Synnefo » snf-ganeti » ganeti-local

#

#

# Copyright (C) 2006, 2007 Google Inc.

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful, but

# WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

# General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.

"""Ganeti exception handling"""

class GenericError(Exception):

  """Base exception for Ganeti.

  """

  pass

class LVMError(GenericError):

  """LVM-related exception.

  This exception codifies problems with LVM setup.

  """

  pass

class LockError(GenericError):

  """Lock error exception.

  This signifies problems in the locking subsystem.

  """

  pass

class HypervisorError(GenericError):

  """Hypervisor-related exception.

  This is raised in case we can't communicate with the hypervisor

  properly.

  """

  pass

class ProgrammerError(GenericError):

  """Programming-related error.

  This is raised in cases we determine that the calling conventions

  have been violated, meaning we got some desynchronisation between

  parts of our code. It signifies a real programming bug.

  """

  pass

class BlockDeviceError(GenericError):

  """Block-device related exception.

  This is raised in case we can't setup the instance's block devices

  properly.

  """

  pass

class ConfigurationError(GenericError):

  """Configuration related exception.

  Things like having an instance with a primary node that doesn't

  exist in the config or such raise this exception.

  """

  pass

class RemoteError(GenericError):

  """Programming-related error on remote call.

  This is raised when an unhandled error occurs in a call to a

  remote node.  It usually signifies a real programming bug.

  """

  pass

class SignatureError(GenericError):

  """Error authenticating a remote message.

  This is raised when the hmac signature on a message doesn't verify correctly

  to the message itself. It can happen because of network unreliability or

  because of spurious traffic.

  """

  pass

class ParameterError(GenericError):

  """A passed parameter to a command is invalid.

  This is raised when the parameter passed to a request function is

  invalid. Correct code should have verified this before passing the

  request structure.

  The argument to this exception should be the parameter name.

  """

  pass

class OpPrereqError(GenericError):

  """Prerequisites for the OpCode are not fulfilled.

  """

class OpExecError(GenericError):

  """Error during OpCode execution.

  """

class OpRetryError(OpExecError):

  """Error during OpCode execution, action can be retried.

  """

class OpCodeUnknown(GenericError):

  """Unknown opcode submitted.

  This signifies a mismatch between the definitions on the client and

  server side.

  """

class JobLost(GenericError):

  """Submitted job lost.

  The job was submitted but it cannot be found in the current job

  list.

  """

class ResolverError(GenericError):

  """Host name cannot be resolved.

  This is not a normal situation for Ganeti, as we rely on having a

  working resolver.

  The non-resolvable hostname is available as the first element of the

  args tuple; the other two elements of the tuple are the first two

  args of the socket.gaierror exception (error code and description).

  """

class HooksFailure(GenericError):

  """A generic hook failure.

  This signifies usually a setup misconfiguration.

  """

class HooksAbort(HooksFailure):

  """A required hook has failed.

  This caused an abort of the operation in the initial phase. This

  exception always has an attribute args which is a list of tuples of:

    - node: the source node on which this hooks has failed

    - script: the name of the script which aborted the run

  """

class UnitParseError(GenericError):

  """Unable to parse size unit.

  """

class TypeEnforcementError(GenericError):

  """Unable to enforce data type.

  """

class SshKeyError(GenericError):

  """Invalid SSH key.

  """

class TagError(GenericError):

  """Generic tag error.

  The argument to this exception will show the exact error.

  """

class CommandError(GenericError):

  """External command error.

  """

class StorageError(GenericError):

  """Storage-related exception.

  """

class InotifyError(GenericError):

  """Error raised when there is a failure setting up an inotify watcher.

  """

class QuitGanetiException(Exception):

  """Signal that Ganeti that it must quit.

  This is not necessarily an error (and thus not a subclass of

  GenericError), but it's an exceptional circumstance and it is thus

  treated. This instance should be instantiated with two values. The

  first one will specify the return code to the caller, and the second

  one will be the returned result (either as an error or as a normal

  result). Usually only the leave cluster rpc call should return

  status True (as there it's expected we quit), every other call will

  return status False (as a critical error was encountered).

  Examples::

    # Return a result of "True" to the caller, but quit ganeti afterwards

    raise QuitGanetiException(True, None)

    # Send an error to the caller, and quit ganeti

    raise QuitGanetiException(False, "Fatal safety violation, shutting down")

  """

class JobQueueError(GenericError):

  """Job queue error.

  """

class JobQueueDrainError(JobQueueError):

  """Job queue is marked for drain error.

  This is raised when a job submission attempt is made but the queue

  is marked for drain.

  """

class JobQueueFull(JobQueueError):

  """Job queue full error.

  Raised when job queue size reached its hard limit.

  """

class ConfdFatalError(GenericError):

  """A fatal failure in Ganeti confd.

  Events that compromise the ability of confd to proceed further.

  (for example: inability to load the config file)

  """

class ConfdRequestError(GenericError):

  """A request error in Ganeti confd.

  Events that should make confd abort the current request and proceed serving

  different ones.

  """

class ConfdMagicError(GenericError):

  """A magic fourcc error in Ganeti confd.

  Errors processing the fourcc in ganeti confd datagrams.

  """

class ConfdClientError(GenericError):

  """A magic fourcc error in Ganeti confd.

  Errors in the confd client library.

  """

class UdpDataSizeError(GenericError):

  """UDP payload too big.

  """

# errors should be added above

def GetErrorClass(name):

  """Return the class of an exception.

  Given the class name, return the class itself.

  @type name: str

  @param name: the exception name

  @rtype: class

  @return: the actual class, or None if not found

  """

  item = globals().get(name, None)

  if item is not None:

    if not (isinstance(item, type(Exception)) and

            issubclass(item, GenericError)):

      item = None

  return item

def EncodeException(err):

  """Encodes an exception into a format that L{MaybeRaise} will recognise.

  The passed L{err} argument will be formatted as a tuple (exception

  name, arguments) that the MaybeRaise function will recognise.

  @type err: GenericError child

  @param err: usually a child of GenericError (but any exception

      will be accepted)

  @rtype: tuple

  @return: tuple of (exception name, exception arguments)

  """

  return (err.__class__.__name__, err.args)

def MaybeRaise(result):

  """Is this looks like an encoded Ganeti exception, raise it.

  This function tries to parse the passed argument and if it looks

  like an encoding done by EncodeException, it will re-raise it.

  """

  tlt = (tuple, list)

  if (isinstance(result, tlt) and len(result) == 2 and

      isinstance(result[1], tlt)):

    # custom ganeti errors

    err_class = GetErrorClass(result[0])

    if err_class is not None:

      raise err_class, tuple(result[1])