[PATCH] New directive and variable to log module

[Maxim Dounin]

Hello!

On Sat, Apr 18, 2026 at 06:40:43PM -0300, Fabiano Furtado wrote:

> Dear freenginx developers,
> 
> I would appreciate it if you could take a look at this patch and
> provide your feedback or suggestions for improvements, or let me know
> if you think it would be a valuable addition to the project.
> 
> This patch introduces the new "log_tag" directive to freenginx, which
> allows you to define a custom tag for each http, server or location
> block. This tag is then referenced using the "$tag" variable within
> the "log_format" directive, making it easier to filter and match logs,
> especially in configurations with many location blocks or complex ones
> using regular expressions.
> 
> As an alternative, the directive and variable could be named as:
>   * "log_label" / "$label"
>   * "log_id" / "$id"

First of all, I would like to note that there should be no 
log-specific variables.  All variables should be universally 
supported by the generic variables infrastructure, without 
exceptions.  In particular, this is an important factor to 
properly support alternative logging modules.

Last log-specific variables were changed to universally supported 
ones in nginx 1.3.12 in Feb 2013 
(http://freenginx.org/hg/nginx/rev/829cc5872186).  Variables
handled directly by the access log module exist only as an 
optimization and exactly match corresponding generic variables.

As for the idea of introducing a (generic) variable to identify 
locations used to handle the request, I don't have a strong 
opinion here.  If I understand the use case correctly, my personal 
approach would be to use "set" to construct appropriate variables 
while in progress, and rewrite the configuration to something 
manageable as soon as possible.

-- 
Maxim Dounin
http://mdounin.ru/