Add dragonflow-status upgrade check command framework

This adds basic framework for dragonflow-status upgrade
check commands. For now it has only "check_placeholder"
check implemented.
Real checks can be added to this tool in the future.

Change-Id: I9791b3fcce65b08f92b3c5d54b529633579f795a
Story: 2003657
Task: 26128

doc/source/cli/dragonflow-status.rst

@@ -0,0 +1,78 @@
+=================
+dragonflow-status
+=================
+
+Synopsis
+========
+
+::
+
+  dragonflow-status <category> <command> [<args>]
+
+Description
+===========
+
+:program:`dragonflow-status` is a tool that provides routines for checking the
+status of a Dragonflow deployment.
+
+Options
+=======
+
+The standard pattern for executing a :program:`dragonflow-status` command is::
+
+    dragonflow-status <category> <command> [<args>]
+
+Run without arguments to see a list of available command categories::
+
+    dragonflow-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::
+
+    dragonflow-status upgrade
+
+These sections describe the available categories and arguments for
+:program:`dragonflow-status`.
+
+Upgrade
+~~~~~~~
+
+.. _dragonflow-status-checks:
+
+``dragonflow-status upgrade check``
+  Performs a release-specific readiness check before restarting services with
+  new code. This command expects to have complete configuration and access
+  to databases and services.
+
+  **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**
+
+  **4.0.0 (Stein)**
+
+  * Placeholder to be filled in with checks as they are added in Stein.

doc/source/cli/index.rst

@@ -0,0 +1,7 @@
+CLI Guide
+=========
+
+.. toctree::
+   :maxdepth: 1
+
+   dragonflow-status

doc/source/index.rst

@@ -39,6 +39,14 @@ Dragonflow Specs
 
    specs/index
 
+CLI Reference
+=============
+
+.. toctree::
+   :maxdepth: 1
+
+   cli/index
+
 Developer References
 ====================
 

dragonflow/cmd/status.py

@@ -0,0 +1,52 @@
+# 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 dragonflow._i18n import _
+
+
+class Checks(upgradecheck.UpgradeCommands):
+
+    """Various upgrade checks should be added as separate methods in this class
+    and added to _upgrade_checks tuple.
+    """
+
+    def _check_placeholder(self):
+        # This is just a placeholder for upgrade checks, it should be
+        # removed when the actual checks are added
+        return upgradecheck.Result(upgradecheck.Code.SUCCESS)
+
+    # The format of the check functions is to return an
+    # oslo_upgradecheck.upgradecheck.Result
+    # object with the appropriate
+    # oslo_upgradecheck.upgradecheck.Code and details set.
+    # If the check hits warnings or failures then those should be stored
+    # in the returned Result's "details" attribute. The
+    # summary will be rolled up at the end of the check() method.
+    _upgrade_checks = (
+        # In the future there should be some real checks added here
+        (_('Placeholder'), _check_placeholder),
+    )
+
+
+def main():
+    return upgradecheck.main(
+        cfg.CONF, project='dragonflow', upgrade_command=Checks())
+
+if __name__ == '__main__':
+    sys.exit(main())

dragonflow/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 dragonflow.cmd import status
+from dragonflow.tests import base as tests_base
+
+
+class TestUpgradeChecks(tests_base.BaseTestCase):
+
+    def setUp(self):
+        super(TestUpgradeChecks, self).setUp()
+        self.cmd = status.Checks()
+
+    def test__check_placeholder(self):
+        check_result = self.cmd._check_placeholder()
+        self.assertEqual(
+            Code.SUCCESS, check_result.code)

lower-constraints.txt

@@ -86,6 +86,7 @@ oslo.reports==1.18.0
 oslo.rootwrap==5.13.0
 oslo.serialization==2.18.0
 oslo.service==1.30.0
+oslo.upgradecheck==0.1.0
 oslo.utils==3.36.0
 oslo.versionedobjects==1.32.0
 oslotest==3.2.0

releasenotes/notes/dragonflow-status-upgrade-check-framework-efd2592c6decdd16.yaml

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

requirements.txt

@@ -19,6 +19,7 @@ oslo.i18n>=3.15.3 # Apache-2.0
 oslo.log>=3.36.0 # Apache-2.0
 oslo.reports>=1.18.0 # Apache-2.0
 oslo.serialization!=2.19.1,>=2.18.0 # Apache-2.0
+oslo.upgradecheck>=0.1.0 # Apache-2.0
 ovsdbapp>=0.11.0 # Apache-2.0
 crc16>=0.1.1 # LGPLv3+
 netaddr>=0.7.18 # BSD

setup.cfg

@@ -58,7 +58,8 @@ console_scripts =
     df-l3-agent = dragonflow.cmd.eventlet.df_l3_agent:main
     df-metadata-service = dragonflow.cmd.eventlet.df_metadata_service:main
     df-bgp-service = dragonflow.cmd.eventlet.df_bgp_service:main
-    df-skydive-service= dragonflow.cmd.df_skydive_service:service_main
+    df-skydive-service = dragonflow.cmd.df_skydive_service:service_main
+    dragonflow-status = dragonflow.cmd.status:main
 dragonflow.pubsub_driver =
     zmq_pubsub_driver = dragonflow.db.pubsub_drivers.zmq_pubsub_driver:ZMQPubSubConnect
     zmq_bind_pubsub_driver = dragonflow.db.pubsub_drivers.zmq_pubsub_driver:ZMQPubSubBind