resource_volume : set topology_request on read

[the-nando]

Fixes: #338

The MR covers only required topology_request as that's what's implemented in the schema for this resource. Should it be extended to account also for preferred? According the the Volume Specification they are both supported.

[lgfa29]

Thanks for the PR @the-nando!

nomad_volume and nomad_external_volume are, due to historical reasons, two weird resources 😅

As noted in the docs and in the comment in the code (though the URL is broken, so we need to fix that), preferred is only supported on volume creation, which nomad_volume does not do, only nomad_external_volume creates volumes.

But the Read method is shared between them, so I think we do need to handle preferred so nomad_external_volume is fully fixed (and maybe add ForceNew there as well). Hopefully Terraform won't complain about the missing field in the schema, though I do think it might 😬

If it does complain, then I think we may need to add it to the schema but as computed so users don't set it.

[lgfa29]

After review this PR I realized that this may be a good time to clean-up the mess around the volume resources since we're planning a major release with some breaking changes, so I opened #344 to do that.

I could apply these changes to that PR (plus in the new resources), or you can rebase and work off that branch.

Let me know what would work best for you.

[the-nando]

Hey @lgfa29, thanks for the clarification regarding the setting of preferred in nomad_volumes vs nomad_external_volume :)

Feel free to bundle up the changes in this PR with the ones in #344 and close this if that's easier for you. I'll wait then for the next major.

Thanks!

[lgfa29]

Looking at it again, #344 was already big and convoluted enough that adding more changes to it would make it even more confusing 😅

So I think I will rebase your branch and keep this PR up for this specific bug fix.

[lgfa29]

I've updated the topology request flattening function to also read preferred and Terraform didn't seem to complain about it, so I didn't have to update the schema. I also noticed that ForceNew didn't work unless it was set in all levels of the schema, so I addedthat as well.

Lastly I rebased your branch to apply the fix to the new nomad_csi_volume and nomad_csi_volume_request resources, so i think we're all good here.

Free to reach out if you notice a problem with these changes.

Thanks again for the PR!