113 lines
3.6 KiB
Python
113 lines
3.6 KiB
Python
# Copyright 2012 OpenStack LLC.
|
|
# All Rights Reserved.
|
|
#
|
|
# 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.
|
|
|
|
"""
|
|
Base utilities to build API operation managers and objects on top of.
|
|
"""
|
|
|
|
|
|
def getid(obj):
|
|
"""Abstracts the common pattern of allowing both an object or an
|
|
object's ID (UUID) as a parameter when dealing with relationships.
|
|
"""
|
|
try:
|
|
return obj.id
|
|
except AttributeError:
|
|
return obj
|
|
|
|
|
|
class Manager(object):
|
|
"""Managers interact with a particular type of API
|
|
(samples, meters, alarms, etc.) and provide CRUD operations for them.
|
|
"""
|
|
resource_class = None
|
|
|
|
def __init__(self, api):
|
|
self.api = api
|
|
|
|
@staticmethod
|
|
def _path(id=None):
|
|
"""Helper method to be defined in subclasses. It returns the
|
|
resource/collection path. If id is given, then single resource
|
|
path is returned. Otherwise the collection path is returned.
|
|
|
|
:param id: id of the resource (optional)
|
|
:type id: string
|
|
|
|
:return: A string representing the API endpoint
|
|
:rtype: string
|
|
"""
|
|
raise NotImplementedError("_path method not implemented.")
|
|
|
|
def _single_path(self, id):
|
|
"""This is like the _path method, but it asserts that the id
|
|
parameter is not None. This is useful e.g. when you want to make sure
|
|
that you can't issue a DELETE request on a collection URL.
|
|
|
|
:param id: id of the resource (not optional)
|
|
:type id: string
|
|
|
|
:return: A string representing the API endpoint
|
|
:rtype: string
|
|
"""
|
|
if not id:
|
|
raise ValueError("{0} id is required."
|
|
.format(self.resource_class))
|
|
return self._path(id)
|
|
|
|
def _create(self, url, body):
|
|
resp, body = self.api.json_request('POST', url, body=body)
|
|
if body:
|
|
return self.resource_class(self, body)
|
|
|
|
def _get(self, url, **kwargs):
|
|
kwargs.setdefault('expect_single', True)
|
|
try:
|
|
return self._list(url, **kwargs)[0]
|
|
except IndexError:
|
|
return None
|
|
|
|
def _list(self, url, response_key=None, obj_class=None, body=None,
|
|
expect_single=False):
|
|
resp, body = self.api.json_request('GET', url)
|
|
|
|
if obj_class is None:
|
|
obj_class = self.resource_class
|
|
|
|
if response_key:
|
|
try:
|
|
data = body[response_key]
|
|
except KeyError:
|
|
return []
|
|
else:
|
|
data = body
|
|
if expect_single:
|
|
data = [data]
|
|
return [obj_class(self, res, loaded=True) for res in data if res]
|
|
|
|
def _update(self, url, body, response_key=None):
|
|
resp, body = self.api.json_request('PUT', url, body=body)
|
|
# PUT requests may not return a body
|
|
if body:
|
|
return self.resource_class(self, body)
|
|
|
|
def _delete(self, url):
|
|
self.api.raw_request('DELETE', url)
|
|
|
|
def _patch(self, url, body, response_key=None):
|
|
resp, body = self.api.json_request('PATCH', url, body=body)
|
|
if body:
|
|
return self.resource_class(self, body)
|