os-brick/os_brick/initiator/linuxrbd.py

237 lines
7.0 KiB
Python

# 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.
"""Generic RBD connection utilities."""
import io
from oslo_log import log as logging
from os_brick import exception
from os_brick.i18n import _
from os_brick import utils
try:
import rados
import rbd
except ImportError:
rados = None
rbd = None
LOG = logging.getLogger(__name__)
class RBDClient(object):
def __init__(self, user, pool, *args, **kwargs):
self.rbd_user = user
self.rbd_pool = pool
for attr in ['rbd_user', 'rbd_pool']:
val = getattr(self, attr)
if val is not None:
setattr(self, attr, utils.convert_str(val))
# allow these to be overridden for testing
self.rados = kwargs.get('rados', rados)
self.rbd = kwargs.get('rbd', rbd)
if self.rados is None:
raise exception.InvalidParameterValue(
err=_('rados module required'))
if self.rbd is None:
raise exception.InvalidParameterValue(
err=_('rbd module required'))
self.rbd_conf = kwargs.get('conffile', '/etc/ceph/ceph.conf')
self.rbd_cluster_name = kwargs.get('rbd_cluster_name', 'ceph')
self.rados_connect_timeout = kwargs.get('rados_connect_timeout', -1)
self.client, self.ioctx = self.connect()
def __enter__(self):
return self
def __exit__(self, type_, value, traceback):
self.disconnect()
def connect(self):
LOG.debug("opening connection to ceph cluster (timeout=%s).",
self.rados_connect_timeout)
client = self.rados.Rados(rados_id=self.rbd_user,
clustername=self.rbd_cluster_name,
conffile=self.rbd_conf)
try:
if self.rados_connect_timeout >= 0:
client.connect(
timeout=self.rados_connect_timeout)
else:
client.connect()
ioctx = client.open_ioctx(self.rbd_pool)
return client, ioctx
except self.rados.Error:
msg = _("Error connecting to ceph cluster.")
LOG.exception(msg)
# shutdown cannot raise an exception
client.shutdown()
raise exception.BrickException(message=msg)
def disconnect(self):
# closing an ioctx cannot raise an exception
self.ioctx.close()
self.client.shutdown()
class RBDVolume(object):
"""Context manager for dealing with an existing rbd volume."""
def __init__(self, client, name, snapshot=None, read_only=False):
if snapshot is not None:
snapshot = utils.convert_str(snapshot)
try:
self.image = client.rbd.Image(client.ioctx,
utils.convert_str(name),
snapshot=snapshot,
read_only=read_only)
except client.rbd.Error:
LOG.exception("error opening rbd image %s", name)
client.disconnect()
raise
# Ceph provides rbd.so to cinder, but we can't
# get volume name from rbd.Image, so, we record
# name here, so other modules can easily get
# volume name.
self.name = name
self.client = client
def close(self):
try:
self.image.close()
finally:
self.client.disconnect()
def __enter__(self):
return self
def __exit__(self, type_, value, traceback):
self.close()
def __getattr__(self, attrib):
return getattr(self.image, attrib)
class RBDImageMetadata(object):
"""RBD image metadata to be used with RBDVolumeIOWrapper."""
def __init__(self, image, pool, user, conf):
self.image = image
self.pool = utils.convert_str(pool or '')
self.user = utils.convert_str(user or '')
self.conf = utils.convert_str(conf or '')
class RBDVolumeIOWrapper(io.RawIOBase):
"""Enables LibRBD.Image objects to be treated as Python IO objects.
Calling unimplemented interfaces will raise IOError.
"""
def __init__(self, rbd_volume):
super(RBDVolumeIOWrapper, self).__init__()
self._rbd_volume = rbd_volume
self._offset = 0
def _inc_offset(self, length):
self._offset += length
@property
def rbd_image(self):
return self._rbd_volume.image
@property
def rbd_user(self):
return self._rbd_volume.user
@property
def rbd_pool(self):
return self._rbd_volume.pool
@property
def rbd_conf(self):
return self._rbd_volume.conf
def read(self, length=None):
offset = self._offset
total = self._rbd_volume.image.size()
# NOTE(dosaboy): posix files do not barf if you read beyond their
# length (they just return nothing) but rbd images do so we need to
# return empty string if we have reached the end of the image.
if (offset >= total):
return b''
if length is None:
length = total
if (offset + length) > total:
length = total - offset
self._inc_offset(length)
return self._rbd_volume.image.read(int(offset), int(length))
def write(self, data):
self._rbd_volume.image.write(data, self._offset)
self._inc_offset(len(data))
def seekable(self):
return True
def seek(self, offset, whence=0):
if whence == 0:
new_offset = offset
elif whence == 1:
new_offset = self._offset + offset
elif whence == 2:
new_offset = self._rbd_volume.image.size()
new_offset += offset
else:
raise IOError(_("Invalid argument - whence=%s not supported") %
(whence))
if (new_offset < 0):
raise IOError(_("Invalid argument"))
self._offset = new_offset
def tell(self):
return self._offset
def flush(self):
try:
self._rbd_volume.image.flush()
except AttributeError:
LOG.warning("flush() not supported in this version of librbd")
def fileno(self):
"""RBD does not have support for fileno() so we raise IOError.
Raising IOError is recommended way to notify caller that interface is
not supported - see http://docs.python.org/2/library/io.html#io.IOBase
"""
raise IOError(_("fileno() not supported by RBD()"))
def close(self):
self.rbd_image.close()