fix: Prevent panic if vcpus is null

[amhn]

Fixes: #82

Creating a VM without vcpus did not work because the addition of ".00" prevented the latter check for "" from working. This resulted in sending "vpus": 0 which is not allowed in netbox.

Additionally a read of a VM without vcpus failed with a panic because netbox sends null as value for vcpus.

Setting vcpus back to null does not work because of limitations in go-swagger or the json library in go. See the primary_ip issue. This is currently silently ignored in the Update.

[smutel]

I did some tests and I have a strange behavior. I am using the file examples/main.tf.

• Without CPU + terraform apply (creation)

  => OK

• terraform apply without change

  => OK

• Add CPU + terraform apply (update)

  => OK

• terraform apply without change

  
  Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  ~ update in-place
  -/+ destroy and then create replacement

Terraform will perform the following actions:

netbox_ipam_ip_addresses.ip_test must be replaced

-/+ resource "netbox_ipam_ip_addresses" "ip_test" { ~ content_type = "ipam.ipaddresse" -> (known after apply) ~ id = "49" -> (known after apply)

• nat_inside_id = 0 -> null ~ primary_ip4 = false -> true # forces replacement

• vrf_id = 0 -> null

  (5 unchanged attributes hidden)

  # (9 unchanged blocks hidden)

  }

  netbox_ipam_service.service_test will be updated in-place

  ~ resource "netbox_ipam_service" "service_test" { id = "29" ~ ip_addresses_id = [

  • 49, ] -> (known after apply) name = "SMTP"

    (6 unchanged attributes hidden)

    (8 unchanged blocks hidden)

    }

[amhn]

Yes. This is triggered by https://github.com/smutel/go-netbox/commit/c6308a5357f811ccd0c64aa492d59bb63c4f274e

Any change of the virtual machine sets the primary_ip4 back to null. I noticed this but did not have time to report this yet.

This is unrelated to my changes. A change in the description would trigger the same replacement.

[smutel]

OK, il will try to fix that in my PR for IPv6.