placement: ignore policy scope check failures if not enforcing scope

Rather than spam the placement API logs with scope check
warnings from oslo.policy when placement isn't configured
for scope type enforcement, ignore those warnings.

Note that the same warnings filter in the placement WarningsFixture
is left intact because the configuration defaults setting code in
wsgi.py which allows the warning filter to be set in deploy.py,
is not run by the functional tests. In future changes this will
be resolved by unifying configuration handling.

Closes-Bug: #1786498
Related-Bug: #1784663
Change-Id: I34e4e550c9c31a654308e555210588156418f9e3
(cherry picked from commit 94617a7176)

nova/api/openstack/placement/deploy.py

@@ -81,6 +81,13 @@ def deploy(conf):
         if middleware:
             application = middleware(application)
 
+    # NOTE(mriedem): Ignore scope check UserWarnings from oslo.policy.
+    if not conf.oslo_policy.enforce_scope:
+        import warnings
+        warnings.filterwarnings('ignore',
+                                message="Policy .* failed scope check",
+                                category=UserWarning)
+
     return application
 
 

nova/api/openstack/placement/wsgi.py

@@ -20,6 +20,7 @@ import os.path
 
 from oslo_log import log as logging
 from oslo_middleware import cors
+from oslo_policy import opts as policy_opts
 from oslo_utils import importutils
 import pbr.version
 
@@ -65,6 +66,10 @@ def _parse_args(argv, default_config_files):
 
     _set_middleware_defaults()
 
+    # This is needed so we can check [oslo_policy]/enforce_scope in the
+    # deploy module.
+    policy_opts.set_defaults(conf.CONF)
+
     conf.CONF(argv[1:], project='nova', version=version_info.version_string(),
               default_config_files=default_config_files)