Synnefo » snf-ganeti » ganeti-local

from ganeti import compat

#: Supported HTTP methods

_SUPPORTED_METHODS = frozenset([

  http.HTTP_DELETE,

  http.HTTP_GET,

  http.HTTP_POST,

  http.HTTP_PUT,

  ])

class _MetaOpcodeResource(type):

  """Meta class for RAPI resources.

  """

  _ATTRS = [(method, "%s_OPCODE" % method, "%s_RENAME" % method,

             "Get%sOpInput" % method.capitalize())

            for method in _SUPPORTED_METHODS]

  def __call__(mcs, *args, **kwargs):

    """Instantiates class and patches it for use by the RAPI daemon.

    """

    # Access to private attributes of a client class, pylint: disable=W0212

    obj = type.__call__(mcs, *args, **kwargs)

    for (method, op_attr, rename_attr, fn_attr) in mcs._ATTRS:

      try:

        opcode = getattr(obj, op_attr)

      except AttributeError:

        # If the "*_OPCODE" attribute isn't set, "*_RENAME" or "Get*OpInput"

        # shouldn't either

        assert not hasattr(obj, rename_attr)

        assert not hasattr(obj, fn_attr)

        continue

      assert not hasattr(obj, method)

      # Generate handler method on handler instance

      setattr(obj, method,

              compat.partial(obj._GenericHandler, opcode,

                             getattr(obj, rename_attr, None),

                             getattr(obj, fn_attr, obj._GetDefaultData)))

    return obj

class OpcodeResource(ResourceBase):

  """Base class for opcode-based RAPI resources.

  Instances of this class automatically gain handler functions through

  L{_MetaOpcodeResource} for any method for which a C{$METHOD$_OPCODE} variable

  is defined at class level. Subclasses can define a C{Get$Method$OpInput}

  method to do their own opcode input processing (e.g. for static values). The

  C{$METHOD$_RENAME} variable defines which values are renamed (see

  L{FillOpcode}).

  @cvar GET_OPCODE: Set this to a class derived from L{opcodes.OpCode} to

    automatically generate a GET handler submitting the opcode

  @cvar GET_RENAME: Set this to rename parameters in the GET handler (see

    L{FillOpcode})

  @ivar GetGetOpInput: Define this to override the default method for

    getting opcode parameters (see L{baserlib.OpcodeResource._GetDefaultData})

  @cvar PUT_OPCODE: Set this to a class derived from L{opcodes.OpCode} to

    automatically generate a PUT handler submitting the opcode

  @cvar PUT_RENAME: Set this to rename parameters in the PUT handler (see

    L{FillOpcode})

  @ivar GetPutOpInput: Define this to override the default method for

    getting opcode parameters (see L{baserlib.OpcodeResource._GetDefaultData})

  @cvar POST_OPCODE: Set this to a class derived from L{opcodes.OpCode} to

    automatically generate a POST handler submitting the opcode

  @cvar POST_RENAME: Set this to rename parameters in the DELETE handler (see

    L{FillOpcode})

  @ivar GetPostOpInput: Define this to override the default method for

    getting opcode parameters (see L{baserlib.OpcodeResource._GetDefaultData})

  @cvar DELETE_OPCODE: Set this to a class derived from L{opcodes.OpCode} to

    automatically generate a GET handler submitting the opcode

  @cvar DELETE_RENAME: Set this to rename parameters in the DELETE handler (see

    L{FillOpcode})

  @ivar GetDeleteOpInput: Define this to override the default method for

    getting opcode parameters (see L{baserlib.OpcodeResource._GetDefaultData})

  """

  __metaclass__ = _MetaOpcodeResource

  def _GetDefaultData(self):

    return (self.request_body, None)

  def _GenericHandler(self, opcode, rename, fn):

    (body, static) = fn()

    op = FillOpcode(opcode, body, static, rename=rename)

    return self.SubmitJob([op])