Create proper change log data when updating objects in custom scripts with NetBox 2.11

[netsandbox]

Hi,

in NetBox 2.10.10 the following worked in a custom script and created proper change log records:

ip_address = IPAddress.objects.get(address="192.168.178.10/24")
ip_address.dns_name = "example.com"
ip_address.save()

In NetBox 2.11.4 the above creates a change log record without Pre-Change Data and Difference.
I always have to create a snapshot after getting the object to have proper change log records:

ip_address = IPAddress.objects.get(address="192.168.178.10/24")
ip_address.snapshot()
ip_address.dns_name = "example.com"
ip_address.save()

Is this the correct way?

9c967ee created a get_object_with_snapshot method on ModelViewSet.
Maybe it makes sense to add such method also to ChangeLoggingMixinso this would work:

ip_address = IPAddress.objects.get_object_with_snapshot(address="192.168.178.10/24")
ip_address.dns_name = "example.com"
ip_address.save()

And this should be also documented at https://netbox.readthedocs.io/en/stable/additional-features/custom-scripts/.

In some custom scripts I use the update_or_create method (e.g. VirtualMachine.objects.update_or_create).
This method also never takes a snapshot so if I update a object with this method the change log records also never have Pre-Change Data and Difference.
Do I now have to rewrite my custom scripts to separate object create and object update, so that I can create a snapshot before updating an object to have proper change log records?

[jeremystretch]

Snapshots aren't taken automatically because doing so effectively saves a copy of the object on itself. This is obviously wasteful if scenarios where there's no intent to modify and save the object.

Is this the correct way?

Yes, calling snapshot() on the instance will capture the pre-change data.

Maybe it makes sense to add such method also to ChangeLoggingMixin

It's probably worth discussing further as a feature request.

Do I now have to rewrite my custom scripts to separate object create and object update

Yes, because it's not possible to capture the pre-change state of an object when writing to the database directly.