Add framework for aodh-status upgrade check

This commit adds the functionality of aodh-status CLI for performing
upgrade checks as part of the Stein cycle upgrade-checkers goal.
It only includes a sample check which must be replaced by real checks in
future.

Change-Id: I21e331266ab061a41d0ffe3c179b10f777af44f5
Story: 2003657
Task: 27733

aodh/cmd/status.py

@@ -0,0 +1,53 @@
+# Copyright (c) 2018 NEC, Corp.
+#
+#    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.
+
+import sys
+
+from oslo_config import cfg
+from oslo_upgradecheck import upgradecheck
+
+from aodh.i18n import _
+
+CONF = cfg.CONF
+
+
+class Checks(upgradecheck.UpgradeCommands):
+
+    """Contains upgrade checks
+
+    Various upgrade checks should be added as separate methods in this class
+    and added to _upgrade_checks tuple.
+    """
+
+    def _sample_check(self):
+        """This is sample check added to test the upgrade check framework
+
+        It needs to be removed after adding any real upgrade check
+        """
+        return upgradecheck.Result(upgradecheck.Code.SUCCESS, 'Sample detail')
+
+    _upgrade_checks = (
+        # Sample check added for now.
+        # Whereas in future real checks must be added here in tuple
+        (_('Sample Check'), _sample_check),
+    )
+
+
+def main():
+    return upgradecheck.main(
+        CONF, project='aodh', upgrade_command=Checks())
+
+
+if __name__ == '__main__':
+    sys.exit(main())

aodh/tests/unit/cmd/test_status.py

@@ -0,0 +1,30 @@
+# Copyright (c) 2018 NEC, Corp.
+#
+#    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_upgradecheck.upgradecheck import Code
+
+from aodh.cmd import status
+from aodh.tests import base
+
+
+class TestUpgradeChecks(base.BaseTestCase):
+
+    def setUp(self):
+        super(TestUpgradeChecks, self).setUp()
+        self.cmd = status.Checks()
+
+    def test__sample_check(self):
+        check_result = self.cmd._sample_check()
+        self.assertEqual(
+            Code.SUCCESS, check_result.code)

doc/source/cli/aodh-status.rst

@@ -0,0 +1,83 @@
+===========
+aodh-status
+===========
+
+--------------------------------------
+CLI interface for Aodh status commands
+--------------------------------------
+
+Synopsis
+========
+
+::
+
+  aodh-status <category> <command> [<args>]
+
+Description
+===========
+
+:program:`aodh-status` is a tool that provides routines for checking the
+status of a Aodh deployment.
+
+Options
+=======
+
+The standard pattern for executing a :program:`aodh-status` command is::
+
+    aodh-status <category> <command> [<args>]
+
+Run without arguments to see a list of available command categories::
+
+    aodh-status
+
+Categories are:
+
+* ``upgrade``
+
+Detailed descriptions are below:
+
+You can also run with a category argument such as ``upgrade`` to see a list of
+all commands in that category::
+
+    aodh-status upgrade
+
+These sections describe the available categories and arguments for
+:program:`aodh-status`.
+
+Upgrade
+~~~~~~~
+
+.. _aodh-status-checks:
+
+``aodh-status upgrade check``
+  Performs a release-specific readiness check before restarting services with
+  new code. For example, missing or changed configuration options,
+  incompatible object states, or other conditions that could lead to
+  failures while upgrading.
+
+  **Return Codes**
+
+  .. list-table::
+     :widths: 20 80
+     :header-rows: 1
+
+     * - Return code
+       - Description
+     * - 0
+       - All upgrade readiness checks passed successfully and there is nothing
+         to do.
+     * - 1
+       - At least one check encountered an issue and requires further
+         investigation. This is considered a warning but the upgrade may be OK.
+     * - 2
+       - There was an upgrade status check failure that needs to be
+         investigated. This should be considered something that stops an
+         upgrade.
+     * - 255
+       - An unexpected error occurred.
+
+  **History of Checks**
+
+  **8.0.0 (Stein)**
+
+  * Sample check to be filled in with checks as they are added in Stein.

doc/source/cli/index.rst

@@ -0,0 +1,11 @@
+======================
+Aodh CLI Documentation
+======================
+
+In this section you will find information on Aodh’s command line
+interface.
+
+.. toctree::
+   :maxdepth: 1
+
+   aodh-status

doc/source/index.rst

@@ -29,6 +29,7 @@ collected by Ceilometer or Gnocchi.
    contributor/index
    admin/index
    configuration/index
+   cli/index
 
 .. toctree::
    :maxdepth: 1

releasenotes/notes/add-upgrade-check-framework-ab35e6eb65504bc3.yaml

@@ -0,0 +1,13 @@
+---
+prelude: >
+    Added new tool ``aodh-status upgrade check``.
+features:
+  - |
+    New framework for ``aodh-status upgrade check`` command is added.
+    This framework allows adding various checks which can be run before a
+    Aodh upgrade to ensure if the upgrade can be performed safely.
+upgrade:
+  - |
+    Operator can now use new CLI tool ``aodh-status upgrade check``
+    to check if Aodh deployment can be safely upgraded from
+    N-1 to N release.

requirements.txt

@@ -15,6 +15,7 @@ oslo.config>=2.6.0 # Apache-2.0
 oslo.i18n>=1.5.0 # Apache-2.0
 oslo.log>=1.2.0 # Apache-2.0
 oslo.policy>=0.5.0 # Apache-2.0
+oslo.upgradecheck>=0.1.1 # Apache-2.0
 PasteDeploy>=1.5.0
 pbr>=2.0.0 # Apache-2.0
 pecan>=0.8.0

setup.cfg

@@ -100,6 +100,7 @@ console_scripts =
     aodh-notifier = aodh.cmd.alarm:notifier
     aodh-listener = aodh.cmd.alarm:listener
     aodh-config-generator = aodh.cmd:config_generator
+    aodh-status = aodh.cmd.status:main
 
 oslo.config.opts =
     aodh = aodh.opts:list_opts