django-concurrency is an optimistic lock implementation for Django.
It prevents users from doing concurrent editing in Django both from UI and from a django command.
from django.db import models
from concurrency.fields import IntegerVersionField
class ConcurrentModel( models.Model ):
version = IntegerVersionField( )
name = models.CharField(max_length=100)Now if you try::
a = ConcurrentModel.objects.get(pk=1)
a.name = '1'
b = ConcurrentModel.objects.get(pk=1)
b.name = '2'
a.save()
b.save()you will get a RecordModifiedError on b.save()
Other projects that handle concurrent editing are django-optimistic-lock and django-locking anyway concurrency is "a batteries included" optimistic lock management system, here some features not available elsewhere:
- can be applied to any model; not only your code (ie. django.contrib.auth.Group)
- handle list-editable ChangeList. (handle
#11313 <https://code.djangoproject.com/ticket/11313>_) - manage concurrency conflicts in admin's actions
- can intercept changes performend out of the django app (ie using pgAdmin, phpMyAdmin, Toads) (using TriggerVersionField)
- can be disabled if needed (see disable_concurrency)
- ConditionalVersionField to handle complex business rules
- Code: https://github.com/saxix/django-concurrency
- Documentation: https://django-concurrency.readthedocs.org/en/latest/
- Issue Tracker: https://github.com/saxix/django-concurrency/issues
- Download Package: http://pypi.python.org/pypi/django-concurrency/