Synnefo » snf-ganeti

#

#

# Copyright (C) 2006, 2007, 2008 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.

"""Remote API base resources library.

"""

# pylint: disable=C0103

# C0103: Invalid name, since the R_* names are not conforming

import logging

from ganeti import luxi

from ganeti import rapi

from ganeti import http

from ganeti import errors

from ganeti import compat

# Dummy value to detect unchanged parameters

_DEFAULT = object()

#: Supported HTTP methods

_SUPPORTED_METHODS = frozenset([

  http.HTTP_DELETE,

  http.HTTP_GET,

  http.HTTP_POST,

  http.HTTP_PUT,

  ])

def _BuildOpcodeAttributes():

  """Builds list of attributes used for per-handler opcodes.

  """

  return [(method, "%s_OPCODE" % method, "%s_RENAME" % method,

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

          for method in _SUPPORTED_METHODS]

_OPCODE_ATTRS = _BuildOpcodeAttributes()

def BuildUriList(ids, uri_format, uri_fields=("name", "uri")):

  """Builds a URI list as used by index resources.

  @param ids: list of ids as strings

  @param uri_format: format to be applied for URI

  @param uri_fields: optional parameter for field IDs

  """

  (field_id, field_uri) = uri_fields

  def _MapId(m_id):

    return {

      field_id: m_id,

      field_uri: uri_format % m_id,

      }

  # Make sure the result is sorted, makes it nicer to look at and simplifies

  # unittests.

  ids.sort()

  return map(_MapId, ids)

def ExtractField(sequence, index):

  """Creates a list containing one column out of a list of lists.

  @param sequence: sequence of lists

  @param index: index of field

  """

  return map(lambda item: item[index], sequence)

def MapFields(names, data):

  """Maps two lists into one dictionary.

  Example::

      >>> MapFields(["a", "b"], ["foo", 123])

      {'a': 'foo', 'b': 123}

  @param names: field names (list of strings)

  @param data: field data (list)

  """

  if len(names) != len(data):

    raise AttributeError("Names and data must have the same length")

  return dict(zip(names, data))

def MapBulkFields(itemslist, fields):

  """Map value to field name in to one dictionary.

  @param itemslist: a list of items values

  @param fields: a list of items names

  @return: a list of mapped dictionaries

  """

  items_details = []

  for item in itemslist:

    mapped = MapFields(fields, item)

    items_details.append(mapped)

  return items_details

def MakeParamsDict(opts, params):

  """Makes params dictionary out of a option set.

  This function returns a dictionary needed for hv or be parameters. But only

  those fields which provided in the option set. Takes parameters frozensets

  from constants.

  @type opts: dict

  @param opts: selected options

  @type params: frozenset

  @param params: subset of options

  @rtype: dict

  @return: dictionary of options, filtered by given subset.

  """

  result = {}

  for p in params:

    try:

      value = opts[p]

    except KeyError:

      continue

    result[p] = value

  return result

def FillOpcode(opcls, body, static, rename=None):

  """Fills an opcode with body parameters.

  Parameter types are checked.

  @type opcls: L{opcodes.OpCode}

  @param opcls: Opcode class

  @type body: dict

  @param body: Body parameters as received from client

  @type static: dict

  @param static: Static parameters which can't be modified by client

  @type rename: dict

  @param rename: Renamed parameters, key as old name, value as new name

  @return: Opcode object

  """

  if body is None:

    params = {}

  else:

    CheckType(body, dict, "Body contents")

    # Make copy to be modified

    params = body.copy()

  if rename:

    for old, new in rename.items():

      if new in params and old in params:

        raise http.HttpBadRequest("Parameter '%s' was renamed to '%s', but"

                                  " both are specified" %

                                  (old, new))

      if old in params:

        assert new not in params

        params[new] = params.pop(old)

  if static:

    overwritten = set(params.keys()) & set(static.keys())

    if overwritten:

      raise http.HttpBadRequest("Can't overwrite static parameters %r" %

                                overwritten)

    params.update(static)

  # Convert keys to strings (simplejson decodes them as unicode)

  params = dict((str(key), value) for (key, value) in params.items())

  try:

    op = opcls(**params) # pylint: disable=W0142

    op.Validate(False)

  except (errors.OpPrereqError, TypeError), err:

    raise http.HttpBadRequest("Invalid body parameters: %s" % err)

  return op

def HandleItemQueryErrors(fn, *args, **kwargs):

  """Converts errors when querying a single item.

  """

  try:

    return fn(*args, **kwargs)

  except errors.OpPrereqError, err:

    if len(err.args) == 2 and err.args[1] == errors.ECODE_NOENT:

      raise http.HttpNotFound()

    raise

def FeedbackFn(msg):

  """Feedback logging function for jobs.

  We don't have a stdout for printing log messages, so log them to the

  http log at least.

  @param msg: the message

  """

  (_, log_type, log_msg) = msg

  logging.info("%s: %s", log_type, log_msg)

def CheckType(value, exptype, descr):

  """Abort request if value type doesn't match expected type.

  @param value: Value

  @type exptype: type

  @param exptype: Expected type

  @type descr: string

  @param descr: Description of value

  @return: Value (allows inline usage)

  """

  if not isinstance(value, exptype):

    raise http.HttpBadRequest("%s: Type is '%s', but '%s' is expected" %

                              (descr, type(value).__name__, exptype.__name__))

  return value

def CheckParameter(data, name, default=_DEFAULT, exptype=_DEFAULT):

  """Check and return the value for a given parameter.

  If no default value was given and the parameter doesn't exist in the input

  data, an error is raise.

  @type data: dict

  @param data: Dictionary containing input data

  @type name: string

  @param name: Parameter name

  @param default: Default value (can be None)

  @param exptype: Expected type (can be None)

  """

  try:

    value = data[name]

  except KeyError:

    if default is not _DEFAULT:

      return default

    raise http.HttpBadRequest("Required parameter '%s' is missing" %

                              name)

  if exptype is _DEFAULT:

    return value

  return CheckType(value, exptype, "'%s' parameter" % name)

class ResourceBase(object):

  """Generic class for resources.

  """

  # Default permission requirements

  GET_ACCESS = []

  PUT_ACCESS = [rapi.RAPI_ACCESS_WRITE]

  POST_ACCESS = [rapi.RAPI_ACCESS_WRITE]

  DELETE_ACCESS = [rapi.RAPI_ACCESS_WRITE]

  def __init__(self, items, queryargs, req, _client_cls=luxi.Client):

    """Generic resource constructor.

    @param items: a list with variables encoded in the URL

    @param queryargs: a dictionary with additional options from URL

    @param req: Request context

    @param _client_cls: L{luxi} client class (unittests only)

    """

    self.items = items

    self.queryargs = queryargs

    self._req = req

    self._client_cls = _client_cls

  def _GetRequestBody(self):

    """Returns the body data.

    """

    return self._req.private.body_data

  request_body = property(fget=_GetRequestBody)

  def _checkIntVariable(self, name, default=0):

    """Return the parsed value of an int argument.

    """

    val = self.queryargs.get(name, default)

    if isinstance(val, list):

      if val:

        val = val[0]

      else:

        val = default

    try:

      val = int(val)

    except (ValueError, TypeError):

      raise http.HttpBadRequest("Invalid value for the"

                                " '%s' parameter" % (name,))

    return val

  def _checkStringVariable(self, name, default=None):

    """Return the parsed value of an int argument.

    """

    val = self.queryargs.get(name, default)

    if isinstance(val, list):

      if val:

        val = val[0]

      else:

        val = default

    return val

  def getBodyParameter(self, name, *args):

    """Check and return the value for a given parameter.

    If a second parameter is not given, an error will be returned,

    otherwise this parameter specifies the default value.

    @param name: the required parameter

    """

    if args:

      return CheckParameter(self.request_body, name, default=args[0])

    return CheckParameter(self.request_body, name)

  def useLocking(self):

    """Check if the request specifies locking.

    """

    return bool(self._checkIntVariable("lock"))

  def useBulk(self):

    """Check if the request specifies bulk querying.

    """

    return bool(self._checkIntVariable("bulk"))

  def useForce(self):

    """Check if the request specifies a forced operation.

    """

    return bool(self._checkIntVariable("force"))

  def dryRun(self):

    """Check if the request specifies dry-run mode.

    """

    return bool(self._checkIntVariable("dry-run"))

  def GetClient(self):

    """Wrapper for L{luxi.Client} with HTTP-specific error handling.

    """

    # Could be a function, pylint: disable=R0201

    try:

      return self._client_cls()

    except luxi.NoMasterError, err:

      raise http.HttpBadGateway("Can't connect to master daemon: %s" % err)

    except luxi.PermissionError:

      raise http.HttpInternalServerError("Internal error: no permission to"

                                         " connect to the master daemon")

  def SubmitJob(self, op, cl=None):

    """Generic wrapper for submit job, for better http compatibility.

    @type op: list

    @param op: the list of opcodes for the job

    @type cl: None or luxi.Client

    @param cl: optional luxi client to use

    @rtype: string

    @return: the job ID

    """

    if cl is None:

      cl = self.GetClient()

    try:

      return cl.SubmitJob(op)

    except errors.JobQueueFull:

      raise http.HttpServiceUnavailable("Job queue is full, needs archiving")

    except errors.JobQueueDrainError:

      raise http.HttpServiceUnavailable("Job queue is drained, cannot submit")

    except luxi.NoMasterError, err:

      raise http.HttpBadGateway("Master seems to be unreachable: %s" % err)

    except luxi.PermissionError:

      raise http.HttpInternalServerError("Internal error: no permission to"

                                         " connect to the master daemon")

    except luxi.TimeoutError, err:

      raise http.HttpGatewayTimeout("Timeout while talking to the master"

                                    " daemon: %s" % err)

def GetResourceOpcodes(cls):

  """Returns all opcodes used by a resource.

  """

  return frozenset(filter(None, (getattr(cls, op_attr, None)

                                 for (_, op_attr, _, _) in _OPCODE_ATTRS)))

class _MetaOpcodeResource(type):

  """Meta class for RAPI resources.

  """

  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 _OPCODE_ATTRS:

      if hasattr(obj, method):

        # If the method handler is already defined, "*_RENAME" or "Get*OpInput"

        # shouldn't be (they're only used by the automatically generated

        # handler)

        assert not hasattr(obj, rename_attr)

        assert not hasattr(obj, fn_attr)

      else:

        # Try to generate handler method on handler instance

        try:

          opcode = getattr(obj, op_attr)

        except AttributeError:

          pass

        else:

          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])