Merge pull request #4232 from edx/nimisha/modulestore-enum-constants

ModulestoreEnum class.

cms/djangoapps/contentstore/management/commands/course_id_clash.py

@@ -3,7 +3,7 @@ Script for finding all courses whose org/name pairs == other courses when ignori
 """
 from django.core.management.base import BaseCommand
 from xmodule.modulestore.django import modulestore
-from xmodule.modulestore import MONGO_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 
 
 #
@@ -16,7 +16,7 @@ class Command(BaseCommand):
     help = 'List all courses ids in the Mongo Modulestore which may collide when ignoring case'
 
     def handle(self, *args, **options):
-        mstore = modulestore()._get_modulestore_by_type(MONGO_MODULESTORE_TYPE)  # pylint: disable=protected-access
+        mstore = modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.mongo)  # pylint: disable=protected-access
         if hasattr(mstore, 'collection'):
             map_fn = '''
                 function () {

cms/djangoapps/contentstore/management/commands/tests/test_migrate_to_split.py

@@ -6,7 +6,7 @@ import unittest
 from django.contrib.auth.models import User
 from django.core.management import CommandError, call_command
 from contentstore.management.commands.migrate_to_split import Command
-from xmodule.modulestore import SPLIT_MONGO_MODULESTORE_TYPE, REVISION_OPTION_PUBLISHED_ONLY
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 from xmodule.modulestore.django import modulestore, clear_existing_modulestores
@@ -56,7 +56,7 @@ class TestMigrateToSplit(ModuleStoreTestCase):
         password = 'foo'
         self.user = User.objects.create_user(uname, email, password)
         self.course = CourseFactory()
-        self.addCleanup(ModuleStoreTestCase.drop_mongo_collections, SPLIT_MONGO_MODULESTORE_TYPE)
+        self.addCleanup(ModuleStoreTestCase.drop_mongo_collections, ModuleStoreEnum.Type.split)
         self.addCleanup(clear_existing_modulestores)
 
     def test_user_email(self):
@@ -84,6 +84,6 @@ class TestMigrateToSplit(ModuleStoreTestCase):
             str(self.user.id),
             "org.dept+name.run",
         )
-        locator = CourseLocator(org="org.dept", offering="name.run", branch=REVISION_OPTION_PUBLISHED_ONLY)
+        locator = CourseLocator(org="org.dept", offering="name.run", branch=ModuleStoreEnum.RevisionOption.published_only)
         course_from_split = modulestore('split').get_course(locator)
         self.assertIsNotNone(course_from_split)

cms/djangoapps/contentstore/tests/test_contentstore.py

@@ -27,10 +27,8 @@ from xmodule.contentstore.content import StaticContent
 from xmodule.contentstore.django import contentstore, _CONTENTSTORE
 from xmodule.contentstore.utils import restore_asset_from_trashcan, empty_asset_trashcan
 from xmodule.exceptions import NotFoundError, InvalidVersionError
-from xmodule.modulestore import (
-    mongo, MONGO_MODULESTORE_TYPE, PublishState,
-    REVISION_OPTION_PUBLISHED_ONLY, REVISION_OPTION_DRAFT_ONLY, KEY_REVISION_PUBLISHED, BRANCH_PUBLISHED_ONLY
-)
+from xmodule.modulestore import mongo, PublishState, ModuleStoreEnum
+from xmodule.modulestore.mongo.base import MongoRevisionKey
 from xmodule.modulestore.mixed import store_branch_setting
 from xmodule.modulestore.django import modulestore
 from xmodule.modulestore.exceptions import ItemNotFoundError
@@ -204,13 +202,13 @@ class ContentStoreToyCourseTest(ContentStoreTestCase):
         store.convert_to_draft(html_module_from_draft_store.location, self.user.id)
 
         # Query get_items() and find the html item. This should just return back a single item (not 2).
-        direct_store_items = store.get_items(course_key, revision=REVISION_OPTION_PUBLISHED_ONLY)
+        direct_store_items = store.get_items(course_key, revision=ModuleStoreEnum.RevisionOption.published_only)
         html_items_from_direct_store = [item for item in direct_store_items if (item.location == html_usage_key)]
         self.assertEqual(len(html_items_from_direct_store), 1)
         self.assertFalse(getattr(html_items_from_direct_store[0], 'is_draft', False))
 
         # Fetch from the draft store.
-        draft_store_items = store.get_items(course_key, revision=REVISION_OPTION_DRAFT_ONLY)
+        draft_store_items = store.get_items(course_key, revision=ModuleStoreEnum.RevisionOption.draft_only)
         html_items_from_draft_store = [item for item in draft_store_items if (item.location == html_usage_key)]
         self.assertEqual(len(html_items_from_draft_store), 1)
         self.assertTrue(getattr(html_items_from_draft_store[0], 'is_draft', False))
@@ -663,9 +661,9 @@ class ContentStoreToyCourseTest(ContentStoreTestCase):
         clone_course(module_store, content_store, source_course_id, dest_course_id, self.user.id)
 
         # first assert that all draft content got cloned as well
-        draft_items = module_store.get_items(source_course_id, revision=REVISION_OPTION_DRAFT_ONLY)
+        draft_items = module_store.get_items(source_course_id, revision=ModuleStoreEnum.RevisionOption.draft_only)
         self.assertGreater(len(draft_items), 0)
-        draft_clone_items = module_store.get_items(dest_course_id, revision=REVISION_OPTION_DRAFT_ONLY)
+        draft_clone_items = module_store.get_items(dest_course_id, revision=ModuleStoreEnum.RevisionOption.draft_only)
         self.assertGreater(len(draft_clone_items), 0)
         self.assertEqual(len(draft_items), len(draft_clone_items))
 
@@ -868,7 +866,7 @@ class ContentStoreToyCourseTest(ContentStoreTestCase):
 
         # add the new private and new public to list of children
         sequential = module_store.get_item(course_id.make_usage_key('sequential', 'vertical_sequential'))
-        private_location_no_draft = private_vertical.location.replace(revision=KEY_REVISION_PUBLISHED)
+        private_location_no_draft = private_vertical.location.replace(revision=MongoRevisionKey.published)
         sequential.children.append(private_location_no_draft)
         sequential.children.append(public_vertical_location)
         module_store.update_item(sequential, self.user.id)
@@ -939,7 +937,11 @@ class ContentStoreToyCourseTest(ContentStoreTestCase):
             target_course_id=course_id,
         )
 
-        items = module_store.get_items(course_id, category='vertical', revision=REVISION_OPTION_PUBLISHED_ONLY)
+        items = module_store.get_items(
+            course_id,
+            category='vertical',
+            revision=ModuleStoreEnum.RevisionOption.published_only
+        )
         self._check_verticals(items)
 
         def verify_item_publish_state(item, publish_state):
@@ -1124,7 +1126,7 @@ class ContentStoreToyCourseTest(ContentStoreTestCase):
         self.assertContains(resp, '/c4x/edX/toy/asset/handouts_sample_handout.txt')
 
     def test_prefetch_children(self):
-        mongo_store = modulestore()._get_modulestore_by_type(MONGO_MODULESTORE_TYPE)
+        mongo_store = modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.mongo)
         import_from_xml(modulestore(), self.user.id, 'common/test/data/', ['toy'])
         course_id = SlashSeparatedCourseKey('edX', 'toy', '2012_Fall')
 
@@ -1132,7 +1134,7 @@ class ContentStoreToyCourseTest(ContentStoreTestCase):
         mongo_store.collection.find = wrapper.find
 
         # set the branch to 'publish' in order to prevent extra lookups of draft versions
-        with store_branch_setting(mongo_store, BRANCH_PUBLISHED_ONLY):
+        with store_branch_setting(mongo_store, ModuleStoreEnum.Branch.published_only):
             course = mongo_store.get_course(course_id, depth=2)
 
             # make sure we haven't done too many round trips to DB

cms/djangoapps/contentstore/tests/test_course_listing.py

@@ -17,7 +17,7 @@ from student.tests.factories import UserFactory
 from student.roles import CourseInstructorRole, CourseStaffRole, GlobalStaff, OrgStaffRole, OrgInstructorRole
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory, check_mongo_calls
-from xmodule.modulestore import MONGO_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from opaque_keys.edx.locations import SlashSeparatedCourseKey
 from xmodule.modulestore.django import modulestore
 from xmodule.error_module import ErrorDescriptor
@@ -199,7 +199,7 @@ class TestCourseListing(ModuleStoreTestCase):
         self.assertGreaterEqual(iteration_over_courses_time_2.elapsed, iteration_over_groups_time_2.elapsed)
 
         # Now count the db queries
-        store = modulestore()._get_modulestore_by_type(MONGO_MODULESTORE_TYPE)
+        store = modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.mongo)
         with check_mongo_calls(store.collection, USER_COURSES_COUNT):
             courses_list = _accessible_courses_list_from_groups(self.request)
 
@@ -262,7 +262,7 @@ class TestCourseListing(ModuleStoreTestCase):
         Create good courses, courses that won't load, and deleted courses which still have
         roles. Test course listing.
         """
-        store = modulestore()._get_modulestore_by_type(MONGO_MODULESTORE_TYPE)
+        store = modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.mongo)
 
         course_location = SlashSeparatedCourseKey('testOrg', 'testCourse', 'RunBabyRun')
         self._create_course_with_access_groups(course_location, self.user)

cms/djangoapps/contentstore/tests/test_crud.py

 import unittest
 
 from xmodule import templates
-from xmodule.modulestore import SPLIT_MONGO_MODULESTORE_TYPE, BRANCH_NAME_DRAFT
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.tests import persistent_factories
 from xmodule.course_module import CourseDescriptor
 from xmodule.modulestore.django import modulestore, clear_existing_modulestores, _MIXED_MODULESTORE, \
@@ -21,9 +21,9 @@ class TemplateTests(unittest.TestCase):
 
     def setUp(self):
         clear_existing_modulestores()  # redundant w/ cleanup but someone was getting errors
-        self.addCleanup(ModuleStoreTestCase.drop_mongo_collections, SPLIT_MONGO_MODULESTORE_TYPE)
+        self.addCleanup(ModuleStoreTestCase.drop_mongo_collections, ModuleStoreEnum.Type.split)
         self.addCleanup(clear_existing_modulestores)
-        self.split_store = modulestore()._get_modulestore_by_type(SPLIT_MONGO_MODULESTORE_TYPE)
+        self.split_store = modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.split)
 
     def test_get_templates(self):
         found = templates.all_templates()
@@ -156,7 +156,7 @@ class TemplateTests(unittest.TestCase):
         persistent_factories.ItemFactory.create(display_name='chapter 1',
             parent_location=test_course.location)
 
-        id_locator = test_course.id.for_branch(BRANCH_NAME_DRAFT)
+        id_locator = test_course.id.for_branch(ModuleStoreEnum.BranchName.draft)
         guid_locator = test_course.location.course_agnostic()
         # verify it can be retrieved by id
         self.assertIsInstance(self.split_store.get_course(id_locator), CourseDescriptor)
@@ -241,7 +241,7 @@ class SplitAndLocMapperTests(unittest.TestCase):
         mapper = loc_mapper()
 
         # instantiate mixed modulestore and thus split
-        split_store = modulestore()._get_modulestore_by_type(SPLIT_MONGO_MODULESTORE_TYPE)
+        split_store = modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.split)
 
         # split must inject the same location mapper object since the mapper existed before it did
         self.assertEqual(split_store.loc_mapper, mapper)
@@ -254,7 +254,7 @@ class SplitAndLocMapperTests(unittest.TestCase):
         self.assertIsNone(_loc_singleton)
 
         # instantiate split before location mapper
-        split_store = modulestore()._get_modulestore_by_type(SPLIT_MONGO_MODULESTORE_TYPE)
+        split_store = modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.split)
 
         # split must have instantiated loc_mapper
         mapper = loc_mapper()

cms/djangoapps/contentstore/views/item.py

@@ -21,7 +21,7 @@ from xblock.fragment import Fragment
 
 import xmodule
 from xmodule.tabs import StaticTab, CourseTabList
-from xmodule.modulestore import PublishState, REVISION_OPTION_ALL
+from xmodule.modulestore import PublishState, ModuleStoreEnum
 from xmodule.modulestore.django import modulestore
 from xmodule.modulestore.draft import DIRECT_ONLY_CATEGORIES
 from xmodule.modulestore.exceptions import ItemNotFoundError, InvalidLocationError, DuplicateItemError
@@ -527,7 +527,7 @@ def orphan_handler(request, course_key_string):
                 # get_orphans returns the deprecated string format w/o revision
                 usage_key = course_usage_key.make_usage_key_from_deprecated_string(itemloc)
                 # need to delete all versions
-                store.delete_item(usage_key, request.user.id, revision=REVISION_OPTION_ALL)
+                store.delete_item(usage_key, request.user.id, revision=ModuleStoreEnum.RevisionOption.all)
             return JsonResponse({'deleted': items})
         else:
             raise PermissionDenied()

cms/envs/common.py

@@ -247,7 +247,7 @@ XBLOCK_MIXINS = (LmsBlockMixin, InheritanceMixin, XModuleMixin)
 XBLOCK_SELECT_FUNCTION = prefer_xmodules
 
 ############################ Modulestore Configuration ################################
-MODULESTORE_BRANCH = 'draft'
+MODULESTORE_BRANCH = 'draft-preferred'
 
 ############################ DJANGO_BUILTINS ################################
 # Change DEBUG/TEMPLATE_DEBUG in your environment settings files, not here

common/djangoapps/static_replace/__init__.py

@@ -6,7 +6,7 @@ from staticfiles import finders
 from django.conf import settings
 
 from xmodule.modulestore.django import modulestore
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.contentstore.content import StaticContent
 
 log = logging.getLogger(__name__)
@@ -119,7 +119,9 @@ def replace_static_urls(text, data_directory, course_id=None, static_asset_path=
         if settings.DEBUG and finders.find(rest, True):
             return original
         # if we're running with a MongoBacked store course_namespace is not None, then use studio style urls
-        elif (not static_asset_path) and course_id and modulestore().get_modulestore_type(course_id) != XML_MODULESTORE_TYPE:
+        elif (not static_asset_path) \
+                and course_id \
+                and modulestore().get_modulestore_type(course_id) != ModuleStoreEnum.Type.xml:
             # first look in the static file pipeline and see if we are trying to reference
             # a piece of static content which is in the edx-platform repo (e.g. JS associated with an xmodule)
 

common/djangoapps/student/migrations/0036_access_roles_orgless.py

@@ -7,7 +7,7 @@ from opaque_keys import InvalidKeyError
 import logging
 from django.db.models.query_utils import Q
 from django.db.utils import IntegrityError
-from xmodule.modulestore import XML_MODULESTORE_TYPE, MONGO_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.mixed import MixedModuleStore
 
 log = logging.getLogger(__name__)
@@ -27,8 +27,8 @@ class Migration(DataMigration):
         # Note: Remember to use orm['appname.ModelName'] rather than "from appname.models..."
         loc_map_collection = loc_mapper().location_map
         mixed_ms = modulestore()
-        xml_ms = mixed_ms._get_modulestore_by_type(XML_MODULESTORE_TYPE)
-        mongo_ms = mixed_ms._get_modulestore_by_type(MONGO_MODULESTORE_TYPE)
+        xml_ms = mixed_ms._get_modulestore_by_type(ModuleStoreEnum.Type.xml)
+        mongo_ms = mixed_ms._get_modulestore_by_type(ModuleStoreEnum.Type.mongo)
 
         query = Q(name__startswith='staff') | Q(name__startswith='instructor') | Q(name__startswith='beta_testers')
         for group in orm['auth.Group'].objects.filter(query).exclude(name__contains="/").all():

common/djangoapps/student/tests/test_course_listing.py

@@ -6,7 +6,7 @@ from mock import patch, Mock
 
 from student.tests.factories import UserFactory
 from student.roles import GlobalStaff
-from xmodule.modulestore import MONGO_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 from opaque_keys.edx.locations import SlashSeparatedCourseKey
@@ -90,7 +90,7 @@ class TestCourseListing(ModuleStoreTestCase):
         Create good courses, courses that won't load, and deleted courses which still have
         roles. Test course listing.
         """
-        mongo_store = modulestore()._get_modulestore_by_type(MONGO_MODULESTORE_TYPE)
+        mongo_store = modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.mongo)
 
         good_location = SlashSeparatedCourseKey('testOrg', 'testCourse', 'RunBabyRun')
         self._create_course_with_access_groups(good_location)

common/djangoapps/student/views.py

@@ -53,7 +53,7 @@ from dark_lang.models import DarkLangConfig
 from xmodule.modulestore.exceptions import ItemNotFoundError
 from xmodule.modulestore.django import modulestore
 from opaque_keys.edx.locations import SlashSeparatedCourseKey
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 
 from collections import namedtuple
 
@@ -462,7 +462,7 @@ def dashboard(request):
     show_email_settings_for = frozenset(
         course.id for course, _enrollment in course_enrollment_pairs if (
             settings.FEATURES['ENABLE_INSTRUCTOR_EMAIL'] and
-            modulestore().get_modulestore_type(course.id) != XML_MODULESTORE_TYPE and
+            modulestore().get_modulestore_type(course.id) != ModuleStoreEnum.Type.xml and
             CourseAuthorization.instructor_email_enabled(course.id)
         )
     )

common/djangoapps/terrain/browser.py

@@ -19,7 +19,7 @@ from json import dumps
 from pymongo import MongoClient
 import xmodule.modulestore.django
 from xmodule.contentstore.django import _CONTENTSTORE
-from xmodule.modulestore import MONGO_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 
 # There is an import issue when using django-staticfiles with lettuce
 # Lettuce assumes that we are using django.contrib.staticfiles,
@@ -190,7 +190,7 @@ def reset_databases(scenario):
     mongo.drop_database(settings.CONTENTSTORE['DOC_STORE_CONFIG']['db'])
     _CONTENTSTORE.clear()
 
-    modulestore = xmodule.modulestore.django.modulestore()._get_modulestore_by_type(MONGO_MODULESTORE_TYPE)
+    modulestore = xmodule.modulestore.django.modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.mongo)
     modulestore.collection.drop()
     xmodule.modulestore.django.clear_existing_modulestores()
 

common/djangoapps/terrain/course_helpers.py

@@ -6,7 +6,7 @@ from lettuce import world
 from django.contrib.auth.models import User, Group
 from student.models import CourseEnrollment
 from xmodule.modulestore.django import modulestore
-from xmodule.modulestore import MONGO_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.contentstore.django import contentstore
 
 
@@ -72,6 +72,6 @@ def clear_courses():
     # (though it shouldn't), do this manually
     # from the bash shell to drop it:
     # $ mongo test_xmodule --eval "db.dropDatabase()"
-    store = modulestore()._get_modulestore_by_type(MONGO_MODULESTORE_TYPE)
+    store = modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.mongo)
     store.collection.drop()
     contentstore().fs_files.drop()

common/djangoapps/xmodule_modifiers.py

@@ -16,7 +16,7 @@ from xblock.fragment import Fragment
 from xmodule.seq_module import SequenceModule
 from xmodule.vertical_module import VerticalModule
 from xmodule.x_module import shim_xmodule_js, XModuleDescriptor, XModule, PREVIEW_VIEWS, STUDIO_VIEW
-from xmodule.modulestore import MONGO_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.django import modulestore
 
 log = logging.getLogger(__name__)
@@ -169,7 +169,7 @@ def add_staff_markup(user, has_instructor_access, block, view, frag, context):
     # TODO: make this more general, eg use an XModule attribute instead
     if isinstance(block, VerticalModule) and (not context or not context.get('child_of_vertical', False)):
         # check that the course is a mongo backed Studio course before doing work
-        is_mongo_course = modulestore().get_modulestore_type(block.location.course_key) == MONGO_MODULESTORE_TYPE
+        is_mongo_course = modulestore().get_modulestore_type(block.location.course_key) == ModuleStoreEnum.Type.mongo
         is_studio_course = block.course_edit_method == "Studio"
 
         if is_studio_course and is_mongo_course:

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

@@ -25,44 +25,51 @@ from xblock.core import XBlock
 
 log = logging.getLogger('edx.modulestore')
 
-# Modulestore Types
 
-SPLIT_MONGO_MODULESTORE_TYPE = 'split'
-MONGO_MODULESTORE_TYPE = 'mongo'
-XML_MODULESTORE_TYPE = 'xml'
-
-
-# Key Revision constants to use for Location and Usage Keys
-# Note: These values are persisted in the database, so should not be changed without migrations
-KEY_REVISION_DRAFT = 'draft'
-KEY_REVISION_PUBLISHED = None
-
-
-# Revision constants to use for Module Store operations
-# Note: These values are passed into store APIs and only used at run time
-
-# both DRAFT and PUBLISHED versions are queried, with preference to DRAFT versions
-REVISION_OPTION_DRAFT_PREFERRED = 'rev-opt-draft-preferred'
+class ModuleStoreEnum(object):
+    """
+    A class to encapsulate common constants that are used with the various modulestores.
+    """
 
-# only DRAFT versions are queried and no PUBLISHED versions
-REVISION_OPTION_DRAFT_ONLY = 'rev-opt-draft-only'
+    class Type(object):
+        """
+        The various types of modulestores provided
+        """
+        split = 'split'
+        mongo = 'mongo'
+        xml = 'xml'
 
-# # only PUBLISHED versions are queried and no DRAFT versions
-REVISION_OPTION_PUBLISHED_ONLY = 'rev-opt-published-only'
+    class RevisionOption(object):
+        """
+        Revision constants to use for Module Store operations
+        Note: These values are passed into store APIs and only used at run time
+        """
+        # both DRAFT and PUBLISHED versions are queried, with preference to DRAFT versions
+        draft_preferred = 'rev-opt-draft-preferred'
 
-# all revisions are queried
-REVISION_OPTION_ALL = 'rev-opt-all'
+        # only DRAFT versions are queried and no PUBLISHED versions
+        draft_only = 'rev-opt-draft-only'
 
+        # # only PUBLISHED versions are queried and no DRAFT versions
+        published_only = 'rev-opt-published-only'
 
-# Branch constants to use for stores, such as Mongo, that have only 2 branches: DRAFT and PUBLISHED
-# Note: These values are taken from server configuration settings, so should not be changed without alerting DevOps
-BRANCH_DRAFT_PREFERRED = 'draft'
-BRANCH_PUBLISHED_ONLY = 'published'
+        # all revisions are queried
+        all = 'rev-opt-all'
 
+    class Branch(object):
+        """
+        Branch constants to use for stores, such as Mongo, that have only 2 branches: DRAFT and PUBLISHED
+        Note: These values are taken from server configuration settings, so should not be changed without alerting DevOps
+        """
+        draft_preferred = 'draft-preferred'
+        published_only = 'published-only'
 
-# Branch constants to use for stores, such as Split, that have named branches
-BRANCH_NAME_DRAFT = 'draft'
-BRANCH_NAME_PUBLISHED = 'published'
+    class BranchName(object):
+        """
+        Branch constants to use for stores, such as Split, that have named branches
+        """
+        draft = 'draft-branch'
+        published = 'published-branch'
 
 
 class PublishState(object):

common/lib/xmodule/xmodule/modulestore/loc_mapper_store.py

@@ -7,7 +7,7 @@ import pymongo
 import bson.son
 import urllib
 
-from xmodule.modulestore import BRANCH_NAME_PUBLISHED, BRANCH_NAME_DRAFT
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.exceptions import InvalidLocationError, ItemNotFoundError
 from opaque_keys.edx.locator import BlockUsageLocator, CourseLocator
 from opaque_keys.edx.locations import SlashSeparatedCourseKey
@@ -55,7 +55,9 @@ class LocMapperStore(object):
 
     # location_map functions
     def create_map_entry(self, course_key, org=None, offering=None,
-                         draft_branch=BRANCH_NAME_DRAFT, prod_branch=BRANCH_NAME_PUBLISHED, block_map=None):
+                         draft_branch=ModuleStoreEnum.BranchName.draft,
+                         prod_branch=ModuleStoreEnum.BranchName.published,
+                         block_map=None):
         """
         Add a new entry to map this SlashSeparatedCourseKey to the new style CourseLocator.org & offering. If
         org and offering are not provided, it defaults them based on course_key.
@@ -245,7 +247,7 @@ class LocMapperStore(object):
         for old_name, cat_to_usage in entry['block_map'].iteritems():
             for category, block_id in cat_to_usage.iteritems():
                 # cache all entries and then figure out if we have the one we want
-                # Always return revision=KEY_REVISION_PUBLISHED because the
+                # Always return revision=MongoRevisionKey.published because the
                 # old draft module store wraps locations as draft before
                 # trying to access things.
                 location = old_course_id.make_usage_key(

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

@@ -110,11 +110,7 @@ class MixedModuleStore(ModuleStoreWriteBase):
     def _get_modulestore_by_type(self, modulestore_type):
         """
         This method should only really be used by tests and migration scripts when necessary.
-        Returns the module store as requested by type.  The type can be:
-
-            SPLIT_MONGO_MODULESTORE_TYPE
-            MONGO_MODULESTORE_TYPE
-            XML_MODULESTORE_TYPE
+        Returns the module store as requested by type.  The type can be a value from ModuleStoreEnum.Type.
         """
         for store in self.modulestores:
             if store.get_modulestore_type() == modulestore_type:

common/lib/xmodule/xmodule/modulestore/mongo/base.py

@@ -33,11 +33,7 @@ from xblock.runtime import KvsFieldData
 from xblock.exceptions import InvalidScopeError
 from xblock.fields import Scope, ScopeIds, Reference, ReferenceList, ReferenceValueDict
 
-from xmodule.modulestore import (
-    ModuleStoreWriteBase, MONGO_MODULESTORE_TYPE,
-    REVISION_OPTION_PUBLISHED_ONLY, REVISION_OPTION_DRAFT_PREFERRED,
-    KEY_REVISION_DRAFT, KEY_REVISION_PUBLISHED
-)
+from xmodule.modulestore import ModuleStoreWriteBase, ModuleStoreEnum
 from opaque_keys.edx.locations import Location
 from xmodule.modulestore.exceptions import ItemNotFoundError, InvalidLocationError, ReferentialIntegrityError
 from xmodule.modulestore.inheritance import own_metadata, InheritanceMixin, inherit_metadata, InheritanceKeyValueStore
@@ -58,6 +54,15 @@ SORT_REVISION_FAVOR_DRAFT = ('_id.revision', pymongo.DESCENDING)
 SORT_REVISION_FAVOR_PUBLISHED = ('_id.revision', pymongo.ASCENDING)
 
 
+class MongoRevisionKey(object):
+    """
+    Key Revision constants to use for Location and Usage Keys in the Mongo modulestore
+    Note: These values are persisted in the database, so should not be changed without migrations
+    """
+    draft = 'draft'
+    published = None
+
+
 class InvalidWriteError(Exception):
     """
     Raised to indicate that writing to a particular key
@@ -303,14 +308,14 @@ def as_draft(location):
     """
     if location.category in DIRECT_ONLY_CATEGORIES:
         return location
-    return location.replace(revision=KEY_REVISION_DRAFT)
+    return location.replace(revision=MongoRevisionKey.draft)
 
 
 def as_published(location):
     """
     Returns the Location that is the published version for `location`
     """
-    return location.replace(revision=KEY_REVISION_PUBLISHED)
+    return location.replace(revision=MongoRevisionKey.published)
 
 
 class MongoModuleStore(ModuleStoreWriteBase):
@@ -744,7 +749,7 @@ class MongoModuleStore(ModuleStoreWriteBase):
             for key in ('tag', 'org', 'course', 'category', 'name', 'revision')
         ])
 
-    def get_items(self, course_id, settings=None, content=None, key_revision=KEY_REVISION_PUBLISHED, **kwargs):
+    def get_items(self, course_id, settings=None, content=None, key_revision=MongoRevisionKey.published, **kwargs):
         """
         Returns:
             list of XModuleDescriptor instances for the matching items within the course with
@@ -763,10 +768,10 @@ class MongoModuleStore(ModuleStoreWriteBase):
             content (dict): fields to look for which have content scope. Follows same syntax and
                 rules as kwargs below.
             key_revision (str): the revision of the items you're looking for.
-                KEY_REVISION_DRAFT - only returns drafts
-                KEY_REVISION_PUBLISHED (equates to None) - only returns published
+                MongoRevisionKey.draft - only returns drafts
+                MongoRevisionKey.published (equates to None) - only returns published
                 If you want one of each matching xblock but preferring draft to published, call this same method
-                on the draft modulestore with REVISION_OPTION_DRAFT_PREFERRED.
+                on the draft modulestore with ModuleStoreEnum.RevisionOption.draft_preferred.
             kwargs (key=value): what to look for within the course.
                 Common qualifiers are ``category`` or any field name. if the target field is a list,
                 then it searches for the given value in the list not list equivalence.
@@ -1003,7 +1008,7 @@ class MongoModuleStore(ModuleStoreWriteBase):
                         value[key] = subvalue.to_deprecated_string()
         return jsonfields
 
-    def get_parent_location(self, location, revision=REVISION_OPTION_PUBLISHED_ONLY, **kwargs):
+    def get_parent_location(self, location, revision=ModuleStoreEnum.RevisionOption.published_only, **kwargs):
         '''
         Find the location that is the parent of this location in this course.
 
@@ -1011,21 +1016,24 @@ class MongoModuleStore(ModuleStoreWriteBase):
 
         Args:
             revision:
-                REVISION_OPTION_PUBLISHED_ONLY - return only the PUBLISHED parent if it exists, else returns None
-                REVISION_OPTION_DRAFT_PREFERRED - return either the DRAFT or PUBLISHED parent,
+                ModuleStoreEnum.RevisionOption.published_only
+                    - return only the PUBLISHED parent if it exists, else returns None
+                ModuleStoreEnum.RevisionOption.draft_preferred
+                    - return either the DRAFT or PUBLISHED parent,
                         preferring DRAFT, if parent(s) exists,
                         else returns None
         '''
         assert location.revision is None
-        assert revision == REVISION_OPTION_PUBLISHED_ONLY or revision == REVISION_OPTION_DRAFT_PREFERRED
+        assert revision == ModuleStoreEnum.RevisionOption.published_only \
+            or revision == ModuleStoreEnum.RevisionOption.draft_preferred
 
         # create a query with tag, org, course, and the children field set to the given location
         query = self._course_key_to_son(location.course_key)
         query['definition.children'] = location.to_deprecated_string()
 
         # if only looking for the PUBLISHED parent, set the revision in the query to None
-        if revision == REVISION_OPTION_PUBLISHED_ONLY:
-            query['_id.revision'] = KEY_REVISION_PUBLISHED
+        if revision == ModuleStoreEnum.RevisionOption.published_only:
+            query['_id.revision'] = MongoRevisionKey.published
 
         # query the collection, sorting by DRAFT first
         parents = self.collection.find(query, {'_id': True}, sort=[SORT_REVISION_FAVOR_DRAFT])
@@ -1034,7 +1042,7 @@ class MongoModuleStore(ModuleStoreWriteBase):
             # no parents were found
             return None
 
-        if revision == REVISION_OPTION_PUBLISHED_ONLY:
+        if revision == ModuleStoreEnum.RevisionOption.published_only:
             if parents.count() > 1:
                 # should never have multiple PUBLISHED parents
                 raise ReferentialIntegrityError(
@@ -1055,16 +1063,11 @@ class MongoModuleStore(ModuleStoreWriteBase):
 
     def get_modulestore_type(self, course_key=None):
         """
-        Returns an enumeration-like type reflecting the type of this modulestore
-        The return can be one of:
-        "xml" (for XML based courses),
-        "mongo" for old-style MongoDB backed courses,
-        "split" for new-style split MongoDB backed courses.
-
+        Returns an enumeration-like type reflecting the type of this modulestore per ModuleStoreEnum.Type
         Args:
             course_key: just for signature compatibility
         """
-        return MONGO_MODULESTORE_TYPE
+        return ModuleStoreEnum.Type.mongo
 
     def get_orphans(self, course_key):
         """
@@ -1114,6 +1117,6 @@ class MongoModuleStore(ModuleStoreWriteBase):
         Check that the db is reachable.
         """
         if self.database.connection.alive():
-            return {MONGO_MODULESTORE_TYPE: True}
+            return {ModuleStoreEnum.Type.mongo: True}
         else:
             raise HeartbeatFailure("Can't connect to {}".format(self.database.name), 'mongo')

common/lib/xmodule/xmodule/modulestore/split_migrator.py

@@ -7,7 +7,7 @@ In general, it's strategy is to treat the other modulestores as read-only and to
 manipulate storage but use existing api's.
 '''
 from xblock.fields import Reference, ReferenceList, ReferenceValueDict
-from xmodule.modulestore import BRANCH_NAME_DRAFT, BRANCH_NAME_PUBLISHED, REVISION_OPTION_DRAFT_ONLY
+from xmodule.modulestore import ModuleStoreEnum
 
 
 class SplitMigrator(object):
@@ -85,7 +85,7 @@ class SplitMigrator(object):
         # after done w/ published items, add version for DRAFT pointing to the published structure
         index_info = self.split_modulestore.get_course_index_info(course_version_locator)
         versions = index_info['versions']
-        versions[BRANCH_NAME_DRAFT] = versions[BRANCH_NAME_PUBLISHED]
+        versions[ModuleStoreEnum.BranchName.draft] = versions[ModuleStoreEnum.BranchName.published]
         self.split_modulestore.update_course_index(index_info)
 
         # clean up orphans in published version: in old mongo, parents pointed to the union of their published and draft
@@ -98,11 +98,11 @@ class SplitMigrator(object):
         """
         # each true update below will trigger a new version of the structure. We may want to just have one new version
         # but that's for a later date.
-        new_draft_course_loc = published_course_key.for_branch(BRANCH_NAME_DRAFT)
+        new_draft_course_loc = published_course_key.for_branch(ModuleStoreEnum.BranchName.draft)
         # to prevent race conditions of grandchilden being added before their parents and thus having no parent to
         # add to
         awaiting_adoption = {}
-        for module in self.draft_modulestore.get_items(course_key, revision=REVISION_OPTION_DRAFT_ONLY):
+        for module in self.draft_modulestore.get_items(course_key, revision=ModuleStoreEnum.RevisionOption.draft_only):
             new_locator = self.loc_mapper.translate_location(
                 module.location, False, add_entry_if_missing=True
             )

common/lib/xmodule/xmodule/modulestore/split_mongo/split.py

@@ -61,7 +61,7 @@ from opaque_keys.edx.locator import (
 from xmodule.modulestore.exceptions import InsufficientSpecificationError, VersionConflictError, DuplicateItemError, \
     DuplicateCourseError
 from xmodule.modulestore import (
-    inheritance, ModuleStoreWriteBase, SPLIT_MONGO_MODULESTORE_TYPE, BRANCH_NAME_DRAFT, BRANCH_NAME_PUBLISHED
+    inheritance, ModuleStoreWriteBase, ModuleStoreEnum
 )
 
 from ..exceptions import ItemNotFoundError
@@ -296,7 +296,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         }
         return envelope
 
-    def get_courses(self, branch=BRANCH_NAME_DRAFT, qualifiers=None):
+    def get_courses(self, branch=ModuleStoreEnum.BranchName.draft, qualifiers=None):
         '''
         Returns a list of course descriptors matching any given qualifiers.
 
@@ -304,9 +304,9 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         legal query for mongo to use against the active_versions collection.
 
         Note, this is to find the current head of the named branch type
-        (e.g., BRANCH_NAME_DRAFT). To get specific versions via guid use get_course.
+        (e.g., ModuleStoreEnum.BranchName.draft). To get specific versions via guid use get_course.
 
-        :param branch: the branch for which to return courses. Default value is BRANCH_NAME_DRAFT.
+        :param branch: the branch for which to return courses. Default value is ModuleStoreEnum.BranchName.draft.
         :param qualifiers: an optional dict restricting which elements should match
         '''
         if qualifiers is None:
@@ -385,9 +385,9 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         :param usage_key: the block to check
         :return: True if the draft and published versions differ
         """
-        draft = self.get_item(usage_key.for_branch(BRANCH_NAME_DRAFT))
+        draft = self.get_item(usage_key.for_branch(ModuleStoreEnum.BranchName.draft))
         try:
-            published = self.get_item(usage_key.for_branch(BRANCH_NAME_PUBLISHED))
+            published = self.get_item(usage_key.for_branch(ModuleStoreEnum.BranchName.published))
         except ItemNotFoundError:
             return True
 
@@ -492,7 +492,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
 
     def get_orphans(self, course_key):
         """
-        Return a dict of all of the orphans in the course.
+        Return an array of all of the orphans in the course.
         """
         detached_categories = [name for name, __ in XBlock.load_tagged_classes("detached")]
         course = self._lookup_course(course_key)
@@ -872,7 +872,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
 
     def create_course(
         self, org, offering, user_id, fields=None,
-        master_branch=BRANCH_NAME_DRAFT, versions_dict=None, root_category='course',
+        master_branch=ModuleStoreEnum.BranchName.draft, versions_dict=None, root_category='course',
         root_block_id='course', **kwargs
     ):
         """
@@ -908,7 +908,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         master_branch: the tag (key) for the version name in the dict which is the DRAFT version. Not the actual
         version guid, but what to call it.
 
-        versions_dict: the starting version ids where the keys are the tags such as DRAFT and REVISION_OPTION_PUBLISHED_ONLY
+        versions_dict: the starting version ids where the keys are the tags such as DRAFT and PUBLISHED
         and the values are structure guids. If provided, the new course will reuse this version (unless you also
         provide any fields overrides, see above). if not provided, will create a mostly empty course
         structure with just a category course root xblock.
@@ -1298,7 +1298,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         self._update_head(index_entry, destination_course.branch, destination_structure['_id'])
 
     def unpublish(self, location, user_id):
-        published_location = location.replace(branch=REVISION_OPTION_PUBLISHED_ONLY)
+        published_location = location.replace(branch=ModuleStoreEnum.BranchName.published)
         self.delete_item(published_location, user_id)
 
     def update_course_index(self, updated_index_entry):
@@ -1456,16 +1456,12 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
 
     def get_modulestore_type(self, course_key=None):
         """
-        Returns an enumeration-like type reflecting the type of this modulestore
-        The return can be one of:
-        "xml" (for XML based courses),
-        "mongo" for old-style MongoDB backed courses,
-        "split" for new-style split MongoDB backed courses.
+        Returns an enumeration-like type reflecting the type of this modulestore, per ModuleStoreEnum.Type.
 
         Args:
             course_key: just for signature compatibility
         """
-        return SPLIT_MONGO_MODULESTORE_TYPE
+        return ModuleStoreEnum.Type.split
 
     def internal_clean_children(self, course_locator):
         """
@@ -1797,7 +1793,7 @@ class SplitMongoModuleStore(ModuleStoreWriteBase):
         """
         Check that the db is reachable.
         """
-        return {SPLIT_MONGO_MODULESTORE_TYPE: self.db_connection.heartbeat()}
+        return {ModuleStoreEnum.Type.split: self.db_connection.heartbeat()}
 
     def compute_publish_state(self, xblock):
         """

common/lib/xmodule/xmodule/modulestore/store_utilities.py

@@ -2,7 +2,7 @@ import re
 import logging
 
 from xmodule.contentstore.content import StaticContent
-from xmodule.modulestore import REVISION_OPTION_PUBLISHED_ONLY, REVISION_OPTION_DRAFT_ONLY
+from xmodule.modulestore import ModuleStoreEnum
 
 
 def _prefix_only_url_replace_regex(prefix):
@@ -136,12 +136,12 @@ def clone_course(modulestore, contentstore, source_course_id, dest_course_id, us
         raise Exception("Cannot find a course at {0}. Aborting".format(source_course_id))
 
     # Get all modules under this namespace which is (tag, org, course) tuple
-    modules = modulestore.get_items(source_course_id, revision=REVISION_OPTION_PUBLISHED_ONLY)
+    modules = modulestore.get_items(source_course_id, revision=ModuleStoreEnum.RevisionOption.published_only)
     _clone_modules(modulestore, modules, source_course_id, dest_course_id, user_id)
     course_location = dest_course_id.make_usage_key('course', dest_course_id.run)
     modulestore.publish(course_location, user_id)
 
-    modules = modulestore.get_items(source_course_id, revision=REVISION_OPTION_DRAFT_ONLY)
+    modules = modulestore.get_items(source_course_id, revision=ModuleStoreEnum.RevisionOption.draft_only)
     _clone_modules(modulestore, modules, source_course_id, dest_course_id, user_id)
 
     # now iterate through all of the assets and clone them

common/lib/xmodule/xmodule/modulestore/tests/django_utils.py

@@ -6,7 +6,7 @@ from uuid import uuid4
 from django.test import TestCase
 from xmodule.modulestore.django import (
     modulestore, clear_existing_modulestores, loc_mapper)
-from xmodule.modulestore import MONGO_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.contentstore.django import contentstore
 
 
@@ -142,7 +142,7 @@ class ModuleStoreTestCase(TestCase):
         return updated_course
 
     @staticmethod
-    def drop_mongo_collections(modulestore_type=MONGO_MODULESTORE_TYPE):
+    def drop_mongo_collections(modulestore_type=ModuleStoreEnum.Type.mongo):
         """
         If using a Mongo-backed modulestore & contentstore, drop the collections.
         """

common/lib/xmodule/xmodule/modulestore/tests/persistent_factories.py

-from xmodule.modulestore import SPLIT_MONGO_MODULESTORE_TYPE, BRANCH_NAME_DRAFT
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.course_module import CourseDescriptor
 from xmodule.x_module import XModuleDescriptor
 import factory
@@ -15,7 +15,7 @@ class SplitFactory(factory.Factory):
         # Delayed import so that we only depend on django if the caller
         # hasn't provided their own modulestore
         from xmodule.modulestore.django import modulestore
-        return modulestore()._get_modulestore_by_type(SPLIT_MONGO_MODULESTORE_TYPE)
+        return modulestore()._get_modulestore_by_type(ModuleStoreEnum.Type.split)
 
 
 class PersistentCourseFactory(SplitFactory):
@@ -25,7 +25,7 @@ class PersistentCourseFactory(SplitFactory):
     keywords: any xblock field plus (note, the below are filtered out; so, if they
     become legitimate xblock fields, they won't be settable via this factory)
     * org: defaults to textX
-    * master_branch: (optional) defaults to BRANCH_NAME_DRAFT
+    * master_branch: (optional) defaults to ModuleStoreEnum.BranchName.draft
     * user_id: (optional) defaults to 'test_user'
     * display_name (xblock field): will default to 'Robot Super Course' unless provided
     """
@@ -34,7 +34,7 @@ class PersistentCourseFactory(SplitFactory):
     # pylint: disable=W0613
     @classmethod
     def _create(cls, target_class, offering='999', org='testX', user_id='test_user',
-                master_branch=BRANCH_NAME_DRAFT, **kwargs):
+                master_branch=ModuleStoreEnum.BranchName.draft, **kwargs):
 
         modulestore = kwargs.pop('modulestore')
         root_block_id = kwargs.pop('root_block_id', 'course')

common/lib/xmodule/xmodule/modulestore/tests/test_mixed_modulestore.py

@@ -7,10 +7,7 @@ from collections import namedtuple
 
 from xmodule.tests import DATA_DIR
 from opaque_keys.edx.locations import Location
-from xmodule.modulestore import (
-    MONGO_MODULESTORE_TYPE, SPLIT_MONGO_MODULESTORE_TYPE, XML_MODULESTORE_TYPE,
-    REVISION_OPTION_DRAFT_PREFERRED, REVISION_OPTION_PUBLISHED_ONLY, BRANCH_DRAFT_PREFERRED
-)
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.exceptions import ItemNotFoundError
 
 from opaque_keys.edx.locator import BlockUsageLocator, CourseLocator
@@ -247,12 +244,12 @@ class TestMixedModuleStore(LocMapperSetupSansDjango):
         """
         self.initdb(default_ms)
         self.assertEqual(self.store.get_modulestore_type(
-            self._course_key_from_string(self.XML_COURSEID1)), XML_MODULESTORE_TYPE
+            self._course_key_from_string(self.XML_COURSEID1)), ModuleStoreEnum.Type.xml
         )
         self.assertEqual(self.store.get_modulestore_type(
-            self._course_key_from_string(self.XML_COURSEID2)), XML_MODULESTORE_TYPE
+            self._course_key_from_string(self.XML_COURSEID2)), ModuleStoreEnum.Type.xml
         )
-        mongo_ms_type = MONGO_MODULESTORE_TYPE if default_ms == 'draft' else SPLIT_MONGO_MODULESTORE_TYPE
+        mongo_ms_type = ModuleStoreEnum.Type.mongo if default_ms == 'draft' else ModuleStoreEnum.Type.split
         self.assertEqual(self.store.get_modulestore_type(
             self._course_key_from_string(self.MONGO_COURSEID)), mongo_ms_type
         )
@@ -352,7 +349,7 @@ class TestMixedModuleStore(LocMapperSetupSansDjango):
         Test that the xml modulestore only loaded the courses from the maps.
         """
         self.initdb('draft')
-        xml_store = self.store._get_modulestore_by_type(XML_MODULESTORE_TYPE)
+        xml_store = self.store._get_modulestore_by_type(ModuleStoreEnum.Type.xml)
         courses = xml_store.get_courses()
         self.assertEqual(len(courses), 2)
         course_ids = [course.id for course in courses]
@@ -366,7 +363,7 @@ class TestMixedModuleStore(LocMapperSetupSansDjango):
         Test that the xml modulestore doesn't allow write ops.
         """
         self.initdb('draft')
-        xml_store = self.store._get_modulestore_by_type(XML_MODULESTORE_TYPE)
+        xml_store = self.store._get_modulestore_by_type(ModuleStoreEnum.Type.xml)
         # the important thing is not which exception it raises but that it raises an exception
         with self.assertRaises(AttributeError):
             xml_store.create_course("org", "course/run", 999)
@@ -420,16 +417,16 @@ class TestMixedModuleStore(LocMapperSetupSansDjango):
 
         self.verify_get_parent_locations_results([
             (child_to_move, new_parent, None),
-            (child_to_move, new_parent, REVISION_OPTION_DRAFT_PREFERRED),
-            (child_to_move, old_parent, REVISION_OPTION_PUBLISHED_ONLY),
+            (child_to_move, new_parent, ModuleStoreEnum.RevisionOption.draft_preferred),
+            (child_to_move, old_parent, ModuleStoreEnum.RevisionOption.published_only),
         ])
 
         # publish the course again
         self.store.publish(self.course.location, self.user_id)
         self.verify_get_parent_locations_results([
             (child_to_move, new_parent, None),
-            (child_to_move, new_parent, REVISION_OPTION_DRAFT_PREFERRED),
-            (child_to_move, new_parent, REVISION_OPTION_PUBLISHED_ONLY),
+            (child_to_move, new_parent, ModuleStoreEnum.RevisionOption.draft_preferred),
+            (child_to_move, new_parent, ModuleStoreEnum.RevisionOption.published_only),
         ])
 
     @ddt.data('draft')
@@ -451,16 +448,16 @@ class TestMixedModuleStore(LocMapperSetupSansDjango):
         self.verify_get_parent_locations_results([
             (child_to_delete, old_parent, None),
             # Note: The following could be an unexpected result, but we want to avoid an extra database call
-            (child_to_delete, old_parent, REVISION_OPTION_DRAFT_PREFERRED),
-            (child_to_delete, old_parent, REVISION_OPTION_PUBLISHED_ONLY),
+            (child_to_delete, old_parent, ModuleStoreEnum.RevisionOption.draft_preferred),
+            (child_to_delete, old_parent, ModuleStoreEnum.RevisionOption.published_only),
         ])
 
         # publish the course again
         self.store.publish(self.course.location, self.user_id)
         self.verify_get_parent_locations_results([
             (child_to_delete, None, None),
-            (child_to_delete, None, REVISION_OPTION_DRAFT_PREFERRED),
-            (child_to_delete, None, REVISION_OPTION_PUBLISHED_ONLY),
+            (child_to_delete, None, ModuleStoreEnum.RevisionOption.draft_preferred),
+            (child_to_delete, None, ModuleStoreEnum.RevisionOption.published_only),
         ])
 
     @ddt.data('draft', 'split')
@@ -529,6 +526,6 @@ def create_modulestore_instance(engine, doc_store_config, options, i18n_service=
 
     return class_(
         doc_store_config=doc_store_config,
-        branch_setting_func=lambda: BRANCH_DRAFT_PREFERRED,
+        branch_setting_func=lambda: ModuleStoreEnum.Branch.draft_preferred,
         **options
     )

common/lib/xmodule/xmodule/modulestore/tests/test_mongo.py

@@ -20,7 +20,7 @@ from xblock.plugin import Plugin
 
 from xmodule.tests import DATA_DIR
 from opaque_keys.edx.locations import Location
-from xmodule.modulestore import MONGO_MODULESTORE_TYPE, BRANCH_DRAFT_PREFERRED
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.mongo import MongoModuleStore, MongoKeyValueStore
 from xmodule.modulestore.draft import DraftModuleStore
 from opaque_keys.edx.locations import SlashSeparatedCourseKey, AssetLocation
@@ -103,7 +103,7 @@ class TestMongoModuleStore(unittest.TestCase):
         draft_store = DraftModuleStore(
             doc_store_config, FS_ROOT, RENDER_TEMPLATE,
             default_class=DEFAULT_CLASS,
-            branch_setting_func=lambda: BRANCH_DRAFT_PREFERRED
+            branch_setting_func=lambda: ModuleStoreEnum.Branch.draft_preferred
         )
         import_from_xml(
             draft_store,
@@ -148,7 +148,7 @@ class TestMongoModuleStore(unittest.TestCase):
             {'host': HOST, 'db': DB, 'collection': COLLECTION},
             FS_ROOT, RENDER_TEMPLATE, default_class=DEFAULT_CLASS
         )
-        assert_equals(store.get_modulestore_type(''), MONGO_MODULESTORE_TYPE)
+        assert_equals(store.get_modulestore_type(''), ModuleStoreEnum.Type.mongo)
 
     def test_get_courses(self):
         '''Make sure the course objects loaded properly'''

common/lib/xmodule/xmodule/modulestore/tests/test_split_migrator.py

@@ -5,7 +5,7 @@ Tests for split_migrator
 import uuid
 import random
 import mock
-from xmodule.modulestore import KEY_REVISION_PUBLISHED
+from xmodule.modulestore.mongo.base import MongoRevisionKey
 from xmodule.modulestore.loc_mapper_store import LocMapperStore
 from xmodule.modulestore.split_migrator import SplitMigrator
 from xmodule.modulestore.tests import test_location_mapper
@@ -178,7 +178,7 @@ class TestMigration(SplitWMongoCourseBoostrapper):
         self.assertEqual(
             presplit_dag_root.location,
             self.loc_mapper.translate_locator_to_location(split_dag_root.location).replace(
-                revision=KEY_REVISION_PUBLISHED
+                revision=MongoRevisionKey.published
             )
         )
         # compare all fields but children

common/lib/xmodule/xmodule/modulestore/tests/test_split_modulestore.py

@@ -11,7 +11,7 @@ import random
 
 from xblock.fields import Scope
 from xmodule.course_module import CourseDescriptor
-from xmodule.modulestore import BRANCH_NAME_PUBLISHED, BRANCH_NAME_DRAFT
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.exceptions import (InsufficientSpecificationError, ItemNotFoundError, VersionConflictError,
             DuplicateItemError, DuplicateCourseError)
 from opaque_keys.edx.locator import CourseLocator, BlockUsageLocator, VersionTree, LocalId
@@ -22,6 +22,10 @@ from xmodule.modulestore.split_mongo.split import SplitMongoModuleStore
 from xmodule.modulestore.tests.test_modulestore import check_has_course_method
 
 
+BRANCH_NAME_DRAFT = ModuleStoreEnum.BranchName.draft
+BRANCH_NAME_PUBLISHED = ModuleStoreEnum.BranchName.published
+
+
 class SplitModuleTest(unittest.TestCase):
     '''
     The base set of tests manually populates a db w/ courses which have

common/lib/xmodule/xmodule/modulestore/tests/test_split_w_old_mongo.py

@@ -9,7 +9,7 @@ from opaque_keys.edx.locator import CourseLocator, BlockUsageLocator
 from xmodule.modulestore.split_mongo.split import SplitMongoModuleStore
 from xmodule.modulestore.mongo import MongoModuleStore, DraftMongoModuleStore
 from xmodule.modulestore.mongo.draft import DIRECT_ONLY_CATEGORIES
-from xmodule.modulestore import BRANCH_DRAFT_PREFERRED, BRANCH_NAME_DRAFT
+from xmodule.modulestore import ModuleStoreEnum
 from mock import Mock
 
 
@@ -41,7 +41,7 @@ class SplitWMongoCourseBoostrapper(unittest.TestCase):
         'xblock_mixins': (InheritanceMixin,)
     }
 
-    split_course_key = CourseLocator('test_org', 'test_course.runid', branch=BRANCH_NAME_DRAFT)
+    split_course_key = CourseLocator('test_org', 'test_course.runid', branch=ModuleStoreEnum.BranchName.draft)
 
     def setUp(self):
         self.db_config['collection'] = 'modulestore{0}'.format(uuid.uuid4().hex[:5])
@@ -56,7 +56,7 @@ class SplitWMongoCourseBoostrapper(unittest.TestCase):
         self.addCleanup(self.tear_down_split)
         self.old_mongo = MongoModuleStore(self.db_config, **self.modulestore_options)
         self.draft_mongo = DraftMongoModuleStore(
-            self.db_config, branch_setting_func=lambda: BRANCH_DRAFT_PREFERRED, **self.modulestore_options
+            self.db_config, branch_setting_func=lambda: ModuleStoreEnum.Branch.draft_preferred, **self.modulestore_options
         )
         self.addCleanup(self.tear_down_mongo)
         self.old_course_key = None

common/lib/xmodule/xmodule/modulestore/tests/test_xml.py

@@ -9,7 +9,7 @@ from mock import patch
 
 from xmodule.modulestore.xml import XMLModuleStore
 from opaque_keys.edx.locations import Location
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 
 from .test_modulestore import check_path_to_location
 from xmodule.tests import DATA_DIR
@@ -43,7 +43,7 @@ class TestXMLModuleStore(unittest.TestCase):
 
     def test_xml_modulestore_type(self):
         store = XMLModuleStore(DATA_DIR, course_dirs=['toy', 'simple'])
-        self.assertEqual(store.get_modulestore_type(), XML_MODULESTORE_TYPE)
+        self.assertEqual(store.get_modulestore_type(), ModuleStoreEnum.Type.xml)
 
     def test_unicode_chars_in_xml_content(self):
         # edX/full/6.002_Spring_2012 has non-ASCII chars, and during

common/lib/xmodule/xmodule/modulestore/xml.py

@@ -19,7 +19,7 @@ from xmodule.errortracker import make_error_tracker, exc_info_to_str
 from xmodule.mako_module import MakoDescriptorSystem
 from xmodule.x_module import XMLParsingSystem, policy_key
 from xmodule.modulestore.xml_exporter import DEFAULT_CONTENT_FIELDS
-from xmodule.modulestore import REVISION_OPTION_PUBLISHED_ONLY
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.tabs import CourseTabList
 from opaque_keys.edx.keys import UsageKey
 from opaque_keys.edx.locations import SlashSeparatedCourseKey
@@ -27,7 +27,7 @@ from opaque_keys.edx.locations import SlashSeparatedCourseKey
 from xblock.field_data import DictFieldData
 from xblock.runtime import DictKeyValueStore, IdGenerator
 
-from . import ModuleStoreReadBase, Location, XML_MODULESTORE_TYPE
+from . import ModuleStoreReadBase, Location, ModuleStoreEnum
 
 from .exceptions import ItemNotFoundError
 from .inheritance import compute_inherited_metadata, inheriting_field_data
@@ -411,7 +411,7 @@ class XMLModuleStore(ModuleStoreReadBase):
         self.i18n_service = i18n_service
 
         # The XML Module Store is a read-only store and only handles published content
-        self.branch_setting_func = lambda: REVISION_OPTION_PUBLISHED_ONLY
+        self.branch_setting_func = lambda: ModuleStoreEnum.RevisionOption.published_only
 
         # If we are specifically asked for missing courses, that should
         # be an error.  If we are asked for "all" courses, find the ones
@@ -800,16 +800,11 @@ class XMLModuleStore(ModuleStoreReadBase):
 
     def get_modulestore_type(self, course_key=None):
         """
-        Returns an enumeration-like type reflecting the type of this modulestore
-        The return can be one of:
-        "xml" (for XML based courses),
-        "mongo" for old-style MongoDB backed courses,
-        "split" for new-style split MongoDB backed courses.
-
+        Returns an enumeration-like type reflecting the type of this modulestore, per ModuleStoreEnum.Type
         Args:
             course_key: just for signature compatibility
         """
-        return XML_MODULESTORE_TYPE
+        return ModuleStoreEnum.Type.xml
 
     def get_courses_for_wiki(self, wiki_slug):
         """
@@ -827,5 +822,5 @@ class XMLModuleStore(ModuleStoreReadBase):
 
         Returns the course count
         """
-        return {XML_MODULESTORE_TYPE: True}
+        return {ModuleStoreEnum.Type.xml: True}
 

common/lib/xmodule/xmodule/modulestore/xml_exporter.py

@@ -7,9 +7,7 @@ import lxml.etree
 from xblock.fields import Scope
 from xmodule.contentstore.content import StaticContent
 from xmodule.exceptions import NotFoundError
-from xmodule.modulestore import (
-    EdxJSONEncoder, BRANCH_PUBLISHED_ONLY, REVISION_OPTION_DRAFT_PREFERRED, REVISION_OPTION_DRAFT_ONLY
-)
+from xmodule.modulestore import EdxJSONEncoder, ModuleStoreEnum
 from xmodule.modulestore.inheritance import own_metadata
 from xmodule.modulestore.mixed import store_branch_setting
 from fs.osfs import OSFS
@@ -47,7 +45,7 @@ def export_to_xml(modulestore, contentstore, course_key, root_dir, course_dir):
     root = lxml.etree.Element('unknown')
 
     # export only the published content
-    with store_branch_setting(course.runtime.modulestore, BRANCH_PUBLISHED_ONLY):
+    with store_branch_setting(course.runtime.modulestore, ModuleStoreEnum.Branch.published_only):
         course.add_xml_to_node(root)
 
     with export_fs.open('course.xml', 'w') as course_xml:
@@ -107,11 +105,18 @@ def export_to_xml(modulestore, contentstore, course_key, root_dir, course_dir):
     # should we change the application, then this assumption will no longer be valid
     # NOTE: we need to explicitly implement the logic for setting the vertical's parent
     # and index here since the XML modulestore cannot load draft modules
-    draft_verticals = modulestore.get_items(course_key, category='vertical', revision=REVISION_OPTION_DRAFT_ONLY)
+    draft_verticals = modulestore.get_items(
+        course_key,
+        category='vertical',
+        revision=ModuleStoreEnum.RevisionOption.draft_only
+    )
     if len(draft_verticals) > 0:
         draft_course_dir = export_fs.makeopendir(DRAFT_DIR)
         for draft_vertical in draft_verticals:
-            parent_loc = modulestore.get_parent_location(draft_vertical.location, revision=REVISION_OPTION_DRAFT_PREFERRED)
+            parent_loc = modulestore.get_parent_location(
+                draft_vertical.location,
+                revision=ModuleStoreEnum.RevisionOption.draft_preferred
+            )
             # Don't try to export orphaned items.
             if parent_loc is not None:
                 logging.debug('parent_loc = {0}'.format(parent_loc))

common/lib/xmodule/xmodule/modulestore/xml_importer.py

@@ -17,7 +17,7 @@ from .store_utilities import rewrite_nonportable_content_links
 import xblock
 from xmodule.tabs import CourseTabList
 from xmodule.modulestore.exceptions import InvalidLocationError
-from xmodule.modulestore import KEY_REVISION_PUBLISHED, KEY_REVISION_DRAFT
+from xmodule.modulestore.mongo.base import MongoRevisionKey
 
 log = logging.getLogger(__name__)
 
@@ -505,14 +505,14 @@ def _import_course_draft(
                         # Update the module's location to DRAFT revision
                         # We need to call this method (instead of updating the location directly)
                         # to ensure that pure XBlock field data is updated correctly.
-                        _update_module_location(module, module.location.replace(revision=KEY_REVISION_DRAFT))
+                        _update_module_location(module, module.location.replace(revision=MongoRevisionKey.draft))
 
                         # make sure our parent has us in its list of children
                         # this is to make sure private only verticals show up
                         # in the list of children since they would have been
                         # filtered out from the non-draft store export
                         if module.location.category == 'vertical':
-                            non_draft_location = module.location.replace(revision=KEY_REVISION_PUBLISHED)
+                            non_draft_location = module.location.replace(revision=MongoRevisionKey.published)
                             sequential_url = module.xml_attributes['parent_sequential_url']
                             index = int(module.xml_attributes['index_in_children_list'])
 

lms/djangoapps/bulk_email/forms.py

@@ -9,7 +9,7 @@ from django.core.exceptions import ValidationError
 from bulk_email.models import CourseEmailTemplate, COURSE_EMAIL_MESSAGE_BODY_TAG, CourseAuthorization
 
 from opaque_keys import InvalidKeyError
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.django import modulestore
 from opaque_keys.edx.keys import CourseKey
 from opaque_keys.edx.locations import SlashSeparatedCourseKey
@@ -78,7 +78,7 @@ class CourseAuthorizationAdminForm(forms.ModelForm):  # pylint: disable=R0924
             raise forms.ValidationError(msg)
 
         # Now, try and discern if it is a Studio course - HTML editor doesn't work with XML courses
-        is_studio_course = modulestore().get_modulestore_type(course_key) != XML_MODULESTORE_TYPE
+        is_studio_course = modulestore().get_modulestore_type(course_key) != ModuleStoreEnum.Type.xml
         if not is_studio_course:
             msg = "Course Email feature is only available for courses authored in Studio. "
             msg += '"{0}" appears to be an XML backed course.'.format(course_key.to_deprecated_string())

lms/djangoapps/bulk_email/tests/test_forms.py

@@ -11,7 +11,7 @@ from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
 from courseware.tests.modulestore_config import TEST_DATA_MIXED_MODULESTORE
 
 from xmodule.modulestore.django import modulestore
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 
 from mock import patch
 
@@ -132,7 +132,7 @@ class CourseAuthorizationXMLFormTest(ModuleStoreTestCase):
     def test_xml_course_authorization(self):
         course_id = SlashSeparatedCourseKey('edX', 'toy', '2012_Fall')
         # Assert this is an XML course
-        self.assertEqual(modulestore().get_modulestore_type(course_id), XML_MODULESTORE_TYPE)
+        self.assertEqual(modulestore().get_modulestore_type(course_id), ModuleStoreEnum.Type.xml)
 
         form_data = {'course_id': course_id.to_deprecated_string(), 'email_enabled': True}
         form = CourseAuthorizationAdminForm(data=form_data)

lms/djangoapps/courseware/courses.py

@@ -8,13 +8,13 @@ from django.http import Http404
 from django.conf import settings
 
 from edxmako.shortcuts import render_to_string
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from opaque_keys.edx.keys import CourseKey
 from xmodule.modulestore.django import modulestore
 from xmodule.contentstore.content import StaticContent
 from xmodule.modulestore.exceptions import ItemNotFoundError
 from static_replace import replace_static_urls
-from xmodule.modulestore import MONGO_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.x_module import STUDENT_VIEW
 
 from courseware.access import has_access
@@ -106,7 +106,7 @@ def get_opt_course_with_access(user, action, course_key):
 def course_image_url(course):
     """Try to look up the image url for the course.  If it's not found,
     log an error and return the dead link"""
-    if course.static_asset_path or modulestore().get_modulestore_type(course.id) == XML_MODULESTORE_TYPE:
+    if course.static_asset_path or modulestore().get_modulestore_type(course.id) == ModuleStoreEnum.Type.xml:
         # If we are a static course with the course_image attribute
         # set different than the default, return that path so that
         # courses can use custom course image paths, otherwise just
@@ -369,7 +369,7 @@ def get_studio_url(course_key, page):
     assert(isinstance(course_key, CourseKey))
     course = get_course_by_id(course_key)
     is_studio_course = course.course_edit_method == "Studio"
-    is_mongo_course = modulestore().get_modulestore_type(course_key) == MONGO_MODULESTORE_TYPE
+    is_mongo_course = modulestore().get_modulestore_type(course_key) == ModuleStoreEnum.Type.mongo
     studio_link = None
     if is_studio_course and is_mongo_course:
         studio_link = get_cms_course_link(course, page)

lms/djangoapps/courseware/tests/test_courses.py

@@ -7,7 +7,7 @@ import mock
 from django.test.utils import override_settings
 from student.tests.factories import UserFactory
 import xmodule.modulestore.django as store_django
-from xmodule.modulestore import BRANCH_DRAFT_PREFERRED
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
 from xmodule.tests.xml import factories as xml
@@ -62,18 +62,18 @@ class ModuleStoreBranchSettingTest(ModuleStoreTestCase):
         mock.Mock(return_value='preview.localhost')
     )
     @override_settings(
-        HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS={r'preview\.': BRANCH_DRAFT_PREFERRED},
+        HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS={r'preview\.': ModuleStoreEnum.Branch.draft_preferred},
         MODULESTORE_BRANCH='fake_default_branch',
     )
     def test_default_modulestore_preview_mapping(self):
-        self.assertEqual(store_django._get_modulestore_branch_setting(), BRANCH_DRAFT_PREFERRED)
+        self.assertEqual(store_django._get_modulestore_branch_setting(), ModuleStoreEnum.Branch.draft_preferred)
 
     @mock.patch(
         'xmodule.modulestore.django.get_current_request_hostname',
         mock.Mock(return_value='localhost')
     )
     @override_settings(
-        HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS={r'preview\.': BRANCH_DRAFT_PREFERRED},
+        HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS={r'preview\.': ModuleStoreEnum.Branch.draft_preferred},
         MODULESTORE_BRANCH='fake_default_branch',
     )
     def test_default_modulestore_branch_mapping(self):

lms/djangoapps/courseware/tests/test_lti_integration.py

@@ -10,7 +10,7 @@ from django.test.utils import override_settings
 from django.core.urlresolvers import reverse
 from django.conf import settings
 
-from xmodule.modulestore import KEY_REVISION_DRAFT
+from xmodule.modulestore.mongo.base import MongoRevisionKey
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory, ItemFactory
 from xmodule.x_module import STUDENT_VIEW
@@ -160,7 +160,7 @@ class TestLTIModuleListing(ModuleStoreTestCase):
             parent_location=self.section2.location,
             display_name="lti draft",
             category="lti",
-            location=self.course.id.make_usage_key('lti', 'lti_published').replace(revision=KEY_REVISION_DRAFT),
+            location=self.course.id.make_usage_key('lti', 'lti_published').replace(revision=MongoRevisionKey.draft),
         )
 
     def expected_handler_url(self, handler):

lms/djangoapps/dashboard/sysadmin.py

@@ -39,7 +39,7 @@ from external_auth.views import generate_password
 from student.models import CourseEnrollment, UserProfile, Registration
 import track.views
 from xmodule.contentstore.django import contentstore
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.django import modulestore
 from xmodule.modulestore.store_utilities import delete_course
 from xmodule.modulestore.xml import XMLModuleStore
@@ -573,7 +573,7 @@ class Courses(SysadminDashboardView):
                         escape(str(err))
                     )
 
-            is_xml_course = (modulestore().get_modulestore_type(course_key) == XML_MODULESTORE_TYPE)
+            is_xml_course = (modulestore().get_modulestore_type(course_key) == ModuleStoreEnum.Type.xml)
             if course_found and is_xml_course:
                 cdir = course.data_dir
                 self.def_ms.courses.pop(cdir)

lms/djangoapps/instructor/tests/test_legacy_email.py

@@ -12,7 +12,7 @@ from courseware.tests.tests import TEST_DATA_MONGO_MODULESTORE
 from student.tests.factories import AdminFactory
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 
 from bulk_email.models import CourseAuthorization
 
@@ -103,7 +103,7 @@ class TestInstructorDashboardEmailView(ModuleStoreTestCase):
         # in `instructor/views/legacy.py` is doing the correct thing.
 
         with patch('xmodule.modulestore.mongo.base.MongoModuleStore.get_modulestore_type') as mock_modulestore:
-            mock_modulestore.return_value = XML_MODULESTORE_TYPE
+            mock_modulestore.return_value = ModuleStoreEnum.Type.xml
 
             # Assert that the URL for the email view is not in the response
             response = self.client.get(self.url)

lms/djangoapps/instructor/views/instructor_dashboard.py

@@ -15,7 +15,7 @@ from django.conf import settings
 from lms.lib.xblock.runtime import quote_slashes
 from xmodule_modifiers import wrap_xblock
 from xmodule.html_module import HtmlDescriptor
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.django import modulestore
 from xblock.field_data import DictFieldData
 from xblock.fields import ScopeIds
@@ -37,7 +37,7 @@ def instructor_dashboard_2(request, course_id):
     """ Display the instructor dashboard for a course. """
     course_key = SlashSeparatedCourseKey.from_deprecated_string(course_id)
     course = get_course_by_id(course_key, depth=None)
-    is_studio_course = (modulestore().get_modulestore_type(course_key) != XML_MODULESTORE_TYPE)
+    is_studio_course = (modulestore().get_modulestore_type(course_key) != ModuleStoreEnum.Type.xml)
 
     access = {
         'admin': request.user.is_staff,

lms/djangoapps/instructor/views/legacy.py

@@ -28,7 +28,7 @@ from django.utils import timezone
 
 from xmodule_modifiers import wrap_xblock
 import xmodule.graders as xmgraders
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.django import modulestore
 from opaque_keys.edx.locations import SlashSeparatedCourseKey
 from xmodule.modulestore.exceptions import ItemNotFoundError
@@ -968,7 +968,7 @@ def instructor_dashboard(request, course_id):
         instructor_tasks = None
 
     # determine if this is a studio-backed course so we can provide a link to edit this course in studio
-    is_studio_course = modulestore().get_modulestore_type(course_key) != XML_MODULESTORE_TYPE
+    is_studio_course = modulestore().get_modulestore_type(course_key) != ModuleStoreEnum.Type.xml
     studio_url = None
     if is_studio_course:
         studio_url = get_cms_course_link(course)

lms/djangoapps/instructor/views/tools.py

@@ -12,7 +12,7 @@ from django.utils.translation import ugettext as _
 
 from courseware.models import StudentModule
 from xmodule.fields import Date
-from xmodule.modulestore import XML_MODULESTORE_TYPE
+from xmodule.modulestore import ModuleStoreEnum
 from xmodule.modulestore.django import modulestore
 
 from bulk_email.models import CourseAuthorization
@@ -59,7 +59,7 @@ def bulk_email_is_enabled_for_course(course_id):
     """
 
     bulk_email_enabled_globally = (settings.FEATURES['ENABLE_INSTRUCTOR_EMAIL'] == True)
-    is_studio_course = (modulestore().get_modulestore_type(course_id) != XML_MODULESTORE_TYPE)
+    is_studio_course = (modulestore().get_modulestore_type(course_id) != ModuleStoreEnum.Type.xml)
     bulk_email_enabled_for_course = CourseAuthorization.instructor_email_enabled(course_id)
 
     if bulk_email_enabled_globally and is_studio_course and bulk_email_enabled_for_course:

lms/envs/cms/dev.py

@@ -44,5 +44,5 @@ DEBUG_TOOLBAR_PANELS += (
 # what the 'default' modulestore to use while processing the request
 # for example 'preview.edx.org' should use the draft modulestore
 HOSTNAME_MODULESTORE_DEFAULT_MAPPINGS = {
-    'preview\.': 'draft'
+    'preview\.': 'draft-preferred'
 }

lms/envs/common.py

@@ -475,7 +475,7 @@ XBLOCK_SELECT_FUNCTION = prefer_xmodules
 
 ############# ModuleStore Configuration ##########
 
-MODULESTORE_BRANCH = 'published'
+MODULESTORE_BRANCH = 'published-only'
 CONTENTSTORE = None
 DOC_STORE_CONFIG = {
     'host': 'localhost',

lms/envs/test.py

@@ -109,7 +109,7 @@ STATICFILES_DIRS += [
     if os.path.isdir(COMMON_TEST_DATA_ROOT / course_dir)
 ]
 
-MODULESTORE_BRANCH = 'draft'
+MODULESTORE_BRANCH = 'draft-preferred'
 update_module_store_settings(
     MODULESTORE,
     module_store_options={