Refactor app and model

.gitignore

@@ -7,5 +7,6 @@ dist/
 test.db
 .tox
 .coverage
+coverage.xml
 docs/_build
 .idea

constance/apps.py

@@ -1,45 +1,9 @@
-from django.db.models import signals
-from django.apps import apps, AppConfig
+from django.apps import AppConfig
 from django.utils.translation import gettext_lazy as _
 
 
 class ConstanceConfig(AppConfig):
     name = 'constance'
     verbose_name = _('Constance')
+    default_auto_field = 'django.db.models.AutoField'
 
-    def ready(self):
-        super().ready()
-        signals.post_migrate.connect(self.create_perm,
-                                     dispatch_uid='constance.create_perm')
-
-    def create_perm(self, using=None, *args, **kwargs):
-        """
-        Creates a fake content type and permission
-        to be able to check for permissions
-        """
-        from django.conf import settings
-
-        constance_dbs = getattr(settings, 'CONSTANCE_DBS', None)
-        if constance_dbs is not None and using not in constance_dbs:
-            return
-        if (
-            apps.is_installed('django.contrib.contenttypes') and
-            apps.is_installed('django.contrib.auth')
-        ):
-            ContentType = apps.get_model('contenttypes.ContentType')
-            Permission = apps.get_model('auth.Permission')
-            content_type, created = ContentType.objects.using(using).get_or_create(
-                app_label='constance',
-                model='config',
-            )
-
-            Permission.objects.using(using).get_or_create(
-                content_type=content_type,
-                codename='change_config',
-                defaults={'name': 'Can change config'},
-            )
-            Permission.objects.using(using).get_or_create(
-                content_type=content_type,
-                codename='view_config',
-                defaults={'name': 'Can view config'},
-            )

constance/backends/database.py

@@ -9,13 +9,13 @@ from django.db import (
 )
 from django.db.models.signals import post_save
 
-from .. import Backend
-from ... import settings, signals, config
+from constance.backends import Backend
+from constance import settings, signals, config
 
 
 class DatabaseBackend(Backend):
     def __init__(self):
-        from .models import Constance
+        from constance.models import Constance
         self._model = Constance
         self._prefix = settings.DATABASE_PREFIX
         self._autofill_timeout = settings.DATABASE_CACHE_AUTOFILL_TIMEOUT

constance/backends/database/apps.py

@@ -1,6 +0,0 @@
-from django.apps import AppConfig
-
-
-class ConstanceConfig(AppConfig):
-    name = 'constance.backends.database'
-    default_auto_field = 'django.db.models.AutoField'

constance/backends/database/migrations/0002_auto_20190129_2304.py

@@ -1,19 +0,0 @@
-# Generated by Django 2.1.5 on 2019-01-30 04:04
-
-from django.db import migrations
-import picklefield.fields
-
-
-class Migration(migrations.Migration):
-
-    dependencies = [
-        ('database', '0001_initial'),
-    ]
-
-    operations = [
-        migrations.AlterField(
-            model_name='constance',
-            name='value',
-            field=picklefield.fields.PickledObjectField(blank=True, editable=False, null=True),
-        ),
-    ]

constance/management/commands/constance.py

@@ -1,4 +1,3 @@
-from django.apps import apps
 from django.conf import settings
 from django.core.exceptions import ValidationError
 from django.core.management import BaseCommand, CommandError
@@ -8,6 +7,7 @@ from django import VERSION
 
 from ... import config
 from ...admin import ConstanceForm, get_values
+from ...models import Constance
 
 
 def _set_constance_value(key, value):
@@ -49,7 +49,6 @@ class Command(BaseCommand):
             help='delete all Constance keys and their values if they are not in settings.CONSTANCE_CONFIG (stale keys)',
         )
 
-
     def _subparsers_add_parser(self, subparsers, name, **kwargs):
         # API in Django >= 2.1 changed and removed cmd parameter from add_parser
         if VERSION >= (2, 1) and 'cmd' in kwargs:
@@ -82,23 +81,16 @@ class Command(BaseCommand):
                 self.stdout.write("{}\t{}".format(k, v), ending="\n")
 
         elif command == 'remove_stale_keys':
-            try:
-                Constance = apps.get_model('database.Constance')
-            except LookupError:
-                Constance = None
 
-            if Constance:
-                actual_keys = settings.CONSTANCE_CONFIG.keys()
+            actual_keys = settings.CONSTANCE_CONFIG.keys()
 
-                stale_records = Constance.objects.exclude(key__in=actual_keys)
-                if stale_records:
-                    self.stdout.write("The following record will be deleted:", ending="\n")
-                else:
-                    self.stdout.write("There are no stale records in database.", ending="\n")
-
-                for stale_record in stale_records:
-                    self.stdout.write("{}\t{}".format(stale_record.key, stale_record.value), ending="\n")
-
-                stale_records.delete()
+            stale_records = Constance.objects.exclude(key__in=actual_keys)
+            if stale_records:
+                self.stdout.write("The following record will be deleted:", ending="\n")
             else:
-                self.stdout.write("Database backend is not set. Nothing is deleted", ending="\n")
+                self.stdout.write("There are no stale records in database.", ending="\n")
+
+            for stale_record in stale_records:
+                self.stdout.write("{}\t{}".format(stale_record.key, stale_record.value), ending="\n")
+
+            stale_records.delete()

constance/migrations/0001_initial.py

@@ -1,24 +1,25 @@
-from django.db import models, migrations
+from django.db import migrations, models
 import picklefield.fields
 
 
 class Migration(migrations.Migration):
+
+    initial = True
+
     dependencies = []
 
     operations = [
         migrations.CreateModel(
             name='Constance',
             fields=[
-                ('id', models.AutoField(verbose_name='ID', primary_key=True,
-                                        auto_created=True, serialize=False)),
-                ('key', models.CharField(unique=True, max_length=255)),
-                ('value', picklefield.fields.PickledObjectField(editable=False)),
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('key', models.CharField(max_length=255, unique=True)),
+                ('value', picklefield.fields.PickledObjectField(blank=True, editable=False, null=True)),
             ],
             options={
                 'verbose_name': 'constance',
                 'verbose_name_plural': 'constances',
-                'db_table': 'constance_config',
+                'permissions': [('change_config', 'Can change config'), ('view_config', 'Can view config')],
             },
-            bases=(models.Model,),
         ),
     ]

constance/migrations/0002_migrate_from_old_table.py

@@ -0,0 +1,33 @@
+from django.core.management.color import no_style
+from django.db import migrations, connection, DatabaseError
+
+
+def _migrate_from_old_table(apps, schema_editor) -> None:
+    """
+    Copies values from old table.
+    On new installations just ignore error that table does not exist.
+    """
+    try:
+        with connection.cursor() as cursor:
+            cursor.execute('INSERT INTO constance_constance ( id, key, value ) SELECT id, key, value FROM constance_config', [])
+            cursor.execute('DROP TABLE constance_config', [])
+
+    except DatabaseError:
+        pass
+
+    Constance = apps.get_model('constance', 'Constance')
+    sequence_sql = connection.ops.sequence_reset_sql(no_style(), [Constance])
+    with connection.cursor() as cursor:
+        for sql in sequence_sql:
+            cursor.execute(sql)
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [('constance', '0001_initial')]
+
+    atomic = False
+
+    operations = [
+        migrations.RunPython(_migrate_from_old_table, reverse_code=lambda x, y: None),
+    ]

constance/models.py

@@ -18,7 +18,10 @@ class Constance(models.Model):
     class Meta:
         verbose_name = _('constance')
         verbose_name_plural = _('constances')
-        db_table = 'constance_config'
+        permissions = [
+            ('change_config', 'Can change config'),
+            ('view_config', 'Can view config'),
+        ]
 
     def __str__(self):
         return self.key

docs/backends.rst

@@ -94,27 +94,17 @@ Defaults to `60` seconds.
 Database
 --------
 
-The database backend is optional and stores the configuration values in a
+Database backend stores configuration values in a
 standard Django model. It requires the package `django-picklefield`_ for
-storing those values. Please install it like so::
-
-  pip install django-constance[database]
+storing those values.
 
 You must set the ``CONSTANCE_BACKEND`` Django setting to::
 
     CONSTANCE_BACKEND = 'constance.backends.database.DatabaseBackend'
 
-Then add the database backend app to your :setting:`INSTALLED_APPS` setting to
-make sure the data model is correctly created::
-
-    INSTALLED_APPS = (
-        # other apps
-        'constance.backends.database',
-    )
-
 Please make sure to apply the database migrations::
 
-    python manage.py migrate database
+    python manage.py migrate
 
 .. note:: If you're upgrading Constance to 1.0 and use Django 1.7 or higher
           please make sure to let the migration system know that you've
@@ -124,10 +114,6 @@ Please make sure to apply the database migrations::
 
               python manage.py migrate database --fake
 
-.. note:: If you have multiple databases you can set what databases
-          will be used with ``CONSTANCE_DBS``
-
-              CONSTANCE_DBS = "default"
 
 Just like the Redis backend you can set an optional prefix that is used during
 database interactions (it defaults to an empty string, ``''``). To use

docs/changes.rst

@@ -1,6 +1,13 @@
 Changelog
 ---------
 
+v3.0.0 (future)
+~~~~~~~~~~~~~~~~~~~
+
+* Refactor database backend
+Backward incompatible changes:
+remove 'constance.backends.database' from INSTALLED_APPS
+
 v2.10.0 (unreleased)
 ~~~~~~~~~~~~~~~~~~
 

example/cheeseshop/settings.py

@@ -44,7 +44,6 @@ INSTALLED_APPS = (
     'cheeseshop.apps.catalog',
     'cheeseshop.apps.storage',
     'constance',
-    'constance.backends.database',
 )
 
 MIDDLEWARE = (
@@ -149,3 +148,5 @@ USE_TZ = True
 # https://docs.djangoproject.com/en/1.8/howto/static-files/
 
 STATIC_URL = '/static/'
+
+DEFAULT_AUTO_FIELD = 'django.db.models.AutoField'

setup.py

@@ -60,8 +60,10 @@ setup(
     include_package_data=True,
     zip_safe=False,
     python_requires='>=3.6',
+    install_requires=[
+        'django-picklefield',
+    ],
     extras_require={
-        'database': ['django-picklefield'],
         'redis': ['redis'],
     },
     entry_points={

tests/test_admin.py

@@ -1,9 +1,8 @@
 from datetime import datetime
 
-import mock
+from unittest import mock
 from django.contrib import admin
 from django.contrib.auth.models import User, Permission
-from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import PermissionDenied
 from django.http import HttpResponseRedirect
 from django.template.defaultfilters import linebreaksbr
@@ -53,10 +52,6 @@ class TestAdmin(TestCase):
         response = self.options.changelist_view(request, {})
         self.assertEqual(response.status_code, 200)
 
-    def test_str(self):
-        ct = ContentType.objects.get(app_label='constance', model='config')
-        self.assertEqual(str(ct), 'config')
-
     def test_linebreaks(self):
         self.client.login(username='admin', password='nimda')
         request = self.rf.get('/admin/constance/config/')

tests/test_app.py

@@ -1,56 +0,0 @@
-from django.apps import apps
-from django.contrib.auth.models import Permission
-from django.contrib.contenttypes.models import ContentType
-from django.db.models import signals
-from django.test import TestCase, override_settings
-
-
-class TestApp(TestCase):
-    databases = ["default", "secondary"]
-
-    def setUp(self):
-        self.app_config = apps.get_app_config('constance')
-
-    def test_post_migrate_signal_creates_content_type_and_permission_in_default_database(self):
-        self.assert_uses_correct_database('default')
-
-    def test_post_migrate_signal_creates_content_type_and_permission_in_secondary_database(self):
-        self.assert_uses_correct_database('secondary')
-
-    def test_uses_default_db_even_without_giving_using_keyword(self):
-        self.call_post_migrate(None)
-
-        self.assert_content_type_and_permission_created('default')
-
-    @override_settings(CONSTANCE_DBS=['default'])
-    def test_only_use_databases_in_constance_dbs(self):
-        Permission.objects.using('default').delete()
-        Permission.objects.using('secondary').delete()
-        self.assert_uses_correct_database('default')
-        with self.assertRaises(AssertionError):
-            self.assert_uses_correct_database('secondary')
-
-    def assert_uses_correct_database(self, database_name):
-        self.call_post_migrate(database_name)
-
-        self.assert_content_type_and_permission_created(database_name)
-
-    def assert_content_type_and_permission_created(self, database_name):
-        content_type_queryset = ContentType.objects.filter(app_label=self.app_config.name) \
-            .using(database_name)
-
-        self.assertTrue(content_type_queryset.exists())
-
-        permission_queryset = Permission.objects.filter(content_type=content_type_queryset.get()) \
-            .using(database_name).exists()
-
-        self.assertTrue(permission_queryset)
-
-    def call_post_migrate(self, database_name):
-        signals.post_migrate.send(
-            sender=self.app_config,
-            app_config=self.app_config,
-            verbosity=None,
-            interactive=None,
-            using=database_name
-        )

tests/test_checks.py

@@ -1,6 +1,6 @@
 import datetime
 from decimal import Decimal
-import mock
+from unittest import mock
 
 from constance.admin import get_values
 from constance.checks import check_fieldsets, get_inconsistent_fieldnames

tests/test_cli.py

@@ -1,7 +1,6 @@
 from datetime import datetime
 from textwrap import dedent
 
-from django.apps import apps
 from django.conf import settings
 from django.core.management import call_command, CommandError
 from django.test import TransactionTestCase
@@ -10,6 +9,7 @@ from django.utils.encoding import smart_str
 from io import StringIO
 
 from constance import config
+from constance.models import Constance
 
 
 class CliTestCase(TransactionTestCase):
@@ -74,11 +74,10 @@ class CliTestCase(TransactionTestCase):
                                  call_command, 'constance', 'set', 'DATETIME_VALUE', '2011-09-24 12:30:25')
 
     def test_delete_stale_records(self):
-        Constance = apps.get_model('database.Constance')
 
         initial_count = Constance.objects.count()
 
         Constance.objects.create(key='STALE_KEY', value=None)
         call_command('constance', 'remove_stale_keys', stdout=self.out)
 
-        self.assertEqual(Constance.objects.count(), initial_count)
+        self.assertEqual(Constance.objects.count(), initial_count, msg=self.out)

tox.ini

@@ -8,7 +8,6 @@ envlist =
 deps =
     redis
     coverage
-    mock
     django-picklefield
     dj22: Django>=2.2,<3.0
     dj30: Django>=3.0,<3.1