Implement policy in code - reno and doc (end)

This commit migrate all policies into code [1].

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

Change-Id: Ibdc8611dbb665595b4b3bca493b8bdb241db3fae
Co-authored-By: Hieu LE <hieulq@vn.fujitsu.com>

.gitignore

@@ -20,3 +20,4 @@ subunit.log
 # Files created by releasenotes build
 releasenotes/build
 /doc/source/contributor/api/
+doc/source/_static/aodh.policy.yaml.sample

doc/source/conf.py

@@ -49,6 +49,8 @@ extensions = [
     'stevedore.sphinxext',
     'oslo_config.sphinxconfiggen',
     'oslo_config.sphinxext',
+    'oslo_policy.sphinxpolicygen',
+    'oslo_policy.sphinxext',
     'sphinxcontrib.httpdomain',
 ]
 
@@ -56,6 +58,11 @@ config_generator_config_file = os.path.join(ROOT,
                                             'aodh/cmd/aodh-config-generator.conf')
 sample_config_basename = '_static/aodh'
 
+policy_generator_config_file = (
+    '../../aodh/cmd/aodh-policy-generator.conf'
+)
+sample_policy_basename = '_static/aodh'
+
 wsme_protocols = ['restjson', 'restxml']
 
 todo_include_todos = True

doc/source/configuration/index.rst

@@ -7,6 +7,5 @@ Configuration Guide
 .. toctree::
     aodh-config-file.rst
     aodh-config-options.rst
-
-
-
+    policy
+    sample-policy-yaml

doc/source/configuration/policy.rst

@@ -0,0 +1,9 @@
+=====================================
+Aodh Sample Policy Configuration File
+=====================================
+
+The following is an overview of all available policies in Aodh.
+For a sample configuration file, refer to :doc:`sample-policy-yaml`.
+
+.. show-policy::
+   :config-file: ../../aodh/cmd/aodh-policy-generator.conf

doc/source/configuration/sample-policy-yaml.rst

@@ -0,0 +1,8 @@
+===========
+policy.yaml
+===========
+
+Use the ``policy.yaml`` file to define additional access controls that will be
+applied to Aodh:
+
+.. literalinclude:: ../_static/aodh.policy.yaml.sample

releasenotes/notes/policy-in-code-79edd9282f1e4603.yaml

@@ -0,0 +1,14 @@
+---
+features:
+  - |
+    Aodh now support policy in code, which means if users didn't modify
+    any of policy rules, they can leave policy file (in `json` or `yaml`
+    format) empty or not deploy it at all. Because from now, Aodh keeps
+    all default policies under `aodh/api/policies` module.
+    Users can still modify/generate `policy.yaml` file which will override
+    policy rules in code if those rules show in `policy.yaml` file.
+other:
+  - |
+    Default `policy.json` file is now removed as Aodh now generate the
+    default policies from code. Please be aware that when using that file in
+    your environment.