49b44934b9
See README.rst for details. The basic gist is that a get_version method is provided. It takes a dict or list of headers and returned a version for a service_type if it can find it.
107 lines
3.4 KiB
Python
107 lines
3.4 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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import collections
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STANDARD_HEADER = 'openstack-api-version'
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def get_version(headers, service_type=None, legacy_type=None):
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"""Parse a microversion out of headers
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:param headers: The headers of a request, dict or list
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:param service_type: The service type being looked for in the headers
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:param legacy_type: The project name to use when looking for fallback
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headers.
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:returns: a version string or "latest"
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:raises: ValueError
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"""
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# If headers is not a dict we assume is an iterator of
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# tuple-like headers, which we will fold into a dict.
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#
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# The flow is that we first look for the new standard singular
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# header:
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# * openstack-api-version: <service> <version>
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# If that's not present we fall back, in order, to:
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# * openstack-<service>-api-version: <version>
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# * openstack-<legacy>-api-version: <version>
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# * x-openstack-<legacy>-api-version: <version>
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#
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# Folded headers are joined by ,
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folded_headers = fold_headers(headers)
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version = check_standard_header(folded_headers, service_type)
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if version:
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return version
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extra_headers = build_headers(service_type, legacy_type)
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version = check_legacy_headers(folded_headers, extra_headers)
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return version
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def build_headers(service_type, legacy_type=None):
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"""Create the headers to be looked at."""
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headers = [
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'openstack-%s-api-version' % service_type
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]
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if legacy_type:
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legacy_headers = [
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'openstack-%s-api-version' % legacy_type,
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'x-openstack-%s-api-version' % legacy_type
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]
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headers.extend(legacy_headers)
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return headers
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def check_legacy_headers(headers, legacy_headers):
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"""Gather values from old headers."""
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for legacy_header in legacy_headers:
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try:
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value = headers[legacy_header]
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return value.split(',')[-1].strip()
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except KeyError:
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pass
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return None
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def check_standard_header(headers, service_type):
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"""Parse the standard header to get value for service."""
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try:
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header = headers[STANDARD_HEADER]
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for header_value in reversed(header.split(',')):
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try:
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service, version = header_value.strip().split(None, 1)
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if service.lower() == service_type.lower():
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return version.strip()
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except ValueError:
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pass
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except (KeyError, ValueError):
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return None
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def fold_headers(headers):
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"""Turn a list of headers into a folded dict."""
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if isinstance(headers, dict):
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# TODO(cdent): canonicalize? (i.e. in lower())
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return headers
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header_dict = collections.defaultdict(list)
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for header, value in headers:
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header_dict[header.lower()].append(value.strip())
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folded_headers = {}
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for header, value in header_dict.items():
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folded_headers[header] = ','.join(value)
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return folded_headers
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