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| [root@controller ~]
import sqlalchemy as sa
from neutron.common import exceptions
from neutron.db import model_base
from neutron.db import models_v2
'''
quota数据库表的表结构，tenant默认集成的配额从这里获取
mysql> desc quotas;
+-----------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-----------+--------------+------+-----+---------+-------+
| id | varchar(36) | NO | PRI | NULL | |
| tenant_id | varchar(255) | YES | MUL | NULL | |
| resource | varchar(255) | YES | | NULL | |
| limit | int(11) | YES | | NULL | |
+-----------+--------------+------+-----+---------+-------+
'''
class Quota(model_base.BASEV2, models_v2.HasId):
"""Represent a single quota override for a tenant.
If there is no row for a given tenant id and resource, then the
default for the quota class is used.
"""
tenant_id = sa.Column(sa.String(255), index=True)
resource = sa.Column(sa.String(255))
limit = sa.Column(sa.Integer)
'''
quota配额的具体实现，根据数据库的配置内容，实现quota的控制，即quota的增删改查方法
'''
class DbQuotaDriver(object):
"""Driver to perform necessary checks to enforce quotas and obtain quota
information.
The default driver utilizes the local database.
"""
'''
得到租户tenant的quota，执行neutron quota-show --tenant-id uuid时调用的方法
'''
@staticmethod
def get_tenant_quotas(context, resources, tenant_id):
"""Given a list of resources, retrieve the quotas for the given
tenant.
:param context: The request context, for access checks.
:param resources: A dictionary of the registered resource keys.
:param tenant_id: The ID of the tenant to return quotas for.
:return dict: from resource name to dict of name and limit
"""
tenant_quota = dict((key, resource.default)
for key, resource in resources.items())
q_qry = context.session.query(Quota).filter_by(tenant_id=tenant_id)
tenant_quota.update((q['resource'], q['limit']) for q in q_qry)
return tenant_quota
'''
quota的删除，即执行neutron quota-delete 的方法，删除之后，tenant将会集成默认的的quota配置
'''
@staticmethod
def delete_tenant_quota(context, tenant_id):
"""Delete the quota entries for a given tenant_id.
Atfer deletion, this tenant will use default quota values in conf.
"""
with context.session.begin():
tenant_quotas = context.session.query(Quota)
tenant_quotas = tenant_quotas.filter_by(tenant_id=tenant_id)
tenant_quotas.delete()
'''
得到所有租户tenant的配额资源，即执行neutron quota-list所查看的内容
'''
@staticmethod
def get_all_quotas(context, resources):
"""Given a list of resources, retrieve the quotas for the all tenants.
:param context: The request context, for access checks.
:param resources: A dictionary of the registered resource keys.
:return quotas: list of dict of tenant_id:, resourcekey1:
resourcekey2: ...
"""
tenant_default = dict((key, resource.default)
for key, resource in resources.items())
all_tenant_quotas = {}
for quota in context.session.query(Quota):
tenant_id = quota['tenant_id']
tenant_quota = all_tenant_quotas.get(tenant_id)
if tenant_quota is None:
tenant_quota = tenant_default.copy()
tenant_quota['tenant_id'] = tenant_id
all_tenant_quotas[tenant_id] = tenant_quota
tenant_quota[quota['resource']] = quota['limit']
return all_tenant_quotas.values()
'''
更新quota的配置，即执行neutron quota-update命令的具体实现
'''
@staticmethod
def update_quota_limit(context, tenant_id, resource, limit):
with context.session.begin():
tenant_quota = context.session.query(Quota).filter_by(
tenant_id=tenant_id, resource=resource).first()
if tenant_quota:
tenant_quota.update({'limit': limit})
else:
tenant_quota = Quota(tenant_id=tenant_id,
resource=resource,
limit=limit)
context.session.add(tenant_quota)
def _get_quotas(self, context, tenant_id, resources, keys):
"""Retrieves the quotas for specific resources.
A helper method which retrieves the quotas for the specific
resources identified by keys, and which apply to the current
context.
:param context: The request context, for access checks.
:param tenant_id: the tenant_id to check quota.
:param resources: A dictionary of the registered resources.
:param keys: A list of the desired quotas to retrieve.
"""
desired = set(keys)
sub_resources = dict((k, v) for k, v in resources.items()
if k in desired)
if len(keys) != len(sub_resources):
unknown = desired - set(sub_resources.keys())
raise exceptions.QuotaResourceUnknown(unknown=sorted(unknown))
quotas = DbQuotaDriver.get_tenant_quotas(
context, sub_resources, tenant_id)
return dict((k, v) for k, v in quotas.items())
'''
neutron quota的校验，即在执行过程中，调用该方法，确认tenant的quota是否在合理的范围内
'''
def limit_check(self, context, tenant_id, resources, values):
"""Check simple quota limits.
For limits--those quotas for which there is no usage
synchronization function--this method checks that a set of
proposed values are permitted by the limit restriction.
This method will raise a QuotaResourceUnknown exception if a
given resource is unknown or if it is not a simple limit
resource.
If any of the proposed values is over the defined quota, an
OverQuota exception will be raised with the sorted list of the
resources which are too high. Otherwise, the method returns
nothing.
:param context: The request context, for access checks.
:param tenant_id: The tenant_id to check the quota.
:param resources: A dictionary of the registered resources.
:param values: A dictionary of the values to check against the
quota.
"""
unders = [key for key, val in values.items() if val < 0]
if unders:
raise exceptions.InvalidQuotaValue(unders=sorted(unders))
quotas = self._get_quotas(context, tenant_id, resources, values.keys())
overs = [key for key, val in values.items()
if quotas[key] >= 0 and quotas[key] < val]
if overs:
raise exceptions.OverQuota(overs=sorted(overs))
|