244 lines
7.1 KiB
Python
244 lines
7.1 KiB
Python
# Licensed under the Apache License, Version 2.0 (the "License"); you may not
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# use this file except in compliance with the License. You may obtain a copy of
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# the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations under
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# the License.
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"""Generic RBD connection utilities."""
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import io
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from oslo_log import log as logging
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from os_brick import exception
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from os_brick.i18n import _
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from os_brick import utils
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try:
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import rados
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import rbd
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except ImportError:
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rados = None
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rbd = None
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LOG = logging.getLogger(__name__)
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class RBDClient(object):
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def __init__(self, user, pool, *args, **kwargs):
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self.rbd_user = user
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self.rbd_pool = pool
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for attr in ['rbd_user', 'rbd_pool']:
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val = getattr(self, attr)
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if val is not None:
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setattr(self, attr, utils.convert_str(val))
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# allow these to be overridden for testing
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self.rados = kwargs.get('rados', rados)
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self.rbd = kwargs.get('rbd', rbd)
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if self.rados is None:
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raise exception.InvalidParameterValue(
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err=_('rados module required'))
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if self.rbd is None:
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raise exception.InvalidParameterValue(
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err=_('rbd module required'))
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self.rbd_conf = kwargs.get('conffile', '/etc/ceph/ceph.conf')
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self.rbd_cluster_name = kwargs.get('rbd_cluster_name', 'ceph')
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self.rados_connect_timeout = kwargs.get('rados_connect_timeout', -1)
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self.client, self.ioctx = self.connect()
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def __enter__(self):
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return self
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def __exit__(self, type_, value, traceback):
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self.disconnect()
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def connect(self):
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LOG.debug("opening connection to ceph cluster (timeout=%s).",
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self.rados_connect_timeout)
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client = self.rados.Rados(rados_id=self.rbd_user,
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clustername=self.rbd_cluster_name,
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conffile=self.rbd_conf)
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try:
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if self.rados_connect_timeout >= 0:
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client.connect(
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timeout=self.rados_connect_timeout)
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else:
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client.connect()
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ioctx = client.open_ioctx(self.rbd_pool)
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return client, ioctx
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except self.rados.Error:
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msg = _("Error connecting to ceph cluster.")
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LOG.exception(msg)
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# shutdown cannot raise an exception
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client.shutdown()
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raise exception.BrickException(message=msg)
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def disconnect(self):
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# closing an ioctx cannot raise an exception
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self.ioctx.close()
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self.client.shutdown()
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class RBDVolume(object):
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"""Context manager for dealing with an existing rbd volume."""
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def __init__(self, client, name, snapshot=None, read_only=False):
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if snapshot is not None:
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snapshot = utils.convert_str(snapshot)
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try:
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self.image = client.rbd.Image(client.ioctx,
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utils.convert_str(name),
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snapshot=snapshot,
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read_only=read_only)
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except client.rbd.Error:
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LOG.exception("error opening rbd image %s", name)
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client.disconnect()
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raise
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# Ceph provides rbd.so to cinder, but we can't
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# get volume name from rbd.Image, so, we record
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# name here, so other modules can easily get
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# volume name.
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self.name = name
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self.client = client
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def close(self):
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try:
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self.image.close()
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finally:
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self.client.disconnect()
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def __enter__(self):
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return self
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def __exit__(self, type_, value, traceback):
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self.close()
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def __getattr__(self, attrib):
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return getattr(self.image, attrib)
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class RBDImageMetadata(object):
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"""RBD image metadata to be used with RBDVolumeIOWrapper."""
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def __init__(self, image, pool, user, conf):
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self.image = image
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self.pool = utils.convert_str(pool or '')
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self.user = utils.convert_str(user or '')
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self.conf = utils.convert_str(conf or '')
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class RBDVolumeIOWrapper(io.RawIOBase):
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"""Enables LibRBD.Image objects to be treated as Python IO objects.
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Calling unimplemented interfaces will raise IOError.
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"""
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def __init__(self, rbd_volume):
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super(RBDVolumeIOWrapper, self).__init__()
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self._rbd_volume = rbd_volume
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self._offset = 0
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def _inc_offset(self, length):
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self._offset += length
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@property
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def rbd_image(self):
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return self._rbd_volume.image
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@property
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def rbd_user(self):
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return self._rbd_volume.user
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@property
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def rbd_pool(self):
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return self._rbd_volume.pool
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@property
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def rbd_conf(self):
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return self._rbd_volume.conf
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def read(self, length=None):
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offset = self._offset
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total = self._rbd_volume.image.size()
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# NOTE(dosaboy): posix files do not barf if you read beyond their
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# length (they just return nothing) but rbd images do so we need to
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# return empty string if we have reached the end of the image.
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if (offset >= total):
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return b''
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if length is None:
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length = total
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if (offset + length) > total:
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length = total - offset
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try:
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data = self._rbd_volume.image.read(int(offset), int(length))
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except Exception:
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LOG.exception('Exception encountered during image read')
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raise
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self._inc_offset(length)
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return data
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def write(self, data):
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self._rbd_volume.image.write(data, self._offset)
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self._inc_offset(len(data))
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def seekable(self):
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return True
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def seek(self, offset, whence=0):
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if whence == 0:
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new_offset = offset
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elif whence == 1:
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new_offset = self._offset + offset
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elif whence == 2:
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new_offset = self._rbd_volume.image.size()
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new_offset += offset
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else:
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raise IOError(_("Invalid argument - whence=%s not supported") %
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(whence))
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if (new_offset < 0):
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raise IOError(_("Invalid argument"))
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self._offset = new_offset
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def tell(self):
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return self._offset
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def flush(self):
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try:
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self._rbd_volume.image.flush()
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except AttributeError:
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LOG.warning("flush() not supported in this version of librbd")
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def fileno(self):
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"""RBD does not have support for fileno() so we raise IOError.
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Raising IOError is recommended way to notify caller that interface is
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not supported - see http://docs.python.org/2/library/io.html#io.IOBase
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"""
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raise IOError(_("fileno() not supported by RBD()"))
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def close(self):
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self.rbd_image.close()
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