proxy_intercept_errors and logging

[Maxim Dounin]

Hello!

On Fri, Jan 13, 2012 at 02:47:00PM -0500, mikeyk wrote:

> Hi there,
> 
> We have nginx proxying to a bunch of django upstreams.
> 
> When those upstreams throw an error, we use proxy_intercept_errors to
> show a custom page. The problem is that this causes those 500s to be
> logged into the global access_log, rather than the access_log specified
> for that location. Here is a (reduced) example:
> 
>     # at the server 
>     access_log /logs/nginx/access.log accesslogformat;
>     proxy_intercept_errors on;
>     location ~ ^/oauth.*$ {
>         proxy_pass        http://appservers;
> 
>         access_log /logs/nginx/app.log applogformat;
>     }
> 
> Is there a way to get errors to log to the app.log in this case, even
> with proxy_intercept_errors to on? Right now we get all the 500s in the
> access.log.

Requests are logged in context of a location where their 
processing ends.  This means that after error_page redirection 
they will logged in the location where error_pages are processed.

If you want them to be logged to the same app.log, you need to 
define location for errors with the same logging.  To avoid mixing 
logs with normal errors, you may want to define separate 
error_page's for your apps.  Something like this should work: 

     location /oauth {
         proxy_pass ...

         proxy_intercept_errors on;
         error_page 502 504 /errors_oauth/5xx.html

         access_log /path/to/app.log applogformat;
     }

     location /errors_oauth/ {
         alias /path/to/errors/;
         access_log /path/to/app.log applogformat;
     }

Maxim Dounin