Add fields to restrict visibility/creation of custom fields

[shane-davidson]

Environment

• Python version: 3.8.2
• NetBox version: 2.8

Proposed Functionality

Adding an option in custom fields to restrict the custom field visibility based on the model fields equality a specific value.

class CustomField(models.Model):

    restrict= models.CharField(
        default=None,
       choices= "custom choice set showing fields available for filtering"
        help_text='Model field used to restrict visibility of this custom field.'
    )

    restrict_value= models.CharField(
        blank=True,
        help_text='Value to match when restrict field is set'
    )

    restrict_negate= models.BooleanField(
        blank=True,
        help_text='Negates restriction match'
    )

when creating a custom field you have the option to select a field and a value to match.
This field and value will decide if the custom field is visible or not.

Use Case

Create a role for a virtual machine called "app server"
Create a custom field you only want visible on virtual machine with the "app server" role

restrict = "role.name"
restrict_value = "app server"

Create a role for a virtual machine called "database server"
Create a custom field you only want visible on virtual machine with the "database server" role

restrict = "role.name"
restrict_value = "database server"

Create a device with type "Cisco Router"
Create a custom field on device

restrict = "device_type.manufacturer.name"
restrict_value = "Cisco"

OR

restrict = "device_type.manufacturer.model"
restrict_value = "Cisco Router XXX"

Other considerations:

• Optional negate on the restriction.
• Setting for if new 'restrict' field doesn't match any model field to show or hide the custom fields

Database Changes

New fields on CustomField

External Dependencies

None

[jeremystretch]

We are not currently accepting feature requests for development related to custom fields.

[jeremystretch]

Please see #4878