Custom validators based on assigned tags

[Mailstorm-ctrl]

Objective:

If you want to apply a tag with name "Monitored" to a device. this should only complete if:

1. The device has a name <- I know I can get this working so it's not in my conditional
2. The device has a primary IP

I understand the basics of custom validators. I'm halfway there but it seems like I can't get it working. I have:

from extras.validators import CustomValidator

class checkMK_TagValidator(CustomValidator):
        def validate(self, instance):
                file1 = open("/opt/netbox/validators/testing/outfile","w")
                file1.write(f"VARS: {vars(instance.tags)}\n")
                file1.write(f"TAGS: {instance.tags}\n")
                file1.write(f"TAG NAMES: {instance.tags.names()}\n")
                #file1.write(f"PIP: {instance.primary_ip}")
                file1.close()
                if "Monitored" in instance.tags.names() and not instance.primary_ip:
                        self.fail("Tag requires a primary IP on the device!", field='tags')

When I look at my outfile, I only see the tag name visible after I edit the object a second time (That is, when adding this tag I don't see its name. On a second edit (such as removing the tag), I see the tag name). However, I need this to operate like a normal validator would.

Not entirely sure if this is possible but would be super rad if it was.

[Mailstorm-ctrl]

And I figured it out through trial and error:

def validate(self, instance):
                if "CheckMK Monitored".upper() in [tag.name.upper() for tag in instance._m2m_values['tags']] and instance.primary_ip is None:
                        self.fail("CheckMK tag requires a primary IP on the device!", field='tags')

Not sure if it's the 100% correct way, but it 100% works

[Azmodeszer]

I used your solution as a template for another tag-based validation rule of my own (since I could not get my desired event rule to work):

    def validate(self, instance, request):
        if ("webmin-autoupdates".upper() in [tag.slug.upper() for tag in instance._m2m_values['tags']] or "webmin-autosecupdates".upper() in [tag.slug.upper() for tag in instance._m2m_values['tags']]) and not "webmin".upper() in [tag.slug.upper() for tag in instance._m2m_values['tags']]:
            self.fail("Can't add specific Webmin tag without basic Webmin tag!", field='tags')

And this works great when I'm editing a single object, but breaks bulk edits:

<class 'KeyError'>

'tags'

Python version: 3.11.2
NetBox version: 4.0.9