[SR-Users] Tips on picking random element from a list

[Ben Kaufman]

How "random" do you need to be here? Given your example, a quick thought would be to just iterate over a list, using a counter and calculating the modulo (remainder) when dividing it by the number of elements you have.

Another thought would be to use the core_hash() function over the call-id. http://www.kamailio.org/docs/modules/5.6.x/modules/cfgutils.html#cfgutils.f.core_hash

Of course, those aren't really "random" in the mathematical sense, but if you're goal is "you have a pool of 10 numbers and want them to be assigned to the p-asserted-identity URI user each one-tenth of the time", either of the above methods should work.  Hashing the call-id would even ensure that the same call will get the same value if you have to recalculate it.

Ben Kaufman
Sr. VoIP Engineer - BCM One

+1.612.735.9309
bkaufman at bcmone.com<mailto:bkaufman at bcmone.com>
24 hour client support: +1.855.639.6300

From: sr-users <sr-users-bounces at lists.kamailio.org> On Behalf Of Joel Serrano
Sent: Tuesday, May 3, 2022 8:40 PM
To: Henning Westerholt <hw at gilawa.com>
Cc: Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org>
Subject: Re: [SR-Users] Tips on picking random element from a list

I did, but I don't see how to limit the range:

>From the docs: Returns a random value from the [0 - 2^31) range.

Is there a way to limit the range from 1-100 for example? Or maybe the way is to use $RANDOM and just rely on the first/last 2 digits (essentially a 00-99 range)?


On Tue, May 3, 2022 at 10:40 AM Henning Westerholt <hw at gilawa.com<mailto:hw at gilawa.com>> wrote:
Hello,

what about just using this PV: https://kamailio.org/docs/modules/5.5.x/modules/cfgutils.html#idm438<https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fkamailio.org%2Fdocs%2Fmodules%2F5.5.x%2Fmodules%2Fcfgutils.html%23idm438&data=05%7C01%7Cbkaufman%40bcmone.com%7Cde7dd7f8eb504d2a662f08da2d6f2f33%7Cafc1818e7b6848568913201b9396c4fc%7C1%7C0%7C637872252819501517%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=JRp6T14RXqTW26xFJ5DWcKPUEqqXy0hkQ1ecuCWyk10%3D&reserved=0>

Cheers,

Henning

--
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From: sr-users <sr-users-bounces at lists.kamailio.org<mailto:sr-users-bounces at lists.kamailio.org>> On Behalf Of Joel Serrano
Sent: Tuesday, May 3, 2022 6:20 PM
To: Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org<mailto:sr-users at lists.kamailio.org>>
Subject: [SR-Users] Tips on picking random element from a list

Hi Everyone,

I have to implement a flow where outbound calls get their caller-id set with a random number from a pool.

I've been looking around and, as most of the time, there are tons of ways to implement something like this... This is a simple implementation, the number pool is fixed and will not change (so I could have it hard-coded in the config if required).

My initial approach was:

1- Try to keep it simple, with no dependencies, and all done in the config script.
2- If #1 is "ugly", then I'd probably go with some inline code using python/lua/etc
3- If #2 is "ugly", then I'd go with having the info in a DB and just run a query

I think #2 and #3 might be overkill for something so "simple" but I haven't had to work too much with randomness in Kamailio, so any tips/suggestions on where to store the number list and how to pick one randomly would be awesome!

Thanks!!
Joel.

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