Closes #13381: Enable plugins to register custom data backends (#14095)

* Initial work on #13381

* Fix backend type display in table column

* Fix data source type choices during bulk edit

* Misc cleanup

* Move backend utils from core app to netbox

* Move backend type validation from serializer to model

netbox/core/forms/bulk_edit.py

@@ -1,10 +1,9 @@
 from django import forms
 from django.utils.translation import gettext_lazy as _
 
-from core.choices import DataSourceTypeChoices
 from core.models import *
 from netbox.forms import NetBoxModelBulkEditForm
-from utilities.forms import add_blank_choice
+from netbox.utils import get_data_backend_choices
 from utilities.forms.fields import CommentField
 from utilities.forms.widgets import BulkEditNullBooleanSelect
 
@@ -16,9 +15,8 @@ __all__ = (
 class DataSourceBulkEditForm(NetBoxModelBulkEditForm):
     type = forms.ChoiceField(
         label=_('Type'),
-        choices=add_blank_choice(DataSourceTypeChoices),
-        required=False,
-        initial=''
+        choices=get_data_backend_choices,
+        required=False
     )
     enabled = forms.NullBooleanField(
         required=False,

netbox/core/forms/filtersets.py

@@ -8,6 +8,7 @@ from core.models import *
 from extras.forms.mixins import SavedFiltersMixin
 from extras.utils import FeatureQuery
 from netbox.forms import NetBoxModelFilterSetForm
+from netbox.utils import get_data_backend_choices
 from utilities.forms import BOOLEAN_WITH_BLANK_CHOICES, FilterForm
 from utilities.forms.fields import ContentTypeChoiceField, DynamicModelMultipleChoiceField
 from utilities.forms.widgets import APISelectMultiple, DateTimePicker
@@ -27,7 +28,7 @@ class DataSourceFilterForm(NetBoxModelFilterSetForm):
     )
     type = forms.MultipleChoiceField(
         label=_('Type'),
-        choices=DataSourceTypeChoices,
+        choices=get_data_backend_choices,
         required=False
     )
     status = forms.MultipleChoiceField(

netbox/core/forms/model_forms.py

@@ -7,6 +7,7 @@ from core.forms.mixins import SyncedDataMixin
 from core.models import *
 from netbox.forms import NetBoxModelForm
 from netbox.registry import registry
+from netbox.utils import get_data_backend_choices
 from utilities.forms import get_field_value
 from utilities.forms.fields import CommentField
 from utilities.forms.widgets import HTMXSelect
@@ -18,6 +19,10 @@ __all__ = (
 
 
 class DataSourceForm(NetBoxModelForm):
+    type = forms.ChoiceField(
+        choices=get_data_backend_choices,
+        widget=HTMXSelect()
+    )
     comments = CommentField()
 
     class Meta:
@@ -26,7 +31,6 @@ class DataSourceForm(NetBoxModelForm):
             'name', 'type', 'source_url', 'enabled', 'description', 'comments', 'ignore_rules', 'tags',
         ]
         widgets = {
-            'type': HTMXSelect(),
             'ignore_rules': forms.Textarea(
                 attrs={
                     'rows': 5,
@@ -56,12 +60,13 @@ class DataSourceForm(NetBoxModelForm):
 
         # Add backend-specific form fields
         self.backend_fields = []
-        for name, form_field in backend.parameters.items():
-            field_name = f'backend_{name}'
-            self.backend_fields.append(field_name)
-            self.fields[field_name] = copy.copy(form_field)
-            if self.instance and self.instance.parameters:
-                self.fields[field_name].initial = self.instance.parameters.get(name)
+        if backend:
+            for name, form_field in backend.parameters.items():
+                field_name = f'backend_{name}'
+                self.backend_fields.append(field_name)
+                self.fields[field_name] = copy.copy(form_field)
+                if self.instance and self.instance.parameters:
+                    self.fields[field_name].initial = self.instance.parameters.get(name)
 
     def save(self, *args, **kwargs):