Conditional access log formatting?

Server NGINX
1

Hi,

I’m using haproxy infront of some NGINX instances, but only for some
instances which are being loadbalanced by haproxy, there are other
instances which go straight through.

I realise I need to change the logging format in NGINX to enable
X-Forwarded-For in the access logs.

The question is whether I can conditionally format the logs, i.e. use
“X-Forwarded-For” if it exists, otherwise use the normal NGINX logging
format.

I’ve had a quick peek at the manual, I’m thinking maybe this can be done
with a map of some sort ? Maybe there’s a better way ? To be honest
I’ve no idea where to start, and I’ve never used maps before anyway !

2

I suggest you use the ‘if’ parameter of 2 access_log directive
(>v1.7.0),
combined with 2 maps with reversed logic.

B. R.

3

On Saturday 18 July 2015 11:37:33 Ben wrote:

“X-Forwarded-For” if it exists, otherwise use the normal NGINX logging
format.

I’ve had a quick peek at the manual, I’m thinking maybe this can be done
with a map of some sort ? Maybe there’s a better way ? To be honest
I’ve no idea where to start, and I’ve never used maps before anyway !

You should use the realip module:
http://nginx.org/en/docs/http/ngx_http_realip_module.html

wbr, Valentin V. Bartenev