2544327979
In this changeset, I decoupled the notion of Goal from the Strategy by making it a distinct object. Goals are plugins that can be loaded just like for the strategies. Partially Implements: blueprint efficacy-indicator Change-Id: I4378dccd508170b305aa968843228bbc8af78895
76 lines
2.7 KiB
Python
76 lines
2.7 KiB
Python
# -*- encoding: utf-8 -*-
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# Copyright (c) 2015 b<>com
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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# implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from oslo_config import cfg
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from oslo_log import log
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from watcher._i18n import _
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from watcher.common import exception
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from watcher.decision_engine.loading import default
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from watcher.decision_engine.strategy.selection import base
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LOG = log.getLogger(__name__)
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CONF = cfg.CONF
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class DefaultStrategySelector(base.BaseSelector):
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def __init__(self, goal_name, strategy_name=None, osc=None):
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"""Default strategy selector
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:param goal_name: Name of the goal
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:param strategy_name: Name of the strategy
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:param osc: an OpenStackClients instance
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"""
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super(DefaultStrategySelector, self).__init__()
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self.goal_name = goal_name
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self.strategy_name = strategy_name
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self.osc = osc
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self.strategy_loader = default.DefaultStrategyLoader()
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def select(self):
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"""Selects a strategy
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:raises: :py:class:`~.LoadingError` if it failed to load a strategy
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:returns: A :py:class:`~.BaseStrategy` instance
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"""
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strategy_to_load = None
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try:
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if self.strategy_name:
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strategy_to_load = self.strategy_name
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else:
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available_strategies = self.strategy_loader.list_available()
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available_strategies_for_goal = list(
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key for key, strat in available_strategies.items()
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if strat.get_goal_name() == self.goal_name)
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if not available_strategies_for_goal:
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raise exception.NoAvailableStrategyForGoal(
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goal=self.goal_name)
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# TODO(v-francoise): We should do some more work here to select
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# a strategy out of a given goal instead of just choosing the
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# 1st one
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strategy_to_load = available_strategies_for_goal[0]
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return self.strategy_loader.load(strategy_to_load, osc=self.osc)
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except exception.NoAvailableStrategyForGoal:
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raise
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except Exception as exc:
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LOG.exception(exc)
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raise exception.LoadingError(
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_("Could not load any strategy for goal %(goal)s"),
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goal=self.goal_name)
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