Create 0032_metadata_transfer.py

tubesync/sync/migrations/0032_metadata_transfer.py

@@ -0,0 +1,36 @@
+# Hand-crafted data migration
+
+from django.db import migrations
+from common.utils import django_queryset_generator as qs_gen
+
+
+def use_tables(apps, schema_editor):
+    Media = apps.get_model('sync', 'Media')
+    qs = Media.objects.filter(metadata__isnull=False)
+    for media in qs_gen(qs):
+        media.save_to_metadata('migrated', True)
+
+def restore_metadata_column(apps, schema_editor):
+    Media = apps.get_model('sync', 'Media')
+    qs = Media.objects.filter(metadata__isnull=False)
+    for media in qs_gen(qs):
+        metadata = media.loaded_metadata
+        del metadata['migrated']
+        del metadata['_using_table']
+        media.metadata = media.metadata_dumps(arg_dict=metadata)
+        media.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('sync', '0031_squashed_metadata_metadataformat'),
+    ]
+
+    operations = [
+        migrations.RunPython(
+            code=use_tables,
+            reverse_code=restore_metadata_column,
+        ),
+    ]
+