aodh/aodh/api/controllers/v2/alarm_rules/threshold.py

#
# 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.

from ceilometerclient import client as ceiloclient
from ceilometerclient import exc as ceiloexc
import pecan
import wsme
from wsme import types as wtypes

from aodh.api.controllers.v2 import base
from aodh.api.controllers.v2 import utils as v2_utils
from aodh.i18n import _
from aodh import keystone_client
from aodh import storage


class AlarmThresholdRule(base.AlarmRule):
    """Alarm Threshold Rule

    Describe when to trigger the alarm based on computed statistics
    """

    meter_name = wsme.wsattr(wtypes.text, mandatory=True)
    "The name of the meter"

    # FIXME(sileht): default doesn't work
    # workaround: default is set in validate method
    query = wsme.wsattr([base.Query], default=[])
    """The query to find the data for computing statistics.
    Ownership settings are automatically included based on the Alarm owner.
    """

    period = wsme.wsattr(wtypes.IntegerType(minimum=1), default=60)
    "The time range in seconds over which query"

    comparison_operator = base.AdvEnum('comparison_operator', str,
                                       'lt', 'le', 'eq', 'ne', 'ge', 'gt',
                                       default='eq')
    "The comparison against the alarm threshold"

    threshold = wsme.wsattr(float, mandatory=True)
    "The threshold of the alarm"

    statistic = base.AdvEnum('statistic', str, 'max', 'min', 'avg', 'sum',
                             'count', default='avg')
    "The statistic to compare to the threshold"

    evaluation_periods = wsme.wsattr(wtypes.IntegerType(minimum=1), default=1)
    "The number of historical periods to evaluate the threshold"

    exclude_outliers = wsme.wsattr(bool, default=False)
    "Whether datapoints with anomalously low sample counts are excluded"

    ceilometer_sample_api_is_supported = None

    def __init__(self, query=None, **kwargs):
        query = [base.Query(**q) for q in query] if query else []
        super(AlarmThresholdRule, self).__init__(query=query, **kwargs)

    @classmethod
    def _check_ceilometer_sample_api(cls):
        # Check it only once
        if cls.ceilometer_sample_api_is_supported is None:

            auth_config = pecan.request.cfg.service_credentials
            client = ceiloclient.get_client(
                version=2,
                session=keystone_client.get_session(pecan.request.cfg),
                # ceiloclient adapter options
                region_name=auth_config.region_name,
                interface=auth_config.interface,
            )
            try:
                client.statistics.list(
                    meter_name="idontthinkthatexistsbutwhatever")
            except Exception as e:
                if isinstance(e, ceiloexc.HTTPException):
                    if e.code == 410:
                        cls.ceilometer_sample_api_is_supported = False
                    elif e.code < 500:
                        cls.ceilometer_sample_api_is_supported = True
                    else:
                        raise
                else:
                    raise
            else:
                # I don't think this meter can exist but how known
                cls.ceilometer_sample_api_is_supported = True

        if cls.ceilometer_sample_api_is_supported is False:
            raise base.ClientSideError(
                "This telemetry installation is not configured to support"
                "alarm of type 'threshold")

    @staticmethod
    def validate(threshold_rule):
        # note(sileht): wsme default doesn't work in some case
        # workaround for https://bugs.launchpad.net/wsme/+bug/1227039
        if not threshold_rule.query:
            threshold_rule.query = []

        # Timestamp is not allowed for AlarmThresholdRule query, as the alarm
        # evaluator will construct timestamp bounds for the sequence of
        # statistics queries as the sliding evaluation window advances
        # over time.
        v2_utils.validate_query(threshold_rule.query,
                                storage.SampleFilter.__init__,
                                allow_timestamps=False)
        return threshold_rule

    @classmethod
    def validate_alarm(cls, alarm):
        cls._check_ceilometer_sample_api()
        # ensure an implicit constraint on project_id is added to
        # the query if not already present
        alarm.threshold_rule.query = v2_utils.sanitize_query(
            alarm.threshold_rule.query,
            storage.SampleFilter.__init__,
            on_behalf_of=alarm.project_id
        )

    @property
    def default_description(self):
        return (_('Alarm when %(meter_name)s is %(comparison_operator)s a '
                  '%(statistic)s of %(threshold)s over %(period)s seconds') %
                dict(comparison_operator=self.comparison_operator,
                     statistic=self.statistic,
                     threshold=self.threshold,
                     meter_name=self.meter_name,
                     period=self.period))

    def as_dict(self):
        rule = self.as_dict_from_keys(['period', 'comparison_operator',
                                       'threshold', 'statistic',
                                       'evaluation_periods', 'meter_name',
                                       'exclude_outliers'])
        rule['query'] = [q.as_dict() for q in self.query]
        return rule

    @classmethod
    def sample(cls):
        return cls(meter_name='cpu_util',
                   period=60,
                   evaluation_periods=1,
                   threshold=300.0,
                   statistic='avg',
                   comparison_operator='gt',
                   query=[{'field': 'resource_id',
                           'value': '2a4d689b-f0b8-49c1-9eef-87cae58d80db',
                           'op': 'eq',
                           'type': 'string'}])