Source code for heat.scaling.cooldown

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#         http://www.apache.org/licenses/LICENSE-2.0
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from oslo_log import log as logging

from heat.common import exception
from heat.common.i18n import _
from heat.common.i18n import _LI
from heat.engine import resource
from oslo_utils import timeutils
import six

LOG = logging.getLogger(__name__)


[docs]class CooldownMixin(object): """Utility class to encapsulate Cooldown related logic. This class is shared between AutoScalingGroup and ScalingPolicy. This logic includes both cooldown timestamp comparing and scaling in progress checking. """ def _check_scaling_allowed(self): metadata = self.metadata_get() if metadata.get('scaling_in_progress'): LOG.info(_LI("Can not perform scaling action: resource %s " "is already in scaling.") % self.name) reason = _('due to scaling activity') raise resource.NoActionRequired(res_name=self.name, reason=reason) try: # Negative values don't make sense, so they are clamped to zero cooldown = max(0, self.properties[self.COOLDOWN]) except TypeError: # If not specified, it will be None, same as cooldown == 0 cooldown = 0 if cooldown != 0: try: if 'cooldown' not in metadata: # Note: this is for supporting old version cooldown logic if metadata: last_adjust = next(six.iterkeys(metadata)) self._cooldown_check(cooldown, last_adjust) else: last_adjust = next(six.iterkeys(metadata['cooldown'])) self._cooldown_check(cooldown, last_adjust) except ValueError: # occurs when metadata has only {scaling_in_progress: False} pass # Assumes _finished_scaling is called # after the scaling operation completes metadata['scaling_in_progress'] = True self.metadata_set(metadata) def _cooldown_check(self, cooldown, last_adjust): if not timeutils.is_older_than(last_adjust, cooldown): LOG.info(_LI("Can not perform scaling action: " "resource %(name)s is in cooldown (%(cooldown)s).") % {'name': self.name, 'cooldown': cooldown}) reason = _('due to cooldown, ' 'cooldown %s') % cooldown raise resource.NoActionRequired( res_name=self.name, reason=reason) def _finished_scaling(self, cooldown_reason, size_changed=True): # If we wanted to implement the AutoScaling API like AWS does, # we could maintain event history here, but since we only need # the latest event for cooldown, just store that for now metadata = self.metadata_get() if size_changed: now = timeutils.utcnow().isoformat() metadata['cooldown'] = {now: cooldown_reason} metadata['scaling_in_progress'] = False try: self.metadata_set(metadata) except exception.NotFound: pass
[docs] def handle_metadata_reset(self): metadata = self.metadata_get() if 'scaling_in_progress' in metadata: metadata['scaling_in_progress'] = False self.metadata_set(metadata)