e346558d5f
Use of Version within the placement service has made it clear that the Version object knowing the min and max versions is useful when making Version.matches comparisons. Therefore the matches method has been updated to refer to min_version and max_version attributes if they are not set in the matches() request. The extract_version function now sets those attributes based on the version_list that is passed to it. If min and max are not set on the Version object, they default to negative versions, which are not possible in microversions and mean matches() (without override args) will be false. The use of explicit values (instead of None) is so python3 is happy (and it is better anyway). Change-Id: I71d091d037abcd068601b32722a09094ae74e658
microversion_parse
A small set of functions to manage OpenStack microversion headers that can be used in middleware, application handlers and decorators to effectively manage microversions.
get_version
A simple parser for OpenStack microversion headers:
import microversion_parse
# headers is a dict of headers with folded (comma-separated
# values) or a list of header, value tuples
version = microversion_parse.get_version(
headers, service_type='compute',
legacy_headers=['x-openstack-nova-api-version'])
# If headers are not already available, a dict of headers
# can be extracted from the WSGI environ
headers = microversion_parse.headers_from_wsgi_environ(environ)
version = microversion_parse.get_version(
headers, service_type='placement')It processes microversion headers with the standard form:
OpenStack-API-Version: compute 2.1In that case, the response will be '2.1'.
If provided with a legacy_headers argument, this is
treated as a list of additional headers to check for microversions. Some
examples of headers include:
OpenStack-telemetry-api-version: 2.1
OpenStack-nova-api-version: 2.1
X-OpenStack-nova-api-version: 2.1If a version string cannot be found, None will be
returned. If the input is incorrect usual Python exceptions (ValueError,
TypeError) are allowed to raise to the caller.
parse_version_string
A function to turn a version string into a Version, a
comparable namedtuple:
version_tuple = microversion_parse.parse_version_string('2.1')If the provided string is not a valid microversion string,
TypeError is raised.
extract_version
Combines get_version and
parse_version_string to find and validate a microversion
for a given service type in a collection of headers:
version_tuple = microversion_parse.extract_version(
headers, # a representation of headers, as accepted by get_version
service_type, # service type identify to match in headers
versions_list, # an ordered list of strings of version numbers that
# are the valid versions presented by this service
)latest will be translated to whatever the max version is
in versions_list.
If the found version is not in versions_list a
ValueError is raised.
Note that extract_version does not support
legacy_headers.