Pause/Resume action for reactive charms

Add pause and resume actions to the Openstack charms. To use these
actions the charm author needs to add an os_actions.py file (which
imports the charm class) and needs to create action symlinks.

Change-Id: Ib882a506b8de6588c556187d526a4028586e5217
This commit is contained in:
Liam Young 2018-09-18 08:08:43 +00:00
parent d6c8112a71
commit 91caccf8e5
3 changed files with 110 additions and 0 deletions

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actions.yaml Normal file
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pause:
description: |
Pause services.
If the deployment is clustered using the hacluster charm, the
corresponding hacluster unit on the node must first be paused as well.
Not doing so may lead to an interruption of service.
resume:
description: |
Resume services.
If the deployment is clustered using the hacluster charm, the
corresponding hacluster unit on the node must be resumed as well.

10
actions/os_actions.py Executable file
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#!/usr/bin/env python3
print("Please specialise this file in the top level charm: ")
print("""
import sys
import os_generic_actions
import charm.openstack.CHARM_NAME # noqa
sys.exit(os_generic_actions.run_action(sys.argv))""")

89
actions/os_generic_actions.py Executable file
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#!/usr/bin/env python3
# Copyright 2016 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 os
import sys
# Load modules from $CHARM_DIR/lib
sys.path.append('lib')
from charms.layer import basic
basic.bootstrap_charm_deps()
basic.init_config_states()
import charms.reactive as reactive
import charmhelpers.core.hookenv as hookenv
import charms_openstack.charm
"""This module defines the generic OpenStack charm actions. To use these the
charm needs to call run_action having imported the charms charm class e.g.
```
#!/usr/bin/env python3
import sys
import os_generic_actions
import charm.openstack.aodh # noqa
sys.exit(os_generic_actions.run_action(sys.argv))
```
The above code can be placed in a file called *os_actions.py* symbolic links
with the action names can then be created.
```
lrwxrwxrwx 1 root root 13 Sep 18 06:45 pause -> os_actions.py
lrwxrwxrwx 1 root root 13 Sep 18 06:45 resume -> os_actions.py
```
"""
def pause_action(*args):
"""Run the pause action."""
with charms_openstack.charm.provide_charm_instance() as charm_instance:
charm_instance.pause()
# Run _assess_status rather than assess_status so the call is not
# deferred.
charm_instance._assess_status()
def resume_action(*args):
"""Run the resume action."""
with charms_openstack.charm.provide_charm_instance() as charm_instance:
charm_instance.resume()
# Run _assess_status rather than assess_status so the call is not
# deferred.
charm_instance._assess_status()
# Actions to function mapping, to allow for illegal python action names that
# can map to a python function.
ACTIONS = {
"pause": pause_action,
"resume": resume_action,
}
def run_action(args):
action_name = os.path.basename(args[0])
try:
action = ACTIONS[action_name]
except KeyError:
return "Action %s undefined" % action_name
else:
try:
action(args)
except Exception as e:
hookenv.action_fail(str(e))