216aaab638
The new API adds better support for storage policies and changes the response from a list of backend urls to a dictionary with a key "endpoints" that's a list of of the backend urls and a new key headers that's a dictionary of headers to send along with the backend request. In the v2 response format for object requests, there the headers key includes "X-Backend-Storage-Policy-Index" which indicates the storage policy index for the endpoints returned in the response. Change-Id: I706a5b5be8002c633fe97b2429256735800a902e
241 lines
8.8 KiB
Python
241 lines
8.8 KiB
Python
# Copyright (c) 2012 OpenStack Foundation
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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List endpoints for an object, account or container.
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This middleware makes it possible to integrate swift with software
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that relies on data locality information to avoid network overhead,
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such as Hadoop.
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Answers requests of the form::
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/endpoints/{account}/{container}/{object}
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/endpoints/{account}/{container}
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/endpoints/{account}
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with a JSON-encoded list of endpoints of the form::
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http://{server}:{port}/{dev}/{part}/{acc}/{cont}/{obj}
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http://{server}:{port}/{dev}/{part}/{acc}/{cont}
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http://{server}:{port}/{dev}/{part}/{acc}
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correspondingly, e.g.::
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http://10.1.1.1:6000/sda1/2/a/c2/o1
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http://10.1.1.1:6000/sda1/2/a/c2
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http://10.1.1.1:6000/sda1/2/a
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The '/endpoints/' path is customizable ('list_endpoints_path'
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configuration parameter).
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Intended for consumption by third-party services living inside the
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cluster (as the endpoints make sense only inside the cluster behind
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the firewall); potentially written in a different language.
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This is why it's provided as a REST API and not just a Python API:
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to avoid requiring clients to write their own ring parsers in their
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languages, and to avoid the necessity to distribute the ring file
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to clients and keep it up-to-date.
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Note that the call is not authenticated, which means that a proxy
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with this middleware enabled should not be open to an untrusted
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environment (everyone can query the locality data using this middleware).
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"""
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from urllib import quote, unquote
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from swift.common.ring import Ring
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from swift.common.utils import json, get_logger, split_path
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from swift.common.swob import Request, Response
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from swift.common.swob import HTTPBadRequest, HTTPMethodNotAllowed
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from swift.common.storage_policy import POLICIES
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from swift.proxy.controllers.base import get_container_info
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RESPONSE_VERSIONS = (1.0, 2.0)
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class ListEndpointsMiddleware(object):
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"""
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List endpoints for an object, account or container.
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See above for a full description.
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Uses configuration parameter `swift_dir` (default `/etc/swift`).
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:param app: The next WSGI filter or app in the paste.deploy
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chain.
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:param conf: The configuration dict for the middleware.
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"""
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def __init__(self, app, conf):
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self.app = app
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self.logger = get_logger(conf, log_route='endpoints')
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self.swift_dir = conf.get('swift_dir', '/etc/swift')
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self.account_ring = Ring(self.swift_dir, ring_name='account')
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self.container_ring = Ring(self.swift_dir, ring_name='container')
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self.endpoints_path = conf.get('list_endpoints_path', '/endpoints/')
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if not self.endpoints_path.endswith('/'):
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self.endpoints_path += '/'
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self.default_response_version = 1.0
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self.response_map = {
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1.0: self.v1_format_response,
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2.0: self.v2_format_response,
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}
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def get_object_ring(self, policy_idx):
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"""
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Get the ring object to use to handle a request based on its policy.
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:policy_idx: policy index as defined in swift.conf
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:returns: appropriate ring object
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"""
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return POLICIES.get_object_ring(policy_idx, self.swift_dir)
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def _parse_version(self, raw_version):
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err_msg = 'Unsupported version %r' % raw_version
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try:
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version = float(raw_version.lstrip('v'))
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except ValueError:
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raise ValueError(err_msg)
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if not any(version == v for v in RESPONSE_VERSIONS):
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raise ValueError(err_msg)
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return version
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def _parse_path(self, request):
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"""
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Parse path parts of request into a tuple of version, account,
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container, obj. Unspecified path parts are filled in as None,
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except version which is always returned as a float using the
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configured default response version if not specified in the
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request.
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:param request: the swob request
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:returns: parsed path parts as a tuple with version filled in as
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configured default response version if not specified.
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:raises: ValueError if path is invalid, message will say why.
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"""
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clean_path = request.path[len(self.endpoints_path) - 1:]
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# try to peel off version
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try:
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raw_version, rest = split_path(clean_path, 1, 2, True)
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except ValueError:
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raise ValueError('No account specified')
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try:
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version = self._parse_version(raw_version)
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except ValueError:
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if raw_version.startswith('v') and '_' not in raw_version:
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# looks more like a invalid version than an account
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raise
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# probably no version specified, but if the client really
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# said /endpoints/v_3/account they'll probably be sorta
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# confused by the useless response and lack of error.
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version = self.default_response_version
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rest = clean_path
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else:
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rest = '/' + rest if rest else '/'
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try:
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account, container, obj = split_path(rest, 1, 3, True)
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except ValueError:
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raise ValueError('No account specified')
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return version, account, container, obj
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def v1_format_response(self, req, endpoints, **kwargs):
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return Response(json.dumps(endpoints),
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content_type='application/json')
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def v2_format_response(self, req, endpoints, storage_policy_index,
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**kwargs):
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resp = {
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'endpoints': endpoints,
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'headers': {},
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}
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if storage_policy_index is not None:
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resp['headers'][
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'X-Backend-Storage-Policy-Index'] = str(storage_policy_index)
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return Response(json.dumps(resp),
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content_type='application/json')
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def __call__(self, env, start_response):
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request = Request(env)
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if not request.path.startswith(self.endpoints_path):
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return self.app(env, start_response)
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if request.method != 'GET':
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return HTTPMethodNotAllowed(
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req=request, headers={"Allow": "GET"})(env, start_response)
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try:
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version, account, container, obj = self._parse_path(request)
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except ValueError as err:
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return HTTPBadRequest(str(err))(env, start_response)
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if account is not None:
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account = unquote(account)
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if container is not None:
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container = unquote(container)
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if obj is not None:
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obj = unquote(obj)
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storage_policy_index = None
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if obj is not None:
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container_info = get_container_info(
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{'PATH_INFO': '/v1/%s/%s' % (account, container)},
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self.app, swift_source='LE')
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storage_policy_index = container_info['storage_policy']
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obj_ring = self.get_object_ring(storage_policy_index)
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partition, nodes = obj_ring.get_nodes(
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account, container, obj)
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endpoint_template = 'http://{ip}:{port}/{device}/{partition}/' + \
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'{account}/{container}/{obj}'
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elif container is not None:
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partition, nodes = self.container_ring.get_nodes(
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account, container)
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endpoint_template = 'http://{ip}:{port}/{device}/{partition}/' + \
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'{account}/{container}'
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else:
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partition, nodes = self.account_ring.get_nodes(
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account)
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endpoint_template = 'http://{ip}:{port}/{device}/{partition}/' + \
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'{account}'
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endpoints = []
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for node in nodes:
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endpoint = endpoint_template.format(
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ip=node['ip'],
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port=node['port'],
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device=node['device'],
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partition=partition,
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account=quote(account),
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container=quote(container or ''),
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obj=quote(obj or ''))
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endpoints.append(endpoint)
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resp = self.response_map[version](
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request, endpoints=endpoints,
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storage_policy_index=storage_policy_index)
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return resp(env, start_response)
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def filter_factory(global_conf, **local_conf):
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conf = global_conf.copy()
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conf.update(local_conf)
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def list_endpoints_filter(app):
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return ListEndpointsMiddleware(app, conf)
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return list_endpoints_filter
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