Alter __str__ of model in custom script

[lanbugs]

Hi @ALL,

I try to build a custom script for creating VMs in one single step.

I have 3 fields at the moment:

• VM Name
• Site (Dropdown with sites)
• Prefix (depends on selected site)

I want to alter the str Meta field of the ipam.prefix model that not only the prefix is shown in the dropdown, I want to print prefix + description.

    class Meta:
        name = "Deploy new VM"
        description = "Provision a new VM"

    vm_name = StringVar(description="Name of the new site")
    site = ObjectVar(description = "Site to be deployed", model=Site)
    prefix = ObjectVar(description = "Prefix", model=Prefix, query_params= {'site_id': '$site'})

    def run(self, data, commit):
        pass

My idea was to inherit the Prefix model and to overwrite the str function in the Meta class but I struggle here:

class PrefixC(Prefix):
    class Meta(Prefix.Meta):
        def __str__(self):
            return "{} - {}".format(str(self.prefix), str(self.description))

class DeployVM(Script):

    class Meta:
        name = "Deploy new VM"
        description = "Provision a new VM"

    vm_name = StringVar(description="Name of the new site")
    site = ObjectVar(description = "Site to be deployed", model=Site)
    prefix = ObjectVar(description = "Prefix", model=PrefixC, query_params= {'site_id': '$site'})

    def run(self, data, commit):
        pass

When I did this i got an error from django:

Model class deploy_vm.PrefixC doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS.

Python version: 3.8.10
NetBox version: 3.0.10

Has someone an idea how i can handle this in a smooth way?

For any help i would be appreciate,

Regards Max

[PieterL75]

Cool Idea.. I had this #6586 idea posted, which kind of handles the same.
Overriding the class is maybe a more flexible way to do so.. if it is possible

[lanbugs]

Nice that I am not the only one :-)

[jeremystretch]

You should never need to override the __str__() method on a class. Just reference whatever particular attributes you want to display instead of relying on the object's default string representation.

[lanbugs]

Do you have an example, i don`t know what you mean.

[PieterL75]

@jeremystretch do you have an example on how to accomplish this ?
Goal is to reference the Prefix, but have the dropdown display more information than the default str returns

[candlerb]

Duplicate of: #6018, #6586 and with useful info here.

In short: if what you want to display is available as an attribute on the model, then you can set display_field='attrname' in the ObjectVar. (EDIT: that option was removed in Netbox 3.0) As far as I can tell you are SOL, unless you are prepared to pre-generate the complete list as a ChoiceVar.