model_fields.py

import uuid

from django.db import models


class UUIDField(
    models.UUIDField
):
    def __init__(self, *args, **kwargs):
        self.version = kwargs.pop('version', 1)
        self.auto = kwargs.pop('auto', True)

        if self.auto or kwargs.get('default'):
            kwargs['blank'] = True

        kwargs.setdefault('editable', False)

        super().__init__(*args, **kwargs)

    def generate_uuid(self):
        if self.version == 4:
            return uuid.uuid4()
        elif self.version == 1:
            return uuid.uuid1()
        else:
            raise ImproperlyConfigured

    def set_default(self, model_instance):
        value = self.generate_uuid()
        setattr(model_instance, self.attname, value)

        return value

    def pre_save(self, model_instance, add):
        value = getattr(model_instance, self.attname)

        if self.auto and add and value is None:
            value = self.set_default(model_instance)
        else:
            if self.auto and not value:
                value = self.set_default(model_instance)

        return value