[FEATURE] Multiple ratesheets per carrier in rate cacher

[osgjps]

Is your feature request related to a problem? Please describe.

Carriers in the US often have rate sheets with 2 or 3 separate prices, usually an intrastate, interstate, and "unknown" rate depending on the area code of the source and destination numbers. I've not been able to come up with a set up that uses the existing structure of rate cacher without defining multiple carrier entries for each actual carrier, adding a rate sheet to each of those, and trying to keep track of what carrierid is for what carrier with what rate pricing.

Describe the solution you'd like

I'd like the option to be able to define multiple ratesheets per carrier entry and then be able to select which ratesheet to choose from in the assorted script functions.

Implementation

• Component: Rate Cacher
• Type: Various parameters

Describe alternatives you've considered

None, but if there's a good proposal, I'll try it out.

Additional context

I've contemplated ways of adding this feature myself and I can if my plan makes sense to the development team. Biggest change will be in the carrier_cell struct. We can either just add a couple of additional members for the extra ratesheets, like what the account_cell struct has for wholesale vs retail. That will work, but it does impose an artificial limit on the number of ratesheets per carrier. Or we can change the existing members to arrays. The script functions will have to be modifed accordingly.

[vladpaiu]

useful indeed, but I found it hard to implement a generic enough differentiation mechanism ( inter/intra for US, other parts of the world have different things ) and then you'd have to pass that 'differentiation' to functions like cost_based_ordering/filtering ( with a default to main rate price if not found in the special ratesheet), so open to suggestions

[osgjps]

This is my first crack at it: https://github.com/osgjps/opensips/tree/newratecache/modules/rate_cacher

A modparam that sets the max number of ratesheets per carrier.
Defines the ratetables for each carrier using a comma separated list in the "vendor_rate" column of rc_vendors, though in my test environment I have a vendor_rate and vendor_rate2 column. One is an int, the other varchar so I can test backwards compatibility simply by changing the column name back and forth.

An optional parameter to specify a "slot" in each of the commands that would pull a vendor price.

I tried to make it backwards compatible so anyone migrating from an earlier version to this version wouldn't have to change database structures or script settings.

[osgjps]

I haven't run the code through a full regression or memory leak check, so feel free to point out anything that you see might be an issue.