Added CORS support to Senlin

OpenStack CrossProject Spec:
   http://specs.openstack.org/openstack/openstack-specs/specs/cors-support.html
Oslo_Middleware Docs:
   http://docs.openstack.org/developer/oslo.middleware/cors.html
OpenStack Cloud Admin Guide:
   http://docs.openstack.org/admin-guide-cloud/cross_project_cors.html

Change-Id: Iedd14f7aebf0969e79b74ec3400e4362029d1b63

etc/senlin/api-paste.ini

@@ -1,7 +1,7 @@
 
 # senlin-api pipeline
 [pipeline:senlin-api]
-pipeline = http_proxy_to_wsgi request_id faultwrap ssl versionnegotiation osprofiler webhook authtoken context trust apiv1app
+pipeline = cors http_proxy_to_wsgi request_id faultwrap ssl versionnegotiation osprofiler webhook authtoken context trust apiv1app
 
 [app:apiv1app]
 paste.app_factory = senlin.api.common.wsgi:app_factory
@@ -44,3 +44,7 @@ paste.filter_factory = keystonemiddleware.auth_token:filter_factory
 
 [filter:osprofiler]
 paste.filter_factory = osprofiler.web:WsgiMiddleware.factory
+
+[filter:cors]
+paste.filter_factory =  oslo_middleware.cors:filter_factory
+oslo_config_project = senlin

senlin/cmd/api.py

@@ -24,6 +24,7 @@ from oslo_service import systemd
 import six
 
 from senlin.api.common import wsgi
+from senlin.common import config
 from senlin.common.i18n import _LI
 from senlin.common import messaging
 from senlin.common import profiler
@@ -40,6 +41,7 @@ def main():
         logging.register_options(cfg.CONF)
         cfg.CONF(project='senlin', prog='senlin-api',
                  version=version.version_info.version_string())
+        config.set_config_defaults()
         logging.setup(cfg.CONF, 'senlin-api')
         objects.register_all()
         messaging.setup()

senlin/cmd/api_wsgi.py

@@ -23,6 +23,7 @@ import oslo_i18n as i18n
 from oslo_log import log as logging
 
 from senlin.api.common import wsgi
+from senlin.common import config
 from senlin.common import messaging
 from senlin.common import profiler
 from senlin import version
@@ -35,6 +36,7 @@ def init_app():
     cfg.CONF(project='senlin', prog='senlin-api',
              version=version.version_info.version_string())
     logging.setup(cfg.CONF, 'senlin-api')
+    config.set_config_defaults()
     messaging.setup()
 
     profiler.setup('senlin-api', cfg.CONF.host)

senlin/common/config.py

@@ -17,6 +17,7 @@ import socket
 
 from keystoneauth1 import loading as ks_loading
 from oslo_config import cfg
+from oslo_middleware import cors
 from osprofiler import opts as profiler
 
 from senlin.api.common import wsgi
@@ -233,3 +234,24 @@ def list_opts():
     yield receiver_group.name, receiver_opts
     yield zaqar_group.name, zaqar_opts
     yield profiler.list_opts()[0]
+
+
+def set_config_defaults():
+    """Update default configuration options for oslo.middleware."""
+    cors.set_defaults(
+        allow_headers=['X-Auth-Token',
+                       'X-Identity-Status',
+                       'X-Roles',
+                       'X-Service-Catalog',
+                       'X-User-Id',
+                       'X-Tenant-Id',
+                       'X-OpenStack-Request-ID'],
+        expose_headers=['X-Auth-Token',
+                        'X-Subject-Token',
+                        'X-Service-Token',
+                        'X-OpenStack-Request-ID'],
+        allow_methods=['GET',
+                       'PUT',
+                       'POST',
+                       'DELETE',
+                       'PATCH'])

setup.cfg

@@ -35,6 +35,9 @@ wsgi_scripts =
 oslo.config.opts =
     senlin.config = senlin.common.config:list_opts
 
+oslo.config.opts.defaults =
+    senlin.config = senlin.common.config:set_config_defaults
+
 senlin.drivers =
     openstack = senlin.drivers.openstack
     openstack_test = senlin.tests.drivers.openstack

tools/config-generator.conf

@@ -6,6 +6,7 @@ namespace = keystonemiddleware.auth_token
 namespace = oslo.db
 namespace = oslo.log
 namespace = oslo.messaging
+namespace = oslo.middleware.cors
 namespace = oslo.middleware.http_proxy_to_wsgi
 namespace = oslo.policy
 namespace = oslo.service.periodic_task