; Amtsgericht Osnabrück, HRB 18998
> Owned and run by Frank Koormann, Bernhard Reiter, Dr. Jan-Oliver Wagner
>

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