Enable accessing related object attributes via dotted path when defining custom validation rules

[jeremystretch]

NetBox version

v3.7.4

Feature type

New functionality

Proposed functionality

When defining custom validation rules as JSON, it is currently possible to access only direct attributes on an object. For example:

CUSTOM_VALIDATORS = {
    "dcim.site": [
        {
            "name": {
                "min_length": 5,
            }
        }
    ]
}

It is not possible to reference an attribute of a related object; this would require creating a CustomValidator subclass in Python with a custom validate() method as discussed here.

This issue proposes a mechanism for referencing attributes of related objects, identified by a dotted path. For example, the following would reference a the name of a site's assigned region:

CUSTOM_VALIDATORS = {
    "dcim.site": [
        {
            "region.name": {
                "eq": "North Carolina",
            }
        }
    ]
}

This could be achieved by employing Python's operator.attrgetter() utility.

Use case

This enhancement will allow users to reach "deeper" into an object when validating it without the need to write a custom subclass in Python.

Database changes

None

External dependencies

None

[jeremystretch]

I may end up implementing this as a byproduct of #14279 as the basic functionality will be required there as well.

[opericgithub]

Dear @jeremystretch, I'm sorry if I ask this question in the inappropriate topic, but I don't understand the documentation.

What should be the syntax of custom_validation rules, if I would like to have the following: the name of the site in the North Carolina region should have the minimum of 5 characters, but the name of the site in any other region should have the minimum of 7 chars?