text: #
  # Copyright Ericsson AB 2013. All rights reserved
  #
  # Authors: Ildiko Vancsa <ildiko.vancsa@ericsson.com>
  #          Balazs Gibizer <balazs.gibizer@ericsson.com>
  #
  # 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.
  """Common functions for MongoDB and DB2 backends
  """
  
  from oslo_log import log
  import pymongo
  
  import ceilometer
  from ceilometer.alarm.storage import base
  from ceilometer.alarm.storage import models
  from ceilometer.storage.mongo import utils as pymongo_utils
  from ceilometer import utils
  
  LOG = log.getLogger(__name__)
  
  
  COMMON_AVAILABLE_CAPABILITIES = {
      'alarms': {'query': {'simple': True,
                           'complex': True},
                 'history': {'query': {'simple': True,
                                       'complex': True}}},
  }
  
  
  AVAILABLE_STORAGE_CAPABILITIES = {
      'storage': {'production_ready': True},
  }
  
  
  class Connection(base.Connection):
      """Base Alarm Connection class for MongoDB and DB2 drivers."""
      CAPABILITIES = utils.update_nested(base.Connection.CAPABILITIES,
                                         COMMON_AVAILABLE_CAPABILITIES)
  
      STORAGE_CAPABILITIES = utils.update_nested(
          base.Connection.STORAGE_CAPABILITIES,
          AVAILABLE_STORAGE_CAPABILITIES,
      )
  
      def upgrade(self):
          # create collection if not present
          if 'alarm' not in self.db.conn.collection_names():
              self.db.conn.create_collection('alarm')
          if 'alarm_history' not in self.db.conn.collection_names():
              self.db.conn.create_collection('alarm_history')
  
      def update_alarm(self, alarm):
          """Update alarm."""
          data = alarm.as_dict()
  
          self.db.alarm.update(
              {'alarm_id': alarm.alarm_id},
              {'$set': data},
              upsert=True)
  
          stored_alarm = self.db.alarm.find({'alarm_id': alarm.alarm_id})[0]
          del stored_alarm['_id']
          self._ensure_encapsulated_rule_format(stored_alarm)
          self._ensure_time_constraints(stored_alarm)
          return models.Alarm(**stored_alarm)
  
      create_alarm = update_alarm
  
      def delete_alarm(self, alarm_id):
          """Delete an alarm."""
          self.db.alarm.remove({'alarm_id': alarm_id})
  
      def record_alarm_change(self, alarm_change):
          """Record alarm change event."""
          self.db.alarm_history.insert(alarm_change.copy())
  
      def get_alarms(self, name=None, user=None, state=None, meter=None,
                     project=None, enabled=None, alarm_id=None, pagination=None,
                     alarm_type=None, severity=None):
          """Yields a lists of alarms that match filters.
  
          :param name: Optional name for alarm.
          :param user: Optional ID for user that owns the resource.
          :param state: Optional string for alarm state.
          :param meter: Optional string for alarms associated with meter.
          :param project: Optional ID for project that owns the resource.
          :param enabled: Optional boolean to list disable alarm.
          :param alarm_id: Optional alarm_id to return one alarm.
          :param pagination: Optional pagination query.
          :param alarm_type: Optional alarm type.
          :param severity: Optional alarm severity.
          """
          if pagination:
              raise ceilometer.NotImplementedError('Pagination not implemented')
  
          q = {}
          if user is not None:
              q['user_id'] = user
          if project is not None:
              q['project_id'] = project
          if name is not None:
              q['name'] = name
          if enabled is not None:
              q['enabled'] = enabled
          if alarm_id is not None:
              q['alarm_id'] = alarm_id
          if state is not None:
              q['state'] = state
          if meter is not None:
              q['rule.meter_name'] = meter
          if alarm_type is not None:
              q['type'] = alarm_type
          if severity is not None:
              q['severity'] = severity
  
          return self._retrieve_alarms(q,
                                       [("timestamp",
                                         pymongo.DESCENDING)],
                                       None)
  
      def get_alarm_changes(self, alarm_id, on_behalf_of,
                            user=None, project=None, alarm_type=None,
                            severity=None, start_timestamp=None,
                            start_timestamp_op=None, end_timestamp=None,
                            end_timestamp_op=None):
          """Yields list of AlarmChanges describing alarm history
  
          Changes are always sorted in reverse order of occurrence, given
          the importance of currency.
  
          Segregation for non-administrative users is done on the basis
          of the on_behalf_of parameter. This allows such users to have
          visibility on both the changes initiated by themselves directly
          (generally creation, rule changes, or deletion) and also on those
          changes initiated on their behalf by the alarming service (state
          transitions after alarm thresholds are crossed).
  
          :param alarm_id: ID of alarm to return changes for
          :param on_behalf_of: ID of tenant to scope changes query (None for
                               administrative user, indicating all projects)
          :param user: Optional ID of user to return changes for
          :param project: Optional ID of project to return changes for
          :param alarm_type: Optional change type
          :param severity: Optional change severity
          :param start_timestamp: Optional modified timestamp start range
          :param start_timestamp_op: Optional timestamp start range operation
          :param end_timestamp: Optional modified timestamp end range
          :param end_timestamp_op: Optional timestamp end range operation
          """
          q = dict(alarm_id=alarm_id)
          if on_behalf_of is not None:
              q['on_behalf_of'] = on_behalf_of
          if user is not None:
              q['user_id'] = user
          if project is not None:
              q['project_id'] = project
          if alarm_type is not None:
              q['type'] = alarm_type
          if severity is not None:
              q['severity'] = severity
          if start_timestamp or end_timestamp:
              ts_range = pymongo_utils.make_timestamp_range(start_timestamp,
                                                            end_timestamp,
                                                            start_timestamp_op,
                                                            end_timestamp_op)
              if ts_range:
                  q['timestamp'] = ts_range
  
          return self._retrieve_alarm_changes(q,
                                              [("timestamp",
                                                pymongo.DESCENDING)],
                                              None)
  
      def query_alarms(self, filter_expr=None, orderby=None, limit=None):
          """Return an iterable of model.Alarm objects."""
          return self._retrieve_data(filter_expr, orderby, limit,
                                     models.Alarm)
  
      def query_alarm_history(self, filter_expr=None, orderby=None, limit=None):
          """Return an iterable of model.AlarmChange objects."""
          return self._retrieve_data(filter_expr,
                                     orderby,
                                     limit,
                                     models.AlarmChange)
  
      def _retrieve_data(self, filter_expr, orderby, limit, model):
          if limit == 0:
              return []
          query_filter = {}
          orderby_filter = [("timestamp", pymongo.DESCENDING)]
          transformer = pymongo_utils.QueryTransformer()
          if orderby is not None:
              orderby_filter = transformer.transform_orderby(orderby)
          if filter_expr is not None:
              query_filter = transformer.transform_filter(filter_expr)
  
          retrieve = {models.Alarm: self._retrieve_alarms,
                      models.AlarmChange: self._retrieve_alarm_changes}
          return retrieve[model](query_filter, orderby_filter, limit)
  
      def _retrieve_alarms(self, query_filter, orderby, limit):
          if limit is not None:
              alarms = self.db.alarm.find(query_filter,
                                          limit=limit,
                                          sort=orderby)
          else:
              alarms = self.db.alarm.find(query_filter, sort=orderby)
  
          for alarm in alarms:
              a = {}
              a.update(alarm)
              del a['_id']
              self._ensure_encapsulated_rule_format(a)
              self._ensure_time_constraints(a)
              yield models.Alarm(**a)
  
      def _retrieve_alarm_changes(self, query_filter, orderby, limit):
          if limit is not None:
              alarms_history = self.db.alarm_history.find(query_filter,
                                                          limit=limit,
                                                          sort=orderby)
          else:
              alarms_history = self.db.alarm_history.find(
                  query_filter, sort=orderby)
  
          for alarm_history in alarms_history:
              ah = {}
              ah.update(alarm_history)
              del ah['_id']
              yield models.AlarmChange(**ah)
  
      @classmethod
      def _ensure_encapsulated_rule_format(cls, alarm):
          """Ensure the alarm returned by the storage have the correct format.
  
          The previous format looks like:
          {
              'alarm_id': '0ld-4l3rt',
              'enabled': True,
              'name': 'old-alert',
              'description': 'old-alert',
              'timestamp': None,
              'meter_name': 'cpu',
              'user_id': 'me',
              'project_id': 'and-da-boys',
              'comparison_operator': 'lt',
              'threshold': 36,
              'statistic': 'count',
              'evaluation_periods': 1,
              'period': 60,
              'state': "insufficient data",
              'state_timestamp': None,
              'ok_actions': [],
              'alarm_actions': ['http://nowhere/alarms'],
              'insufficient_data_actions': [],
              'repeat_actions': False,
              'matching_metadata': {'key': 'value'}
              # or 'matching_metadata': [{'key': 'key', 'value': 'value'}]
          }
          """
  
          if isinstance(alarm.get('rule'), dict):
              return
  
          alarm['type'] = 'threshold'
          alarm['rule'] = {}
          alarm['matching_metadata'] = cls._decode_matching_metadata(
              alarm['matching_metadata'])
          for field in ['period', 'evaluation_periods', 'threshold',
                        'statistic', 'comparison_operator', 'meter_name']:
              if field in alarm:
                  alarm['rule'][field] = alarm[field]
                  del alarm[field]
  
          query = []
          for key in alarm['matching_metadata']:
              query.append({'field': key,
                            'op': 'eq',
                            'value': alarm['matching_metadata'][key],
                            'type': 'string'})
          del alarm['matching_metadata']
          alarm['rule']['query'] = query
  
      @staticmethod
      def _decode_matching_metadata(matching_metadata):
          if isinstance(matching_metadata, dict):
              # note(sileht): keep compatibility with alarm
              # with matching_metadata as a dict
              return matching_metadata
          else:
              new_matching_metadata = {}
              for elem in matching_metadata:
                  new_matching_metadata[elem['key']] = elem['value']
              return new_matching_metadata
  
      @staticmethod
      def _ensure_time_constraints(alarm):
          """Ensures the alarm has a time constraints field."""
          if 'time_constraints' not in alarm:
              alarm['time_constraints'] = []
  