trove/reddwarf/quota/models.py
Steve Leon c4848cd472 Quota feature
Quota check for create/delete/resize volume
Quota is implemented as a decorator, which can be easy enabled and disabled if wanted.
The quota feature uses a reservation system that reserves resources prior to usage.

BP https://blueprints.launchpad.net/reddwarf/+spec/quotas

Change-Id: I5df82c8f1d7b40311b5d5d7301992607f98e9b2a
2013-03-05 09:44:47 -08:00

109 lines
3.0 KiB
Python

# Copyright 2011 OpenStack LLC
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
from reddwarf.common import cfg
from reddwarf.common import utils
from reddwarf.db import models as dbmodels
from reddwarf.openstack.common import log as logging
LOG = logging.getLogger(__name__)
CONF = cfg.CONF
def enum(**enums):
return type('Enum', (), enums)
class Quota(dbmodels.DatabaseModelBase):
"""Defines the base model class for a quota."""
_data_fields = ['created', 'updated', 'tenant_id', 'resource',
'hard_limit', 'id']
def __init__(self, tenant_id, resource, hard_limit,
id=utils.generate_uuid(), created=utils.utcnow(),
update=utils.utcnow()):
self.tenant_id = tenant_id
self.resource = resource
self.hard_limit = hard_limit
self.id = id
self.created = created
self.update = update
class QuotaUsage(dbmodels.DatabaseModelBase):
"""Defines the quota usage for a tenant."""
_data_fields = ['created', 'updated', 'tenant_id', 'resource',
'in_use', 'reserved', 'id']
class Reservation(dbmodels.DatabaseModelBase):
"""Defines the reservation for a quota."""
_data_fields = ['created', 'updated', 'usage_id',
'id', 'delta', 'status']
Statuses = enum(NEW='New',
RESERVED='Reserved',
COMMITTED='Committed',
ROLLEDBACK='Rolled Back')
def persisted_models():
return {
'quotas': Quota,
'quota_usages': QuotaUsage,
'reservations': Reservation,
}
class Resource(object):
"""Describe a single resource for quota checking."""
INSTANCES = 'instances'
VOLUMES = 'volumes'
def __init__(self, name, flag=None):
"""
Initializes a Resource.
:param name: The name of the resource, i.e., "volumes".
:param flag: The name of the flag or configuration option
which specifies the default value of the quota
for this resource.
"""
self.name = name
self.flag = flag
def __str__(self):
return self.name
def __hash__(self):
return hash(self.name)
def __eq__(self, other):
return (isinstance(other, Resource) and
self.name == other.name and
self.flag == other.flag)
@property
def default(self):
"""Return the default value of the quota."""
return CONF[self.flag] if self.flag else -1