Add primary_ip_interface option to nb_inventory

[jorgenspange]

Summary

• Adds a new primary_ip_interface boolean option to the nb_inventory plugin that exposes the interface name of the primary IP as a host var (primary_ip_interface)
• When only this option is set, a targeted fetch queries only the primary IP IDs already present on the fetched devices/VMs — rather than all IP addresses in NetBox — keeping overhead minimal (~0.6s in testing)
• When used alongside interfaces: true, dns_name: true, or ansible_host_dns_name: true, the existing full IP fetch is reused with no duplicate requests

Closes #1530

Test plan

• Unit tests updated and passing (test_group_extractors)
• Changelog fragment added (changelogs/fragments/1530-primary-ip-interface.yml)
• Enable primary_ip_interface: true in an inventory config and verify the primary_ip_interface host var is populated with the correct interface name
• Verify hosts without a primary IP, or whose primary IP is not assigned to an interface, have no primary_ip_interface var set
• Verify no regression when primary_ip_interface: false (default)

[jorgenspange]

@sc68cal Would you be able to take a look at this one, when you have got the time?

[sc68cal]

This seems like something that can already be done, via an nb_lookup query, for those that require it. Can you discuss why this should be used instead of a nb_lookup query?

[jorgenspange]

I have to admit that I am not familiar with the nb_lookup query, where would I find the documentation for this?

[jorgenspange]

I think I got it now, looking into the nb_lookup plugin. Using the lookup_plugin would require me to run this task for all my hosts while having it in the inventory plugin makes primary_ip_interface available as a native host var before any play runs, just like primary_ip4 already. This is also consistent with how dns_name is already handled in the inventory plugin.

[jorgenspange]

I think I got it now, looking into the nb_lookup plugin. Using the lookup_plugin would require me to run this task for all my hosts while having it in the inventory plugin makes primary_ip_interface available as a native host var before any play runs, just like primary_ip4 already. This is also consistent with how dns_name is already handled in the inventory plugin.

Any thoughts on this @sc68cal?

[sc68cal]

My concern is that we already have a couple of different ways that people want to connect to devices, by using different settings in the netbox inventory plugin. I don't think we should continue to add more and more different ways. If you have some preferred way to connect to your device based on netbox data that is not primary_ip4 or dns_name, you should use the nb_query plugin with add_host or set host_vars from the inventory data. I don't think we should keep growing the complexity in nb_inventory for each different way that people want to connect to devices that deviates from primary_ip4

[jorgenspange]

@sc68cal This is not used to connect to the device really, what I am mostly interested in is to retreive the primary interface name, so that I can populate this in different variables I have in my configuration.

[sc68cal]

what I am mostly interested in is to retreive the primary interface name, so that I can populate this in different variables I have in my configuration.

That's a usecase that the nb_query plugin is meant for.