MIT: CCX. Address performance issues.

Use client's session to set POC for test, now that we have the capability to do that.

Use a middleware to set the current POC one time per request, and avoid having to look up the stack for the current request in 'get_current_poc'.

Fetch all overrides for a block at one time.

Speed up the lineage computation by doing some caching.

Unused import.

Get field overrides once per user per block.

Streamline configuration.

Fix poc config tuples

lms/djangoapps/courseware/field_overrides.py

@@ -199,7 +199,20 @@ def _lineage(block):
     Returns an iterator over all ancestors of the given block, starting with
     its immediate parent and ending at the root of the block tree.
     """
-    location = modulestore().get_parent_location(block.location)
-    while location:
-        yield modulestore().get_item(location)
-        location = modulestore().get_parent_location(location)
+    parent = _get_parent(block)
+    while parent:
+        yield parent
+        parent = _get_parent(parent)
+
+
+def _get_parent(block):
+    """
+    Gets parent of a block, trying to cache result.
+    """
+    if not hasattr(block, '_parent'):
+        store = modulestore()
+        # Call to get_parent_location is fairly expensive.  Is there a more
+        # performant way to get at the ancestors of a block?
+        location = store.get_parent_location(block.location)
+        block._parent = store.get_item(location) if location else None
+    return block._parent

lms/djangoapps/courseware/student_field_overrides.py

@@ -24,18 +24,31 @@ def get_override_for_user(user, block, name, default=None):
     specify the block and the name of the field.  If the field is not
     overridden for the given user, returns `default`.
     """
-    try:
-        override = StudentFieldOverride.objects.get(
-            course_id=block.runtime.course_id,
-            location=block.location,
-            student_id=user.id,
-            field=name
-        )
-        field = block.fields[name]
-        return field.from_json(json.loads(override.value))
-    except StudentFieldOverride.DoesNotExist:
-        pass
-    return default
+    if not hasattr(block, '_student_overrides'):
+        block._student_overrides = {}
+    overrides = block._student_overrides.get(user.id)
+    if overrides is None:
+        overrides = _get_overrides_for_user(user, block)
+        block._student_overrides[user.id] = overrides
+    return overrides.get(name, default)
+
+
+def _get_overrides_for_user(user, block):
+    """
+    Gets all of the individual student overrides for given user and block.
+    Returns a dictionary of field override values keyed by field name.
+    """
+    query = StudentFieldOverride.objects.filter(
+        course_id=block.runtime.course_id,
+        location=block.location,
+        student_id=user.id,
+    )
+    overrides = {}
+    for override in query:
+        field = block.fields[override.field]
+        value = field.from_json(json.loads(override.value))
+        overrides[override.field] = value
+    return overrides
 
 
 def override_field_for_user(user, block, name, value):

lms/djangoapps/pocs/overrides.py

@@ -7,7 +7,6 @@ import threading
 
 from contextlib import contextmanager
 
-from courseware.courses import get_request_for_thread
 from courseware.field_overrides import FieldOverrideProvider
 from pocs import ACTIVE_POC_KEY
 
@@ -54,34 +53,12 @@ def poc_context(poc):
 
 def get_current_poc(user):
     """
-    Return the poc that is active for this user
-
-    The user's session data is used to look up the active poc by id
-    If no poc is active, None is returned and MOOC view will take precedence
-    Active poc can be overridden by context manager (see `poc_context`)
+    Return the poc that is active for this request.
     """
-    # If poc context is explicitly set, that takes precedence over the user's
-    # session.
     poc = _POC_CONTEXT.poc
     if poc:
         return poc
 
-    request = get_request_for_thread()
-    if request is None:
-        return None
-
-    poc = None
-    poc_id = request.session.get(ACTIVE_POC_KEY, None)
-    if poc_id is not None:
-        try:
-            membership = PocMembership.objects.get(
-                student=user, active=True, poc__id__exact=poc_id
-            )
-            poc = membership.poc
-        except PocMembership.DoesNotExist:
-            pass
-    return poc
-
 
 def get_override_for_poc(poc, block, name, default=None):
     """
@@ -89,16 +66,30 @@ def get_override_for_poc(poc, block, name, default=None):
     specify the block and the name of the field.  If the field is not
     overridden for the given poc, returns `default`.
     """
-    try:
-        override = PocFieldOverride.objects.get(
-            poc=poc,
-            location=block.location,
-            field=name)
-        field = block.fields[name]
-        return field.from_json(json.loads(override.value))
-    except PocFieldOverride.DoesNotExist:
-        pass
-    return default
+    if not hasattr(block, '_poc_overrides'):
+        block._poc_overrides = {}
+    overrides = block._poc_overrides.get(poc.id)
+    if overrides is None:
+        overrides = _get_overrides_for_poc(poc, block)
+        block._poc_overrides[poc.id] = overrides
+    return overrides.get(name, default)
+
+
+def _get_overrides_for_poc(poc, block):
+    """
+    Returns a dictionary mapping field name to overriden value for any
+    overrides set on this block for this POC.
+    """
+    overrides = {}
+    query = PocFieldOverride.objects.filter(
+        poc=poc,
+        location=block.location
+    )
+    for override in query:
+        field = block.fields[override.field]
+        value = field.from_json(json.loads(override.value))
+        overrides[override.field] = value
+    return overrides
 
 
 def override_field_for_poc(poc, block, name, value):
@@ -115,6 +106,9 @@ def override_field_for_poc(poc, block, name, value):
     override.value = json.dumps(field.to_json(value))
     override.save()
 
+    if hasattr(block, '_poc_overrides'):
+        del block._poc_overrides[poc.id]
+
 
 def clear_override_for_poc(poc, block, name):
     """
@@ -128,5 +122,36 @@ def clear_override_for_poc(poc, block, name):
             poc=poc,
             location=block.location,
             field=name).delete()
+
+        if hasattr(block, '_poc_overrides'):
+            del block._poc_overrides[poc.id]
+
     except PocFieldOverride.DoesNotExist:
         pass
+
+
+class PocMiddleware(object):
+    """
+    Checks to see if current session is examining a POC and sets the POC as
+    the current POC for the override machinery if so.
+    """
+    def process_request(self, request):
+        """
+        Do the check.
+        """
+        poc_id = request.session.get(ACTIVE_POC_KEY, None)
+        if poc_id is not None:
+            try:
+                membership = PocMembership.objects.get(
+                    student=request.user, active=True, poc__id__exact=poc_id
+                )
+                _POC_CONTEXT.poc = membership.poc
+            except PocMembership.DoesNotExist:
+                pass
+
+    def process_response(self, request, response):
+        """
+        Clean up afterwards.
+        """
+        _POC_CONTEXT.poc = None
+        return response

lms/djangoapps/pocs/tests/test_views.py

@@ -29,11 +29,8 @@ from ..models import (
     PocMembership,
     PocFutureMembership,
 )
-from ..overrides import (
-    get_override_for_poc,
-    override_field_for_poc,
-    poc_context,
-)
+from ..overrides import get_override_for_poc, override_field_for_poc
+from .. import ACTIVE_POC_KEY
 from .factories import (
     PocFactory,
     PocMembershipFactory,
@@ -525,19 +522,20 @@ class TestPocGrades(ModuleStoreTestCase, LoginEnrollmentTestCase):
         self.addCleanup(patch_context.stop)
 
         self.client.login(username=self.student.username, password="test")
+        session = self.client.session
+        session[ACTIVE_POC_KEY] = self.poc.id
+        session.save()
+        self.client.session.get(ACTIVE_POC_KEY)
         url = reverse(
             'progress',
             kwargs={'course_id': self.course.id.to_deprecated_string()}
         )
-
-        with poc_context(self.poc):
-
-            response = self.client.get(url)
-            self.assertEqual(response.status_code, 200)
-            grades = response.mako_context['grade_summary']
-            self.assertEqual(grades['percent'], 0.5)
-            self.assertEqual(grades['grade_breakdown'][0]['percent'], 0.5)
-            self.assertEqual(len(grades['section_breakdown']), 4)
+        response = self.client.get(url)
+        self.assertEqual(response.status_code, 200)
+        grades = response.mako_context['grade_summary']
+        self.assertEqual(grades['percent'], 0.5)
+        self.assertEqual(grades['grade_breakdown'][0]['percent'], 0.5)
+        self.assertEqual(len(grades['section_breakdown']), 4)
 
 
 class TestSwitchActivePoc(ModuleStoreTestCase, LoginEnrollmentTestCase):

lms/djangoapps/pocs/views.py

@@ -26,7 +26,6 @@ from django_future.csrf import ensure_csrf_cookie
 from django.contrib.auth.decorators import login_required
 from django.contrib.auth.models import User
 
-from courseware.courses import get_course
 from courseware.courses import get_course_by_id
 from courseware.field_overrides import disable_overrides
 from courseware.grades import iterate_grades_for
@@ -50,7 +49,6 @@ from .overrides import (
 from .utils import (
     enroll_email,
     unenroll_email,
-    get_all_pocs_for_user,
 )
 from pocs import ACTIVE_POC_KEY
 
@@ -89,24 +87,27 @@ def dashboard(request, course):
     Display the POC Coach Dashboard.
     """
     poc = get_poc_for_coach(course, request.user)
-    schedule = get_poc_schedule(course, poc)
-    grading_policy = get_override_for_poc(poc, course, 'grading_policy',
-                                          course.grading_policy)
     context = {
         'course': course,
         'poc': poc,
-        'schedule': json.dumps(schedule, indent=4),
-        'save_url': reverse('save_poc', kwargs={'course_id': course.id}),
-        'poc_members': PocMembership.objects.filter(poc=poc),
-        'gradebook_url': reverse('poc_gradebook',
-                                 kwargs={'course_id': course.id}),
-        'grades_csv_url': reverse('poc_grades_csv',
-                                  kwargs={'course_id': course.id}),
-        'grading_policy': json.dumps(grading_policy, indent=4),
-        'grading_policy_url': reverse('poc_set_grading_policy',
-                                      kwargs={'course_id': course.id}),
     }
-    if not poc:
+
+    if poc:
+        schedule = get_poc_schedule(course, poc)
+        grading_policy = get_override_for_poc(
+            poc, course, 'grading_policy', course.grading_policy)
+        context['schedule'] = json.dumps(schedule, indent=4)
+        context['save_url'] = reverse(
+            'save_poc', kwargs={'course_id': course.id})
+        context['poc_members'] = PocMembership.objects.filter(poc=poc)
+        context['gradebook_url'] = reverse(
+            'poc_gradebook', kwargs={'course_id': course.id})
+        context['grades_csv_url'] = reverse(
+            'poc_grades_csv', kwargs={'course_id': course.id})
+        context['grading_policy'] = json.dumps(grading_policy, indent=4)
+        context['grading_policy_url'] = reverse(
+            'poc_set_grading_policy', kwargs={'course_id': course.id})
+    else:
         context['create_poc_url'] = reverse(
             'create_poc', kwargs={'course_id': course.id})
     return render_to_response('pocs/coach_dashboard.html', context)

lms/envs/aws.py

@@ -576,3 +576,17 @@ ONLOAD_BEACON_SAMPLE_RATE = ENV_TOKENS.get('ONLOAD_BEACON_SAMPLE_RATE', ONLOAD_B
 ECOMMERCE_API_URL = ENV_TOKENS.get('ECOMMERCE_API_URL', ECOMMERCE_API_URL)
 ECOMMERCE_API_SIGNING_KEY = AUTH_TOKENS.get('ECOMMERCE_API_SIGNING_KEY', ECOMMERCE_API_SIGNING_KEY)
 ECOMMERCE_API_TIMEOUT = ENV_TOKENS.get('ECOMMERCE_API_TIMEOUT', ECOMMERCE_API_TIMEOUT)
+
+##### Personal Online Courses #####
+if FEATURES.get('PERSONAL_ONLINE_COURSES'):
+    INSTALLED_APPS += ('pocs',)
+    MIDDLEWARE_CLASSES += ('pocs.overrides.PocMiddleware',)
+    FIELD_OVERRIDE_PROVIDERS += (
+        'pocs.overrides.PersonalOnlineCoursesOverrideProvider',
+    )
+
+##### Individual Due Date Extensions #####
+if FEATURES.get('INDIVIDUAL_DUE_DATES'):
+    FIELD_OVERRIDE_PROVIDERS += (
+        'courseware.student_field_overrides.IndividualStudentOverrideProvider',
+    )

lms/envs/test.py

@@ -471,3 +471,4 @@ FEATURES['CERTIFICATES_HTML_VIEW'] = True
 
 ######### personal online courses #########
 INSTALLED_APPS += ('pocs',)
+MIDDLEWARE_CLASSES += ('pocs.overrides.PocMiddleware',)