Source code for heat.scaling.cooldown
#
# 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 datetime
from heat.common import exception
from heat.common.i18n import _
from heat.engine import resource
from oslo_log import log as logging
from oslo_utils import timeutils
LOG = logging.getLogger(__name__)
[docs]
class CooldownMixin(object):
"""Utility class to encapsulate Cooldown related logic.
This logic includes both cooldown timestamp comparing and scaling in
progress checking.
"""
def _sanitize_cooldown(self, cooldown):
if cooldown is None:
return 0
return max(0, cooldown)
def _check_scaling_allowed(self, cooldown):
metadata = self.metadata_get()
if metadata.get('scaling_in_progress'):
LOG.info("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)
cooldown = self._sanitize_cooldown(cooldown)
# if both cooldown and cooldown_end not in metadata
if all(k not in metadata for k in ('cooldown', 'cooldown_end')):
# Note: this is for supporting old version cooldown checking
metadata.pop('scaling_in_progress', None)
if metadata and cooldown != 0:
last_adjust = next(iter(metadata.keys()))
if not timeutils.is_older_than(last_adjust, cooldown):
self._log_and_raise_no_action(cooldown)
elif 'cooldown_end' in metadata:
cooldown_end = next(iter(metadata['cooldown_end'].keys()))
now = timeutils.utcnow().isoformat()
if now < cooldown_end:
self._log_and_raise_no_action(cooldown)
elif cooldown != 0:
# Note: this is also for supporting old version cooldown checking
last_adjust = next(iter(metadata['cooldown'].keys()))
if not timeutils.is_older_than(last_adjust, cooldown):
self._log_and_raise_no_action(cooldown)
# Assumes _finished_scaling is called
# after the scaling operation completes
metadata['scaling_in_progress'] = True
self.metadata_set(metadata)
def _log_and_raise_no_action(self, cooldown):
LOG.info("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,
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:
cooldown = self._sanitize_cooldown(cooldown)
cooldown_end = (timeutils.utcnow() + datetime.timedelta(
seconds=cooldown)).isoformat()
if 'cooldown_end' in metadata:
cooldown_end = max(
next(iter(metadata['cooldown_end'].keys())),
cooldown_end)
metadata['cooldown_end'] = {cooldown_end: cooldown_reason}
metadata['scaling_in_progress'] = False
try:
self.metadata_set(metadata)
except exception.NotFound:
pass
