93 lines
3.2 KiB
Python
93 lines
3.2 KiB
Python
# ======== Offline calculation of grades =============================================================================
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#
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# Computing grades of a large number of students can take a long time. These routines allow grades to
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# be computed offline, by a batch process (eg cronjob).
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#
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# The grades are stored in the OfflineComputedGrade table of the courseware model.
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import json
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import time
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from json import JSONEncoder
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from courseware import grades, models
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from courseware.courses import get_course_by_id
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from django.contrib.auth.models import User
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from instructor.utils import DummyRequest
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class MyEncoder(JSONEncoder):
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def _iterencode(self, obj, markers=None):
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if isinstance(obj, tuple) and hasattr(obj, '_asdict'):
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gen = self._iterencode_dict(obj._asdict(), markers)
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else:
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gen = JSONEncoder._iterencode(self, obj, markers)
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for chunk in gen:
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yield chunk
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def offline_grade_calculation(course_id):
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'''
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Compute grades for all students for a specified course, and save results to the DB.
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'''
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tstart = time.time()
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enrolled_students = User.objects.filter(
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courseenrollment__course_id=course_id,
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courseenrollment__is_active=1
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).prefetch_related("groups").order_by('username')
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enc = MyEncoder()
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print "%d enrolled students" % len(enrolled_students)
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course = get_course_by_id(course_id)
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for student in enrolled_students:
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request = DummyRequest()
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request.user = student
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request.session = {}
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gradeset = grades.grade(student, request, course, keep_raw_scores=True)
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gs = enc.encode(gradeset)
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ocg, created = models.OfflineComputedGrade.objects.get_or_create(user=student, course_id=course_id)
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ocg.gradeset = gs
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ocg.save()
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print "%s done" % student # print statement used because this is run by a management command
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tend = time.time()
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dt = tend - tstart
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ocgl = models.OfflineComputedGradeLog(course_id=course_id, seconds=dt, nstudents=len(enrolled_students))
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ocgl.save()
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print ocgl
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print "All Done!"
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def offline_grades_available(course_id):
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'''
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Returns False if no offline grades available for specified course.
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Otherwise returns latest log field entry about the available pre-computed grades.
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'''
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ocgl = models.OfflineComputedGradeLog.objects.filter(course_id=course_id)
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if not ocgl:
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return False
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return ocgl.latest('created')
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def student_grades(student, request, course, keep_raw_scores=False, use_offline=False):
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'''
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This is the main interface to get grades. It has the same parameters as grades.grade, as well
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as use_offline. If use_offline is True then this will look for an offline computed gradeset in the DB.
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'''
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if not use_offline:
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return grades.grade(student, request, course, keep_raw_scores=keep_raw_scores)
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try:
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ocg = models.OfflineComputedGrade.objects.get(user=student, course_id=course.id)
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except models.OfflineComputedGrade.DoesNotExist:
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return dict(raw_scores=[], section_breakdown=[],
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msg='Error: no offline gradeset available for %s, %s' % (student, course.id))
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return json.loads(ocg.gradeset)
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