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Merge pull request #1478 from MITx/bugfix/dave/too_many_sql_queries

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Reduce SQL queries in courseware by model caching a User's groups
This commit is contained in:
David Ormsbee
2013-03-01 08:24:30 -08:00
parent c581ecd897 1d4defd0ea
commit e1fcf4c317
2 changed files with 76 additions and 64 deletions
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112
lms/djangoapps/courseware/access.py
View File

@@ -1,10 +1,10 @@
"""This file contains (or should), all access control logic for the courseware.
Ideally, it will be the only place that needs to know about any special settings
like DISABLE_START_DATES"""
import logging
import time
from datetime import datetime, timedelta
from functools import partial
from django.conf import settings
from django.contrib.auth.models import Group
@@ -363,6 +363,30 @@ def _course_org_staff_group_name(location, course_context=None):
return 'staff_%s' % course_id.split('/')[0]
def group_names_for(role, location, course_context=None):
"""Returns the group names for a given role with this location. Plural
because it will return both the name we expect now as well as the legacy
group name we support for backwards compatibility. This should not check
the DB for existence of a group (like some of its callers do) because that's
a DB roundtrip, and we expect this might be invoked many times as we crawl
an XModule tree."""
loc = Location(location)
legacy_group_name = '{0}_{1}'.format(role, loc.course)
if loc.category == 'course':
course_id = loc.course_id
else:
if course_context is None:
raise CourseContextRequired()
course_id = course_context
group_name = '{0}_{1}'.format(role, course_id)
return [group_name, legacy_group_name]
group_names_for_staff = partial(group_names_for, 'staff')
group_names_for_instructor = partial(group_names_for, 'instructor')
def _course_staff_group_name(location, course_context=None):
"""
Get the name of the staff group for a location in the context of a course run.
@@ -375,33 +399,12 @@ def _course_staff_group_name(location, course_context=None):
using course_id rather than just the course number. So first check to see if the group name exists
"""
loc = Location(location)
legacy_name = 'staff_%s' % loc.course
if _does_course_group_name_exist(legacy_name):
return legacy_name
group_name, legacy_group_name = group_names_for_staff(location, course_context)
if loc.category == 'course':
course_id = loc.course_id
else:
if course_context is None:
raise CourseContextRequired()
course_id = course_context
return 'staff_%s' % course_id
def course_beta_test_group_name(location):
"""
Get the name of the beta tester group for a location. Right now, that's
beta_testers_COURSE.
location: something that can passed to Location.
"""
return 'beta_testers_{0}'.format(Location(location).course)
# nosetests thinks that anything with _test_ in the name is a test.
# Correct this (https://nose.readthedocs.org/en/latest/finding_tests.html)
course_beta_test_group_name.__test__ = False
if _does_course_group_name_exist(legacy_group_name):
return legacy_group_name
return group_name
def _course_org_instructor_group_name(location, course_context=None):
"""
@@ -437,18 +440,26 @@ def _course_instructor_group_name(location, course_context=None):
using course_id rather than just the course number. So first check to see if the group name exists
"""
loc = Location(location)
legacy_name = 'instructor_%s' % loc.course
if _does_course_group_name_exist(legacy_name):
return legacy_name
group_name, legacy_group_name = group_names_for_instructor(location, course_context)
if loc.category == 'course':
course_id = loc.course_id
else:
if course_context is None:
raise CourseContextRequired()
course_id = course_context
if _does_course_group_name_exist(legacy_group_name):
return legacy_group_name
return group_name
def course_beta_test_group_name(location):
"""
Get the name of the beta tester group for a location. Right now, that's
beta_testers_COURSE.
location: something that can passed to Location.
"""
return 'beta_testers_{0}'.format(Location(location).course)
# nosetests thinks that anything with _test_ in the name is a test.
# Correct this (https://nose.readthedocs.org/en/latest/finding_tests.html)
course_beta_test_group_name.__test__ = False
return 'instructor_%s' % course_id
def _has_global_staff_access(user):
@@ -540,23 +551,22 @@ def _has_access_to_location(user, location, access_level, course_context):
user_groups = [g.name for g in user.groups.all()]
if access_level == 'staff':
staff_group = _course_staff_group_name(location, course_context)
# org_staff_group is a group for an entire organization
org_staff_group = _course_org_staff_group_name(location, course_context)
if staff_group in user_groups or org_staff_group in user_groups:
debug("Allow: user in group %s", staff_group)
return True
debug("Deny: user not in group %s", staff_group)
staff_groups = group_names_for_staff(location, course_context) + \
[_course_org_staff_group_name(location, course_context)]
for staff_group in staff_groups:
if staff_group in user_groups:
debug("Allow: user in group %s", staff_group)
return True
debug("Deny: user not in groups %s", staff_groups)
if access_level == 'instructor' or access_level == 'staff': # instructors get staff privileges
instructor_group = _course_instructor_group_name(location, course_context)
instructor_staff_group = _course_org_instructor_group_name(
location, course_context)
if instructor_group in user_groups or instructor_staff_group in user_groups:
debug("Allow: user in group %s", instructor_group)
return True
debug("Deny: user not in group %s", instructor_group)
instructor_groups = group_names_for_instructor(location, course_context) + \
[_course_org_instructor_group_name(location, course_context)]
for instructor_group in instructor_groups:
if instructor_group in user_groups:
debug("Allow: user in group %s", instructor_group)
return True
debug("Deny: user not in groups %s", instructor_groups)
else:
log.debug("Error in access._has_access_to_location access_level=%s unknown" % access_level)

28
lms/djangoapps/courseware/views.py
View File

@@ -86,7 +86,8 @@ def render_accordion(request, course, chapter, section):
Returns the html string'''
# grab the table of contents
toc = toc_for_course(request.user, request, course, chapter, section)
user = User.objects.prefetch_related("groups").get(id=request.user.id)
toc = toc_for_course(user, request, course, chapter, section)
context = dict([('toc', toc),
('course_id', course.id),
@@ -250,23 +251,24 @@ def index(request, course_id, chapter=None, section=None,
- HTTPresponse
"""
course = get_course_with_access(request.user, course_id, 'load', depth=2)
staff_access = has_access(request.user, course, 'staff')
registered = registered_for_course(course, request.user)
user = User.objects.prefetch_related("groups").get(id=request.user.id)
course = get_course_with_access(user, course_id, 'load', depth=2)
staff_access = has_access(user, course, 'staff')
registered = registered_for_course(course, user)
if not registered:
# TODO (vshnayder): do course instructors need to be registered to see course?
log.debug('User %s tried to view course %s but is not enrolled' % (request.user, course.location.url()))
log.debug('User %s tried to view course %s but is not enrolled' % (user, course.location.url()))
return redirect(reverse('about_course', args=[course.id]))
try:
student_module_cache = StudentModuleCache.cache_for_descriptor_descendents(
course.id, request.user, course, depth=2)
course.id, user, course, depth=2)
# Has this student been in this course before?
first_time = student_module_cache.lookup(course_id, 'course', course.location.url()) is None
# Load the module for the course
course_module = get_module_for_descriptor(request.user, request, course, student_module_cache, course.id)
course_module = get_module_for_descriptor(user, request, course, student_module_cache, course.id)
if course_module is None:
log.warning('If you see this, something went wrong: if we got this'
' far, should have gotten a course module for this user')
@@ -288,7 +290,7 @@ def index(request, course_id, chapter=None, section=None,
chapter_descriptor = course.get_child_by(lambda m: m.url_name == chapter)
if chapter_descriptor is not None:
instance_module = get_instance_module(course_id, request.user, course_module, student_module_cache)
instance_module = get_instance_module(course_id, user, course_module, student_module_cache)
save_child_position(course_module, chapter, instance_module)
else:
raise Http404('No chapter descriptor found with name {}'.format(chapter))
@@ -307,9 +309,9 @@ def index(request, course_id, chapter=None, section=None,
# Load all descendants of the section, because we're going to display its
# html, which in general will need all of its children
section_module_cache = StudentModuleCache.cache_for_descriptor_descendents(
course.id, request.user, section_descriptor, depth=None)
course.id, user, section_descriptor, depth=None)
section_module = get_module(request.user, request, section_descriptor.location,
section_module = get_module(user, request, section_descriptor.location,
section_module_cache, course.id, position=position, depth=None)
if section_module is None:
# User may be trying to be clever and access something
@@ -317,12 +319,12 @@ def index(request, course_id, chapter=None, section=None,
raise Http404
# Save where we are in the chapter
instance_module = get_instance_module(course_id, request.user, chapter_module, student_module_cache)
instance_module = get_instance_module(course_id, user, chapter_module, student_module_cache)
save_child_position(chapter_module, section, instance_module)
# check here if this section *is* a timed module.
if section_module.category == 'timelimit':
timer_context = update_timelimit_module(request.user, course_id, student_module_cache,
timer_context = update_timelimit_module(user, course_id, student_module_cache,
section_descriptor, section_module)
if 'timer_expiration_duration' in timer_context:
context.update(timer_context)
@@ -363,7 +365,7 @@ def index(request, course_id, chapter=None, section=None,
log.exception("Error in index view: user={user}, course={course},"
" chapter={chapter} section={section}"
"position={position}".format(
user=request.user,
user=user,
course=course,
chapter=chapter,
section=section,