[placement] Raising http codes on old microversion

Currently only HTTP 404 can be raised. This enables other HTTP status
to be raised if microversion does not match with the minimum required.
This is useful for new methods created to raise other http status code
for older placement microversions, like 405 HTTPMethodNotAllowed.

Change-Id: I2b684fcfd93fc70fe385a93346ee255279909489

doc/source/placement_dev.rst

@@ -169,8 +169,9 @@ compared as such or there is a ``matches`` method.
 In other cases there are some helper methods in the microversion
 package:
 
-* The ``raise_404_if_not_version`` utility will cause a 404 if the
-  requested microversion is not within a described version window.
+* The ``raise_http_status_code_if_not_version`` utility will raise a
+  http status code if the requested microversion is not within a
+  described version window.
 * The ``version_handler`` decorator makes it possible to have
   multiple different handler methods of the same (fully-qualified by
   package) name, each available for a different microversion window.

nova/api/openstack/placement/handlers/aggregate.py

@@ -52,7 +52,7 @@ def get_aggregates(req):
     On success return a 200 with an application/json body containing a
     list of aggregate uuids.
     """
-    microversion.raise_404_if_not_version(req, (1, 1))
+    microversion.raise_http_status_code_if_not_version(req, 404, (1, 1))
     context = req.environ['placement.context']
     uuid = util.wsgi_path_item(req.environ, 'uuid')
     resource_provider = objects.ResourceProvider.get_by_uuid(
@@ -65,7 +65,7 @@ def get_aggregates(req):
 @webob.dec.wsgify
 @util.require_content('application/json')
 def set_aggregates(req):
-    microversion.raise_404_if_not_version(req, (1, 1))
+    microversion.raise_http_status_code_if_not_version(req, 404, (1, 1))
     context = req.environ['placement.context']
     uuid = util.wsgi_path_item(req.environ, 'uuid')
     resource_provider = objects.ResourceProvider.get_by_uuid(

nova/api/openstack/placement/microversion.py

@@ -73,11 +73,22 @@ def parse_version_string(version_string):
             version_string, exc))
 
 
-def raise_404_if_not_version(req, min_version, max_version=None):
-    """Utility to raise a 404 if the wanted microversion does not match."""
+def raise_http_status_code_if_not_version(req, status_code, min_version,
+                                          max_version=None):
+    """Utility to raise a http status code if the wanted microversion does not
+       match.
+
+    :param req: The HTTP request for the placement api
+    :param status_code: HTTP status code (integer value) to be raised
+    :param min_version: Minimum placement microversion level
+    :param max_version: Maximum placement microversion level
+    :returns: None
+    :raises: HTTP status code if the specified microversion does not match
+    :raises: KeyError if status_code is not a valid HTTP status code
+    """
     want_version = req.environ[MICROVERSION_ENVIRON]
     if not want_version.matches(min_version, max_version):
-        raise webob.exc.HTTPNotFound
+        raise webob.exc.status_map[status_code]
 
 
 class MicroversionMiddleware(object):

nova/tests/unit/api/openstack/placement/test_microversion.py

@@ -16,6 +16,7 @@ import collections
 import operator
 
 import mock
+import webob
 
 # import the handlers to load up handler decorators
 import nova.api.openstack.placement.handler  # noqa
@@ -106,3 +107,23 @@ class TestMicroversionIntersection(test.NoDBTestCase):
             self.assertFalse(
                 self._check_intersection(method_info),
                 'method %s has intersecting versioned handlers' % method_name)
+
+
+class TestMicroversionUtility(test.NoDBTestCase):
+
+    req = webob.Request.blank('/', method="GET")
+    req.accept = 'application/json'
+
+    def test_raise_405_out_of_date_version(self):
+        version_obj = microversion.parse_version_string('1.4')
+        self.req.environ['placement.microversion'] = version_obj
+        self.assertRaises(webob.exc.HTTPMethodNotAllowed,
+             microversion.raise_http_status_code_if_not_version,
+             self.req, 405, (1, 5))
+
+    def test_raise_keyerror_out_of_date_version(self):
+        version_obj = microversion.parse_version_string('1.4')
+        self.req.environ['placement.microversion'] = version_obj
+        self.assertRaises(KeyError,
+             microversion.raise_http_status_code_if_not_version,
+             self.req, 999, (1, 5))