Add stdout progress logging to cable migration

netbox/dcim/migrations/0075_cable_devices.py

@@ -5,21 +5,32 @@ import django.db.models.deletion
 def cache_cable_devices(apps, schema_editor):
     Cable = apps.get_model('dcim', 'Cable')
 
+    print("\nUpdatng cable device terminations...")
+    cable_count = Cable.objects.count()
+
     # Cache A/B termination devices on all existing Cables. Note that the custom save() method on Cable is not
     # available during a migration, so we replicate its logic here.
-    for cable in Cable.objects.all():
+    for i, cable in enumerate(Cable.objects.all(), start=1):
+
+        if not i % 1000:
+            print("[{}/{}]".format(i, cable_count))
 
         termination_a_model = apps.get_model(cable.termination_a_type.app_label, cable.termination_a_type.model)
+        termination_a_device = None
         if hasattr(termination_a_model, 'device'):
             termination_a = termination_a_model.objects.get(pk=cable.termination_a_id)
-            cable._termination_a_device = termination_a.device
+            termination_a_device = termination_a.device
 
         termination_b_model = apps.get_model(cable.termination_b_type.app_label, cable.termination_b_type.model)
+        termination_b_device = None
         if hasattr(termination_b_model, 'device'):
             termination_b = termination_b_model.objects.get(pk=cable.termination_b_id)
-            cable._termination_b_device = termination_b.device
+            termination_b_device = termination_b.device
 
-        cable.save()
+        Cable.objects.filter(pk=cable.pk).update(
+            _termination_a_device=termination_a_device,
+            _termination_b_device=termination_b_device
+        )
 
 
 class Migration(migrations.Migration):