Command errors out with ObjectNotFound exception

[glennmatthews]

Environment

• Python version: 3.7
• Nautobot version: 1.0.0b1
• nautobot-netbox-importer version: 1.0.0

Expected Behavior

Import should run to completion successfully.

Observed Behavior

Traceback (most recent call last):
  File "/usr/local/bin/nautobot-server", line 5, in <module>
    main()
  File "/opt/nautobot/nautobot/core/cli.py", line 62, in main
    initializer=_configure_settings,  # Called after defaults
  File "/opt/nautobot/nautobot/core/runner/runner.py", line 268, in run_app
    management.execute_from_command_line([runner_name, command] + command_args)
  File "/usr/local/lib/python3.7/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.7/site-packages/django/core/management/__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.7/site-packages/django/core/management/base.py", line 330, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.7/site-packages/django/core/management/base.py", line 371, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python3.7/site-packages/nautobot_netbox_importer/management/commands/import_netbox_json.py", line 91, in handle
    target.sync_from(source, flags=DiffSyncFlags.SKIP_UNMATCHED_DST)
  File "/usr/local/lib/python3.7/site-packages/nautobot_netbox_importer/diffsync/adapters/abstract.py", line 299, in sync_from
    return super().sync_from(source, diff_class=diff_class, flags=flags)
  File "/usr/local/lib/python3.7/site-packages/diffsync/__init__.py", line 464, in sync_from
    result = syncer.perform_sync()
  File "/usr/local/lib/python3.7/site-packages/diffsync/helpers.py", line 251, in perform_sync
    changed |= self.sync_diff_element(element)
  File "/usr/local/lib/python3.7/site-packages/diffsync/helpers.py", line 283, in sync_diff_element
    changed, modified_model = self.sync_model(model, ids, attrs)
  File "/usr/local/lib/python3.7/site-packages/diffsync/helpers.py", line 329, in sync_model
    model = self.model_class.create(diffsync=self.dst_diffsync, ids=ids, attrs=attrs)
  File "/usr/local/lib/python3.7/site-packages/nautobot_netbox_importer/diffsync/models/abstract.py", line 192, in create
    diffsync_ids, nautobot_ids = cls.clean_ids(diffsync, ids)
  File "/usr/local/lib/python3.7/site-packages/nautobot_netbox_importer/diffsync/models/abstract.py", line 168, in clean_ids
    return cls.clean_ids_or_attrs(diffsync, ids)
  File "/usr/local/lib/python3.7/site-packages/nautobot_netbox_importer/diffsync/models/abstract.py", line 114, in clean_ids_or_attrs
    target_record = diffsync.get(target_class, diffsync_value)
  File "/usr/local/lib/python3.7/site-packages/diffsync/__init__.py", line 567, in get
    raise ObjectNotFound(f"{modelname} {uid} not present in {self.name}")
diffsync.exceptions.ObjectNotFound: interface {'site': {'name': 'some site'}, 'tenant': None, 'name': 'some device'}__mgmt0 not present in          NautobotDiffSync

Steps to Reproduce

Details of the data being imported are unavailable at this time.

[glennmatthews]

Missing error handling in the GenericForeignKey case; error handling for ObjectNotFound is already present in handling ordinary ForeignKey fields (as well as one-to-one, one-to-many, and many-to-many fields). Will add appropriate logic.