Error handling from filter modules

[Maxim Dounin]

Hello!

On Mon, Oct 19, 2015 at 11:02:53PM +0100, Steven Hartland wrote:

[...]

> >When the NGX_ERROR case is triggered, no response is returned, the
> >connection is just closed.
> It does seem like the connection to the client is just closed however a 206
> response is logged for the request in the access log, hence my confusion; is
> that expected?

Yes.  Once set, status code will be logged even if an error occurs 
later.

> >As this expected to happen if and only
> >if we weren't able to allocate memory, this is believed to be
> >perfectly correct behaviour.  Trying to do anything else is very
> >unlikely to succeed, but likely to result in additional problems.
> >
> In the current code yes, but in the patch that I was testing there's one
> additional case which can return an error. This was caused by an intentional
> configuration error (test designed to confirm the behaviour in this case).
> 
> Its likely going to be difficult to discuss fully without the patch to
> comment against so I'll finalise that and get it posted as soon as I can.

General recommendation is to avoid cases when you have to return  
error pages from filter modules.  But yes, it's difficult to 
disscuss without the code.

-- 
Maxim Dounin
http://nginx.org/