def acquire(self):
basedir = os.path.dirname(self.fname)
if not os.path.exists(basedir):
fileutils.ensure_tree(basedir)
LOG.info(_LI('Created lock path: %s'), basedir)
self.lockfile = open(self.fname, 'w')
while True:
try:
# Using non-blocking locks since green threads are not
# patched to deal with blocking locking calls.
# Also upon reading the MSDN docs for locking(), it seems
# to have a laughable 10 attempts "blocking" mechanism.
self.trylock()
LOG.debug('Got file lock "%s"', self.fname)
return True
except IOError as e:
if e.errno in (errno.EACCES, errno.EAGAIN):
# external locks synchronise things like iptables
# updates - give it some time to prevent busy spinning
time.sleep(0.01)
else:
raise threading.ThreadError(_("Unable to acquire lock on"
" `%(filename)s` due to"
" %(exception)s") %
{'filename': self.fname,
'exception': e})
def create_iscsi_target(self, name, tid, lun, path,
chap_auth=None, **kwargs):
# Note(jdg) tid and lun aren't used by TgtAdm but remain for
# compatibility
fileutils.ensure_tree(self.volumes_dir)
vol_id = name.split(':')[1]
if chap_auth is None:
volume_conf = self.VOLUME_CONF % (name, path)
else:
volume_conf = self.VOLUME_CONF_WITH_CHAP_AUTH % (name,
path, chap_auth)
LOG.info(_('Creating iscsi_target for: %s') % vol_id)
volumes_dir = self.volumes_dir
postfix = ".conf"
volume_path = os.path.join(volumes_dir, vol_id) + postfix
f = open(volume_path, 'w+')
f.write(volume_conf)
f.close()
LOG.debug(_('Created volume path %(vp)s,\n'
'content: %(vc)s')
% {'vp': volume_path, 'vc': volume_conf})
old_persist_file = None
old_name = kwargs.get('old_name', None)
if old_name is not None:
old_persist_file = os.path.join(volumes_dir, old_name)
try:
# with the persistent tgts we create them
# by creating the entry in the persist file
# and then doing an update to get the target
# created.
(out, err) = self._execute('tgt-admin', '--update', name,
run_as_root=True,
root_helper=self._root_helper)
LOG.debug("StdOut from tgt-admin --update: %s", out)
LOG.debug("StdErr from tgt-admin --update: %s", err)
# Grab targets list for debug
# Consider adding a check for lun 0 and 1 for tgtadm
# before considering this as valid
(out, err) = self._execute('tgtadm',
'--lld',
'iscsi',
'--op',
'show',
'--mode',
'target',
run_as_root=True,
root_helper=self._root_helper)
LOG.debug("Targets after update: %s" % out)
except putils.ProcessExecutionError as e:
LOG.warning(_("Failed to create iscsi target for volume "
"id:%(vol_id)s: %(e)s")
% {'vol_id': vol_id, 'e': e})
#Don't forget to remove the persistent file we created
os.unlink(volume_path)
raise exception.ISCSITargetCreateFailed(volume_id=vol_id)
iqn = '%s%s' % (self.iscsi_target_prefix, vol_id)
tid = self._get_target(iqn)
if tid is None:
LOG.error(_("Failed to create iscsi target for volume "
"id:%(vol_id)s. Please ensure your tgtd config file "
"contains 'include %(volumes_dir)s/*'") % {
'vol_id': vol_id,
'volumes_dir': volumes_dir, })
raise exception.NotFound()
# NOTE(jdg): Sometimes we have some issues with the backing lun
# not being created, believe this is due to a device busy
# or something related, so we're going to add some code
# here that verifies the backing lun (lun 1) was created
# and we'll try and recreate it if it's not there
if not self._verify_backing_lun(iqn, tid):
try:
self._recreate_backing_lun(iqn, tid, name, path)
except putils.ProcessExecutionError:
os.unlink(volume_path)
raise exception.ISCSITargetCreateFailed(volume_id=vol_id)
# Finally check once more and if no go, fail and punt
if not self._verify_backing_lun(iqn, tid):
os.unlink(volume_path)
raise exception.ISCSITargetCreateFailed(volume_id=vol_id)
if old_persist_file is not None and os.path.exists(old_persist_file):
os.unlink(old_persist_file)
return tid
def lock(name, lock_file_prefix=None, external=False, lock_path=None):
"""Context based lock
This function yields a `threading.Semaphore` instance (if we don't use
eventlet.monkey_patch(), else `semaphore.Semaphore`) unless external is
True, in which case, it'll yield an InterProcessLock instance.
:param lock_file_prefix: The lock_file_prefix argument is used to provide
lock files on disk with a meaningful prefix.
:param external: The external keyword argument denotes whether this lock
should work across multiple processes. This means that if two different
workers both run a a method decorated with @synchronized('mylock',
external=True), only one of them will execute at a time.
:param lock_path: The lock_path keyword argument is used to specify a
special location for external lock files to live. If nothing is set, then
CONF.lock_path is used as a default.
"""
with _semaphores_lock:
try:
sem = _semaphores[name]
except KeyError:
sem = threading.Semaphore()
_semaphores[name] = sem
with sem:
LOG.debug(_('Got semaphore "%(lock)s"'), {'lock': name})
# NOTE(mikal): I know this looks odd
if not hasattr(local.strong_store, 'locks_held'):
local.strong_store.locks_held = []
local.strong_store.locks_held.append(name)
try:
if external and not CONF.disable_process_locking:
LOG.debug(_('Attempting to grab file lock "%(lock)s"'),
{'lock': name})
# We need a copy of lock_path because it is non-local
local_lock_path = lock_path or CONF.lock_path
if not local_lock_path:
raise cfg.RequiredOptError('lock_path')
if not os.path.exists(local_lock_path):
fileutils.ensure_tree(local_lock_path)
LOG.info(_('Created lock path: %s'), local_lock_path)
def add_prefix(name, prefix):
if not prefix:
return name
sep = '' if prefix.endswith('-') else '-'
return '%s%s%s' % (prefix, sep, name)
# NOTE(mikal): the lock name cannot contain directory
# separators
lock_file_name = add_prefix(name.replace(os.sep, '_'),
lock_file_prefix)
lock_file_path = os.path.join(local_lock_path, lock_file_name)
try:
lock = InterProcessLock(lock_file_path)
with lock as lock:
LOG.debug(_('Got file lock "%(lock)s" at %(path)s'),
{'lock': name, 'path': lock_file_path})
yield lock
finally:
LOG.debug(_('Released file lock "%(lock)s" at %(path)s'),
{'lock': name, 'path': lock_file_path})
else:
yield sem
finally:
local.strong_store.locks_held.remove(name)
def create_iscsi_target(self, name, tid, lun, path,
chap_auth=None, **kwargs):
# Note(jdg) tid and lun aren't used by TgtAdm but remain for
# compatibility
fileutils.ensure_tree(self.volumes_dir)
vol_id = name.split(':')[1]
write_cache = kwargs.get('write_cache', 'on')
if chap_auth is None:
volume_conf = self.VOLUME_CONF % (name, path, write_cache)
else:
volume_conf = self.VOLUME_CONF_WITH_CHAP_AUTH % (name,
path, chap_auth,
write_cache)
LOG.info(_('Creating iscsi_target for: %s') % vol_id)
volumes_dir = self.volumes_dir
volume_path = os.path.join(volumes_dir, vol_id)
f = open(volume_path, 'w+')
f.write(volume_conf)
f.close()
LOG.debug('Created volume path %(vp)s,\n'
'content: %(vc)s'
% {'vp': volume_path, 'vc': volume_conf})
old_persist_file = None
old_name = kwargs.get('old_name', None)
if old_name is not None:
old_persist_file = os.path.join(volumes_dir, old_name)
try:
# with the persistent tgts we create them
# by creating the entry in the persist file
# and then doing an update to get the target
# created.
(out, err) = self._execute('tgt-admin', '--update', name,
run_as_root=True)
LOG.debug("StdOut from tgt-admin --update: %s", out)
LOG.debug("StdErr from tgt-admin --update: %s", err)
# Grab targets list for debug
# Consider adding a check for lun 0 and 1 for tgtadm
# before considering this as valid
(out, err) = self._execute('tgtadm',
'--lld',
'iscsi',
'--op',
'show',
'--mode',
'target',
run_as_root=True)
LOG.debug("Targets after update: %s" % out)
except putils.ProcessExecutionError as e:
LOG.warning(_("Failed to create iscsi target for volume "
"id:%(vol_id)s: %(e)s")
% {'vol_id': vol_id, 'e': e})
#Don't forget to remove the persistent file we created
os.unlink(volume_path)
raise exception.ISCSITargetCreateFailed(volume_id=vol_id)
iqn = '%s%s' % (self.iscsi_target_prefix, vol_id)
tid = self._get_target(iqn)
if tid is None:
LOG.error(_("Failed to create iscsi target for volume "
"id:%(vol_id)s. Please ensure your tgtd config file "
"contains 'include %(volumes_dir)s/*'") % {
'vol_id': vol_id,
'volumes_dir': volumes_dir, })
raise exception.NotFound()
# NOTE(jdg): Sometimes we have some issues with the backing lun
# not being created, believe this is due to a device busy
# or something related, so we're going to add some code
# here that verifies the backing lun (lun 1) was created
# and we'll try and recreate it if it's not there
if not self._verify_backing_lun(iqn, tid):
try:
self._recreate_backing_lun(iqn, tid, name, path)
except putils.ProcessExecutionError:
os.unlink(volume_path)
raise exception.ISCSITargetCreateFailed(volume_id=vol_id)
# Finally check once more and if no go, fail and punt
if not self._verify_backing_lun(iqn, tid):
os.unlink(volume_path)
raise exception.ISCSITargetCreateFailed(volume_id=vol_id)
if old_persist_file is not None and os.path.exists(old_persist_file):
os.unlink(old_persist_file)
return tid
