lock manager app updates

This commit is contained in:
Roberto Rosario
2011-08-23 17:34:05 -04:00
parent b6d2e95a91
commit 9185ed335d
5 changed files with 62 additions and 31 deletions

View File

@@ -2,42 +2,14 @@ import datetime
from django.db import models
from django.utils.translation import ugettext_lazy as _
from django.db.utils import IntegrityError
from django.db import transaction
from lock_manager.managers import LockManager
from lock_manager.conf.settings import DEFAULT_LOCK_TIMEOUT
class LockError(Exception):
pass
class LockManager(models.Manager):
@transaction.commit_manually
def acquire_lock(self, name):
lock = self.model(name=name)
try:
lock.save(force_insert=True)
except IntegrityError:
transaction.rollback()
# There is already an existing lock
# Check it's expiration date and if expired delete it and
# re-create it
lock = Lock.objects.get(name=name)
if datetime.datetime.now() > lock.creation_datetime + datetime.timedelta(seconds=lock.expiration):
release_lock(self)
lock.save()
else:
raise LockError('Unable to acquire lock')
else:
transaction.commit()
@transaction.commit_manually
def release_lock(self, name):
lock = Lock.objects.get(name=name)
lock.delete()
transaction.commit()
class Lock(models.Model):
creation_datetime = models.DateTimeField(verbose_name=_(u'creation datetime'))
expiration_time = models.IntegerField(default=3600, verbose_name=_(u'expiration time'))
timeout = models.IntegerField(default=DEFAULT_LOCK_TIMEOUT, verbose_name=_(u'timeout'))
name = models.CharField(max_length=32, verbose_name=_(u'name'), unique=True)
objects = LockManager()