Why is mod_wsgi not able to write data? IOError: failed to write data

Question

What could be causing this error:

$ sudo tail -n 100 /var/log/apache2/error.log\'

[Wed Dec 29 15:20:03 2010] [error] [client 220.181.108.181] mod_wsg         


        

Answer 1

That error, without any sort of Python traceback, may be a variation on issue described in:

http://code.google.com/p/modwsgi/issues/detail?id=29&can=1

That is, occurs when HTTP client connection is lost before the full response could be written back by the web server. It can manifest as 'client closed connection', 'failed to write data' or 'failed to flush data' IOError in Apache error log only. Ie., not seen by WSGI applicaton because the writing of data is occurring after WSGI application has returned and so can't throw exception back to the application to do anything with.

The question is whether you get an error message from Django if you configure errors to be sent to you in email. If you do, then instead is something happening in Django.