"""
To understand why this file is here, please read:
http://cookiecutter-django.readthedocs.io/en/latest/faq.html#why-is-there-a-django-contrib-sites-directory-in-cookiecutter-django
"""
from django.conf import settings
from django.db import migrations
def _update_or_create_site_with_sequence(site_model, connection, domain, name):
"""Update or create the site with default ID and keep the DB sequence in sync."""
site, created = site_model.objects.update_or_create(
id=settings.SITE_ID,
defaults={
"domain": domain,
"name": name,
},
)
if created:
# We provided the ID explicitly when creating the Site entry, therefore the DB
# sequence to auto-generate them wasn't used and is now out of sync. If we
# don't do anything, we'll get a unique constraint violation the next time a
# site is created.
# To avoid this, we need to manually update DB sequence and make sure it's
# greater than the maximum value.
max_id = site_model.objects.order_by("-id").first().id
with connection.cursor() as cursor:
cursor.execute("SELECT last_value from django_site_id_seq")
(current_id,) = cursor.fetchone()
if current_id <= max_id:
cursor.execute(
"alter sequence django_site_id_seq restart with %s",
[max_id + 1],
)
def update_site_forward(apps, schema_editor):
"""Set site domain and name."""
Site = apps.get_model("sites", "Site")
_update_or_create_site_with_sequence(
Site,
schema_editor.connection,
"resources.joannalemon.com",
"pyblackbird-cc",
)
def update_site_backward(apps, schema_editor):
"""Revert site domain and name to default."""
Site = apps.get_model("sites", "Site")
_update_or_create_site_with_sequence(
Site,
schema_editor.connection,
"example.com",
"example.com",
)
class Migration(migrations.Migration):
dependencies = [("sites", "0002_alter_domain_unique")]
operations = [migrations.RunPython(update_site_forward, update_site_backward)]
