[fix] Fix updating SubnetDivisionRule label openwisp#547

Use iterator() instead of all() on queryset, since the number
of database row will be large for SubnetDivisionIndex.

Closes openwisp#547

openwisp_controller/subnet_division/tasks.py

@@ -27,15 +27,16 @@ def update_subnet_division_index(rule_id):
         )
         return
 
-    index_queryset = division_rule.subnetdivisionindex_set.all()
-    for index in index_queryset:
+    for index in division_rule.subnetdivisionindex_set.only('keyword').iterator():
         identifiers = index.keyword.split('_')
-        identifiers[0] = division_rule.label
-        index.keyword = '_'.join(identifiers)
-
-    SubnetDivisionIndex.objects.bulk_update(
-        index_queryset, fields=['keyword'], batch_size=20
-    )
+        if index.ip_id is not None:
+            required_identifiers = 2
+        else:
+            required_identifiers = 1
+        index.keyword = '_'.join(
+            [division_rule.label] + identifiers[-required_identifiers:]
+        )
+        index.save()
 
 
 @shared_task

openwisp_controller/subnet_division/tests/test_models.py

@@ -208,7 +208,7 @@ def test_provisioned_subnets(self):
 
     def test_rule_label_updated(self):
         new_rule_label = 'TSDR'
-        rule = self._get_vpn_subdivision_rule()
+        rule = self._get_vpn_subdivision_rule(label='VPN_OW')
         self.config.templates.add(self.template)
         index_queryset = rule.subnetdivisionindex_set.filter(config_id=self.config.id)
         subnet_queryset = self.subnet_query.filter(
@@ -218,7 +218,7 @@ def test_rule_label_updated(self):
         )
         index_count = index_queryset.count()
         subnet_count = subnet_queryset.count()
-        rule.label = 'TSDR'
+        rule.label = new_rule_label
         rule.save()
         rule.refresh_from_db()
 
@@ -230,6 +230,14 @@ def test_rule_label_updated(self):
         ).count()
         self.assertEqual(index_count, new_index_count)
 
+        # Verify context of config
+        context = self.config.get_subnet_division_context()
+        self.assertIn(f'{rule.label}_prefixlen', context)
+        for subnet_id in range(1, rule.number_of_subnets + 1):
+            self.assertIn(f'{rule.label}_subnet{subnet_id}', context)
+            for ip_id in range(1, rule.number_of_ips + 1):
+                self.assertIn(f'{rule.label}_subnet{subnet_id}_ip{ip_id}', context)
+
         # Assert name and description of Subnet are updated
         new_subnet_count = subnet_queryset.filter(
             name__startswith=new_rule_label, description__contains=new_rule_label,