Moved CORS middleware configuration into oslo-config-generator

The default values needed for aodh's implementation of cors
middleware have been moved from paste.ini into the configuration
hooks provided by oslo.config. Furthermore, these values have been
added to aodh's default configuration parsing. This ensures
that if a value remains unset in aodh.conf, it will be set
to use sane defaults, and that an operator modifying the
configuration file will be presented with a default set of
necessary sane headers.

Change-Id: Iccdbbfcc300f4a63fe7a58f0742eef782aff6844
Closes-Bug: 1551836

aodh/conf/defaults.py

@@ -0,0 +1,35 @@
+# Copyright 2016 Hewlett Packard Enterprise Development Company, L.P.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+from oslo_config import cfg
+from oslo_middleware import cors
+
+
+def set_cors_middleware_defaults():
+    """Update default configuration options for oslo.middleware."""
+    # CORS Defaults
+    # TODO(krotscheck): Update with https://review.openstack.org/#/c/285368/
+    cfg.set_defaults(cors.CORS_OPTS,
+                     allow_headers=['X-Auth-Token',
+                                    'X-Openstack-Request-Id',
+                                    'X-Subject-Token'],
+                     expose_headers=['X-Auth-Token',
+                                     'X-Openstack-Request-Id',
+                                     'X-Subject-Token'],
+                     allow_methods=['GET',
+                                    'PUT',
+                                    'POST',
+                                    'DELETE',
+                                    'PATCH']
+                     )

aodh/service.py

@@ -22,6 +22,7 @@ import oslo_i18n
 from oslo_log import log
 from oslo_policy import opts as policy_opts
 
+from aodh.conf import defaults
 from aodh import keystone_client
 from aodh import messaging
 
@@ -54,6 +55,7 @@ def prepare_service(argv=None, config_files=None):
     log_levels = (conf.default_log_levels +
                   ['stevedore=INFO', 'keystoneclient=INFO'])
     log.set_defaults(default_log_levels=log_levels)
+    defaults.set_cors_middleware_defaults()
     db_options.set_defaults(conf)
     policy_opts.set_defaults(conf)
     from aodh import opts

aodh/tests/functional/gabbi/gabbi_paste.ini

@@ -19,6 +19,3 @@ paste.filter_factory = oslo_middleware:RequestId.factory
 [filter:cors]
 paste.filter_factory = oslo_middleware.cors:filter_factory
 oslo_config_project = aodh
-latent_allow_headers = X-Auth-Token, X-Openstack-Request-Id, X-Subject-Token
-latent_expose_headers = X-Auth-Token, X-Openstack-Request-Id, X-Subject-Token
-latent_allow_methods = GET, PUT, POST, DELETE, PATCH

etc/aodh/api_paste.ini

@@ -19,7 +19,4 @@ paste.filter_factory = oslo_middleware:RequestId.factory
 
 [filter:cors]
 paste.filter_factory = oslo_middleware.cors:filter_factory
-oslo_config_project = aodh
-latent_allow_headers = X-Auth-Token, X-Openstack-Request-Id, X-Subject-Token
-latent_expose_headers = X-Auth-Token, X-Openstack-Request-Id, X-Subject-Token
-latent_allow_methods = GET, PUT, POST, DELETE, PATCH
+oslo_config_project = aodh

setup.cfg

@@ -114,6 +114,9 @@ oslo.config.opts =
     aodh = aodh.opts:list_opts
     aodh-auth = aodh.opts:list_keystoneauth_opts
 
+oslo.config.opts.defaults =
+    oslo.middleware.cors = aodh.conf.defaults:set_cors_middleware_defaults
+
 keystoneauth1.plugin =
     password-aodh-legacy = aodh.keystone_client:LegacyAodhKeystoneLoader