backport libraries home performance fix

cms/djangoapps/contentstore/rest_api/v1/views/home.py

@@ -215,4 +215,5 @@ def get(self, request: Request):
 
         library_context = get_library_context(request)
         serializer = LibraryTabSerializer(library_context)
+
         return Response(serializer.data)

cms/djangoapps/contentstore/views/course.py

@@ -52,7 +52,7 @@
     CourseStaffRole,
     GlobalStaff,
     UserBasedRole,
-    OrgStaffRole
+    OrgStaffRole,
 )
 from common.djangoapps.util.json_request import JsonResponse, JsonResponseBadRequest, expect_json
 from common.djangoapps.util.string_utils import _has_non_ascii_characters

common/djangoapps/student/auth.py

@@ -23,7 +23,7 @@
     OrgContentCreatorRole,
     OrgInstructorRole,
     OrgLibraryUserRole,
-    OrgStaffRole
+    OrgStaffRole,
 )
 
 # Studio permissions:
@@ -106,6 +106,7 @@ def get_user_permissions(user, course_key, org=None):
     # Staff have all permissions except EDIT_ROLES:
     if OrgStaffRole(org=org).has_user(user) or (course_key and user_has_role(user, CourseStaffRole(course_key))):
         return STUDIO_VIEW_USERS | STUDIO_EDIT_CONTENT | STUDIO_VIEW_CONTENT
+
     # Otherwise, for libraries, users can view only:
     if course_key and isinstance(course_key, LibraryLocator):
         if OrgLibraryUserRole(org=org).has_user(user) or user_has_role(user, LibraryUserRole(course_key)):

common/djangoapps/student/role_helpers.py

@@ -75,4 +75,4 @@ def get_course_roles(user: User) -> list[CourseAccessRole]:
     """
     # pylint: disable=protected-access
     role_cache = get_role_cache(user)
-    return list(role_cache._roles)
+    return list(role_cache.all_roles_set)

common/djangoapps/student/roles.py

@@ -4,9 +4,9 @@
 """
 
 
+from collections import defaultdict
 import logging
 from abc import ABCMeta, abstractmethod
-from collections import defaultdict
 from contextlib import contextmanager
 
 from django.contrib.auth.models import User  # lint-amnesty, pylint: disable=imported-auth-user
@@ -23,6 +23,9 @@
 # A mapping of roles to the roles that they inherit permissions from.
 ACCESS_ROLES_INHERITANCE = {}
 
+# The key used to store roles for a user in the cache that do not belong to a course or do not have a course id.
+ROLE_CACHE_UNGROUPED_ROLES__KEY = 'ungrouped'
+
 
 def register_access_role(cls):
     """
@@ -60,21 +63,52 @@ def strict_role_checking():
     ACCESS_ROLES_INHERITANCE.update(OLD_ACCESS_ROLES_INHERITANCE)
 
 
+def get_role_cache_key_for_course(course_key=None):
+    """
+    Get the cache key for the course key.
+    """
+    return str(course_key) if course_key else ROLE_CACHE_UNGROUPED_ROLES__KEY
+
+
 class BulkRoleCache:  # lint-amnesty, pylint: disable=missing-class-docstring
+    """
+    This class provides a caching mechanism for roles grouped by users and courses,
+    using a nested dictionary structure to optimize lookup performance. The cache structure is designed as follows:
+
+    {
+        user_id_1: {
+            course_id_1: {role1, role2, role3},  # Set of roles associated with course_id_1
+            course_id_2: {role4, role5, role6},  # Set of roles associated with course_id_2
+            [ROLE_CACHE_UNGROUPED_ROLES_KEY]: {role7, role8}  # Set of roles not tied to any specific course or library
+        },
+        user_id_2: { ... }  # Similar structure for another user
+    }
+
+    - Each top-level dictionary entry keys by `user_id` to access role data for a specific user.
+    - Nested within each user's dictionary, entries are keyed by `course_id` grouping roles by course.
+    - The special key `ROLE_CACHE_UNGROUPED_ROLES_KEY` (a constant defined above)
+        stores roles that are not associated with any specific course or library.
+    """
+
     CACHE_NAMESPACE = "student.roles.BulkRoleCache"
     CACHE_KEY = 'roles_by_user'
 
     @classmethod
     def prefetch(cls, users):  # lint-amnesty, pylint: disable=missing-function-docstring
-        roles_by_user = defaultdict(set)
+        roles_by_user = defaultdict(lambda: defaultdict(set))
         get_cache(cls.CACHE_NAMESPACE)[cls.CACHE_KEY] = roles_by_user
 
         for role in CourseAccessRole.objects.filter(user__in=users).select_related('user'):
-            roles_by_user[role.user.id].add(role)
+            user_id = role.user.id
+            course_id = get_role_cache_key_for_course(role.course_id)
+
+            # Add role to the set in roles_by_user[user_id][course_id]
+            user_roles_set_for_course = roles_by_user[user_id][course_id]
+            user_roles_set_for_course.add(role)
 
         users_without_roles = [u for u in users if u.id not in roles_by_user]
         for user in users_without_roles:
-            roles_by_user[user.id] = set()
+            roles_by_user[user.id] = {}
 
     @classmethod
     def get_user_roles(cls, user):
@@ -83,15 +117,32 @@ def get_user_roles(cls, user):
 
 class RoleCache:
     """
-    A cache of the CourseAccessRoles held by a particular user
+    A cache of the CourseAccessRoles held by a particular user.
+    Internal data structures should be accessed by getter and setter methods;
+    don't use `_roles_by_course_id` or `_roles` directly.
+    _roles_by_course_id: This is the data structure as saved in the RequestCache.
+        It contains all roles for a user as a dict that's keyed by course_id.
+        The key ROLE_CACHE_UNGROUPED_ROLES__KEY is used for all roles
+        that are not associated with a course.
+    _roles: This is a set of all roles for a user, ungrouped. It's used for some types of
+        lookups and collected from _roles_by_course_id on initialization
+        so that it doesn't need to be recalculated.
+
     """
     def __init__(self, user):
         try:
-            self._roles = BulkRoleCache.get_user_roles(user)
+            self._roles_by_course_id = BulkRoleCache.get_user_roles(user)
         except KeyError:
-            self._roles = set(
-                CourseAccessRole.objects.filter(user=user).all()
-            )
+            self._roles_by_course_id = {}
+            roles = CourseAccessRole.objects.filter(user=user).all()
+            for role in roles:
+                course_id = get_role_cache_key_for_course(role.course_id)
+                if not self._roles_by_course_id.get(course_id):
+                    self._roles_by_course_id[course_id] = set()
+                self._roles_by_course_id[course_id].add(role)
+        self._roles = set()
+        for roles_for_course in self._roles_by_course_id.values():
+            self._roles.update(roles_for_course)
 
     @staticmethod
     def get_roles(role):
@@ -100,16 +151,24 @@ def get_roles(role):
         """
         return ACCESS_ROLES_INHERITANCE.get(role, set()) | {role}
 
+    @property
+    def all_roles_set(self):
+        return self._roles
+
+    @property
+    def roles_by_course_id(self):
+        return self._roles_by_course_id
+
     def has_role(self, role, course_id, org):
         """
         Return whether this RoleCache contains a role with the specified role
         or a role that inherits from the specified role, course_id and org.
         """
+        course_id_string = get_role_cache_key_for_course(course_id)
+        course_roles = self._roles_by_course_id.get(course_id_string, [])
         return any(
-            access_role.role in self.get_roles(role) and
-            access_role.course_id == course_id and
-            access_role.org == org
-            for access_role in self._roles
+            access_role.role in self.get_roles(role) and access_role.org == org
+            for access_role in course_roles
         )
 
 

common/djangoapps/student/tests/test_roles.py

@@ -6,6 +6,7 @@
 import ddt
 from django.test import TestCase
 from opaque_keys.edx.keys import CourseKey
+from opaque_keys.edx.locator import LibraryLocator
 
 from common.djangoapps.student.roles import (
     CourseAccessRole,
@@ -22,7 +23,9 @@
     OrgContentCreatorRole,
     OrgInstructorRole,
     OrgStaffRole,
-    RoleCache
+    RoleCache,
+    get_role_cache_key_for_course,
+    ROLE_CACHE_UNGROUPED_ROLES__KEY
 )
 from common.djangoapps.student.role_helpers import get_course_roles, has_staff_roles
 from common.djangoapps.student.tests.factories import AnonymousUserFactory, InstructorFactory, StaffFactory, UserFactory
@@ -35,7 +38,7 @@ class RolesTestCase(TestCase):
 
     def setUp(self):
         super().setUp()
-        self.course_key = CourseKey.from_string('edX/toy/2012_Fall')
+        self.course_key = CourseKey.from_string('course-v1:course-v1:edX+toy+2012_Fall')
         self.course_loc = self.course_key.make_usage_key('course', '2012_Fall')
         self.anonymous_user = AnonymousUserFactory()
         self.student = UserFactory()
@@ -189,8 +192,9 @@ def test_get_orgs_for_user(self):
 @ddt.ddt
 class RoleCacheTestCase(TestCase):  # lint-amnesty, pylint: disable=missing-class-docstring
 
-    IN_KEY = CourseKey.from_string('edX/toy/2012_Fall')
-    NOT_IN_KEY = CourseKey.from_string('edX/toy/2013_Fall')
+    IN_KEY_STRING = 'course-v1:edX+toy+2012_Fall'
+    IN_KEY = CourseKey.from_string(IN_KEY_STRING)
+    NOT_IN_KEY = CourseKey.from_string('course-v1:edX+toy+2013_Fall')
 
     ROLES = (
         (CourseStaffRole(IN_KEY), ('staff', IN_KEY, 'edX')),
@@ -233,3 +237,75 @@ def test_only_in_role(self, role, target):
     def test_empty_cache(self, role, target):  # lint-amnesty, pylint: disable=unused-argument
         cache = RoleCache(self.user)
         assert not cache.has_role(*target)
+
+    def test_get_role_cache_key_for_course_for_course_object_gets_string(self):
+        """
+        Given a valid course key object, get_role_cache_key_for_course
+        should return the string representation of the key.
+        """
+        course_string = 'course-v1:edX+toy+2012_Fall'
+        key = CourseKey.from_string(course_string)
+        key = get_role_cache_key_for_course(key)
+        assert key == course_string
+
+    def test_get_role_cache_key_for_course_for_undefined_object_returns_default(self):
+        """
+        Given a value None, get_role_cache_key_for_course
+        should return the default key for ungrouped courses.
+        """
+        key = get_role_cache_key_for_course(None)
+        assert key == ROLE_CACHE_UNGROUPED_ROLES__KEY
+
+    def test_role_cache_get_roles_set(self):
+        """
+        Test that the RoleCache.all_roles_set getter method returns a flat set of all roles for a user
+        and that the ._roles attribute is the same as the set to avoid legacy behavior being broken.
+        """
+        lib0 = LibraryLocator.from_string('library-v1:edX+quizzes')
+        course0 = CourseKey.from_string('course-v1:edX+toy+2012_Summer')
+        course1 = CourseKey.from_string('course-v1:edX+toy2+2013_Fall')
+        role_library_v1 = LibraryUserRole(lib0)
+        role_course_0 = CourseInstructorRole(course0)
+        role_course_1 = CourseInstructorRole(course1)
+
+        role_library_v1.add_users(self.user)
+        role_course_0.add_users(self.user)
+        role_course_1.add_users(self.user)
+
+        cache = RoleCache(self.user)
+        assert cache.has_role('library_user', lib0, 'edX')
+        assert cache.has_role('instructor', course0, 'edX')
+        assert cache.has_role('instructor', course1, 'edX')
+
+        assert len(cache.all_roles_set) == 3
+        roles_set = cache.all_roles_set
+        for role in roles_set:
+            assert role.course_id.course in ('quizzes', 'toy2', 'toy')
+
+        assert roles_set == cache._roles  # pylint: disable=protected-access
+
+    def test_role_cache_roles_by_course_id(self):
+        """
+        Test that the RoleCache.roles_by_course_id getter method returns a dictionary of roles for a user
+        that are grouped by course_id or if ungrouped by the ROLE_CACHE_UNGROUPED_ROLES__KEY.
+        """
+        lib0 = LibraryLocator.from_string('library-v1:edX+quizzes')
+        course0 = CourseKey.from_string('course-v1:edX+toy+2012_Summer')
+        course1 = CourseKey.from_string('course-v1:edX+toy2+2013_Fall')
+        role_library_v1 = LibraryUserRole(lib0)
+        role_course_0 = CourseInstructorRole(course0)
+        role_course_1 = CourseInstructorRole(course1)
+        role_org_staff = OrgStaffRole('edX')
+
+        role_library_v1.add_users(self.user)
+        role_course_0.add_users(self.user)
+        role_course_1.add_users(self.user)
+        role_org_staff.add_users(self.user)
+
+        cache = RoleCache(self.user)
+        roles_dict = cache.roles_by_course_id
+        assert len(roles_dict) == 4
+        assert roles_dict.get(ROLE_CACHE_UNGROUPED_ROLES__KEY).pop().role == 'staff'
+        assert roles_dict.get('library-v1:edX+quizzes').pop().course_id.course == 'quizzes'
+        assert roles_dict.get('course-v1:edX+toy+2012_Summer').pop().course_id.course == 'toy'
+        assert roles_dict.get('course-v1:edX+toy2+2013_Fall').pop().course_id.course == 'toy2'