Provides a system to determine available interfaces in a range

[abates]

This request adds a method to slice lists of interfaces in order to facilitate provisioning. Sometimes upstream connections are placed within a given range of interfaces. For instance, a primary connection may always go in the range of Ethernet[1-24] and a secondary connection may go into Ethernet[25-48]. If a switch has all the interfaces Ethernet[1-48] available, then the two needed slices are returned. If a subset of needed interfaces are available, then only those interfaces in the subset are returned. For instance:

slice_interface_range(["Ethernet2", "Ethernet3", "Ethernet4", "Ethernet6", "Ethernet7", "Ethernet8"], "Ethernet1", "Ethernet5")

will effectively produce:

["Ethernet2", "Ethernet3", "Ethernet4"], ["Ethernet6", "Ethernet7", "Ethernet8"]

[itdependsnetworks]

This makes sense to me, but in my mind should also be extended to start. Having to always define the first element (Ethernet1 in tests below) seems off to me.

I could understand either both start and end needing to be explicit or neither being explicit, but start being explicit and end being implicit is a bit confusing to me.

[abates]

Alright, I think my intent maybe wasn't very clear.

The idea is that, for example, I always connect access ports (servers) to switch ports Ethernet1-Ethernet24, and so the slice_interface_range would look for all of the interfaces in that range that are in the available interface_names list. The starting point doesn't have to be at the beginning, though, it could be a range of Ethernet16-Ethernet32.

The list of available interfaces may be a superset of the ranges provided in the cut list, so I can't really think of a way to implicitly choose a start and end. For instance, if the available interfaces list is Ethernet1-Ethernet48 and my intended range is Ethernet16-Ethernet32 how would we run this function with either of those values implied?

I think what you are suggesting is that this should work similar to python list slicing, which allows no start and/or end allowing implied start and end of 0 and -1. This is a language syntax convention, and I don't know how to extend that concept to function arguments.

I'm certainly open to changing this behavior. Can you provide some examples of how you'd like to see the method used with implied start and/or ends?

[mpenning]

Suggestions for an API enhancement... using ciscoconfparse2 for API reference implementation...

Full-disclosure, I'm the ciscoconfparse2 owner...

Don't fear the GPL in my case... if I was going to fuss about GPL viral licensing, Cisco would already be hot sauce for using it all over the place with non-GPL licensing.

❯ python
Python 3.13.0 (main, Dec  1 2024, 17:40:20) [GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> from ciscoconfparse2 import CiscoRange
>>>
>>> intfs = CiscoRange("Ethernet2-4,6-8")
>>> for intf in intfs:
...     print(intf)
...
Ethernet2
Ethernet3
Ethernet4
Ethernet6
Ethernet7
Ethernet8
>>>
>>> CiscoRange("Ethernet2-4") in intfs
True
>>>
>>> CiscoRange("Ethernet47-48") in intfs
False
>>>

[itdependsnetworks]

@mpenning wanted to start with a quick thanks for your open source contributions! Appreciate and notice all of your hard work over the years

Don't fear the GPL in my case

Our lawyers say otherwise, so while I understand the spirit of what you are saying, in practice my hands our tied.

[mpenning]

@itdependsnetworks

The point was twofold...

• Yes, just use the GPL CiscoRange() if there were no such things as lawyers
• If you don't adopt the GPL code, you can still use the CiscoRange() API, which doesn't require manually touching lists of string interface names