[SR-Users] Computing a time difference when handling a stateless SIP request

[Alex Balashov]

route {
    $avp(proc_start) = $TV(Sn);

    ...

    $avp(proc_start) = $TV(Sn);

    $var(proc_diff) = (
       (((
         $(var(cur_time){s.select,0,.}{s.int}) -
         $(avp(proc_start){s.select,0,.}{s.int})
       ) * 1000000)
       +
       (
        $(var(cur_time){s.select,1,.}{s.int}) -
        $(avp(proc_start){s.select,1,.}{s.int})
       ) / 1000) mod 1000
    );

    xlog("L_INFO", "Request processing time: $var(proc_diff) ms\n");

    if(!t_relay())
       sl_reply_error();
}


On 9/25/20 3:11 PM, Henning Westerholt wrote:
> Hello,
> 
> you could probably combine some string transformation to get the desired 
> result.
> 
> If your requirements are related to accounting, the acc module might bei 
> easier to use.
> 
> Cheers,
> 
> Henning
> 
> -- 
> Henning Westerholt - https://skalatan.de/blog/
> Kamailio services - https://skalatan.de/services
> ------------------------------------------------------------------------
> *From:* sr-users <sr-users-bounces at lists.kamailio.org> on behalf of 
> Chaigneau, Nicolas <nicolas.chaigneau at capgemini.com>
> *Sent:* Friday, September 25, 2020 6:34:30 PM
> *To:* Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org>
> *Subject:* Re: [SR-Users] Computing a time difference when handling a 
> stateless SIP request
> 
>> > 
>> > --snip 
>> > I would like to compute a time difference (with microseconds
>> > precision) when handling a stateless SIP request.
>> > --snip
>>
>> Welcome!
>>
>> Take a look at:
>> https://www.kamailio.org/wiki/cookbooks/5.4.x/pseudovariables#timeval
>>
>> You can get down to the microsecond level.
> 
> 
> Thanks!
> 
> Looking at src\modules\pv\pv_time.c, it seems TV functions just use 
> "gettimeofday".
> I was looking for a time difference based on a monotonically increasing 
> clock (to avoid possible NTP drifting imprecision).
> 
> I've looked at the "benchmark" module which seems to do something like 
> that, but I don't think I can use it for what I need...
> 
> 
> 
> Anyhow, I have another question. Using the TV I've come up with the 
> following.
> This works, except that I don't know how to convert an int to a string 
> padded with zeroes (e.g. 51 => "051").
> Is there a transformation that allows to do that?
> 
> 
>          $var(start_time) = $TV(Sn); # allows to cache $TV(s) and $TV(u)
> 
>          (...)
> 
>          $var(end_time) = $TV(Sn);
>          $var(end_s) = $TV(sn);
>          $var(end_us) = $TV(un);
>          $var(diff_us) = $var(end_us) - $TV(u) + (1000000 * ($var(end_s) 
> - $TV(s)));
> 
>          # convert this to ms (integer part) and us (fractional part)
>          $var(diff_ms) = $var(diff_us) / 1000;
>          $var(diff_us_f) = $var(diff_us) - (1000 * $var(diff_ms));
> 
>          $var(diff_ms_us) = $var(diff_ms) + "." + $var(diff_us_f); # 
> need to format on 3 digits... can we do the equivalent of 
> sprintf("%03u") somehow ?
> 
> 
> 
> 
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-- 
Alex Balashov | Principal | Evariste Systems LLC

Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/