Requesting a Nginx Variable - "client_time_taken" (similar to request_time & upstream_response_time)

[Maxim Dounin]

Hello!

On Sun, Oct 01, 2023 at 08:20:23PM +0530, Devarajan D via nginx wrote:

> Currently, there is no straightforward way to measure the time 
> taken by client to upload the request body. 
> 
> 1. A variable similar to request_time, upstream_response_time 
> can be helpful to easily log this time taken by client.
>     So it will be easy to prove to the client where the slowness 
> is.

In general, $request_time minus $upstream_response_time is the 
slowness introduced by the client.  (In some cases, 
$upstream_response_time might also depend on the client behaviour, 
such as with "proxy_request_buffering off;" or with 
"proxy_buffering off;" and/or due to proxy_max_temp_file_size 
reached.)

Further, $request_time can be saved at various request processing 
stages, such as after reading request headers via the "set" 
directive, or via a map when sending the response headers.  This 
provides mostly arbitrary time measurements if you need it.

For detailed investigation on what happens with the particular 
client, debugging log is the most efficient instrument, notably 
the "debug_connection" directive which makes it possible to 
activate debug logging only for a particular client 
(http://nginx.org/r/debug_connection).

> 2. Also, is there a timeout for the whole request? 
> 
>     (say request should be timed out if it is more than 15 
> minutes)

No.

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