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OpenStack Study: remotefs.py**** CubicPower OpenStack Study ****
# Copyright (c) 2013 OpenStack Foundation # 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. """Remote filesystem client utilities.""" import hashlib import os import re import six from cinder.brick import exception from cinder.openstack.common.gettextutils import _ from cinder.openstack.common import log as logging from cinder.openstack.common import processutils as putils LOG = logging.getLogger(__name__)
**** CubicPower OpenStack Study **** class RemoteFsClient(object):
**** CubicPower OpenStack Study **** def __init__(self, mount_type, root_helper, execute=putils.execute, *args, **kwargs): self._mount_type = mount_type if mount_type == "nfs": self._mount_base = kwargs.get('nfs_mount_point_base', None) if not self._mount_base: raise exception.InvalidParameterValue( err=_('nfs_mount_point_base required')) self._mount_options = kwargs.get('nfs_mount_options', None) self._check_nfs_options() elif mount_type == "glusterfs": self._mount_base = kwargs.get('glusterfs_mount_point_base', None) if not self._mount_base: raise exception.InvalidParameterValue( err=_('glusterfs_mount_point_base required')) self._mount_options = None else: raise exception.ProtocolNotSupported(protocol=mount_type) self.root_helper = root_helper self.set_execute(execute)
**** CubicPower OpenStack Study **** def set_execute(self, execute): self._execute = execute
**** CubicPower OpenStack Study **** def _get_hash_str(self, base_str): """Return a string that represents hash of base_str (in a hex format). """ return hashlib.md5(base_str).hexdigest()
**** CubicPower OpenStack Study **** def get_mount_point(self, device_name): """Get Mount Point. :param device_name: example 172.18.194.100:/var/nfs """ return os.path.join(self._mount_base, self._get_hash_str(device_name))
**** CubicPower OpenStack Study **** def _read_mounts(self): (out, err) = self._execute('mount', check_exit_code=0) lines = out.split('\n') mounts = {} for line in lines: tokens = line.split() if 2 < len(tokens): device = tokens[0] mnt_point = tokens[2] mounts[mnt_point] = device return mounts
**** CubicPower OpenStack Study **** def mount(self, share, flags=None): """Mount given share.""" mount_path = self.get_mount_point(share) if mount_path in self._read_mounts(): LOG.info(_('Already mounted: %s') % mount_path) return self._execute('mkdir', '-p', mount_path, check_exit_code=0) if self._mount_type == 'nfs': self._mount_nfs(share, mount_path, flags) else: self._do_mount(self._mount_type, share, mount_path, self._mount_options, flags)
**** CubicPower OpenStack Study **** def _do_mount(self, mount_type, share, mount_path, mount_options=None, flags=None): """Mounts share based on the specified params.""" mnt_cmd = ['mount', '-t', mount_type] if mount_options is not None: mnt_cmd.extend(['-o', mount_options]) if flags is not None: mnt_cmd.extend(flags) mnt_cmd.extend([share, mount_path]) self._execute(*mnt_cmd, root_helper=self.root_helper, run_as_root=True, check_exit_code=0)
**** CubicPower OpenStack Study **** def _mount_nfs(self, nfs_share, mount_path, flags=None): """Mount nfs share using present mount types.""" mnt_errors = {} # This loop allows us to first try to mount with NFS 4.1 for pNFS # support but falls back to mount NFS 4 or NFS 3 if either the client # or server do not support it. for mnt_type in sorted(self._nfs_mount_type_opts.keys(), reverse=True): options = self._nfs_mount_type_opts[mnt_type] try: self._do_mount('nfs', nfs_share, mount_path, options, flags) LOG.debug(_('Mounted %(sh)s using %(mnt_type)s.') % {'sh': nfs_share, 'mnt_type': mnt_type}) return except Exception as e: mnt_errors[mnt_type] = six.text_type(e) LOG.debug(_('Failed to do %s mount.'), mnt_type) raise exception.BrickException(_("NFS mount failed for share %(sh)s." "Error - %(error)s") % {'sh': nfs_share, 'error': mnt_errors})
**** CubicPower OpenStack Study **** def _check_nfs_options(self): """Checks and prepares nfs mount type options.""" self._nfs_mount_type_opts = {'nfs': self._mount_options} nfs_vers_opt_patterns = ['^nfsvers', '^vers', '^v[\d]'] for opt in nfs_vers_opt_patterns: if self._option_exists(self._mount_options, opt): return # pNFS requires NFS 4.1. The mount.nfs4 utility does not automatically # negotiate 4.1 support, we have to ask for it by specifying two # options: vers=4 and minorversion=1. pnfs_opts = self._update_option(self._mount_options, 'vers', '4') pnfs_opts = self._update_option(pnfs_opts, 'minorversion', '1') self._nfs_mount_type_opts['pnfs'] = pnfs_opts
**** CubicPower OpenStack Study **** def _option_exists(self, options, opt_pattern): """Checks if the option exists in nfs options and returns position.""" options = [x.strip() for x in options.split(',')] if options else [] pos = 0 for opt in options: pos = pos + 1 if re.match(opt_pattern, opt, flags=0): return pos return 0
**** CubicPower OpenStack Study **** def _update_option(self, options, option, value=None): """Update option if exists else adds it and returns new options.""" opts = [x.strip() for x in options.split(',')] if options else [] pos = self._option_exists(options, option) if pos: opts.pop(pos - 1) opt = '%s=%s' % (option, value) if value else option opts.append(opt) return ",".join(opts) if len(opts) > 1 else opts[0]
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