update method to remove city duplicates

apps/gallery/migrations/0008_merge_20191212_0752.py

@@ -0,0 +1,14 @@
+# Generated by Django 2.2.7 on 2019-12-12 07:52
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('gallery', '0007_auto_20191110_1329'),
+        ('gallery', '0007_auto_20191211_1528'),
+    ]
+
+    operations = [
+    ]

apps/location/models.py

@@ -154,6 +154,29 @@ class City(GalleryModelMixin):
     def __str__(self):
         return self.name
 
+    @property
+    def _related_objects(self) -> list:
+        """Return list of related objects."""
+        related_objects = []
+        for related_object in self._meta.related_objects:
+            related_objects.append(related_object)
+        return related_objects
+
+    @property
+    def _related_instances(self) -> set:
+        """Return list of related instances."""
+        related_instances = []
+        related_names = [related_object.related_name
+                         if related_object.related_name
+                         else f'{related_object.name}_set'
+                         for related_object in self._related_objects]
+        for related_object in related_names:
+            instances = getattr(self, f'{related_object}')
+            if instances.exists():
+                for instance in instances.all():
+                    related_instances.append(instance)
+        return set(related_instances)
+
 
 class CityGallery(IntermediateGalleryModelMixin):
     """Gallery for model City."""

apps/location/transfer_data.py

@@ -489,22 +489,29 @@ def fix_location_models():
     except FileNotFoundError:
         ruby_data = get_ruby_data()
 
+    print('add_correct_location_models')
     add_correct_location_models(ruby_data)
-
+    print('fix_location_address')
     fix_location_address()
+    print('fix_location_collection')
     fix_location_collection()
+    print('fix_award_type')
     fix_award_type()
+    print('fix_role')
     fix_role()
+    print('fix_news')
     fix_news()
+    print('fix_reviews')
     fix_reviews()
+    print('fix_tag_category')
     fix_tag_category()
+    print('fix_chosen_tag')
     fix_chosen_tag()
 
 
 def remove_old_records():
     clean_old_records(City, {"mysql_id__isnull": True})
     clean_old_records(Region, {"mysql_ids__isnull": True})
-    clean_old_records(City, {"mysql_id__isnull": True})
 
 
 def transfer_city_gallery():
@@ -716,7 +723,6 @@ data_types = {
     "remove_old_locations": [
         remove_old_records
     ],
-    
     "fill_city_gallery": [
         transfer_city_gallery
     ],

apps/transfer/utils.py

@@ -23,6 +23,7 @@ def transfer_objects(data_type):
 
 def clean_old_records(model, conditions):
     error_file = open(f"{settings.PROJECT_ROOT}/apps/transfer/clear.error.txt", "w")
+    non_existed_correct_city_ids = []
 
     try:
         old_records = model.objects.filter(**conditions)
@@ -31,7 +32,27 @@ def clean_old_records(model, conditions):
         return
 
     for old_record in old_records:
-        try:
-            old_record.delete()
-        except Exception as e:
-            error_file.write(f"Cannot delete object {old_record}: {e}")
+        correct_record_qs = model.objects.exclude(id=old_record.id) \
+                                         .exclude(**conditions) \
+                                         .filter(name=old_record.name)
+        if correct_record_qs.exists():
+            correct_record = correct_record_qs.first()
+            for rel_instance in old_record._related_instances:
+                field_name = [related_field.name
+                              for related_field in rel_instance._meta.fields
+                              if related_field.related_model == correct_record._meta.model][0]
+                # rebinding correct dependency instances
+                if getattr(rel_instance, field_name) != correct_record:
+                    setattr(rel_instance, field_name, correct_record)
+                    rel_instance.save()
+        else:
+            non_existed_correct_city_ids.append(old_record.id)
+
+    if non_existed_correct_city_ids:
+        print(f"Non existed correct city ids: {non_existed_correct_city_ids}")
+        return
+
+    # delete old records
+    counter = old_records.count()
+    old_records.delete()
+    print(f'Deleted {counter} objects.')