add a set_modulestore_configuration to the modulestore interface. This can be used to pass in settings run the Django tier

cms/one_time_startup.py

@@ -9,8 +9,11 @@ from django.core.cache import get_cache
 CACHE = get_cache('mongo_metadata_inheritance')
 for store_name in settings.MODULESTORE:
     store = modulestore(store_name)
-    store.metadata_inheritance_cache_subsystem = CACHE
-    store.request_cache = RequestCache.get_request_cache()
+
+    store.set_modulestore_configuration({
+        'metadata_inheritance_cache_subsystem': CACHE,
+        'request_cache': RequestCache.get_request_cache()
+    })
 
     modulestore_update_signal = Signal(providing_args=['modulestore', 'course_id', 'location'])
     store.modulestore_update_signal = modulestore_update_signal

common/lib/xmodule/xmodule/modulestore/__init__.py

@@ -384,6 +384,13 @@ class ModuleStore(object):
         """
         raise NotImplementedError
 
+    def set_modulestore_configuration(self, config_dict):
+        '''
+        Allows for runtime configuration of the modulestore. In particular this is how the
+        application (LMS/CMS) can pass down Django related configuration information, e.g. caches, etc.
+        '''
+        raise NotImplementedError
+
 
 class ModuleStoreBase(ModuleStore):
     '''
@@ -395,6 +402,7 @@ class ModuleStoreBase(ModuleStore):
         '''
         self._location_errors = {}  # location -> ErrorLog
         self.metadata_inheritance_cache = None
+        self.request_cache = None
         self.modulestore_update_signal = None  # can be set by runtime to route notifications of datastore changes
 
     def _get_errorlog(self, location):
@@ -439,6 +447,14 @@ class ModuleStoreBase(ModuleStore):
                 return c
         return None
 
+    def set_modulestore_configuration(self, config_dict):
+        """
+        This is the base implementation of the interface, all we need to do is store
+        two possible configurations as attributes on the class
+        """
+        self.metadata_inheritance_cache = config_dict.get('metadata_inheritance_cache_subsystem', None)
+        self.request_cache = config_dict.get('request_cache', None)
+
 
 def namedtuple_to_son(namedtuple, prefix=''):
     """

common/lib/xmodule/xmodule/modulestore/mixed.py

@@ -100,7 +100,21 @@ class MixedModuleStore(ModuleStoreBase):
         return courses
 
     def get_course(self, course_id):
+        """
+        returns the course module associated with the course_id
+        """
         return self._get_modulestore_for_courseid(course_id).get_course(course_id)
 
     def get_parent_locations(self, location, course_id):
+        """
+        returns the parent locations for a given lcoation and course_id
+        """
         return self._get_modulestore_for_courseid(course_id).get_parent_locations(location, course_id)
+
+    def set_modulestore_configuration(self, config_dict):
+        """
+        This implementation of the interface method will pass along the configuration to all ModuleStore
+        instances
+        """
+        for store in self.modulestores.values():
+            store.set_modulestore_configuration(config_dict)

lms/one_time_startup.py

@@ -8,8 +8,10 @@ from django.core.cache import get_cache
 cache = get_cache('mongo_metadata_inheritance')
 for store_name in settings.MODULESTORE:
     store = modulestore(store_name)
-    store.metadata_inheritance_cache_subsystem = cache
-    store.request_cache = RequestCache.get_request_cache()
+    store.set_modulestore_configuration({
+        'metadata_inheritance_cache_subsystem': cache,
+        'request_cache': RequestCache.get_request_cache()
+    })
 
 if hasattr(settings, 'DATADOG_API'):
     dog_http_api.api_key = settings.DATADOG_API