Nginx logging phase

[Maxim Dounin]

Hello!

On Thu, Oct 29, 2020 at 06:23:59PM +0530, Vikas Kumar wrote:

> Do you have a recommendation on what handlers are suitable for my use case?

In nginx itself, proper approach to count in-flight request would 
be:

1. Increment the counter only if no module's cleanup handler is installed 
   in the request pool.  This way the counter can be incremented 
   in any phase, which makes it possible to do this in a 
   particular location.  If the handler is called multiple times,
   additional calls are simply ignored.

2. Once the counter incremented, install module's cleanup handler 
   to decrement the counter.  This ensures that the counter is 
   always properly decremented when the requst is freed.

This is more or less what limit_conn module does (except it uses 
some bits in the request structure to optimize checking if the 
cleanup handler is installed).

No idea though if something similar can be done with the Lua 
module you are trying to use.

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