Add support for specifying -4 option to nsupdate

[accorvin]

In our environment, our DNS server requires passing the "-4" argument to
the nsupdate command. This change adds support for configuring OSIA to
use this option when using the nsupdate dns provider.

[accorvin]

@mijaros can I get your thoughts on this?

[mijaros]

@accorvin this is certainly a good idea and thank you for the contribution, we might add a dns option to enforce this, if you'd agree, something like --dns-use-ipv4 and default option to settings.yml to the dns part?

[accorvin]

@mijaros that makes sense to me. I can work on updating this PR to do that.

[mijaros]

@accorvin if you can I'd be grateful. Thank you.
I think that it should be enough to add the option to the ARGUMENTS list in

osia/osia/cli.py

Line 71 in 647a226

'dns': {

with 'action': 'store_true'and rename the __init__ argument in NSUpdate class to the same name (without the dns_ prefix), so in the situation above it would be use_ipv4=False for argument dns_use_ipv4.

[accorvin]

@mijaros Updated. Let me know what you think.

[mijaros]

Blimey, store_true won't work together with dynaconf in the current setup. The problem is that the store_true action always defaults to false. The way how the overriding from command line now works with osia is, that if the key in command line arguments is not None it means we're overriding anything that's in the settings.yaml. Since store_true always keeps the key in the arguments, it basically overrides all the time. I've found a potential workaround, to use store_const (see suggested change) with the value of True. This will mean, that if the option is not passed it will have a value of None and if it is passed, it will have the value of True. Hence it can be stored in the settings.yaml as well as overridden from the command line if needed.

[mijaros]

@accorvin ok it seems that now it's only the linter complaining, could I ask you to rearrange the code (it will only be necessary to add a line and align it in cli.py). Then you can run the following command

poetry run flake8 osia --max-line-length 100 --show-source --statistics

and it should be clean.
As the last thing, I'd ask you to squash all of those commits, please (and maybe rebase). After that, I think we're ready to merge and test/release.

[accorvin]

@mijaros done

[mijaros]

I've tried it, and the option works as well as the configuration in settings.yaml. Going to merge now, and then release.

[accorvin]

Awesome! Thanks for the quick turnaround @mijaros!

[zdtsw]

Bumped into this flag "--dns-use-ipv4" when trying to provision from my local RHEL8 then realized nsupdate does not support "-4" (seems the same case as on Mac) but on F37 it works.

Thinking if it is a good idea to add check logic in the script, say, when user uses this flag, it still checks to see if installed nsupdate work fine? if not, then set nsupdate_args.append('') even the flag is supplied.