91 lines
3.6 KiB
Python
91 lines
3.6 KiB
Python
# 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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"""WSGI middleware for getting microversion info."""
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import webob
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import webob.dec
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import microversion_parse
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class MicroversionMiddleware(object):
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"""WSGI middleware for getting microversion info.
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The application will get a WSGI environ with a
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'SERVICE_TYPE.microversion' key that has a value of the microversion
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found at an 'openstack-api-version' header that matches SERVICE_TYPE. If
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no header is found, the minimum microversion will be set. If the
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special keyword 'latest' is used, the maximum microversion will be
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set.
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If the requested microversion is not available a 406 response is
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returned.
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If there is an error parsing a provided header, a 400 response is
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returned.
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Otherwise the application is called.
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"""
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def __init__(self, application, service_type, versions,
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json_error_formatter=None):
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"""Create the WSGI middleware.
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:param application: The application hosting the service.
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:param service_type: The service type (entry in keystone catalog)
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of the application.
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:param versions: An ordered list of legitimate versions for the
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application.
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:param json_error_formatter: A Webob exception error formatter.
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See Webob for details.
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"""
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self.application = application
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self.service_type = service_type
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self.microversion_environ = '%s.microversion' % service_type
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self.versions = versions
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self.json_error_formatter = json_error_formatter
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@webob.dec.wsgify
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def __call__(self, req):
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try:
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microversion = microversion_parse.extract_version(
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req.headers, self.service_type, self.versions)
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# TODO(cdent): These error response are not formatted according to
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# api-sig guidelines, unless a json_error_formatter is provided
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# that can do it. For an example, see the placement service.
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except ValueError as exc:
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raise webob.exc.HTTPNotAcceptable(
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('Invalid microversion: %(error)s') % {'error': exc},
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json_formatter=self.json_error_formatter)
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except TypeError as exc:
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raise webob.exc.HTTPBadRequest(
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('Invalid microversion: %(error)s') % {'error': exc},
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json_formatter=self.json_error_formatter)
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req.environ[self.microversion_environ] = microversion
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microversion_header = '%s %s' % (self.service_type, microversion)
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standard_header = microversion_parse.STANDARD_HEADER
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try:
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response = req.get_response(self.application)
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except webob.exc.HTTPError as exc:
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# If there was an HTTPError in the application we still need
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# to send the microversion header, so add the header and
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# re-raise the exception.
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exc.headers.add(standard_header, microversion_header)
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raise exc
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response.headers.add(standard_header, microversion_header)
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response.headers.add('vary', standard_header)
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return response
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