Implementation of deferred restarts

Add deferred restart actions and config.

Change-Id: I34ceac5b62e079259a25a11edcedc30f943888d7

src/actions.yaml

@@ -0,0 +1,27 @@
+restart-services:
+  description: |
+    Restarts services this charm manages.
+  params:
+    deferred-only:
+      type: boolean
+      default: false
+      description: |
+        Restart all deferred services.
+    services:
+      type: string
+      default: ""
+      description: |
+        List of services to restart.
+    run-hooks:
+      type: boolean
+      default: true
+      description: |
+        Run any hooks which have been deferred.
+run-deferred-hooks:
+  description: |
+    Run deferable hooks and restart services.
+    .
+    NOTE: Service will be restarted as needed irrespective of enable-auto-restarts
+show-deferred-events:
+    descrpition: |
+        Show the outstanding restarts

src/actions/restart-services

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+# Copyright 2021 Canonical Ltd
+#
+# 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
+
+
+sys.path.append('actions')
+
+
+import os_deferred_event_actions
+
+
+if __name__ == "__main__":
+    sys.exit(os_deferred_event_actions.main(sys.argv))

src/actions/run-deferred-hooks

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+# Copyright 2021 Canonical Ltd
+#
+# 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
+
+
+sys.path.append('actions')
+
+
+import os_deferred_event_actions
+
+
+if __name__ == "__main__":
+    sys.exit(os_deferred_event_actions.main(sys.argv))

src/actions/show-deferred-events

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+# Copyright 2021 Canonical Ltd
+#
+# 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
+
+
+sys.path.append('actions')
+
+
+import os_deferred_event_actions
+
+
+if __name__ == "__main__":
+    sys.exit(os_deferred_event_actions.main(sys.argv))

src/config.yaml

@@ -14,3 +14,10 @@ options:
       a hypervisor hosts an instance in a subnet, so the volume should be
       relatively low. If you set this number too high you may put an
       unnecessary toll on the OVN Southbound database server.
+  enable-auto-restarts:
+    type: boolean
+    default: True
+    description: |
+      Allow the charm and packages to restart services automatically when
+      required.
+

src/lib/charm/openstack/ovn_chassis.py

@@ -20,7 +20,8 @@ import charms.ovn_charm
 charm.use_defaults('charm.default-select-release')
 
 
-class TrainOVNChassisCharm(charms.ovn_charm.BaseTrainOVNChassisCharm):
+class TrainOVNChassisCharm(charms.ovn_charm.DeferredEventMixin,
+                           charms.ovn_charm.BaseTrainOVNChassisCharm):
     # OpenvSwitch and OVN is distributed as part of the Ubuntu Cloud Archive
     # Pockets get their name from OpenStack releases
     release = 'train'
@@ -31,7 +32,8 @@ class TrainOVNChassisCharm(charms.ovn_charm.BaseTrainOVNChassisCharm):
     source_config_key = ''
 
 
-class UssuriOVNChassisCharm(charms.ovn_charm.BaseUssuriOVNChassisCharm):
+class UssuriOVNChassisCharm(charms.ovn_charm.DeferredEventMixin,
+                            charms.ovn_charm.BaseUssuriOVNChassisCharm):
     # OpenvSwitch and OVN is distributed as part of the Ubuntu Cloud Archive
     # Pockets get their name from OpenStack releases
     release = 'ussuri'

src/reactive/ovn_chassis_handlers.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import charms.reactive as reactive
+import charms_openstack.charm as charm
 
 from . import ovn_chassis_charm_handlers
 
@@ -20,3 +21,9 @@ from . import ovn_chassis_charm_handlers
 def enable_ovn_chassis_handlers():
     reactive.set_flag(
         ovn_chassis_charm_handlers.OVN_CHASSIS_ENABLE_HANDLERS_FLAG)
+
+
+@reactive.when_not('is-update-status-hook')
+def configure_deferred_restarts():
+    with charm.provide_charm_instance() as instance:
+        instance.configure_deferred_restarts()

src/tests/tests.yaml

@@ -26,6 +26,7 @@ target_deploy_status:
 configure:
 - zaza.openstack.charm_tests.vault.setup.auto_initialize_no_validation
 tests:
+- zaza.openstack.charm_tests.ovn.tests.OVNChassisDeferredRestartTest
 - zaza.openstack.charm_tests.ovn.tests.ChassisCharmOperationTest
 tests_options:
   force_deploy:

unit_tests/test_reactive_ovn_chassis_handlers.py

@@ -26,6 +26,7 @@ class TestRegisteredHooks(test_utils.TestRegisteredHooks):
         hook_set = {
             'when_not': {
                 'enable_ovn_chassis_handlers': ('MOCKED_FLAG',),
+                'configure_deferred_restarts': ('is-update-status-hook',),
             },
         }
         # test that the hooks were registered via the