tiramisu/config.py

   1 # -*- coding: utf-8 -*-
   2 "options handler global entry point"
   3 # Copyright (C) 2012-2013 Team tiramisu (see AUTHORS for all contributors)
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 2 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program; if not, write to the Free Software
  17 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18 #
  19 # The original `Config` design model is unproudly borrowed from
  20 # the rough pypy's guys: http://codespeak.net/svn/pypy/dist/pypy/config/
  21 # the whole pypy projet is under MIT licence
  22 # ____________________________________________________________
  23 import weakref
  24 from tiramisu.error import PropertiesOptionError, ConfigError
  25 from tiramisu.option import OptionDescription, Option, SymLinkOption
  26 from tiramisu.setting import groups, Settings, default_encoding
  27 from tiramisu.storage import get_storages, get_storage, set_storage, \
  28     _impl_getstate_setting
  29 from tiramisu.value import Values, Multi
  30 from tiramisu.i18n import _
  31
  32
  33 class SubConfig(object):
  34     "sub configuration management entry"
  35     __slots__ = ('_impl_context', '_impl_descr', '_impl_path')
  36
  37     def __init__(self, descr, context, subpath=None):
  38         """ Configuration option management master class
  39
  40         :param descr: describes the configuration schema
  41         :type descr: an instance of ``option.OptionDescription``
  42         :param context: the current root config
  43         :type context: `Config`
  44         :type subpath: `str` with the path name
  45         """
  46         # main option description
  47         if not isinstance(descr, OptionDescription):
  48             raise TypeError(_('descr must be an optiondescription, not {0}'
  49                               ).format(type(descr)))
  50         self._impl_descr = descr
  51         # sub option descriptions
  52         if not isinstance(context, weakref.ReferenceType):
  53             raise ValueError('context must be a Weakref')
  54         self._impl_context = context
  55         self._impl_path = subpath
  56
  57     def cfgimpl_reset_cache(self, only_expired=False, only=('values',
  58                                                             'settings')):
  59         self._cfgimpl_get_context().cfgimpl_reset_cache(only_expired, only)
  60
  61     def cfgimpl_get_home_by_path(self, path, force_permissive=False,
  62                                  force_properties=None):
  63         """:returns: tuple (config, name)"""
  64         path = path.split('.')
  65         for step in path[:-1]:
  66             self = self._getattr(step,
  67                                  force_permissive=force_permissive,
  68                                  force_properties=force_properties)
  69         return self, path[-1]
  70
  71     def __hash__(self):
  72         return hash(self.cfgimpl_get_description().impl_getkey(self))
  73
  74     def __eq__(self, other):
  75         "Config's comparison"
  76         if not isinstance(other, Config):
  77             return False
  78         return self.cfgimpl_get_description().impl_getkey(self) == \
  79             other.cfgimpl_get_description().impl_getkey(other)
  80
  81     def __ne__(self, other):
  82         "Config's comparison"
  83         if not isinstance(other, Config):
  84             return True
  85         return not self == other
  86
  87     # ______________________________________________________________________
  88     def __iter__(self):
  89         """Pythonesque way of parsing group's ordered options.
  90         iteration only on Options (not OptionDescriptions)"""
  91         for child in self.cfgimpl_get_description().impl_getchildren():
  92             if not isinstance(child, OptionDescription):
  93                 try:
  94                     yield child._name, getattr(self, child._name)
  95                 except GeneratorExit:
  96                     raise StopIteration
  97                 except PropertiesOptionError:
  98                     pass  # option with properties
  99
 100     def iter_all(self):
 101         """A way of parsing options **and** groups.
 102         iteration on Options and OptionDescriptions."""
 103         for child in self.cfgimpl_get_description().impl_getchildren():
 104             try:
 105                 yield child._name, getattr(self, child._name)
 106             except GeneratorExit:
 107                 raise StopIteration
 108             except PropertiesOptionError:
 109                 pass  # option with properties
 110
 111     def iter_groups(self, group_type=None):
 112         """iteration on groups objects only.
 113         All groups are returned if `group_type` is `None`, otherwise the groups
 114         can be filtered by categories (families, or whatever).
 115
 116         :param group_type: if defined, is an instance of `groups.GroupType`
 117                            or `groups.MasterGroupType` that lives in
 118                            `setting.groups`
 119         """
 120         if group_type is not None and not isinstance(group_type,
 121                                                      groups.GroupType):
 122             raise TypeError(_("unknown group_type: {0}").format(group_type))
 123         for child in self.cfgimpl_get_description().impl_getchildren():
 124             if isinstance(child, OptionDescription):
 125                 try:
 126                     if group_type is None or (group_type is not None and
 127                                               child.impl_get_group_type()
 128                                               == group_type):
 129                         yield child._name, getattr(self, child._name)
 130                 except GeneratorExit:
 131                     raise StopIteration
 132                 except PropertiesOptionError:
 133                     pass
 134     # ______________________________________________________________________
 135
 136     def __str__(self):
 137         "Config's string representation"
 138         lines = []
 139         for name, grp in self.iter_groups():
 140             lines.append("[{0}]".format(name))
 141         for name, value in self:
 142             try:
 143                 lines.append("{0} = {1}".format(name, value))
 144             except UnicodeEncodeError:
 145                 lines.append("{0} = {1}".format(name,
 146                                                 value.encode(default_encoding)))
 147             except PropertiesOptionError:
 148                 pass
 149         return '\n'.join(lines)
 150
 151     __repr__ = __str__
 152
 153     def _cfgimpl_get_context(self):
 154         return self._impl_context()
 155
 156     def cfgimpl_get_description(self):
 157         if self._impl_descr is None:
 158             raise ConfigError(_('no option description found for this config'
 159                                 ' (may be metaconfig without meta)'))
 160         else:
 161             return self._impl_descr
 162
 163     def cfgimpl_get_settings(self):
 164         return self._cfgimpl_get_context()._impl_settings
 165
 166     def cfgimpl_get_values(self):
 167         return self._cfgimpl_get_context()._impl_values
 168
 169     # ____________________________________________________________
 170     # attribute methods
 171     def __setattr__(self, name, value):
 172         "attribute notation mechanism for the setting of the value of an option"
 173         if name.startswith('_impl_'):
 174             object.__setattr__(self, name, value)
 175             return
 176         self._setattr(name, value)
 177
 178     def _setattr(self, name, value, force_permissive=False):
 179         if '.' in name:
 180             homeconfig, name = self.cfgimpl_get_home_by_path(name)
 181             return homeconfig.__setattr__(name, value)
 182         child = getattr(self.cfgimpl_get_description(), name)
 183         if not isinstance(child, SymLinkOption):
 184             if self._impl_path is None:
 185                 path = name
 186             else:
 187                 path = self._impl_path + '.' + name
 188             self.cfgimpl_get_values().setitem(child, value, path,
 189                                               force_permissive=force_permissive)
 190         else:
 191             context = self._cfgimpl_get_context()
 192             path = context.cfgimpl_get_description().impl_get_path_by_opt(
 193                 child._opt)
 194             context._setattr(path, value, force_permissive=force_permissive)
 195
 196     def __delattr__(self, name):
 197         child = getattr(self.cfgimpl_get_description(), name)
 198         self.cfgimpl_get_values().__delitem__(child)
 199
 200     def __getattr__(self, name):
 201         return self._getattr(name)
 202
 203     def _getattr(self, name, force_permissive=False, force_properties=None,
 204                  validate=True):
 205         """
 206         attribute notation mechanism for accessing the value of an option
 207         :param name: attribute name
 208         :return: option's value if name is an option name, OptionDescription
 209                  otherwise
 210         """
 211         # attribute access by passing a path,
 212         # for instance getattr(self, "creole.general.family.adresse_ip_eth0")
 213         if '.' in name:
 214             homeconfig, name = self.cfgimpl_get_home_by_path(
 215                 name, force_permissive=force_permissive,
 216                 force_properties=force_properties)
 217             return homeconfig._getattr(name, force_permissive=force_permissive,
 218                                        force_properties=force_properties,
 219                                        validate=validate)
 220         opt_or_descr = getattr(self.cfgimpl_get_description(), name)
 221         if self._impl_path is None:
 222             subpath = name
 223         else:
 224             subpath = self._impl_path + '.' + name
 225         # symlink options
 226         if isinstance(opt_or_descr, SymLinkOption):
 227             context = self._cfgimpl_get_context()
 228             path = context.cfgimpl_get_description().impl_get_path_by_opt(
 229                 opt_or_descr._opt)
 230             return context._getattr(path, validate=validate,
 231                                     force_properties=force_properties,
 232                                     force_permissive=force_permissive)
 233         elif isinstance(opt_or_descr, OptionDescription):
 234             self.cfgimpl_get_settings().validate_properties(
 235                 opt_or_descr, True, False, path=subpath,
 236                 force_permissive=force_permissive,
 237                 force_properties=force_properties)
 238             return SubConfig(opt_or_descr, self._impl_context, subpath)
 239         else:
 240             return self.cfgimpl_get_values().getitem(
 241                 opt_or_descr, path=subpath,
 242                 validate=validate,
 243                 force_properties=force_properties,
 244                 force_permissive=force_permissive)
 245
 246     def find(self, bytype=None, byname=None, byvalue=None, type_='option'):
 247         """
 248             finds a list of options recursively in the config
 249
 250             :param bytype: Option class (BoolOption, StrOption, ...)
 251             :param byname: filter by Option._name
 252             :param byvalue: filter by the option's value
 253             :returns: list of matching Option objects
 254         """
 255         return self._cfgimpl_get_context()._find(bytype, byname, byvalue,
 256                                                  first=False,
 257                                                  type_=type_,
 258                                                  _subpath=self.cfgimpl_get_path()
 259                                                  )
 260
 261     def find_first(self, bytype=None, byname=None, byvalue=None,
 262                    type_='option', display_error=True):
 263         """
 264             finds an option recursively in the config
 265
 266             :param bytype: Option class (BoolOption, StrOption, ...)
 267             :param byname: filter by Option._name
 268             :param byvalue: filter by the option's value
 269             :returns: list of matching Option objects
 270         """
 271         return self._cfgimpl_get_context()._find(
 272             bytype, byname, byvalue, first=True, type_=type_,
 273             _subpath=self.cfgimpl_get_path(), display_error=display_error)
 274
 275     def _find(self, bytype, byname, byvalue, first, type_='option',
 276               _subpath=None, check_properties=True, display_error=True):
 277         """
 278         convenience method for finding an option that lives only in the subtree
 279
 280         :param first: return only one option if True, a list otherwise
 281         :return: find list or an exception if nothing has been found
 282         """
 283         def _filter_by_name():
 284             try:
 285                 if byname is None or path == byname or \
 286                         path.endswith('.' + byname):
 287                     return True
 288             except IndexError:
 289                 pass
 290             return False
 291
 292         def _filter_by_value():
 293             if byvalue is None:
 294                 return True
 295             try:
 296                 value = getattr(self, path)
 297                 if isinstance(value, Multi):
 298                     return byvalue in value
 299                 else:
 300                     return value == byvalue
 301             except PropertiesOptionError:  # a property is a restriction
 302                                            # upon the access of the value
 303                 return False
 304
 305         def _filter_by_type():
 306             if bytype is None:
 307                 return True
 308             if isinstance(option, bytype):
 309                 return True
 310             return False
 311
 312         if type_ not in ('option', 'path', 'value'):
 313             raise ValueError(_('unknown type_ type {0}'
 314                                'for _find').format(type_))
 315         find_results = []
 316         opts, paths = self.cfgimpl_get_description()._cache_paths
 317         for index in range(0, len(paths)):
 318             option = opts[index]
 319             if isinstance(option, OptionDescription):
 320                 continue
 321             path = paths[index]
 322             if _subpath is not None and not path.startswith(_subpath + '.'):
 323                 continue
 324             if not _filter_by_name():
 325                 continue
 326             if not _filter_by_value():
 327                 continue
 328             if not _filter_by_type():
 329                 continue
 330             #remove option with propertyerror, ...
 331             if byvalue is None and check_properties:
 332                 try:
 333                     value = getattr(self, path)
 334                 except PropertiesOptionError:
 335                     # a property restricts the access of the value
 336                     continue
 337             if type_ == 'value':
 338                 retval = value
 339             elif type_ == 'path':
 340                 retval = path
 341             elif type_ == 'option':
 342                 retval = option
 343             if first:
 344                 return retval
 345             else:
 346                 find_results.append(retval)
 347         return self._find_return_results(find_results, display_error)
 348
 349     def _find_return_results(self, find_results, display_error):
 350         if find_results == []:
 351             if display_error:
 352                 raise AttributeError(_("no option found in config"
 353                                        " with these criteria"))
 354             else:
 355                 # translation is slow
 356                 raise AttributeError()
 357         else:
 358             return find_results
 359
 360     def make_dict(self, flatten=False, _currpath=None, withoption=None,
 361                   withvalue=None):
 362         """exports the whole config into a `dict`, for example:
 363
 364         >>> print cfg.make_dict()
 365         {'od2.var4': None, 'od2.var5': None, 'od2.var6': None}
 366
 367
 368
 369         :param flatten: returns a dict(name=value) instead of a dict(path=value)
 370                         ::
 371
 372                             >>> print cfg.make_dict(flatten=True)
 373                             {'var5': None, 'var4': None, 'var6': None}
 374
 375         :param withoption: returns the options that are present in the very same
 376                            `OptionDescription` than the `withoption` itself::
 377
 378                                 >>> print cfg.make_dict(withoption='var1')
 379                                 {'od2.var4': None, 'od2.var5': None,
 380                                 'od2.var6': None,
 381                                 'od2.var1': u'value',
 382                                 'od1.var1': None,
 383                                 'od1.var3': None,
 384                                 'od1.var2': None}
 385
 386         :param withvalue: returns the options that have the value `withvalue`
 387                           ::
 388
 389                             >>> print c.make_dict(withoption='var1',
 390                                                   withvalue=u'value')
 391                             {'od2.var4': None,
 392                             'od2.var5': None,
 393                             'od2.var6': None,
 394                             'od2.var1': u'value'}
 395
 396         :returns: dict of Option's name (or path) and values
 397         """
 398         pathsvalues = []
 399         if _currpath is None:
 400             _currpath = []
 401         if withoption is None and withvalue is not None:
 402             raise ValueError(_("make_dict can't filtering with value without "
 403                                "option"))
 404         if withoption is not None:
 405             mypath = self.cfgimpl_get_path()
 406             for path in self._cfgimpl_get_context()._find(bytype=Option,
 407                                                           byname=withoption,
 408                                                           byvalue=withvalue,
 409                                                           first=False,
 410                                                           type_='path',
 411                                                           _subpath=mypath):
 412                 path = '.'.join(path.split('.')[:-1])
 413                 opt = self._cfgimpl_get_context().cfgimpl_get_description(
 414                 ).impl_get_opt_by_path(path)
 415                 if mypath is not None:
 416                     if mypath == path:
 417                         withoption = None
 418                         withvalue = None
 419                         break
 420                     else:
 421                         tmypath = mypath + '.'
 422                         if not path.startswith(tmypath):
 423                             raise AttributeError(_('unexpected path {0}, '
 424                                                    'should start with {1}'
 425                                                    '').format(path, mypath))
 426                         path = path[len(tmypath):]
 427                 self._make_sub_dict(opt, path, pathsvalues, _currpath, flatten)
 428         #withoption can be set to None below !
 429         if withoption is None:
 430             for opt in self.cfgimpl_get_description().impl_getchildren():
 431                 path = opt._name
 432                 self._make_sub_dict(opt, path, pathsvalues, _currpath, flatten)
 433         if _currpath == []:
 434             options = dict(pathsvalues)
 435             return options
 436         return pathsvalues
 437
 438     def _make_sub_dict(self, opt, path, pathsvalues, _currpath, flatten):
 439         if isinstance(opt, OptionDescription):
 440             try:
 441                 pathsvalues += getattr(self, path).make_dict(flatten,
 442                                                              _currpath +
 443                                                              path.split('.'))
 444             except PropertiesOptionError:
 445                 pass  # this just a hidden or disabled option
 446         else:
 447             try:
 448                 value = self._getattr(opt._name)
 449                 if flatten:
 450                     name = opt._name
 451                 else:
 452                     name = '.'.join(_currpath + [opt._name])
 453                 pathsvalues.append((name, value))
 454             except PropertiesOptionError:
 455                 pass  # this just a hidden or disabled option
 456
 457     def cfgimpl_get_path(self):
 458         descr = self.cfgimpl_get_description()
 459         context_descr = self._cfgimpl_get_context().cfgimpl_get_description()
 460         return context_descr.impl_get_path_by_opt(descr)
 461
 462
 463 class CommonConfig(SubConfig):
 464     "abstract base class for the Config and the MetaConfig"
 465     __slots__ = ('_impl_values', '_impl_settings', '_impl_meta')
 466
 467     def _impl_build_all_paths(self):
 468         self.cfgimpl_get_description().impl_build_cache()
 469
 470     def read_only(self):
 471         "read only is a global config's setting, see `settings.py`"
 472         self.cfgimpl_get_settings().read_only()
 473
 474     def read_write(self):
 475         "read write is a global config's setting, see `settings.py`"
 476         self.cfgimpl_get_settings().read_write()
 477
 478     def getowner(self, opt):
 479         """convenience method to retrieve an option's owner
 480         from the config itself
 481         """
 482         if not isinstance(opt, Option) and not isinstance(opt, SymLinkOption):
 483             raise TypeError(_('opt in getowner must be an option not {0}'
 484                               '').format(type(opt)))
 485         return self.cfgimpl_get_values().getowner(opt)
 486
 487     def unwrap_from_path(self, path, force_permissive=False):
 488         """convenience method to extract and Option() object from the Config()
 489         and it is **fast**: finds the option directly in the appropriate
 490         namespace
 491
 492         :returns: Option()
 493         """
 494         if '.' in path:
 495             homeconfig, path = self.cfgimpl_get_home_by_path(
 496                 path, force_permissive=force_permissive)
 497             return getattr(homeconfig.cfgimpl_get_description(), path)
 498         return getattr(self.cfgimpl_get_description(), path)
 499
 500     def cfgimpl_get_path(self):
 501         return None
 502
 503     def cfgimpl_get_meta(self):
 504         return self._impl_meta
 505
 506     # information
 507     def impl_set_information(self, key, value):
 508         """updates the information's attribute
 509
 510         :param key: information's key (ex: "help", "doc"
 511         :param value: information's value (ex: "the help string")
 512         """
 513         self._impl_values.set_information(key, value)
 514
 515     def impl_get_information(self, key, default=None):
 516         """retrieves one information's item
 517
 518         :param key: the item string (ex: "help")
 519         """
 520         return self._impl_values.get_information(key, default)
 521
 522
 523 # ____________________________________________________________
 524 class Config(CommonConfig):
 525     "main configuration management entry"
 526     __slots__ = ('__weakref__', '_impl_test')
 527
 528     def __init__(self, descr, session_id=None, persistent=False):
 529         """ Configuration option management master class
 530
 531         :param descr: describes the configuration schema
 532         :type descr: an instance of ``option.OptionDescription``
 533         :param context: the current root config
 534         :type context: `Config`
 535         :param session_id: session ID is import with persistent Config to
 536         retrieve good session
 537         :type session_id: `str`
 538         :param persistent: if persistent, don't delete storage when leaving
 539         :type persistent: `boolean`
 540         """
 541         settings, values = get_storages(self, session_id, persistent)
 542         self._impl_settings = Settings(self, settings)
 543         self._impl_values = Values(self, values)
 544         super(Config, self).__init__(descr, weakref.ref(self))
 545         self._impl_build_all_paths()
 546         self._impl_meta = None
 547         #undocumented option used only in test script
 548         self._impl_test = False
 549
 550     def __getstate__(self):
 551         if self._impl_meta is not None:
 552             raise ConfigError('cannot serialize Config with meta')
 553         slots = set()
 554         for subclass in self.__class__.__mro__:
 555             if subclass is not object:
 556                 slots.update(subclass.__slots__)
 557         slots -= frozenset(['_impl_context', '__weakref__'])
 558         state = {}
 559         for slot in slots:
 560             try:
 561                 state[slot] = getattr(self, slot)
 562             except AttributeError:
 563                 pass
 564         storage = self._impl_values._p_._storage
 565         if not storage.serializable:
 566             raise ConfigError('this storage is not serialisable, could be a '
 567                               'none persistent storage')
 568         state['_storage'] = {'session_id': storage.session_id,
 569                              'persistent': storage.persistent}
 570         state['_impl_setting'] = _impl_getstate_setting()
 571         return state
 572
 573     def __setstate__(self, state):
 574         for key, value in state.items():
 575             if key not in ['_storage', '_impl_setting']:
 576                 setattr(self, key, value)
 577         set_storage(**state['_impl_setting'])
 578         self._impl_context = weakref.ref(self)
 579         self._impl_settings.context = weakref.ref(self)
 580         self._impl_values.context = weakref.ref(self)
 581         storage = get_storage(test=self._impl_test, **state['_storage'])
 582         self._impl_values._impl_setstate(storage)
 583         self._impl_settings._impl_setstate(storage)
 584
 585     def cfgimpl_reset_cache(self,
 586                             only_expired=False,
 587                             only=('values', 'settings')):
 588         if 'values' in only:
 589             self.cfgimpl_get_values().reset_cache(only_expired=only_expired)
 590         if 'settings' in only:
 591             self.cfgimpl_get_settings().reset_cache(only_expired=only_expired)
 592
 593
 594 #class MetaConfig(CommonConfig):
 595 #    __slots__ = ('_impl_children',)
 596
 597 #    def __init__(self, children, meta=True, session_id=None, persistent=False):
 598 #        if not isinstance(children, list):
 599 #            raise ValueError(_("metaconfig's children must be a list"))
 600 #        self._impl_descr = None
 601 #        self._impl_path = None
 602 #        if meta:
 603 #            for child in children:
 604 #                if not isinstance(child, CommonConfig):
 605 #                    raise TypeError(_("metaconfig's children "
 606 #                                      "must be config, not {0}"
 607 #                                      ).format(type(child)))
 608 #                if self._impl_descr is None:
 609 #                    self._impl_descr = child.cfgimpl_get_description()
 610 #                elif not self._impl_descr is child.cfgimpl_get_description():
 611 #                    raise ValueError(_('all config in metaconfig must '
 612 #                                       'have the same optiondescription'))
 613 #                if child.cfgimpl_get_meta() is not None:
 614 #                    raise ValueError(_("child has already a metaconfig's"))
 615 #                child._impl_meta = self
 616
 617 #        self._impl_children = children
 618 #        settings, values = get_storages(self, session_id, persistent)
 619 #        self._impl_settings = Settings(self, settings)
 620 #        self._impl_values = Values(self, values)
 621 #        self._impl_meta = None
 622
 623 #    def cfgimpl_get_children(self):
 624 #        return self._impl_children
 625
 626 #    def cfgimpl_get_context(self):
 627 #        "a meta config is a config wich has a setting, that is itself"
 628 #        return self
 629
 630 #    def cfgimpl_reset_cache(self,
 631 #                            only_expired=False,
 632 #                            only=('values', 'settings')):
 633 #        if 'values' in only:
 634 #            self.cfgimpl_get_values().reset_cache(only_expired=only_expired)
 635 #        if 'settings' in only:
 636 #            self.cfgimpl_get_settings().reset_cache(only_expired=only_expired)
 637 #        for child in self._impl_children:
 638 #            child.cfgimpl_reset_cache(only_expired=only_expired, only=only)
 639
 640 #    def set_contexts(self, path, value):
 641 #        for child in self._impl_children:
 642 #            try:
 643 #                if not isinstance(child, MetaConfig):
 644 #                    setattr(child, path, value)
 645 #                else:
 646 #                    child.set_contexts(path, value)
 647 #            except PropertiesOptionError:
 648 #                pass
 649
 650 #    def find_first_contexts(self, byname=None, bypath=None, byvalue=None,
 651 #                            type_='path', display_error=True):
 652 #        ret = []
 653 #        try:
 654 #            if bypath is None and byname is not None and \
 655 #                    self.cfgimpl_get_description() is not None:
 656 #                bypath = self._find(bytype=None, byvalue=None, byname=byname,
 657 #                                    first=True, type_='path',
 658 #                                    check_properties=False,
 659 #                                    display_error=display_error)
 660 #        except ConfigError:
 661 #            pass
 662 #        for child in self._impl_children:
 663 #            try:
 664 #                if not isinstance(child, MetaConfig):
 665 #                    if bypath is not None:
 666 #                        if byvalue is not None:
 667 #                            if getattr(child, bypath) == byvalue:
 668 #                                ret.append(child)
 669 #                        else:
 670 #                            #not raise
 671 #                            getattr(child, bypath)
 672 #                            ret.append(child)
 673 #                    else:
 674 #                        ret.append(child.find_first(byname=byname,
 675 #                                                    byvalue=byvalue,
 676 #                                                    type_=type_,
 677 #                                                    display_error=False))
 678 #                else:
 679 #                    ret.extend(child.find_first_contexts(byname=byname,
 680 #                                                         bypath=bypath,
 681 #                                                         byvalue=byvalue,
 682 #                                                         type_=type_,
 683 #                                                         display_error=False))
 684 #            except AttributeError:
 685 #                pass
 686 #        return self._find_return_results(ret, display_error)
 687
 688
 689 def mandatory_warnings(config):
 690     """convenience function to trace Options that are mandatory and
 691     where no value has been set
 692
 693     :returns: generator of mandatory Option's path
 694
 695     """
 696     #if value in cache, properties are not calculated
 697     config.cfgimpl_reset_cache(only=('values',))
 698     for path in config.cfgimpl_get_description().impl_getpaths(
 699             include_groups=True):
 700         try:
 701             config._getattr(path, force_properties=frozenset(('mandatory',)))
 702         except PropertiesOptionError as err:
 703             if err.proptype == ['mandatory']:
 704                 yield path
 705     config.cfgimpl_reset_cache(only=('values',))