Closes #20241: Record A & B terminations on cable changelog record

netbox/dcim/models/cables.py

@@ -18,6 +18,7 @@ from utilities.conversion import to_meters
 from utilities.exceptions import AbortRequest
 from utilities.fields import ColorField, GenericArrayForeignKey
 from utilities.querysets import RestrictedQuerySet
+from utilities.serialization import serialize_object
 from wireless.models import WirelessLink
 from .device_components import FrontPort, RearPort, PathEndpoint
 
@@ -119,6 +120,9 @@ class Cable(PrimaryModel):
         pk = self.pk or self._pk
         return self.label or f'#{pk}'
 
+    def get_status_color(self):
+        return LinkStatusChoices.colors.get(self.status)
+
     @property
     def a_terminations(self):
         if hasattr(self, '_a_terminations'):
@@ -208,7 +212,7 @@ class Cable(PrimaryModel):
             for termination in self.b_terminations:
                 CableTermination(cable=self, cable_end='B', termination=termination).clean()
 
-    def save(self, *args, **kwargs):
+    def save(self, *args, force_insert=False, force_update=False, using=None, update_fields=None):
         _created = self.pk is None
 
         # Store the given length (if any) in meters for use in database ordering
@@ -221,17 +225,55 @@ class Cable(PrimaryModel):
         if self.length is None:
             self.length_unit = None
 
-        super().save(*args, **kwargs)
-
-        # Update the private pk used in __str__ in case this is a new object (i.e. just got its pk)
+        # If this is a new Cable, save it before attempting to create its CableTerminations
+        if self._state.adding:
+            super().save(*args, force_insert=True, using=using, update_fields=update_fields)
+            # Update the private PK used in __str__()
             self._pk = self.pk
 
-        # Retrieve existing A/B terminations for the Cable
-        a_terminations = {ct.termination: ct for ct in self.terminations.filter(cable_end='A')}
-        b_terminations = {ct.termination: ct for ct in self.terminations.filter(cable_end='B')}
-
-        # Delete stale CableTerminations
         if self._terminations_modified:
+            self.update_terminations()
+
+        super().save(*args, force_update=True, using=using, update_fields=update_fields)
+
+        try:
+            trace_paths.send(Cable, instance=self, created=_created)
+        except UnsupportedCablePath as e:
+            raise AbortRequest(e)
+
+    def serialize_object(self, exclude=None):
+        data = serialize_object(self, exclude=exclude or [])
+
+        # Add A & B terminations to the serialized data
+        a_terminations, b_terminations = self.get_terminations()
+        data['a_terminations'] = sorted([ct.pk for ct in a_terminations.values()])
+        data['b_terminations'] = sorted([ct.pk for ct in b_terminations.values()])
+
+        return data
+
+    def get_terminations(self):
+        """
+        Return two dictionaries mapping A & B side terminating objects to their corresponding CableTerminations
+        for this Cable.
+        """
+        a_terminations = {}
+        b_terminations = {}
+
+        for ct in CableTermination.objects.filter(cable=self).prefetch_related('termination'):
+            if ct.cable_end == CableEndChoices.SIDE_A:
+                a_terminations[ct.termination] = ct
+            else:
+                b_terminations[ct.termination] = ct
+
+        return a_terminations, b_terminations
+
+    def update_terminations(self):
+        """
+        Create/delete CableTerminations for this Cable to reflect its current state.
+        """
+        a_terminations, b_terminations = self.get_terminations()
+
+        # Delete any stale CableTerminations
         for termination, ct in a_terminations.items():
             if termination.pk and termination not in self.a_terminations:
                 ct.delete()
@@ -239,21 +281,13 @@ class Cable(PrimaryModel):
             if termination.pk and termination not in self.b_terminations:
                 ct.delete()
 
-        # Save new CableTerminations (if any)
-        if self._terminations_modified:
+        # Save any new CableTerminations
         for termination in self.a_terminations:
             if not termination.pk or termination not in a_terminations:
                 CableTermination(cable=self, cable_end='A', termination=termination).save()
         for termination in self.b_terminations:
             if not termination.pk or termination not in b_terminations:
                 CableTermination(cable=self, cable_end='B', termination=termination).save()
-        try:
-            trace_paths.send(Cable, instance=self, created=_created)
-        except UnsupportedCablePath as e:
-            raise AbortRequest(e)
-
-    def get_status_color(self):
-        return LinkStatusChoices.colors.get(self.status)
 
 
 class CableTermination(ChangeLoggedModel):