aodh.evaluator.composite

Source code for aodh.evaluator.composite

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from oslo_log import log
import six
import stevedore

from aodh import evaluator
from aodh.evaluator import threshold
from aodh.i18n import _

LOG = log.getLogger(__name__)

STATE_CHANGE = {evaluator.ALARM: 'outside their threshold.',
                evaluator.OK: 'inside their threshold.',
                evaluator.UNKNOWN: 'state evaluated to unknown.'}


[docs]class RuleTarget(object): def __init__(self, rule, rule_evaluator, rule_name): self.rule = rule self.type = rule.get('type') self.rule_evaluator = rule_evaluator self.rule_name = rule_name self.state = None self.trending_state = None self.statistics = None self.evaluated = False
[docs] def evaluate(self): # Evaluate a sub-rule of composite rule if not self.evaluated: LOG.debug('Evaluating %(type)s rule: %(rule)s', {'type': self.type, 'rule': self.rule}) try: self.state, self.trending_state, self.statistics, __, __ = \ self.rule_evaluator.evaluate_rule(self.rule) except threshold.InsufficientDataError as e: self.state = evaluator.UNKNOWN self.trending_state = None self.statistics = e.statistics self.evaluated = True
[docs]class RuleEvaluationBase(object): def __init__(self, rule_target): self.rule_target = rule_target def __str__(self): return self.rule_target.rule_name
[docs]class OkEvaluation(RuleEvaluationBase): def __bool__(self): self.rule_target.evaluate() return self.rule_target.state == evaluator.OK __nonzero__ = __bool__
[docs]class AlarmEvaluation(RuleEvaluationBase): def __bool__(self): self.rule_target.evaluate() return self.rule_target.state == evaluator.ALARM __nonzero__ = __bool__
[docs]class AndOp(object): def __init__(self, rule_targets): self.rule_targets = rule_targets def __bool__(self): return all(self.rule_targets) def __str__(self): return '(' + ' and '.join(six.moves.map(str, self.rule_targets)) + ')' __nonzero__ = __bool__
[docs]class OrOp(object): def __init__(self, rule_targets): self.rule_targets = rule_targets def __bool__(self): return any(self.rule_targets) def __str__(self): return '(' + ' or '.join(six.moves.map(str, self.rule_targets)) + ')' __nonzero__ = __bool__
[docs]class CompositeEvaluator(evaluator.Evaluator): def __init__(self, conf): super(CompositeEvaluator, self).__init__(conf) self.conf = conf self._threshold_evaluators = None self.rule_targets = [] self.rule_name_prefix = 'rule' self.rule_num = 0 @property def threshold_evaluators(self): if not self._threshold_evaluators: threshold_types = ('threshold', 'gnocchi_resources_threshold', 'gnocchi_aggregation_by_metrics_threshold', 'gnocchi_aggregation_by_resources_threshold') self._threshold_evaluators = stevedore.NamedExtensionManager( 'aodh.evaluator', threshold_types, invoke_on_load=True, invoke_args=(self.conf,)) return self._threshold_evaluators def _parse_composite_rule(self, alarm_rule): """Parse the composite rule. The composite rule is assembled by sub threshold rules with 'and', 'or', the form can be nested. e.g. the form of composite rule can be like this: { "and": [threshold_rule0, threshold_rule1, {'or': [threshold_rule2, threshold_rule3, threshold_rule4, threshold_rule5]}] } """ if (isinstance(alarm_rule, dict) and len(alarm_rule) == 1 and list(alarm_rule)[0] in ('and', 'or')): and_or_key = list(alarm_rule)[0] if and_or_key == 'and': rules = (self._parse_composite_rule(r) for r in alarm_rule['and']) rules_alarm, rules_ok = zip(*rules) return AndOp(rules_alarm), OrOp(rules_ok) else: rules = (self._parse_composite_rule(r) for r in alarm_rule['or']) rules_alarm, rules_ok = zip(*rules) return OrOp(rules_alarm), AndOp(rules_ok) else: rule_evaluator = self.threshold_evaluators[alarm_rule['type']].obj self.rule_num += 1 name = self.rule_name_prefix + str(self.rule_num) rule = RuleTarget(alarm_rule, rule_evaluator, name) self.rule_targets.append(rule) return AlarmEvaluation(rule), OkEvaluation(rule) def _reason(self, alarm, new_state, rule_target_alarm): transition = alarm.state != new_state reason_data = { 'type': 'composite', 'composition_form': str(rule_target_alarm)} root_cause_rules = {} for rule in self.rule_targets: if rule.state == new_state: root_cause_rules.update({rule.rule_name: rule.rule}) reason_data.update(causative_rules=root_cause_rules) params = {'state': new_state, 'expression': str(rule_target_alarm), 'rules': ', '.join(sorted(root_cause_rules)), 'description': STATE_CHANGE[new_state]} if transition: reason = (_('Composite rule alarm with composition form: ' '%(expression)s transition to %(state)s, due to ' 'rules: %(rules)s %(description)s') % params) else: reason = (_('Composite rule alarm with composition form: ' '%(expression)s remaining as %(state)s, due to ' 'rules: %(rules)s %(description)s') % params) return reason, reason_data def _evaluate_sufficient(self, alarm, rule_target_alarm, rule_target_ok): # Some of evaluated rules are unknown states or trending states. for rule in self.rule_targets: if rule.trending_state is not None: if alarm.state == evaluator.UNKNOWN: rule.state = rule.trending_state elif rule.trending_state == evaluator.ALARM: rule.state = evaluator.OK elif rule.trending_state == evaluator.OK: rule.state = evaluator.ALARM else: rule.state = alarm.state alarm_triggered = bool(rule_target_alarm) if alarm_triggered: reason, reason_data = self._reason(alarm, evaluator.ALARM, rule_target_alarm) self._refresh(alarm, evaluator.ALARM, reason, reason_data) return True ok_result = bool(rule_target_ok) if ok_result: reason, reason_data = self._reason(alarm, evaluator.OK, rule_target_alarm) self._refresh(alarm, evaluator.OK, reason, reason_data) return True return False
[docs] def evaluate(self, alarm): if not self.within_time_constraint(alarm): LOG.debug('Attempted to evaluate alarm %s, but it is not ' 'within its time constraint.', alarm.alarm_id) return LOG.debug("Evaluating composite rule alarm %s ...", alarm.alarm_id) self.rule_targets = [] self.rule_num = 0 rule_target_alarm, rule_target_ok = self._parse_composite_rule( alarm.rule) sufficient = self._evaluate_sufficient(alarm, rule_target_alarm, rule_target_ok) if not sufficient: for rule in self.rule_targets: rule.evaluate() sufficient = self._evaluate_sufficient(alarm, rule_target_alarm, rule_target_ok) if not sufficient: # The following unknown situations is like these: # 1. 'unknown' and 'alarm' # 2. 'unknown' or 'ok' reason, reason_data = self._reason(alarm, evaluator.UNKNOWN, rule_target_alarm) if alarm.state != evaluator.UNKNOWN: self._refresh(alarm, evaluator.UNKNOWN, reason, reason_data) else: LOG.debug(reason)
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