683206d237
This patch follows the rules about import in HACKING.rst https://github.com/openstack/marconi/blob/master/HACKING.rst#imports * reorder imports * Add missing blank lines before code Change-Id: I4abcfb3a2640499c5df34cbf75b5eaecb3d19823
91 lines
3.3 KiB
Python
91 lines
3.3 KiB
Python
# Copyright (c) 2013 Rackspace Hosting, Inc.
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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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"""forward: exposes a mixin class appropriate for forwarding requests."""
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import falcon
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from marconi.openstack.common import log
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from marconi.proxy.utils import helpers
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from marconi.proxy.utils import http
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from marconi.proxy.utils import lookup
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LOG = log.getLogger(__name__)
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class ForwardMixin(object):
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"""Implements falcon-compatible forwarding for resources
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:param partitions_controller: talks to partitions storage
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:param catalogue_controller: talks to catalogue storage
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:param cache: localized, fast lookups
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:param selector: @see utils.round_robin - host selection order
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:param methods: [text] - allowed methods, e.g., ['get', 'post']
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"""
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def __init__(self, partitions_controller, catalogue_controller,
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cache, selector, methods):
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self._catalogue = catalogue_controller
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self._partitions = partitions_controller
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self._cache = cache
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self._selector = selector
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for method in methods:
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assert method.lower() in http.METHODS
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setattr(self, 'on_' + method.lower(), self.forward)
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def forward(self, request, response, queue, **kwargs):
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"""Forwards requests in a selector-driven fashion."""
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project = helpers.get_project(request)
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LOG.debug('FORWARD - project/queue: {0}/{1}'.format(
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project, queue
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))
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partition = lookup.partition(project, queue,
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self._catalogue,
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self._cache)
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# NOTE(cpp-cabrera): we tried to look up a catalogue
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# entry and it failed. This happens if the associated
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# queue doesn't exist under that project.
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if not partition:
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LOG.debug('Catalogue entry not found')
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raise falcon.HTTPNotFound()
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hosts = lookup.hosts(partition, self._partitions, self._cache)
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# NOTE(cpp-cabrera): we tried to look up a partition, and it
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# failed. This only happens if a partition is deleted from
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# the primary store between here and the last call.
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if not hosts:
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LOG.debug('Partition not found')
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raise falcon.HTTPNotFound()
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# round robin to choose the desired host
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host = self._selector.next(partition, hosts)
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# send the request, update the response
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resp = helpers.forward(host, request)
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# NOTE(zyuan): normalize the lower-case header from
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# `requests` to Caml-Case and forward the headers back
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response.set_headers(helpers.capitalized(resp.headers))
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response.status = http.status(resp.status_code)
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response.body = resp.content
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# NOTE(cpp-cabrera): in case responder must do more afterwards
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return resp
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