Implement policy in code (1)

This commit will prepare for implementing policies in code [1].

Like oslo.config, with oslo.policy, we can define all of
default rules in code base and only change some rules
via policy file. Another thing that we should use yaml
format instead of json format.

[1] https://governance.openstack.org/tc/goals/queens/policy-in-code.html

Change-Id: I8cd6e148d9b6bb1dc61e2cb1728acafc325bca65
Co-authored-By: Hieu LE <hieulq@vn.fujitsu.com>

.gitignore

@@ -26,3 +26,4 @@ tags
 .tox
 .venv
 .DS_Store
+.stestr

etc/senlin/policy.json

@@ -1,7 +1,4 @@
 {
-    "context_is_admin":  "role:admin",
-    "deny_everybody": "!",
-
     "build_info:build_info": "",
     "profile_types:index": "",
     "profile_types:get": "",

senlin/common/policies/__init__.py

@@ -0,0 +1,26 @@
+# All Rights Reserved.
+#
+#    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.
+#
+# Borrowed from Zun
+
+
+import itertools
+
+from senlin.common.policies import base
+
+
+def list_rules():
+    return itertools.chain(
+        base.list_rules()
+    )

senlin/common/policies/base.py

@@ -0,0 +1,35 @@
+# All Rights Reserved.
+#
+#    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_policy import policy
+
+
+ROLE_ADMIN = 'role:admin'
+DENY_EVERYBODY = '!'
+
+rules = [
+    policy.RuleDefault(
+        name="context_is_admin",
+        check_str=ROLE_ADMIN
+    ),
+    policy.RuleDefault(
+        name="deny_everybody",
+        check_str=DENY_EVERYBODY
+    )
+]
+
+
+def list_rules():
+    return rules

senlin/common/policy.py

@@ -19,6 +19,7 @@ from oslo_config import cfg
 from oslo_policy import policy
 
 from senlin.common import exception
+from senlin.common import policies
 
 POLICY_ENFORCER = None
 CONF = cfg.CONF
@@ -34,6 +35,7 @@ def _get_enforcer(policy_file=None, rules=None, default_rule=None):
                                           policy_file=policy_file,
                                           rules=rules,
                                           default_rule=default_rule)
+        POLICY_ENFORCER.register_defaults(policies.list_rules())
     return POLICY_ENFORCER
 
 

setup.cfg

@@ -37,6 +37,9 @@ oslo.config.opts =
 oslo.config.opts.defaults =
     senlin.config = senlin.common.config:set_config_defaults
 
+oslo.policy.policies =
+    senlin = senlin.common.policies:list_rules
+
 senlin.drivers =
     openstack = senlin.drivers.openstack
     openstack_test = senlin.tests.drivers.openstack

tools/gen-policy

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+oslopolicy-sample-generator --config-file tools/policy-generator.conf

tools/policy-generator.conf

@@ -0,0 +1,3 @@
+[DEFAULT]
+output_file = etc/senlin/policy.yaml.sample
+namespace = senlin

tox.ini

@@ -67,6 +67,11 @@ envdir = {toxworkdir}/venv
 commands =
   {toxinidir}/tools/gen-config
 
+[testenv:genpolicy]
+envdir = {toxworkdir}/venv
+commands =
+  {toxinidir}/tools/gen-policy
+
 [testenv:venv]
 commands = {posargs}