Moved CORS middleware configuration into oslo-config-generator

The default values needed for magnum'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 the default initialization procedure. This ensures
that if a value remains unset in the configuration file, it will
fallback to using sane defaults. It also ensures that an operator
modifying the configuration will be presented with that same
set of defaults.

Change-Id: I7d8f8708d53bbab117600070982ac80482fa0a77
Closes-Bug: 1551836

etc/magnum/api-paste.ini

@@ -14,6 +14,3 @@ paste.filter_factory = oslo_middleware:RequestId.factory
 [filter:cors]
 paste.filter_factory =  oslo_middleware.cors:filter_factory
 oslo_config_project = magnum
-latent_allow_methods = GET, PUT, POST, DELETE, PATCH
-latent_allow_headers = X-Auth-Token, X-Identity-Status, X-Roles, X-Service-Catalog, X-User-Id, X-Tenant-Id, X-OpenStack-Request-ID
-latent_expose_headers = X-Auth-Token, X-Subject-Token, X-Service-Token, X-OpenStack-Request-ID

magnum/api/app.py

@@ -18,6 +18,7 @@ import pecan
 
 from magnum.api import config as api_config
 from magnum.api import middleware
+from magnum.common import config as common_config
 from magnum.i18n import _
 
 # Register options for the service
@@ -58,6 +59,7 @@ def setup_app(config=None):
         config = get_pecan_config()
 
     app_conf = dict(config.app)
+    common_config.set_config_defaults()
 
     app = pecan.make_app(
         app_conf.pop('root'),

magnum/common/config.py

@@ -16,6 +16,7 @@
 #    under the License.
 
 from oslo_config import cfg
+from oslo_middleware import cors
 
 from magnum.common import rpc
 from magnum import version
@@ -28,3 +29,34 @@ def parse_args(argv, default_config_files=None):
              version=version.version_info.release_string(),
              default_config_files=default_config_files)
     rpc.init(cfg.CONF)
+
+
+def set_config_defaults():
+    """This method updates all configuration default values."""
+    set_cors_middleware_defaults()
+
+
+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-Identity-Status',
+                                    'X-Roles',
+                                    'X-Service-Catalog',
+                                    'X-User-Id',
+                                    'X-Tenant-Id',
+                                    'X-OpenStack-Request-ID',
+                                    'X-Server-Management-Url'],
+                     expose_headers=['X-Auth-Token',
+                                     'X-Subject-Token',
+                                     'X-Service-Token',
+                                     'X-OpenStack-Request-ID',
+                                     'X-Server-Management-Url'],
+                     allow_methods=['GET',
+                                    'PUT',
+                                    'POST',
+                                    'DELETE',
+                                    'PATCH']
+                     )

magnum/common/service.py

@@ -39,4 +39,6 @@ def prepare_service(argv=None):
         argv = []
     logging.register_options(cfg.CONF)
     config.parse_args(argv)
+    config.set_config_defaults()
+
     logging.setup(cfg.CONF, 'magnum')

setup.cfg

@@ -52,6 +52,9 @@ console_scripts =
 oslo.config.opts =
     magnum = magnum.opts:list_opts
 
+oslo.config.opts.defaults =
+    oslo.middleware.cors = magnum.common.config:set_cors_middleware_defaults
+
 magnum.template_definitions =
     magnum_vm_atomic_k8s = magnum.conductor.template_definition:AtomicK8sTemplateDefinition
     magnum_vm_coreos_k8s = magnum.conductor.template_definition:CoreOSK8sTemplateDefinition