Source code for watcher.decision_engine.strategy.selection.default

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from oslo_log import log

from watcher._i18n import _
from watcher.common import exception
from watcher.decision_engine.loading import default
from watcher.decision_engine.strategy.selection import base

LOG = log.getLogger(__name__)


[docs]class DefaultStrategySelector(base.BaseSelector): def __init__(self, goal_name, strategy_name=None, osc=None): """Default strategy selector :param goal_name: Name of the goal :param strategy_name: Name of the strategy :param osc: an OpenStackClients instance """ super(DefaultStrategySelector, self).__init__() self.goal_name = goal_name self.strategy_name = strategy_name self.osc = osc self.strategy_loader = default.DefaultStrategyLoader()
[docs] def select(self): """Selects a strategy :raises: :py:class:`~.LoadingError` if it failed to load a strategy :returns: A :py:class:`~.BaseStrategy` instance """ strategy_to_load = None try: if self.strategy_name: strategy_to_load = self.strategy_name else: available_strategies = self.strategy_loader.list_available() available_strategies_for_goal = list( key for key, strat in available_strategies.items() if strat.get_goal_name() == self.goal_name) if not available_strategies_for_goal: raise exception.NoAvailableStrategyForGoal( goal=self.goal_name) # TODO(v-francoise): We should do some more work here to select # a strategy out of a given goal instead of just choosing the # 1st one strategy_to_load = available_strategies_for_goal[0] return self.strategy_loader.load(strategy_to_load, osc=self.osc) except exception.NoAvailableStrategyForGoal: raise except Exception as exc: LOG.exception(exc) raise exception.LoadingError( _("Could not load any strategy for goal %(goal)s"), goal=self.goal_name)