Upgrade check command - add support for 3rd party checks

CLI command "neutron-status upgrade check" now can load
checks from 3rd party and stadium projects using entry_points.

Such additional checks should be available under
"neutron.status.upgrade.checks" namespace in entry_points.

Change-Id: I416abbcdd7b397ec6acd2827129d7a56095ea63d
Story: 2003657

doc/source/contributor/index.rst

@@ -65,6 +65,7 @@ the developer guide includes information about Neutron testing infrastructure.
    neutron_api
    client_command_extensions
    alembic_migrations
+   upgrade_checks
    testing/index
 
 Neutron Internals

doc/source/contributor/upgrade_checks.rst

@@ -0,0 +1,59 @@
+..
+      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.
+
+
+      Convention for heading levels in Neutron devref:
+      =======  Heading 0 (reserved for the title in a document)
+      -------  Heading 1
+      ~~~~~~~  Heading 2
+      +++++++  Heading 3
+      '''''''  Heading 4
+      (Avoid deeper levels because they do not render well.)
+
+.. _upgrade_checks:
+
+Upgrade checks
+==============
+
+Introduction
+------------
+
+CLI tool ``neutron-status upgrade check`` contains checks which perform a
+release-specific readiness check before restarting services with new code.
+For more details see `neutron-status command-line client
+</cli/neutron-status.html>`_ page.
+
+3rd party plugins checks
+------------------------
+
+Neutron upgrade checks script allows to add checks by stadium and 3rd party
+projects.
+The ``neutron-status`` script detects which sub-projects have been installed by
+enumerating the ``neutron.status.upgrade.checks`` entrypoints. For more details
+see the `Entry Points section of Contributing extensions to Neutron
+<contribute.html#entry-points>`_.
+Checks can be run in random order and should be independent from each other.
+
+The recommended entry point name is a repository name: For example,
+'neutron-fwaas' for FWaaS and 'networking-sfc' for SFC:
+
+.. code-block:: ini
+
+    neutron.status.upgrade.checks =
+        neutron-fwaas = neutron_fwaas.upgrade.checks:Checks
+
+Entrypoint should be class which inherits from
+``neutron.cmd.upgrade_checks.base.BaseChecks``.
+
+An example of a checks class can be found in
+``neutron.cmd.upgrade_checks.checks.CoreChecks``.

neutron/cmd/status.py

@@ -12,13 +12,35 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+from neutron_lib.utils import runtime
 from oslo_config import cfg
+from oslo_log import log as logging
 from oslo_upgradecheck import upgradecheck
 
-from neutron._i18n import _
+CHECKS_ENTRYPOINTS = 'neutron.status.upgrade.checks'
+LOG = logging.getLogger(__name__)
 
 
-class Checks(upgradecheck.UpgradeCommands):
+def load_checks():
+    checks = []
+    ns_plugin = runtime.NamespacedPlugins(CHECKS_ENTRYPOINTS)
+    # TODO(slaweq): stop using private attribute of runtime.NamespacedPlugins
+    # class when it will provide some better way to access extensions
+    for module_name, module in ns_plugin._extensions.items():
+        try:
+            project_checks_class = module.entry_point.load()
+            project_checks = project_checks_class().get_checks()
+            if project_checks:
+                checks.append(project_checks)
+        except Exception as e:
+            LOG.exception("Checks class %(entrypoint)s failed to load. "
+                          "Error: %(err)s",
+                          {'entrypoint': module_name, 'err': e})
+            continue
+    return tuple(checks)
+
+
+class Checker(upgradecheck.UpgradeCommands):
 
     """Various upgrade checks should be added as separate methods in this class
     and added to _upgrade_checks tuple.
@@ -29,11 +51,6 @@ class Checks(upgradecheck.UpgradeCommands):
     like the database schema migrations.
     """
 
-    def _check_nothing(self):
-        # NOTE(slaweq) This is only example Noop check, it can be removed when
-        # some real check methods will be 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
@@ -41,13 +58,9 @@ class Checks(upgradecheck.UpgradeCommands):
     # 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 = (
-        # Check nothing
-        # In the future there should be some real checks added here
-        (_('Check nothing'), _check_nothing),
-    )
+    _upgrade_checks = load_checks()
 
 
 def main():
     return upgradecheck.main(
-        cfg.CONF, project='neutron', upgrade_command=Checks())
+        cfg.CONF, project='neutron', upgrade_command=Checker())

neutron/cmd/upgrade_checks/base.py

@@ -0,0 +1,36 @@
+# Copyright 2018 Red Hat Inc.
+#
+# 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 abc
+
+import six
+
+
+@six.add_metaclass(abc.ABCMeta)
+class BaseChecks(object):
+
+    """Base class providing upgrade checks.
+
+    Stadium projects which want to provide their own upgrade checks to
+    neutron-status CLI tool should inherit from this class.
+
+    Each check method have to accept neutron.cmd.status.Checker
+    class as an argument because all checkes will be run in context of
+    this class.
+    """
+
+    @abc.abstractmethod
+    def get_checks(self):
+        """Get tuple with check methods and check names to run."""
+        pass

neutron/cmd/upgrade_checks/checks.py

@@ -0,0 +1,33 @@
+# Copyright 2018 Red Hat Inc.
+#
+# 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 import upgradecheck
+
+from neutron._i18n import _
+from neutron.cmd.upgrade_checks import base
+
+
+class CoreChecks(base.BaseChecks):
+
+    def get_checks(self):
+        return (
+            (_("Check nothing"), self.noop_check)
+        )
+
+    @staticmethod
+    def noop_check(checker):
+        # NOTE(slaweq) This is only example Noop check, it can be removed when
+        # some real check methods will be added
+        return upgradecheck.Result(
+            upgradecheck.Code.SUCCESS, _("Always succeed (placeholder)"))

neutron/tests/unit/cmd/test_status.py

@@ -12,7 +12,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
-from oslo_upgradecheck.upgradecheck import Code
+import mock
 
 from neutron.cmd import status
 from neutron.tests import base
@@ -20,10 +20,19 @@ from neutron.tests import base
 
 class TestUpgradeChecks(base.BaseTestCase):
 
-    def setUp(self):
-        super(TestUpgradeChecks, self).setUp()
-        self.cmd = status.Checks()
-
-    def test__check_nothing(self):
-        check_result = self.cmd._check_nothing()
-        self.assertEqual(Code.SUCCESS, check_result.code)
+    def test_load_checks(self):
+        expected_checks = tuple(
+            ("test check", "test_check_method"))
+        checks_class_1 = mock.MagicMock()
+        checks_class_1.entry_point.load()().get_checks.return_value = (
+            expected_checks)
+        checks_class_2 = mock.MagicMock()
+        checks_class_2.entry_point.load()().get_checks.return_value = None
+        with mock.patch(
+            "neutron_lib.utils.runtime.NamespacedPlugins"
+        ) as namespace_plugins_mock:
+            namespace_plugins = namespace_plugins_mock.return_value
+            namespace_plugins._extensions = {
+                "tests": checks_class_1,
+                "no-checks-class": checks_class_2}
+            self.assertEqual((expected_checks,), status.load_checks())

neutron/tests/unit/cmd/upgrade_checks/test_checks.py

@@ -0,0 +1,33 @@
+# Copyright 2018 Red Hat Inc.
+#
+# 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 mock
+from oslo_upgradecheck.upgradecheck import Code
+
+from neutron.cmd.upgrade_checks import checks
+from neutron.tests import base
+
+
+class TestChecks(base.BaseTestCase):
+
+    def setUp(self):
+        super(TestChecks, self).setUp()
+        self.checks = checks.CoreChecks()
+
+    def test_get_checks_list(self):
+        self.assertIsInstance(self.checks.get_checks(), tuple)
+
+    def test_noop_check(self):
+        check_result = checks.CoreChecks.noop_check(mock.Mock())
+        self.assertEqual(Code.SUCCESS, check_result.code)

releasenotes/notes/Neutron-status-upgrade-check-framework-fc34d03c8829672c.yaml

@@ -6,6 +6,9 @@ features:
     New framework for ``neutron-status upgrade check`` command is added.
     This framework allows adding various checks which can be run before a
     Neutron upgrade to ensure if the upgrade can be performed safely.
+    Stadium and 3rd party projects can register their own checks to this new
+    neutron-status CLI tool using entrypoints in
+    ``neutron.status.upgrade.checks`` namespace.
 upgrade:
   - |
     Operator can now use new CLI tool ``neutron-status upgrade check``

setup.cfg

@@ -231,7 +231,8 @@ neutron.objects =
     SubnetServiceType = neutron.objects.subnet:SubnetServiceType
     Tag = neutron.objects.tag:Tag
     Trunk = neutron.objects.trunk:Trunk
-
+neutron.status.upgrade.checks =
+    neutron = neutron.cmd.upgrade_checks.checks:CoreChecks
 
 [extract_messages]
 keywords = _ gettext ngettext l_ lazy_gettext