data_storage.py

# Copyright (c) 2014 Mirantis Inc.
#
# 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 cfglib import CONF
from cloudferrylib.utils import utils

LOG = utils.get_log(__name__)

# we don't want to create connection to database on module import - so that
# we will create it only on first database call
# also we don't want all users to install redis-client


CONNECTION = [None]


def redis_socket_to_kwargs(function):
    def wrapper(*args, **kwargs):
        if not CONNECTION[0]:
            import redis
            check_redis_config()
            CONNECTION[0] = redis.StrictRedis(
                host=CONF.database.host,
                port=CONF.database.port)
        return function(*args, connection=CONNECTION[0], **kwargs)
    return wrapper


def check_redis_config():
    errors_found = False
    host = CONF.database.host
    port = CONF.database.port

    if host is None or host == "" or not isinstance(host, basestring):
        message = ("Invalid configuration value set for Redis DB host. "
                   "Please check 'host' option value in [database] group.")
        LOG.error(message)
        errors_found = True

    if (port is None or
            not isinstance(port, basestring) and
            not isinstance(port, int) or port == ""):
        message = ("Invalid configuration value for Redis DB port. "
                   "Please check 'port' option value in [database] group.")
        LOG.error(message)
        errors_found = True

    import redis
    from redis import exceptions as redis_exceptions
    try:
        r = redis.StrictRedis(host=host, port=port)
        r.ping()
    except redis_exceptions.RedisError as e:
        LOG.error("Redis connection failed: %s", e)
        errors_found = True

    if errors_found:
        raise ValueError("Invalid configuration of Redis DB.")


@redis_socket_to_kwargs
def put(key, value, connection):
    connection.set(key, value)


@redis_socket_to_kwargs
def get(key, connection):
    return connection.get(key)


@redis_socket_to_kwargs
def delete(key, connection):
    return connection.delete(key)


@redis_socket_to_kwargs
def delete_batch(keys, connection):
    pipe = connection.pipeline()
    for key in keys:
        pipe.delete(key)
    pipe.execute()


@redis_socket_to_kwargs
def keys(pattern, connection):
    return connection.keys(pattern)