Merge pull request #13609 from edx/dump-to-neo4j-updates-plus-signals

Dump to neo4j updates plus signals

cms/envs/common.py

@@ -878,6 +878,9 @@ INSTALLED_APPS = (
     'openedx.core.djangoapps.content.course_structures.apps.CourseStructuresConfig',
     'openedx.core.djangoapps.content.block_structure.apps.BlockStructureConfig',
 
+    # Coursegraph
+    'openedx.core.djangoapps.coursegraph.apps.CoursegraphConfig',
+
     # Credit courses
     'openedx.core.djangoapps.credit',
 

lms/envs/common.py

@@ -2039,6 +2039,9 @@ INSTALLED_APPS = (
     'openedx.core.djangoapps.content.block_structure.apps.BlockStructureConfig',
     'lms.djangoapps.course_blocks',
 
+    # Coursegraph
+    'openedx.core.djangoapps.coursegraph.apps.CoursegraphConfig',
+
     # Old course structure API
     'course_structure_api',
 

openedx/core/djangoapps/coursegraph/apps.py

+"""
+Coursegraph Application Configuration
+
+Signal handlers are connected here.
+"""
+
+from django.apps import AppConfig
+
+
+class CoursegraphConfig(AppConfig):
+    """
+    AppConfig for courseware app
+    """
+    name = 'openedx.core.djangoapps.coursegraph'
+
+    def ready(self):
+        """
+        Import signals on startup
+        """
+        from openedx.core.djangoapps.coursegraph import signals  # pylint: disable=unused-variable

openedx/core/djangoapps/coursegraph/signals.py

+"""
+Signal handlers for the CourseGraph application
+"""
+from django.dispatch.dispatcher import receiver
+from xmodule.modulestore.django import SignalHandler
+
+from openedx.core.djangoapps.coursegraph.utils import CourseLastPublishedCache
+
+
+@receiver(SignalHandler.course_published)
+def _listen_for_course_publish(sender, course_key, **kwargs):  # pylint: disable=unused-argument
+    """
+    Register when the course was published on a course publish event
+    """
+    CourseLastPublishedCache().set(course_key)

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

+"""
+Tests for coursegraph's signal handler on course publish
+"""
+from __future__ import unicode_literals
+
+from opaque_keys.edx.keys import CourseKey
+
+from openedx.core.djangoapps.coursegraph.signals import _listen_for_course_publish
+from openedx.core.djangoapps.coursegraph.utils import CourseLastPublishedCache
+from openedx.core.djangolib.testing.utils import CacheIsolationTestCase
+
+
+class TestCourseGraphSignalHandler(CacheIsolationTestCase):
+    """
+    Tests for the course publish course handler
+    """
+    ENABLED_CACHES = ['default']
+
+    def test_cache_set_on_course_publish(self):
+        """
+        Tests that the last published cache is set on course publish
+        """
+        course_key = CourseKey.from_string('course-v1:org+course+run')
+        last_published_cache = CourseLastPublishedCache()
+        self.assertIsNone(last_published_cache.get(course_key))
+        _listen_for_course_publish(None, course_key)
+        self.assertIsNotNone(last_published_cache.get(course_key))

openedx/core/djangoapps/coursegraph/utils.py

+"""
+Helpers for the CourseGraph app
+"""
+from django.core.cache import cache
+from django.utils import timezone
+
+
+class TimeRecordingCacheBase(object):
+    """
+    A base class for caching the current time for some key.
+    """
+    # cache_prefix should be defined in children classes
+    cache_prefix = None
+    _cache = cache
+
+    def _key(self, course_key):
+        """
+        Make a cache key from the prefix and a course_key
+        :param course_key: CourseKey object
+        :return: a cache key
+        """
+        return self.cache_prefix + unicode(course_key)
+
+    def get(self, course_key):
+        """
+        Gets the time value associated with the CourseKey.
+        :param course_key: a CourseKey object.
+        :return: the time the key was last set.
+        """
+        return self._cache.get(self._key(course_key))
+
+    def set(self, course_key):
+        """
+        Sets the current time for a CourseKey key.
+        :param course_key: a CourseKey object.
+        """
+        return self._cache.set(self._key(course_key), timezone.now())
+
+
+class CourseLastPublishedCache(TimeRecordingCacheBase):
+    """
+    Used to record the last time that a course had a publish event run on it.
+    """
+    cache_prefix = u'course_last_published'
+
+
+class CommandLastRunCache(TimeRecordingCacheBase):
+    """
+    Used to record the last time that the dump_to_neo4j command was run on a
+    course.
+    """
+    cache_prefix = u'dump_to_neo4j_command_last_run'