make last_run_at tz aware before passing to celery (#233)

celery always makes TZ aware and will wrongly assume UTC, even when the
dates from the django model have an (implicit) TZ.

Author: costela

django_celery_beat/schedulers.py

@@ -94,12 +94,7 @@ def __init__(self, model, app=None):
         if not model.last_run_at:
             model.last_run_at = self._default_now()
 
-        last_run_at = model.last_run_at
-
-        if getattr(settings, 'DJANGO_CELERY_BEAT_TZ_AWARE', True):
-            last_run_at = make_aware(last_run_at)
-
-        self.last_run_at = last_run_at
+        self.last_run_at = model.last_run_at
 
     def _disable(self, model):
         model.no_changes = True
@@ -134,7 +129,7 @@ def is_due(self):
             self.model.save()
             return schedules.schedstate(False, None)  # Don't recheck
 
-        return self.schedule.is_due(self.last_run_at)
+        return self.schedule.is_due(make_aware(self.last_run_at))
 
     def _default_now(self):
         # The PyTZ datetime must be localised for the Django-Celery-Beat

django_celery_beat/utils.py

@@ -21,6 +21,10 @@ def make_aware(value):
         # then convert to the Django configured timezone.
         default_tz = timezone.get_default_timezone()
         value = timezone.localtime(value, default_tz)
+    else:
+        # naive datetimes are assumed to be in local timezone.
+        if timezone.is_naive(value):
+            value = timezone.make_aware(value, timezone.get_default_timezone())
     return value
 
 

t/unit/test_schedulers.py

@@ -9,7 +9,8 @@
 
 from django.contrib.admin.sites import AdminSite
 from django.contrib.messages.storage.fallback import FallbackStorage
-from django.test import RequestFactory
+from django.test import RequestFactory, override_settings
+from django.utils import timezone
 
 from celery.five import monotonic, text_t
 from celery.schedules import schedule, crontab, solar
@@ -137,6 +138,27 @@ def test_entry(self):
         assert e3.last_run_at > e2.last_run_at
         assert e3.total_run_count == 1
 
+    @override_settings(
+        USE_TZ=False,
+        DJANGO_CELERY_BEAT_TZ_AWARE=False
+    )
+    @timezone.override('Europe/Berlin')
+    @pytest.mark.celery(timezone='Europe/Berlin')
+    def test_entry_is_due__no_use_tz(self):
+        assert self.app.timezone.zone == 'Europe/Berlin'
+
+        # simulate last_run_at from DB - not TZ aware but localtime
+        right_now = timezone.now()
+
+        m = self.create_model_crontab(
+            crontab(minute='*/10'),
+            last_run_at=right_now,
+        )
+        e = self.Entry(m, app=self.app)
+
+        assert e.is_due().is_due is False
+        assert e.is_due().next <= 600  # 10 minutes; see above
+
     def test_task_with_start_time(self):
         interval = 10
         right_now = self.app.now()