Add support for auto_weight counter on choices when loading selection field from custom_fields.yml

This also fixes a bug when using the same value for 2 different custom fields breaks becuase it tries to
create a new CustomFieldChoice object instead of reusing the one that already exists.

initializers/custom_fields.yml

@@ -40,6 +40,21 @@
 #     weight: 50
 #   - value: Fourth Item
 #     weight: 40
+# selection_field_auto_weight:
+#    type: selection
+#    label: Choose between items
+#    required: false
+#    filterable: true
+#    weight: 30
+#    on_objects:
+#     - dcim.models.Device
+#    choices:
+#     - value: A
+#     - value: B
+#     - value: C
+#     - value: "D like deprecated"
+#       weight: 999
+#     - value: E
 # boolean_field:
 #   type: boolean
 #   label: Yes Or No?

startup_scripts/20_custom_fields.py

@@ -56,13 +56,14 @@ with open('/opt/netbox/initializers/custom_fields.yml', 'r') as stream:
 
         custom_field.save()
 
-        for choice_details in cf_details.get('choices', []):
-          choice = CustomFieldChoice.objects.create(
+        for idx, choice_details in enumerate(cf_details.get('choices', [])):
+          choice, created = CustomFieldChoice.objects.get_or_create(
             field=custom_field,
-            value=choice_details['value'])
-
-          if choice_details.get('weight', 0):
-            choice.weight = choice_details['weight']
-            choice.save()
+            value=choice_details['value'],
+          )
+          # Add weight after initial creation to fix a bug if you use the same 'value'
+          # for multiple custom fields.
+          choice.weight = choice_details.get('weight', idx * 10)
+          choice.save()
 
         print("🔧 Created custom field", cf_name)