69 lines
2.5 KiB
Python
69 lines
2.5 KiB
Python
# Copyright 2015-2016 Canonical Ltd.
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#
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# This file is part of the Leadership Layer for Juju.
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License version 3, as
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# published by the Free Software Foundation.
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#
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# This program is distributed in the hope that it will be useful, but
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# WITHOUT ANY WARRANTY; without even the implied warranties of
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# MERCHANTABILITY, SATISFACTORY QUALITY, or FITNESS FOR A PARTICULAR
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# PURPOSE. See the GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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from charmhelpers.core import hookenv
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from charmhelpers.core import unitdata
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from charms import reactive
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from charms.leadership import leader_get, leader_set
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__all__ = ['leader_get', 'leader_set'] # Backwards compatibility
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def initialize_leadership_state():
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'''Initialize leadership.* states from the hook environment.
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Invoked by hookenv.atstart() so states are available in
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@hook decorated handlers.
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'''
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is_leader = hookenv.is_leader()
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if is_leader:
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hookenv.log('Initializing Leadership Layer (is leader)')
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else:
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hookenv.log('Initializing Leadership Layer (is follower)')
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reactive.helpers.toggle_state('leadership.is_leader', is_leader)
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previous = unitdata.kv().getrange('leadership.settings.', strip=True)
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current = hookenv.leader_get()
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# Handle deletions.
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for key in set(previous.keys()) - set(current.keys()):
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current[key] = None
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any_changed = False
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for key, value in current.items():
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reactive.helpers.toggle_state('leadership.changed.{}'.format(key),
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value != previous.get(key))
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if value != previous.get(key):
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any_changed = True
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reactive.helpers.toggle_state('leadership.set.{}'.format(key),
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value is not None)
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reactive.helpers.toggle_state('leadership.changed', any_changed)
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unitdata.kv().update(current, prefix='leadership.settings.')
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# Per https://github.com/juju-solutions/charms.reactive/issues/33,
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# this module may be imported multiple times so ensure the
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# initialization hook is only registered once. I have to piggy back
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# onto the namespace of a module imported before reactive discovery
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# to do this.
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if not hasattr(reactive, '_leadership_registered'):
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hookenv.atstart(initialize_leadership_state)
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reactive._leadership_registered = True
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