Default timezone of CrontabSchedule from 'CELERY_TIMEZONE' setting. (celery#346)

* Default timezone of CrontabSchedule model from 'CELERY_TIMEZONE' setting.

* Add test for CrontabSchedule default timezone.

* Lint test for CrontabSchedule default timezone.

* Lint models, skip linting for new migration and fix 'CrontabSchedule.timezone.help_text' double space.

* Minor change in migration

* Lint models with 'pydocstyle'.

* Get CELERY_TIMEZONE setting from current app namespace.

* Regenerate new migration file

Author: mondeja

django_celery_beat/migrations/0013_auto_20200609_0727.py

@@ -0,0 +1,20 @@
+# Generated by Django 3.0.6 on 2020-06-09 07:27
+# flake8: noqa
+from django.db import migrations
+import django_celery_beat.models
+import timezone_field.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('django_celery_beat', '0012_periodictask_expire_seconds'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='crontabschedule',
+            name='timezone',
+            field=timezone_field.fields.TimeZoneField(default=django_celery_beat.models.crontab_schedule_celery_timezone, help_text='Timezone to Run the Cron Schedule on. Default is UTC.', verbose_name='Cron Timezone'),
+        ),
+    ]

django_celery_beat/models.py

@@ -2,7 +2,7 @@
 from datetime import timedelta
 
 import timezone_field
-from celery import schedules
+from celery import schedules, current_app
 from django.conf import settings
 from django.core.exceptions import MultipleObjectsReturned, ValidationError
 from django.core.validators import MaxValueValidator, MinValueValidator
@@ -46,6 +46,21 @@ def cronexp(field):
     return field and str(field).replace(' ', '') or '*'
 
 
+def crontab_schedule_celery_timezone():
+    """Return timezone string from Django settings `CELERY_TIMEZONE` variable.
+
+    If is not defined or is not a valid timezone, return `"UTC"` instead.
+    """
+    try:
+        CELERY_TIMEZONE = getattr(
+            settings, '%s_TIMEZONE' % current_app.namespace)
+    except AttributeError:
+        return 'UTC'
+    return CELERY_TIMEZONE if CELERY_TIMEZONE in [
+        choice[0].zone for choice in timezone_field.TimeZoneField.CHOICES
+    ] else 'UTC'
+
+
 class SolarSchedule(models.Model):
     """Schedule following astronomical patterns.
 
@@ -277,10 +292,10 @@ class CrontabSchedule(models.Model):
     )
 
     timezone = timezone_field.TimeZoneField(
-        default='UTC',
+        default=crontab_schedule_celery_timezone,
         verbose_name=_('Cron Timezone'),
         help_text=_(
-            'Timezone to Run the Cron Schedule on.  Default is UTC.'),
+            'Timezone to Run the Cron Schedule on. Default is UTC.'),
     )
 
     class Meta:

locale/es/LC_MESSAGES/django.po

@@ -266,7 +266,7 @@ msgid "Cron Timezone"
 msgstr "Zona horaria Cron"
 
 #: django_celery_beat/models.py:293
-msgid "Timezone to Run the Cron Schedule on.  Default is UTC."
+msgid "Timezone to Run the Cron Schedule on. Default is UTC."
 msgstr "Zona horaria donde ejecutar la programación Cron. Por defecto UTC."
 
 #: django_celery_beat/models.py:299

locale/fr/LC_MESSAGES/django.po

@@ -267,7 +267,7 @@ msgid "Cron Timezone"
 msgstr "Fuseau Horaire Cron"
 
 #: django_celery_beat/models.py:293
-msgid "Timezone to Run the Cron Schedule on.  Default is UTC."
+msgid "Timezone to Run the Cron Schedule on. Default is UTC."
 msgstr ""
 "Fuseau Horaire pour lequel démarrer la planification Cron. UTC par défaut."
 

locale/ru/LC_MESSAGES/django.po

@@ -251,7 +251,7 @@ msgid "Cron Timezone"
 msgstr "Временная зона для Cron"
 
 #: django_celery_beat/models.py:273
-msgid "Timezone to Run the Cron Schedule on.  Default is UTC."
+msgid "Timezone to Run the Cron Schedule on. Default is UTC."
 msgstr "Временная зона для Cron расписания. UTC по умолчанию."
 
 #: django_celery_beat/models.py:279

t/unit/test_models.py

@@ -1,13 +1,16 @@
 import os
 
-from django.test import TestCase
+from django.test import TestCase, override_settings
 from django.apps import apps
 from django.db.migrations.state import ProjectState
 from django.db.migrations.autodetector import MigrationAutodetector
 from django.db.migrations.loader import MigrationLoader
 from django.db.migrations.questioner import NonInteractiveMigrationQuestioner
 
+import timezone_field
+
 from django_celery_beat import migrations as beat_migrations
+from django_celery_beat.models import crontab_schedule_celery_timezone
 
 
 class MigrationTests(TestCase):
@@ -54,3 +57,14 @@ def test_models_match_migrations(self):
         self.assertTrue(
             not changes,
             msg='Model changes exist that do not have a migration')
+
+
+class CrontabScheduleTestCase(TestCase):
+    FIRST_VALID_TIMEZONE = timezone_field.TimeZoneField.CHOICES[0][0].zone
+
+    def test_default_timezone_without_settings_config(self):
+        assert crontab_schedule_celery_timezone() == "UTC"
+
+    @override_settings(CELERY_TIMEZONE=FIRST_VALID_TIMEZONE)
+    def test_default_timezone_with_settings_config(self):
+        assert crontab_schedule_celery_timezone() == self.FIRST_VALID_TIMEZONE