class Snapshot(object):
"""Snapshot state machine"""
def __init__(self, name, size, mountpoint):
self.name = name
self.size = size
self.mountpoint = mountpoint
self.callbacks = {}
self.sigmgr = SignalManager()
def start(self, volume):
"""Start the snapshot process to snapshot the logical volume
that ``path`` exists on.
"""
self.sigmgr.trap(signal.SIGINT, signal.SIGTERM, signal.SIGHUP)
try:
self._apply_callbacks('initialize', self)
except CallbackFailuresError, exc:
return self.error(None, exc)
return self.create_snapshot(volume)
class Snapshot(object):
"""Snapshot state machine"""
def __init__(self, name, size, mountpoint):
self.name = name
self.size = size
self.mountpoint = mountpoint
self.callbacks = {}
self.sigmgr = SignalManager()
def start(self, volume):
"""Start the snapshot process to snapshot the logical volume
that ``path`` exists on.
"""
self.sigmgr.trap(signal.SIGINT, signal.SIGTERM, signal.SIGHUP)
try:
self._apply_callbacks('initialize', self)
except CallbackFailuresError, exc:
return self.error(None, exc)
return self.create_snapshot(volume)
def __init__(self, name, size, mountpoint):
self.name = name
self.size = size
self.mountpoint = mountpoint
self.callbacks = {}
self.sigmgr = SignalManager()
class Snapshot(object):
"""Snapshot state machine"""
def __init__(self, name, size, mountpoint):
self.name = name
self.size = size
self.mountpoint = mountpoint
self.callbacks = {}
self.sigmgr = SignalManager()
def start(self, volume):
"""Start the snapshot process to snapshot the logical volume
that ``path`` exists on.
"""
self.sigmgr.trap(signal.SIGINT, signal.SIGTERM, signal.SIGHUP)
try:
self._apply_callbacks('initialize', self)
except CallbackFailuresError as exc:
return self.error(None, exc)
return self.create_snapshot(volume)
def create_snapshot(self, logical_volume):
"""Create a snapshot for the given logical volume
"""
try:
self._apply_callbacks('pre-snapshot', self, None)
snapshot = logical_volume.snapshot(self.name, self.size)
LOG.info("Created snapshot volume %s", snapshot.device_name())
except (LVMCommandError, CallbackFailuresError) as exc:
return self.error(None, exc)
try:
self._apply_callbacks('post-snapshot', self, snapshot)
except CallbackFailuresError as exc:
return self.error(snapshot, exc)
return self.mount_snapshot(snapshot)
def mount_snapshot(self, snapshot):
"""Mount the snapshot"""
try:
self._apply_callbacks('pre-mount', self, snapshot)
options = None
if snapshot.filesystem() == 'xfs':
LOG.info(
"xfs filesystem detected on %s. "
"Using mount -o nouuid", snapshot.device_name())
options = 'nouuid'
snapshot.mount(self.mountpoint, options)
LOG.info("Mounted %s on %s", snapshot.device_name(),
self.mountpoint)
self._apply_callbacks('post-mount', self, snapshot)
except (CallbackFailuresError, LVMCommandError) as exc:
return self.error(snapshot, exc)
return self.unmount_snapshot(snapshot)
def unmount_snapshot(self, snapshot):
"""Unmount the snapshot"""
try:
self._apply_callbacks('pre-unmount', snapshot)
snapshot.unmount()
LOG.info("Unmounted %s", snapshot.device_name())
except (CallbackFailuresError, LVMCommandError) as exc:
return self.error(snapshot, exc)
try:
self._apply_callbacks('post-unmount', snapshot)
except CallbackFailuresError as exc:
return self.error(snapshot, exc)
return self.remove_snapshot(snapshot)
def remove_snapshot(self, snapshot):
"""Remove the snapshot"""
try:
self._apply_callbacks('pre-remove', snapshot)
snapshot.remove()
LOG.info("Removed snapshot %s", snapshot.device_name())
except (CallbackFailuresError, LVMCommandError) as exc:
return self.error(snapshot, exc)
try:
self._apply_callbacks('post-remove', snapshot)
except (CallbackFailuresError) as exc:
return self.error(snapshot, exc)
return self.finish()
def finish(self):
"""Finish the snapshotting process"""
pending = self.sigmgr.pending[:]
self.sigmgr.restore()
if signal.SIGINT in pending:
raise KeyboardInterrupt()
self._apply_callbacks('finish', self)
if sys.exc_info()[1]:
raise
def error(self, snapshot, exc):
"""Handle an error during the snapshot process"""
LOG.debug("Error encountered during snapshot processing: %s", exc)
if snapshot and snapshot.exists():
snapshot.reload()
if 'S' in snapshot.lv_attr:
LOG.error(
"Snapshot space (%s) exceeded. "
"Snapshot %s is no longer valid", snapshot.device_name(),
format_bytes(int(snapshot.lv_size)))
try:
if snapshot.is_mounted():
snapshot.unmount()
LOG.info("Unmounting snapshot %s on cleanup",
snapshot.device_name())
if snapshot.exists():
snapshot.remove()
LOG.info("Removed snapshot %s on cleanup",
snapshot.device_name())
except LVMCommandError as exc:
LOG.error("Failed to remove snapshot %s", exc)
return self.finish()
def register(self, event, callback, priority=100):
"""Register a callback for ``event`` with ``priority``
"""
self.callbacks.setdefault(event, []).append((priority, callback))
def unregister(self, event, callback):
"""Remove a previously registered callback"""
pending = []
for info in self.callbacks.get(event, []):
if callback in info:
pending.append(info)
for item in pending:
self.callbacks[event].remove(item)
def _apply_callbacks(self, event, *args, **kwargs):
"""Apply callbacks for event"""
callback_list = list(self.callbacks.get(event, []))
callback_list.sort()
callback_list.reverse()
callback_list = [callback[1] for callback in callback_list]
for callback in callback_list:
try:
LOG.debug("Calling %s", callback)
callback(event, *args, **kwargs)
except:
LOG.debug("Callback %r failed for event %s",
callback,
event,
exc_info=True)
exc = sys.exc_info()[1]
raise CallbackFailuresError([(callback, exc)])
def __init__(self, name, size, mountpoint):
self.name = name
self.size = size
self.mountpoint = mountpoint
self.callbacks = {}
self.sigmgr = SignalManager()
class Snapshot(object):
"""Snapshot state machine"""
def __init__(self, name, size, mountpoint):
self.name = name
self.size = size
self.mountpoint = mountpoint
self.callbacks = {}
self.sigmgr = SignalManager()
def start(self, volume):
"""Start the snapshot process to snapshot the logical volume
that ``path`` exists on.
"""
self.sigmgr.trap(signal.SIGINT, signal.SIGTERM, signal.SIGHUP)
try:
self._apply_callbacks("initialize", self)
except CallbackFailuresError as exc:
return self.error(None, exc)
return self.create_snapshot(volume)
def create_snapshot(self, logical_volume):
"""Create a snapshot for the given logical volume
"""
try:
self._apply_callbacks("pre-snapshot", self, None)
snapshot = logical_volume.snapshot(self.name, self.size)
LOG.info("Created snapshot volume %s", snapshot.device_name())
except (LVMCommandError, CallbackFailuresError) as exc:
return self.error(None, exc)
try:
self._apply_callbacks("post-snapshot", self, snapshot)
except CallbackFailuresError as exc:
return self.error(snapshot, exc)
return self.mount_snapshot(snapshot)
def mount_snapshot(self, snapshot):
"""Mount the snapshot"""
try:
self._apply_callbacks("pre-mount", self, snapshot)
options = None
try:
filesystem = snapshot.filesystem()
except BaseException:
return self.error(snapshot, "Failed looking up filesystem")
if filesystem == "xfs":
LOG.info(
"xfs filesystem detected on %s. " "Using mount -o nouuid",
snapshot.device_name(),
)
options = "nouuid"
snapshot.mount(self.mountpoint, options)
LOG.info("Mounted %s on %s", snapshot.device_name(), self.mountpoint)
self._apply_callbacks("post-mount", self, snapshot)
except (CallbackFailuresError, LVMCommandError) as exc:
return self.error(snapshot, exc)
return self.unmount_snapshot(snapshot)
def unmount_snapshot(self, snapshot):
"""Unmount the snapshot"""
try:
self._apply_callbacks("pre-unmount", snapshot)
snapshot.unmount()
LOG.info("Unmounted %s", snapshot.device_name())
except (CallbackFailuresError, LVMCommandError) as exc:
return self.error(snapshot, exc)
try:
self._apply_callbacks("post-unmount", snapshot)
except CallbackFailuresError as exc:
return self.error(snapshot, exc)
return self.remove_snapshot(snapshot)
def remove_snapshot(self, snapshot):
"""Remove the snapshot"""
try:
self._apply_callbacks("pre-remove", snapshot)
snapshot.remove()
LOG.info("Removed snapshot %s", snapshot.device_name())
except (CallbackFailuresError, LVMCommandError) as exc:
return self.error(snapshot, exc)
try:
self._apply_callbacks("post-remove", snapshot)
except (CallbackFailuresError) as exc:
return self.error(snapshot, exc)
return self.finish()
def finish(self):
"""Finish the snapshotting process"""
pending = self.sigmgr.pending[:]
self.sigmgr.restore()
if signal.SIGINT in pending:
raise KeyboardInterrupt()
self._apply_callbacks("finish", self)
if sys.exc_info()[1]:
raise # pylint: disable= misplaced-bare-raise
def error(self, snapshot, exc):
"""Handle an error during the snapshot process"""
LOG.debug("Error encountered during snapshot processing: %s", exc)
if snapshot and snapshot.exists():
snapshot.reload()
if "S" in snapshot.lv_attr:
LOG.error(
"Snapshot space (%s) exceeded. " "Snapshot %s is no longer valid",
snapshot.device_name(),
format_bytes(int(snapshot.lv_size)),
)
try:
if snapshot.is_mounted():
snapshot.unmount()
LOG.info("Unmounting snapshot %s on cleanup", snapshot.device_name())
except LVMCommandError as ex:
LOG.error("Failed to unmount snapshot %s", ex)
try:
if snapshot.exists():
snapshot.remove()
LOG.info("Removed snapshot %s on cleanup", snapshot.device_name())
except LVMCommandError as ex:
LOG.error("Failed to remove snapshot %s", ex)
return self.finish()
def register(self, event, callback, priority=100):
"""Register a callback for ``event`` with ``priority``
"""
self.callbacks.setdefault(event, []).append((priority, callback))
def unregister(self, event, callback):
"""Remove a previously registered callback"""
pending = []
for info in self.callbacks.get(event, []):
if callback in info:
pending.append(info)
for item in pending:
self.callbacks[event].remove(item)
def _apply_callbacks(self, event, *args, **kwargs):
"""Apply callbacks for event"""
callback_list = list(self.callbacks.get(event, []))
callback_list.sort()
callback_list.reverse()
callback_list = [callback[1] for callback in callback_list]
for callback in callback_list:
try:
LOG.debug("Calling %s", event)
callback(event, *args, **kwargs)
except:
LOG.debug("Callback %r failed for event %s", callback, event, exc_info=True)
exc = sys.exc_info()[1]
raise CallbackFailuresError([(callback, exc)])
