Missing Add Button in Plugin - any ideas why?

[geckigek]

Hi there,

I am trying to learn the development of netbox plugins. I am currently trying to adapt the tutorial on to my own plugin. But I am stuck on a problem at step 5: views. At the end of step 5 you should see a add button on the top right to add new objects. But in my case there is no add button. Is there maybe a chance that someone could have a look at my code and maybe tell me what my error is?

Here is my code:

init.py.:

from extras.plugins import PluginConfig


class VIPConfig(PluginConfig):
    name = "vip_plugin"
    verbose_name = "VIP"
    description = "Manage data structure of VideoIPath"
    version = "0.1"
    base_url = "vip"


config = VIPConfig

setup.py:

from setuptools import find_packages, setup

setup(
    name="vip-plugin",
    version="0.1",
    description="Manage data structure of VideoIPath",
    install_requires=[],
    packages=find_packages(),
    include_package_data=True,
    package_data={"vip_plugin": ["templates/vip_plugin/*.html"]},
    zip_safe=False,
)

models.py:

from django.db import models
from django.urls import reverse
from netbox.models import NetBoxModel


class VideoIPathDevicetype(NetBoxModel):

    name = models.CharField(max_length=100)

    devicetype = models.ForeignKey(
        to="dcim.DeviceType", on_delete=models.CASCADE, blank=False
    )
    extradata = models.JSONField(blank=True, null=True)

    comments = models.TextField(blank=True)

    class Meta:
        ordering = ("name",)

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse("plugins:vip_plugin:vipdevtype", args=[self.pk])

tables.py:

import django_tables2 as tables

from netbox.tables import NetBoxTable, ChoiceFieldColumn
from .models import VideoIPathDevicetype


class VideoIPathDevicetypeTable(NetBoxTable):

    name = tables.Column(linkify=True)

    class Meta(NetBoxTable.Meta):
        model = VideoIPathDevicetype
        fields = ("pk", "id", "name", "devicetype", "comments")
        default_columns = ("name", "devicetype")

forms.py:

from netbox.forms import NetBoxModelForm
from .models import VideoIPathDevicetype
from utilities.forms.fields import CommentField, DynamicModelChoiceField
from dcim.models import DeviceType


class VideoIPathDevicetypeForm(NetBoxModelForm):

    comments = CommentField()

    devicetype = DynamicModelChoiceField(queryset=VideoIPathDevicetype.objects.all())

    class Meta:
        model = VideoIPathDevicetype
        fields = ("name", "devicetype", "comments", "tags")

views.py:

from django.urls import reverse_lazy
from netbox.views import generic
from . import forms, models, tables


class VideoIPathDevicetypeView(generic.ObjectView):
    queryset = models.VideoIPathDevicetype.objects.all()


class VideoIPathDevicetypeListView(generic.ObjectListView):
    queryset = models.VideoIPathDevicetype.objects.all()
    table = tables.VideoIPathDevicetypeTable


class VideoIPathDevicetypeEditView(generic.ObjectEditView):
    queryset = models.VideoIPathDevicetype.objects.all()
    form = forms.VideoIPathDevicetypeForm


class VideoIPathDevicetypeDeleteView(generic.ObjectDeleteView):
    queryset = models.VideoIPathDevicetype.objects.all()

urls.py:

from django.urls import path
from . import models, views

from netbox.views.generic import ObjectChangeLogView

urlpatterns = (
    path("vipdevtype/", views.VideoIPathDevicetypeListView.as_view(), name="vip_list"),
    path(
        "vipdevtype/add/", views.VideoIPathDevicetypeEditView.as_view(), name="vip_add"
    ),
    path("vipdevtype/<int:pk>/", views.VideoIPathDevicetypeView.as_view(), name="vip"),
    path(
        "vipdevtype/<int:pk>/edit/",
        views.VideoIPathDevicetypeEditView.as_view(),
        name="vip_edit",
    ),
    path(
        "vipdevtype/<int:pk>/delete/",
        views.VideoIPathDevicetypeDeleteView.as_view(),
        name="vip_delete",
    ),
    path(
        "vipdevtype/<int:pk>/changelog/",
        ObjectChangeLogView.as_view(),
        name="vip_changelog",
        kwargs={"model": models.VideoIPathDevicetype},
    ),
)

[geckigek]

[mvrp21]

A bit late, but if anyone ends up with this problem: The issue arises because of the expected name for the urls.

Basically, NetBox can't find the actual vip_edit view. And, assuming you didn't really want to make one, NetBox simply doesn't show the add button which is essentially a link to it.

Detecting the error

One of the ways you can detect this error is by proceeding with the tutorial anyways into the API part and creating a model. You can also do this using the manage.py nbshell command, without the API part:

vip = VideoIPathDevicetype(name='whatever', devicetype=DeviceType.objects.all()[0])
vip.save()

Then, when you go back to the https://<your-instance>/plugins/vip/vipdevtype/ URL you'll get the following Exception:

NoReverseMatch at /plugins/vip/vipdevtype/

Reverse for 'vipdevtype' not found. 'vipdevtype' is not a valid view function or pattern name.

Looking a bit into it, it seems Django looks for a URL with name vipdevtype, however you named your URL vip. Changing the reverse() method for your model like this:

def get_absolute_url(self):
    return reverse("plugins:vip_plugin:vip", args=[self.pk])

Fixes that, but results in another error:

Reverse for 'videoipathdevicetype_edit' not found. 'videoipathdevicetype_edit' is not a valid view function or pattern name.

Let's get more in-depth here

Looking at the traceback, we eventually discover that the reverse being called is the function get_viewname() in the netbox/tables/columns.py file. It even seems to be the same function today.

What is the expecteed viewname for a NetBox plugin? plugins:{app_label}:{model_name}. Key here is the model_name part.

If you look closely you'll see that in the tutorial all url names are actually the model name in lowercase. Which is the only real difference between this code and the tutorial's code.

The plugin tutorial does say:

"However, it is recommended to retain the naming scheme shown, as several NetBox features rely on it."

Which is honestly a bit vague.

Wait a second

Why did the first url work? (After modifying the get_absolute_url() method)

Again, looking at the traceback: The actual model's method is called (return context.get_absolute_url()). While in the "action" view's case it calls url = reverse(get_viewname(model, action), kwargs={'pk': record.pk}) which assumes your url names to be the model's name.

In my opinion this is non-trivial behavior, but it works if you figure it out.

Should I maybe make a PR better specifying what the "naming scheme" even is for the urls, and which "several NetBox features" rely on it? Probably.

TL;DR

Just set the URL names to be the model name in lowercase. Even if it can be different somehow, why bother?

Update your model's get_absolute_url to:

def get_absolute_url(self):
    return reverse("plugins:vip_plugin:videoipathdevicetype", args=[self.pk])

And urls to:

urlpatterns = (
    path("vipdevtype/", views.VideoIPathDevicetypeListView.as_view(), name="videoipathdevicetype_list"),
    path(
        "vipdevtype/add/", views.VideoIPathDevicetypeEditView.as_view(), name="videoipathdevicetype_add"
    ),
    path("vipdevtype/<int:pk>/", views.VideoIPathDevicetypeView.as_view(), name="videoipathdevicetype"),
    path(
        "vipdevtype/<int:pk>/edit/",
        views.VideoIPathDevicetypeEditView.as_view(),
        name="videoipathdevicetype_edit",
    ),
    path(
        "vipdevtype/<int:pk>/delete/",
        views.VideoIPathDevicetypeDeleteView.as_view(),
        name="videoipathdevicetype_delete",
    ),
    path(
        "vipdevtype/<int:pk>/changelog/",
        ObjectChangeLogView.as_view(),
        name="videoipathdevicetype_changelog",
        kwargs={"model": models.VideoIPathDevicetype},
    ),
)

(Better yet might be to use the actual model name as a variable and not even type it, but this works)

And voilà: