6f9a3911e5
This abstract class contains most of the fields (aside from the id and foreign key to StudentModule that the subclasses need to manage). It also provides a get_history method that abstracts searching across multiple backends. Move router code to openedx/core We need to use it from cms and lms. Ensure aws_migrate can be used for migrating both the lms and cms. Handle queries directed to student_module_history vs default and the extra queries generated by Django 1.8 (SAVEPOINTS, etc). Additionally, flag testing classes as multi_db so that Django will flush the non-default database between unit tests. Further decouple the foreignkey relation between csm and csmhe When calling StudentModule().delete() Django will try to delete CSMHE objects, but naively does so in the database, not by consulting the database router. Instead, we disable django cascading deletes and listen for post_delete signals and clean up CSMHE by hand. Add feature flags for CSMHE One to turn it on/off so we can control the deploy. The other will control whether or not we read from two database tables or one when searching. Update tests to explicitly use this get_history method rather than looking directly into StudentModuleHistory or StudentModuleHistoryExtended. Inform lettuce to avoid the coursewarehistoryextended app Otherwise it fails when it can't find features/ in that app. Add Pg support, this is not tested automatically.
65 lines
2.8 KiB
Python
65 lines
2.8 KiB
Python
"""
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WE'RE USING MIGRATIONS!
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If you make changes to this model, be sure to create an appropriate migration
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file and check it in at the same time as your model changes. To do that,
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1. Go to the edx-platform dir
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2. ./manage.py schemamigration courseware --auto description_of_your_change
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3. Add the migration file created in edx-platform/lms/djangoapps/coursewarehistoryextended/migrations/
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ASSUMPTIONS: modules have unique IDs, even across different module_types
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"""
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from django.db import models
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from django.db.models.signals import post_save, post_delete
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from django.dispatch import receiver
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from coursewarehistoryextended.fields import UnsignedBigIntAutoField
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from courseware.models import StudentModule, BaseStudentModuleHistory
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class StudentModuleHistoryExtended(BaseStudentModuleHistory):
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"""Keeps a complete history of state changes for a given XModule for a given
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Student. Right now, we restrict this to problems so that the table doesn't
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explode in size.
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This new extended CSMH has a larger primary key that won't run out of space
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so quickly."""
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class Meta(object):
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app_label = 'coursewarehistoryextended'
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get_latest_by = "created"
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id = UnsignedBigIntAutoField(primary_key=True) # pylint: disable=invalid-name
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student_module = models.ForeignKey(StudentModule, db_index=True, db_constraint=False, on_delete=models.DO_NOTHING)
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@receiver(post_save, sender=StudentModule)
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def save_history(sender, instance, **kwargs): # pylint: disable=no-self-argument, unused-argument
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"""
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Checks the instance's module_type, and creates & saves a
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StudentModuleHistoryExtended entry if the module_type is one that
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we save.
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"""
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if instance.module_type in StudentModuleHistoryExtended.HISTORY_SAVING_TYPES:
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history_entry = StudentModuleHistoryExtended(student_module=instance,
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version=None,
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created=instance.modified,
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state=instance.state,
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grade=instance.grade,
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max_grade=instance.max_grade)
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history_entry.save()
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@receiver(post_delete, sender=StudentModule)
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def delete_history(sender, instance, **kwargs): # pylint: disable=no-self-argument, unused-argument
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"""
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Django can't cascade delete across databases, so we tell it at the model level to
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on_delete=DO_NOTHING and then listen for post_delete so we can clean up the CSMHE rows.
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"""
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StudentModuleHistoryExtended.objects.filter(student_module=instance).all().delete()
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def __unicode__(self):
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return unicode(repr(self))
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