Move cert date signals to avoid race conditions

COURSE_CERT_DATE_CHANGE was being called before saving the new data in
the course overview. The listeners were expecting to pull the data out
of the course overview, and thus were only right about half the time.
This moves the signal to trigger after the course publish signals are
handled.

openedx/core/djangoapps/content/course_overviews/signals.py

@@ -8,6 +8,7 @@ import logging
 from django.dispatch import Signal
 from django.dispatch.dispatcher import receiver
 
+from openedx.core.djangoapps.signals.signals import COURSE_CERT_DATE_CHANGE
 from xmodule.modulestore.django import SignalHandler
 
 from .models import CourseOverview
@@ -50,6 +51,7 @@ def _check_for_course_changes(previous_course_overview, updated_course_overview)
     if previous_course_overview:
         _check_for_course_date_changes(previous_course_overview, updated_course_overview)
         _check_for_pacing_changes(previous_course_overview, updated_course_overview)
+        _check_for_cert_availability_date_changes(previous_course_overview, updated_course_overview)
 
 
 def _check_for_course_date_changes(previous_course_overview, updated_course_overview):
@@ -83,3 +85,8 @@ def _check_for_pacing_changes(previous_course_overview, updated_course_overview)
             updated_course_overview=updated_course_overview,
             previous_self_paced=previous_course_overview.self_paced,
         )
+
+
+def _check_for_cert_availability_date_changes(previous_course_overview, updated_course_overview):
+    if previous_course_overview.certificate_available_date != updated_course_overview.certificate_available_date:
+        COURSE_CERT_DATE_CHANGE.send_robust(sender=None, course_key=updated_course_overview.id)

openedx/core/djangoapps/content/course_overviews/tests/test_signals.py

@@ -90,3 +90,7 @@ class CourseOverviewSignalsTestCase(ModuleStoreTestCase):
     @patch('openedx.core.djangoapps.content.course_overviews.signals.COURSE_PACING_CHANGED.send')
     def test_pacing_changed(self, mock_signal):
         self.assert_changed_signal_sent('self_paced', True, False, mock_signal)
+
+    @patch('openedx.core.djangoapps.content.course_overviews.signals.COURSE_CERT_DATE_CHANGE.send_robust')
+    def test_cert_date_changed(self, mock_signal):
+        self.assert_changed_signal_sent('certificate_available_date', self.TODAY, self.NEXT_WEEK, mock_signal)

openedx/core/djangoapps/courseware_api/views.py

@@ -6,7 +6,6 @@ import json
 
 from completion.exceptions import UnavailableCompletionData
 from completion.utilities import get_key_to_last_completed_block
-from django.conf import settings
 from django.urls import reverse
 from django.utils.translation import ugettext as _
 from edx_rest_framework_extensions.auth.jwt.authentication import JwtAuthentication

openedx/core/djangoapps/models/course_details.py

@@ -6,11 +6,8 @@ CourseDetails
 import logging
 import re
 
-import six
 from django.conf import settings
 
-from openedx.core.djangoapps.models.config.waffle import enable_course_detail_update_certificate_date
-from openedx.core.djangoapps.signals.signals import COURSE_CERT_DATE_CHANGE
 from openedx.core.djangolib.markup import HTML
 from openedx.core.lib.courses import course_image_url
 from xmodule.fields import Date
@@ -246,8 +243,6 @@ class CourseDetails(object):
         if converted != descriptor.certificate_available_date:
             dirty = True
             descriptor.certificate_available_date = converted
-            if enable_course_detail_update_certificate_date(course_key):
-                COURSE_CERT_DATE_CHANGE.send_robust(sender=cls, course_key=six.text_type(course_key))
 
         if 'course_image_name' in jsondict and jsondict['course_image_name'] != descriptor.course_image:
             descriptor.course_image = jsondict['course_image_name']

openedx/core/djangoapps/programs/signals.py

@@ -8,6 +8,7 @@ import logging
 from django.dispatch import receiver
 
 from openedx.core.djangoapps.credentials.helpers import is_learner_records_enabled_for_org
+from openedx.core.djangoapps.models.config.waffle import enable_course_detail_update_certificate_date
 from openedx.core.djangoapps.signals.signals import (
     COURSE_CERT_AWARDED,
     COURSE_CERT_CHANGED,
@@ -82,8 +83,7 @@ def handle_course_cert_changed(sender, user, course_key, mode, status, **kwargs)
 
         Returns:
             None
-
-        """
+    """
     # Import here instead of top of file since this module gets imported before
     # the credentials app is loaded, resulting in a Django deprecation warning.
     from openedx.core.djangoapps.credentials.models import CredentialsApiConfig
@@ -196,6 +196,10 @@ def handle_course_cert_date_change(sender, course_key, **kwargs):  # lint-amnest
         None
 
     """
+    # Stop if cert date updating isn't in effect for the course
+    if not enable_course_detail_update_certificate_date(course_key):
+        return
+
     # Import here instead of top of file since this module gets imported before
     # the credentials app is loaded, resulting in a Django deprecation warning.
     from openedx.core.djangoapps.credentials.models import CredentialsApiConfig
@@ -209,6 +213,7 @@ def handle_course_cert_date_change(sender, course_key, **kwargs):  # lint-amnest
         'handling COURSE_CERT_DATE_CHANGE for course %s',
         course_key,
     )
+
     # import here, because signal is registered at startup, but items in tasks are not yet loaded
     from openedx.core.djangoapps.programs.tasks import update_certificate_visible_date_on_course_update
-    update_certificate_visible_date_on_course_update.delay(course_key)
+    update_certificate_visible_date_on_course_update.delay(str(course_key))

openedx/core/djangoapps/programs/tasks.py

@@ -606,7 +606,6 @@ def update_certificate_visible_date_on_course_update(self, course_key):
     # feature, it may indicate a condition where processing of such tasks
     # has been temporarily disabled.  Since this is a recoverable situation,
     # mark this task for retry instead of failing it altogether.
-
     if not CredentialsApiConfig.current().is_learner_issuance_enabled:
         error_msg = (
             "Task update_certificate_visible_date_on_course_update cannot be executed when credentials issuance is "
@@ -622,5 +621,9 @@ def update_certificate_visible_date_on_course_update(self, course_key):
         course_id=course_key
     ).values_list('user__username', flat=True)
 
+    LOGGER.info(
+        "Task update_certificate_visible_date_on_course_update resending course certificates"
+        f"for {len(users_with_certificates_in_course)} users in course {course_key}."
+    )
     for user in users_with_certificates_in_course:
         award_course_certificate.delay(user, str(course_key))

openedx/core/djangoapps/programs/tests/test_signals.py

@@ -238,6 +238,7 @@ class CertRevokedReceiverTest(TestCase):
     new_callable=mock.PropertyMock,
     return_value=False,
 )
+@mock.patch("openedx.core.djangoapps.programs.signals.enable_course_detail_update_certificate_date")
 class CourseCertAvailableDateChangedReceiverTest(TestCase):
     """
     Tests for the `handle_course_cert_date_change` signal handler function.
@@ -253,7 +254,7 @@ class CourseCertAvailableDateChangedReceiverTest(TestCase):
             'course_key': TEST_COURSE_KEY,
         }
 
-    def test_signal_received(self, mock_is_learner_issuance_enabled, mock_task):  # pylint: disable=unused-argument
+    def test_signal_received(self, mock_enable_update, mock_is_learner_issuance_enabled, mock_task):  # pylint: disable=unused-argument
         """
         Ensures the receiver function is invoked when COURSE_CERT_DATE_CHANGE is
         sent.
@@ -262,23 +263,26 @@ class CourseCertAvailableDateChangedReceiverTest(TestCase):
         to the way django signals work), we mock a configuration call that is
         known to take place inside the function.
         """
+        mock_enable_update.return_value = True
         COURSE_CERT_DATE_CHANGE.send(**self.signal_kwargs)
         assert mock_is_learner_issuance_enabled.call_count == 1
 
-    def test_programs_disabled(self, mock_is_learner_issuance_enabled, mock_task):
+    def test_programs_disabled(self, mock_enable_update, mock_is_learner_issuance_enabled, mock_task):
         """
         Ensures that the receiver function does nothing when the credentials API
         configuration is not enabled.
         """
+        mock_enable_update.return_value = True
         handle_course_cert_date_change(**self.signal_kwargs)
         assert mock_is_learner_issuance_enabled.call_count == 1
         assert mock_task.call_count == 0
 
-    def test_programs_enabled(self, mock_is_learner_issuance_enabled, mock_task):
+    def test_programs_enabled(self, mock_enable_update, mock_is_learner_issuance_enabled, mock_task):
         """
         Ensures that the receiver function invokes the expected celery task
         when the credentials API configuration is enabled.
         """
+        mock_enable_update.return_value = True
         mock_is_learner_issuance_enabled.return_value = True
 
         handle_course_cert_date_change(**self.signal_kwargs)