Create task to process a batch of grade computations.

lms/djangoapps/grades/new/course_grade.py

@@ -368,7 +368,7 @@ def create(self, student, course, collected_block_structure=None, read_only=True
 
     GradeResult = namedtuple('GradeResult', ['student', 'course_grade', 'err_msg'])
 
-    def iter(self, course, students):
+    def iter(self, course, students, read_only=True):
         """
         Given a course and an iterable of students (User), yield a GradeResult
         for every student enrolled in the course.  GradeResult is a named tuple of:
@@ -388,7 +388,7 @@ def iter(self, course, students):
         for student in students:
             with dog_stats_api.timer('lms.grades.CourseGradeFactory.iter', tags=[u'action:{}'.format(course.id)]):
                 try:
-                    course_grade = CourseGradeFactory().create(student, course, collected_block_structure)
+                    course_grade = CourseGradeFactory().create(student, course, collected_block_structure, read_only=read_only)
                     yield self.GradeResult(student, course_grade, "")
 
                 except Exception as exc:  # pylint: disable=broad-except

lms/djangoapps/grades/tasks.py

@@ -19,8 +19,10 @@
 from celery_utils.persist_on_failure import PersistOnFailureTask
 from courseware.model_data import get_score
 from lms.djangoapps.course_blocks.api import get_course_blocks
-from opaque_keys.edx.keys import UsageKey
+from lms.djangoapps.courseware import courses
+from opaque_keys.edx.keys import CourseKey, UsageKey
 from opaque_keys.edx.locator import CourseLocator
+from student.models import CourseEnrollment
 from submissions import api as sub_api
 from track.event_transaction_utils import (
     set_event_transaction_type,
@@ -31,6 +33,7 @@
 
 from .constants import ScoreDatabaseTableEnum
 from .new.subsection_grade import SubsectionGradeFactory
+from .new.course_grade import CourseGradeFactory
 from .signals.signals import SUBSECTION_SCORE_CHANGED
 from .transformer import GradesTransformer
 
@@ -58,12 +61,24 @@ class _BaseTask(PersistOnFailureTask, LoggedTask):  # pylint: disable=abstract-m
     abstract = True
 
 
-@task
-def compute_grades_for_course(course_key, offset, batch_size):  # pylint: disable=unused-argument
+@task(base=_BaseTask)
+def compute_grades_for_course(course_key, offset, batch_size):
     """
-    TODO: TNL-6690: Fill this task in and remove pylint disables
+    Compute grades for a set of students in the specified course.
+
+    The set of students will be determined by the order of enrollment date, and
+    limited to at most <batch_size> students, starting from the specified
+    offset.
     """
-    pass
+
+    course = courses.get_course_by_id(CourseKey.from_string(course_key))
+    enrollments = CourseEnrollment.objects.filter(course_id=course.id).order_by('created')
+    student_iter = (enrollment.user for enrollment in enrollments[offset:offset + batch_size])
+    list(CourseGradeFactory().iter(
+        course,
+        students=student_iter,
+        read_only=False,
+    ))
 
 
 @task(bind=True, base=_BaseTask, default_retry_delay=30, routing_key=settings.RECALCULATE_GRADES_ROUTING_KEY)
@@ -136,7 +151,7 @@ def _recalculate_subsection_grade(self, **kwargs):
                 self.request.id,
                 kwargs,
             ))
-        raise _retry_recalculate_subsection_grade(self, exc=exc, **kwargs)
+        raise self.retry(kwargs=kwargs, exc=exc)
 
 
 def _has_db_updated_with_new_score(self, scored_block_usage_key, **kwargs):
@@ -218,11 +233,3 @@ def _update_subsection_grades(
                     user=student,
                     subsection_grade=subsection_grade,
                 )
-
-
-def _retry_recalculate_subsection_grade(self, exc=None, **kwargs):
-    """
-    Calls retry for the recalculate_subsection_grade task with the
-    given inputs.
-    """
-    self.retry(kwargs=kwargs, exc=exc)

lms/djangoapps/grades/tests/test_tasks.py

@@ -11,10 +11,11 @@
 import itertools
 from mock import patch, MagicMock
 import pytz
+import six
 from util.date_utils import to_timestamp
 
 from openedx.core.djangoapps.content.block_structure.exceptions import BlockStructureNotFound
-from student.models import anonymous_id_for_user
+from student.models import CourseEnrollment, anonymous_id_for_user
 from student.tests.factories import UserFactory
 from track.event_transaction_utils import (
     create_new_event_transaction_id,
@@ -29,22 +30,17 @@
 from lms.djangoapps.grades.constants import ScoreDatabaseTableEnum
 from lms.djangoapps.grades.models import PersistentCourseGrade, PersistentSubsectionGrade
 from lms.djangoapps.grades.signals.signals import PROBLEM_WEIGHTED_SCORE_CHANGED
-from lms.djangoapps.grades.tasks import recalculate_subsection_grade_v3, RECALCULATE_GRADE_DELAY
+from lms.djangoapps.grades.tasks import (
+    compute_grades_for_course,
+    recalculate_subsection_grade_v3,
+    RECALCULATE_GRADE_DELAY
+)
 
 
-@patch.dict(settings.FEATURES, {'PERSISTENT_GRADES_ENABLED_FOR_ALL_TESTS': False})
-@ddt.ddt
-class RecalculateSubsectionGradeTest(ModuleStoreTestCase):
+class HasCourseWithProblemsMixin(object):
     """
-    Ensures that the recalculate subsection grade task functions as expected when run.
+    Mixin to provide tests with a sample course with graded subsections
     """
-    ENABLED_SIGNALS = ['course_published', 'pre_publish']
-
-    def setUp(self):
-        super(RecalculateSubsectionGradeTest, self).setUp()
-        self.user = UserFactory()
-        PersistentGradesEnabledFlag.objects.create(enabled_for_all_courses=True, enabled=True)
-
     def set_up_course(self, enable_persistent_grades=True, create_multiple_subsections=False):
         """
         Configures the course for this test.
@@ -100,6 +96,20 @@ def set_up_course(self, enable_persistent_grades=True, create_multiple_subsectio
         _ = anonymous_id_for_user(self.user, self.course.id)
         # pylint: enable=attribute-defined-outside-init,no-member
 
+
+@patch.dict(settings.FEATURES, {'PERSISTENT_GRADES_ENABLED_FOR_ALL_TESTS': False})
+@ddt.ddt
+class RecalculateSubsectionGradeTest(HasCourseWithProblemsMixin, ModuleStoreTestCase):
+    """
+    Ensures that the recalculate subsection grade task functions as expected when run.
+    """
+    ENABLED_SIGNALS = ['course_published', 'pre_publish']
+
+    def setUp(self):
+        super(RecalculateSubsectionGradeTest, self).setUp()
+        self.user = UserFactory()
+        PersistentGradesEnabledFlag.objects.create(enabled_for_all_courses=True, enabled=True)
+
     @contextmanager
     def mock_get_score(self, score=MagicMock(grade=1.0, max_grade=2.0)):
         """
@@ -363,3 +373,47 @@ def _assert_retry_not_called(self, mock_retry):
         Verifies the task was not retried.
         """
         self.assertFalse(mock_retry.called)
+
+
+@ddt.ddt
+class ComputeGradesForCourseTest(HasCourseWithProblemsMixin, ModuleStoreTestCase):
+    """
+    Test compute_grades_for_course task.
+    """
+
+    ENABLED_SIGNALS = ['course_published', 'pre_publish']
+
+    def setUp(self):
+        super(ComputeGradesForCourseTest, self).setUp()
+        self.users = [UserFactory.create() for _ in xrange(12)]
+        self.set_up_course()
+        for user in self.users:
+            CourseEnrollment.enroll(user, self.course.id)
+
+    @ddt.data(*xrange(0, 12, 3))
+    def test_behavior(self, batch_size):
+        result = compute_grades_for_course.delay(
+            course_key=six.text_type(self.course.id),
+            batch_size=batch_size,
+            offset=4
+        )
+        self.assertTrue(result.successful)
+        self.assertEqual(
+            PersistentCourseGrade.objects.filter(course_id=self.course.id).count(),
+            min(batch_size, 8)  # No more than 8 due to offset
+        )
+        self.assertEqual(
+            PersistentSubsectionGrade.objects.filter(course_id=self.course.id).count(),
+            min(batch_size, 8)  # No more than 8 due to offset
+        )
+
+    @ddt.data(*xrange(1, 12, 3))
+    def test_database_calls(self, batch_size):
+        per_user_queries = 16 * min(batch_size, 6)  # No more than 6 due to offset
+        with self.assertNumQueries(3 + 16 * min(batch_size, 6)):
+            with check_mongo_calls(1):
+                compute_grades_for_course.delay(
+                    course_key=six.text_type(self.course.id),
+                    batch_size=batch_size,
+                    offset=6,
+                )