overriding nginx access_log directive - duplicate log entries

I'm using the default nginx package on Ubuntu 14.04 server. It is using /etc/nginx/nginx.conf as the main config, and then includes configs from /etc/nginx/conf.d/*.conf and /etc/nginx/sites-enabled/*.

The default nginx config has this directive for logging to the access log

access_log /var/log/nginx/access.log;

I'd like to add the X-Forwarded-For header, so I do this inside of the conf.d folder:

log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                 '$status $body_bytes_sent "$http_referer" '
                 '"$http_user_agent" "$http_x_forwarded_for"';

access_log  /var/log/nginx/access.log  main;

The problem I have is that then I'm getting two records inside my access.log file - one with the header info and another one without.

I know I can overwrite the nginx.conf file itself, but I'd rather avoid it if possible. I would also like to keep using the same log file (access.log).

Is there a way to tell nginx to override the previous directive and simply change the log format without modifying the main nginx.conf file?

Solution 1:

the answer to your question is NO, you can't override a log_format at any level in nginx and you can't override access_log when in the same level, except switching it off. However, you can achieve what you wanted without changing nginx.conf but you will have to do it at server {} level.

The issue here is that the include of conf.d/* is inside the http {}, which is exactly where the access_log directive is. What you can do without touching nginx.conf is to change whatever server{} you are using (if you didn't setup one you are using the default one located at /etc/nginx/sites-enabled/default). So to achieve the same without changing nginx.conf you should change your file in the conf.d folder to: log_format main '$remote_addr - $remote_user [$time_local] "$request" ' '$status $body_bytes_sent "$http_referer" ' '"$http_user_agent" "$http_x_forwarded_for"'; access_log off;

And then inside your server{} put: access_log /var/log/nginx/access.log main;

That should get you what you wanted at the beginning.