Restore using import_string for jobs

Using the 'import_string()' utility from Django allows the job script
class to be simplified, as module imports no longer need to avoid loops.
This should make it easier to queue and maintain jobs.

netbox/core/jobs.py

@@ -1,6 +1,10 @@
 import logging
 
+from netbox.search.backends import search_backend
 from utilities.jobs import BackgroundJob
+from .choices import DataSourceStatusChoices
+from .exceptions import SyncError
+from .models import DataSource
 
 logger = logging.getLogger(__name__)
 
@@ -12,11 +16,6 @@ class SyncDataSourceJob(BackgroundJob):
 
     @classmethod
     def run(cls, job, *args, **kwargs):
-        from netbox.search.backends import search_backend
-        from .choices import DataSourceStatusChoices
-        from .exceptions import SyncError
-        from .models import DataSource
-
         datasource = DataSource.objects.get(pk=job.object_id)
 
         try:

netbox/core/models/data.py

@@ -12,6 +12,7 @@
 from django.db import models
 from django.urls import reverse
 from django.utils import timezone
+from django.utils.module_loading import import_string
 from django.utils.translation import gettext as _
 
 from netbox.constants import CENSOR_TOKEN, CENSOR_TOKEN_CHANGED
@@ -161,7 +162,7 @@ def enqueue_sync_job(self, request):
         DataSource.objects.filter(pk=self.pk).update(status=self.status)
 
         # Enqueue a sync job
-        from ..jobs import SyncDataSourceJob
+        SyncDataSourceJob = import_string('core.jobs.SyncDataSourceJob')
         return SyncDataSourceJob.enqueue(
             instance=self,
             user=request.user