Merge pull request #533 from mitodl/bug/skm/529_vocab_cache

Fixed caching bug.

search/search_indexes.py

@@ -68,7 +68,8 @@ def get_vocabs(course_id, resource_id, solo_update=False):
     # terms for that LearningResource. Otherwise, looking up the vocabularies
     # for that resource will refill the cache for the entire course. If there
     # is already a value, retain it.
-    resource_ids = LearningResource.objects.all().values_list('id', flat=True)
+    resource_ids = LearningResource.objects.filter(
+        course__id=course_id).values_list('id', flat=True)
     for resource_id in resource_ids:
         rkey = "vocab_cache_{0}".format(resource_id)
         cache.set(rkey, cache.get(rkey, {}))

search/tests/test_indexing.py

@@ -10,6 +10,23 @@
 log = logging.getLogger(__name__)
 
 
+def copy_instance(instance):
+    """
+    Make a copy of a model instance. The copy will need to be saved by the
+    caller because this function doesn't know what fields must be unique.
+
+    Args:
+        instance (models.Model): models.Model instance
+    Returns:
+        original (models.Model): models.Model instance
+        clone (models.Model): models.Model instance
+    """
+    original_id = instance.pk
+    clone = instance
+    clone.pk = None
+    return instance.__class__.objects.get(id=original_id), clone
+
+
 def set_cache_timeout(seconds):
     """Override the cache timeout for testing."""
     cache.default_timeout = seconds
@@ -245,3 +262,38 @@ def test_term_cache_without_data(self):
         a LearningResource isn't tagged with any terms.
         """
         self.thrice()
+
+    def test_vocab_cache_by_course(self):
+        """
+        Ensure that get_vocabs for one course doesn't
+        pollute the cache for another course.
+        """
+        # Create a resource in a separate course.
+        self.course, course2 = copy_instance(self.course)
+        self.resource, resource2 = copy_instance(self.resource)
+        course2.run = "{0} part 2".format(self.course.run)
+        course2.save()
+        resource2.course = course2
+        resource2.save()
+
+        key1 = "vocab_cache_{0}".format(self.resource.id)
+        key2 = "vocab_cache_{0}".format(resource2.id)
+
+        # Resources were recently saved, so the keys should be in the cache.
+        self.assertIn(key1, cache)
+        self.assertIn(key2, cache)
+
+        # Getting vocabs for a resource should not refresh the cache for
+        # resources in another course.
+        cache.clear()
+        self.resource.save()
+        self.assertIn(key1, cache)
+        self.assertNotIn(key2, cache)
+
+        # Resource for the same course are updated.
+        resource2.course = self.resource.course
+        resource2.save()
+        cache.clear()
+        self.resource.save()
+        self.assertIn(key1, cache)
+        self.assertIn(key2, cache)