zaqar/marconi/queues/storage/utils.py
Alejandro Cabrera 280da9d054 fix(shards): guard against registering bad shard URIs
Whenever an admin would attempt to register a new shard, the shard was
admitted whether or not the shard URI actually existed, and whether or
not marconi could handle shards of that type.

This patch makes it so that a DataDriver instance is temporarily
instantiated prior to storing the shard entry. This instance uses
is_alive() to determine whether or not the shard can be reached/is
supported. This applies to both PUT/PATCH. HTTP 400 is returned if the
registration fails, as a result.

To enable this change, the ability to create a dynamic configuration
object was extracted from sharding.Catalog. Tests were written for
this new function.

The unit tests were updated accordingly, expanding the coverage of
test_shards to include the new failure cases.

Some changes needed to be made to handle new oslo.cache interface:
- cache.unset doesn't exist - now using cache.unset_many
- cache.get_cache() takes a URI, not a ConfigOpts

Change-Id: I40509f525466da01baad2a5aef81c7b99c8d2f97
Closes-Bug: #1258591
Closes-Bug: #1273376
Closes-Bug: #1273377
2014-02-11 15:12:33 -05:00

136 lines
4.4 KiB
Python

# Copyright (c) 2013 Rackspace, 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 oslo.config import cfg
import six
from stevedore import driver
from marconi.common import errors
from marconi.common import utils
from marconi.openstack.common import log
LOG = log.getLogger(__name__)
def dynamic_conf(uri, options):
"""Given metadata, yields a dynamic configuration.
:param uri: shard location
:type uri: six.text_type
:param options: additional shard metadata
:type options: dict
:returns: Configuration object suitable for constructing storage
drivers
:rtype: oslo.config.cfg.ConfigOpts
"""
# NOTE(cpp-cabrera): make it *very* clear to data storage
# drivers that we are operating in a dynamic mode.
general_opts = utils.dict_to_conf({'dynamic': True})
# NOTE(cpp-cabrera): parse general opts: 'drivers'
storage_type = six.moves.urllib_parse.urlparse(uri).scheme
driver_opts = utils.dict_to_conf({'storage': storage_type})
# NOTE(cpp-cabrera): parse storage-specific opts:
# 'drivers:storage:{type}'
storage_opts = utils.dict_to_conf({'uri': uri, 'options': options})
storage_group = u'drivers:storage:%s' % storage_type
# NOTE(cpp-cabrera): register those options!
conf = cfg.ConfigOpts()
conf.register_opts(general_opts)
conf.register_opts(driver_opts, group=u'drivers')
conf.register_opts(storage_opts, group=storage_group)
return conf
def load_storage_driver(conf, cache, control_mode=False):
"""Loads a storage driver and returns it.
The driver's initializer will be passed conf and cache as
its positional args.
:param conf: Configuration instance to use for loading the
driver. Must include a 'drivers' group.
:param cache: Cache instance that the driver can (optionally)
use to reduce latency for some operations.
:param control_mode: (Default False). Determines which
driver type to load; if False, the data driver is
loaded. If True, the control driver is loaded.
"""
mode = 'control' if control_mode else 'data'
driver_type = 'marconi.queues.{0}.storage'.format(mode)
try:
mgr = driver.DriverManager(driver_type,
conf['drivers'].storage,
invoke_on_load=True,
invoke_args=[conf, cache])
return mgr.driver
except RuntimeError as exc:
LOG.exception(exc)
raise errors.InvalidDriver(exc)
def keyify(key, iterable):
"""Make an iterator from an iterable of dicts compared with a key.
:param key: A key exists for all dict inside the iterable object
:param iterable: The input iterable object
"""
class Keyed(object):
def __init__(self, obj):
self.obj = obj
def __cmp__(self, other):
return cmp(self.obj[key], other.obj[key])
# TODO(zyuan): define magic operators to make py3 work
# http://code.activestate.com/recipes/576653/
for item in iterable:
yield Keyed(item)
def can_connect(uri):
"""Given a URI, verifies whether its possible to connect to it.
:param uri: connection string to a storage endpoint
:type uri: six.text_type
:returns: True if can connect else False
:rtype: bool
"""
driver_type = 'marconi.queues.data.storage'
storage_type = six.moves.urllib.parse.urlparse(uri).scheme
try:
# NOTE(cabrera): create a mock configuration containing only
# the URI field. This should be sufficient to initialize a
# storage driver.
conf = dynamic_conf(uri, {})
mgr = driver.DriverManager(driver_type,
storage_type,
invoke_on_load=True,
invoke_args=[conf, None])
return mgr.driver.is_alive()
except RuntimeError:
return False