#
# Copyright 2017 the original author or authors.
#
# 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 re

from hash_ring import HashRing
from structlog import get_logger
from twisted.internet import reactor
from twisted.internet.base import DelayedCall
from twisted.internet.defer import inlineCallbacks, DeferredList, returnValue
from simplejson import dumps, loads

from common.utils.asleep import asleep
from common.utils.id_generation import get_next_core_id

log = get_logger()


class ConfigMappingException(Exception):
    pass


class Leader(object):
    """
    A single instance of this object shall exist across the whole cluster.
    This is guaranteed by the coordinator which instantiates this class
    only when it secured the leadership lock, as well as calling the halt()
    method in cases it looses the leadership lock.
    """

    ID_EXTRACTOR = '^(%s)([^/]+)$'