Rehome `QuotaDriverAPI` class

This class is the API to create a Neutron Quota engine driver.
Any other project is able to create its own Neutron Quota engine
driver.

Change-Id: Ia96f1f87d7bf30ffdfa1f9bac23845675b6539fd

neutron_lib/db/quota_api.py

@@ -0,0 +1,169 @@
+# Copyright (c) 2021 Red Hat, Inc.
+#
+#    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.
+
+import abc
+
+
+class QuotaDriverAPI(object, metaclass=abc.ABCMeta):
+
+    @staticmethod
+    @abc.abstractmethod
+    def get_default_quotas(context, resources, project_id):
+        """Retrieve the default quotas for the list of resources and project.
+
+        :param context: The request context, for access checks.
+        :param resources: A dictionary of the registered resource keys.
+        :param project_id: The ID of the project to return default quotas for.
+        :return: dict from resource name to dict of name and limit
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    def get_project_quotas(context, resources, project_id):
+        """Retrieve the quotas for the given list of resources and project
+
+        :param context: The request context, for access checks.
+        :param resources: A dictionary of the registered resource keys.
+        :param project_id: The ID of the project to return quotas for.
+        :return: dict from resource name to dict of name and limit
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    def get_detailed_project_quotas(context, resources, project_id):
+        """Retrieve detailed quotas for the given list of resources and project
+
+        :param context: The request context, for access checks.
+        :param resources: A dictionary of the registered resource keys.
+        :param project_id: The ID of the project to return quotas for.
+        :return dict: mapping resource name in dict to its corresponding limit
+                      used and reserved. Reserved currently returns default
+                      value of 0
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    def delete_project_quota(context, project_id):
+        """Delete the quota entries for a given project_id.
+
+        After deletion, this project will use default quota values in conf.
+        Raise a "not found" error if the quota for the given project was
+        never defined.
+
+        :param context: The request context, for access checks.
+        :param project_id: The ID of the project to return quotas for.
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    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 project_id:, resourcekey1:
+                 resourcekey2: ...
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    def update_quota_limit(context, project_id, resource, limit):
+        """Update the quota limit for a resource in a project
+
+        :param context: The request context, for access checks.
+        :param project_id: The ID of the project to update the quota.
+        :param resource: the resource to update the quota.
+        :param limit: new resource quota limit.
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    def make_reservation(context, project_id, resources, deltas, plugin):
+        """Make multiple resource reservations for a given project
+
+        :param context: The request context, for access checks.
+        :param resources: A dictionary of the registered resource keys.
+        :param project_id: The ID of the project to make the reservations for.
+        :return: ``ReservationInfo`` object.
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    def commit_reservation(context, reservation_id):
+        """Commit a reservation register
+
+        :param context: The request context, for access checks.
+        :param reservation_id: ID of the reservation register to commit.
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    def cancel_reservation(context, reservation_id):
+        """Cancel a reservation register
+
+        :param context: The request context, for access checks.
+        :param reservation_id: ID of the reservation register to cancel.
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    def limit_check(context, project_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.
+
+        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 project_id: The ID of the project to make the reservations for.
+        :param resources: A dictionary of the registered resource.
+        :param values: A dictionary of the values to check against the
+                       quota.
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    def get_resource_usage(context, project_id, resources, resource_name):
+        """Return the resource current usage
+
+        :param context: The request context, for access checks.
+        :param project_id: The ID of the project to make the reservations for.
+        :param resources: A dictionary of the registered resources.
+        :param resource_name: The name of the resource to retrieve the usage.
+        :return: The current resource usage.
+        """
+
+    @staticmethod
+    @abc.abstractmethod
+    def quota_limit_check(context, project_id, resources, deltas):
+        """Check the current resource usage against a set of deltas.
+
+        This method will check if the provided resource deltas could be
+        assigned depending on the current resource usage and the quota limits.
+        If the resource deltas plus the resource usage fit under the quota
+        limit, the method will pass. If not, a ``OverQuota`` will be raised.
+
+        :param context: The request context, for access checks.
+        :param project_id: The ID of the project to make the reservations for.
+        :param resources: A dictionary of the registered resource.
+        :param deltas: A dictionary of the values to check against the
+                       quota limits.
+        :return: None if passed; ``OverQuota`` if quota limits are exceeded,
+                 ``InvalidQuotaValue`` if delta values are invalid.
+        """

releasenotes/notes/add_QuotaDriverAPI_abc_class-1d02d0823a8886a1.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    Added ``QuotaDriverAPI`` abstract class. This class is the API to create
+    any Neutron Quota engine driver.