Fixes #3440: Total cable trace length

netbox/dcim/models.py

@@ -2950,6 +2950,8 @@ class Cable(ChangeLoggedModel):
         # Store the given length (if any) in meters for use in database ordering
         if self.length and self.length_unit:
             self._abs_length = to_meters(self.length, self.length_unit)
+        else:
+            self._abs_length = None
 
         # Store the parent Device for the A and B terminations (if applicable) to enable filtering
         if hasattr(self.termination_a, 'device'):

netbox/dcim/views.py

@@ -1754,10 +1754,13 @@ class CableTraceView(PermissionRequiredMixin, View):
     def get(self, request, model, pk):
 
         obj = get_object_or_404(model, pk=pk)
+        trace = obj.trace(follow_circuits=True)
+        total_length = sum([entry[1]._abs_length for entry in trace if entry[1] and entry[1]._abs_length])
 
         return render(request, 'dcim/cable_trace.html', {
             'obj': obj,
-            'trace': obj.trace(follow_circuits=True),
+            'trace': trace,
+            'total_length': total_length,
         })