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Rough Notes on Grades Event POC

[From Matt Tuchfarber] Our top two use cases for message bus are:

• Syncing catalog data from Discovery to Credentials, and

• Syncing course certificate and grade data from LMS to Credentials

  • My first thought would be the GeneratedCertificate create/update/delete event, but in actuality we send a lot of auxiliary data with that API call now, and I don't know if it makes sense for you to build all that auxiliary data into the POC, and it'd be kinda of useless without it. It's an option though.

  • A grade change event would probably be a lot easier to POC since there's a lot less data to care about. So I'd vote that.

  • On grade change a signal gets sent that we listen to in our platform app: * https://github.com/edx/edx-platform/blob/3152c14192dcccac79b7b7a76eba91b380eba78a/openedx/core/djangoapps/credentials/apps.py#L33-L34

  • That signal handler just pipes to our send_grade_if_interesting code which only sends grade changes that are related to a GeneratedCertificate and are part of a course in a program. This is historically to avoid flooding the celery queue with grades we don't care about. With course certs eventually making their way to Credentials, those requirements wouldn't be worthwhile.

    • https://github.com/edx/edx-platform/blob/d7a4947ea97ade19ae39684a429533e77baad891/openedx/core/djangoapps/credentials/tasks/v1/tasks.py#L255

  • That sends a call to Credentials that looks like:

    • Code Block
      credentials_client.grades.post({ 'username': username, 'course_run': str(course_key), 'letter_grade': letter_grade, 'percent_grade': percent_grade, 'verified': verified, })

  • Credentials just has a UserGrade model with a DRF API that only does writes:

    • https://github.com/edx/credentials/blob/2a7a6475141333cc9b90d4d803d8f19041ae2a34/credentials/apps/api/v2/views.py#L136

  • If we published the data, we could just make a listener on Credentials that filters it down to things we care about, and creates/updates those objects. Pretty straightforward I think

• Additional Notes:

  • edx-platform sends three signals in this code:

    • Code Block

      COURSE_GRADE_CHANGED.send_robust( sender=None, user=user, course_grade=course_grade, course_key=course_data.course_key, deadline=course_data.course.end, ) if course_grade.passed: COURSE_GRADE_NOW_PASSED.send( sender=CourseGradeFactory, user=user, course_id=course_data.course_key, ) else: COURSE_GRADE_NOW_FAILED.send( sender=CourseGradeFactory, user=user, course_id=course_data.course_key, grade=course_grade, )