# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# All Rights Reserved.
#
#    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.

"""
Datastore:

MAKE Sure that ReDIS is running, and your flags are set properly,
before trying to run this.
"""

import logging
import redis

from nova import flags

FLAGS = flags.FLAGS
flags.DEFINE_string('redis_host', '127.0.0.1',
                    'Host that redis is running on.')
flags.DEFINE_integer('redis_port', 6379,
                    'Port that redis is running on.')
flags.DEFINE_integer('redis_db', 0, 'Multiple DB keeps tests away')


class Redis(object):
    def __init__(self):
        if hasattr(self.__class__, '_instance'):
            raise Exception('Attempted to instantiate singleton')

    @classmethod
    def instance(cls):
        if not hasattr(cls, '_instance'):
            inst = redis.Redis(host=FLAGS.redis_host,
                               port=FLAGS.redis_port,
                               db=FLAGS.redis_db)
            cls._instance = inst
        return cls._instance