abrt.git - Unnamed repository; edit this file 'description' to name the repository.

diff options

Diffstat (limited to 'lib/Plugins/Kerneloops.cpp')

0 files changed, 0 insertions, 0 deletions

53'>53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942

# Authors:
#   Jason Gerard DeRose <jderose@redhat.com>
#
# Copyright (C) 2008  Red Hat
# see file 'COPYING' for use and warranty information
#
# 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; version 2 only
#
# 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

"""
Base classes for all front-end plugins.
"""

import re
import inspect
import plugable
from plugable import lock, check_name
import errors
from errors import check_type, check_isinstance, raise_TypeError
import ipa_types


RULE_FLAG = 'validation_rule'

def rule(obj):
    assert not hasattr(obj, RULE_FLAG)
    setattr(obj, RULE_FLAG, True)
    return obj

def is_rule(obj):
    return callable(obj) and getattr(obj, RULE_FLAG, False) is True


class DefaultFrom(plugable.ReadOnly):
    """
    Derive a default value from other supplied values.

    For example, say you wanted to create a default for the user's login from
    the user's first and last names. It could be implemented like this:

    >>> login = DefaultFrom(lambda first, last: first[0] + last)
    >>> login(first='John', last='Doe')
    'JDoe'

    If you do not explicitly provide keys when you create a DefaultFrom
    instance, the keys are implicitly derived from your callback by
    inspecting ``callback.func_code.co_varnames``. The keys are available
    through the ``DefaultFrom.keys`` instance attribute, like this:

    >>> login.keys
    ('first', 'last')

    The callback is available through the ``DefaultFrom.callback`` instance
    attribute, like this:

    >>> login.callback
    <function <lambda> at 0x7fdd225cd7d0>
    >>> login.callback.func_code.co_varnames # The keys
    ('first', 'last')

    The keys can be explicitly provided as optional positional arguments after
    the callback. For example, this is equivalent to the ``login`` instance
    above:

    >>> login2 = DefaultFrom(lambda a, b: a[0] + b, 'first', 'last')
    >>> login2.keys
    ('first', 'last')
    >>> login2.callback.func_code.co_varnames # Not the keys
    ('a', 'b')
    >>> login2(first='John', last='Doe')
    'JDoe'

    If any keys are missing when calling your DefaultFrom instance, your
    callback is not called and None is returned. For example:

    >>> login(first='John', lastname='Doe') is None
    True
    >>> login() is None
    True

    Any additional keys are simply ignored, like this:

    >>> login(last='Doe', first='John', middle='Whatever')
    'JDoe'

    As above, because `DefaultFrom.__call__` takes only pure keyword
    arguments, they can be supplied in any order.

    Of course, the callback need not be a lambda expression. This third
    example is equivalent to both the ``login`` and ``login2`` instances
    above:

    >>> def get_login(first, last):
    ...     return first[0] + last
    ...
    >>> login3 = DefaultFrom(get_login)
    >>> login3.keys
    ('first', 'last')
    >>> login3.callback.func_code.co_varnames
    ('first', 'last')
    >>> login3(first='John', last='Doe')
    'JDoe'
    """

    def __init__(self, callback, *keys):
        """
        :param callback: The callable to call when all keys are present.
        :param keys: Optional keys used for source values.
        """
        if not callable(callback):
            raise TypeError('callback must be callable; got %r' % callback)
        self.callback = callback
        if len(keys) == 0:
            self.keys = callback.func_code.co_varnames
        else:
            self.keys = keys
        for key in self.keys:
            if type(key) is not str:
                raise_TypeError(key, str, 'keys')
        lock(self)

    def __call__(self, **kw):
        """
        If all keys are present, calls the callback; otherwise returns None.

        :param kw: The keyword arguments.
        """
        vals = tuple(kw.get(k, None) for k in self.keys)
        if None in vals:
            return
        try:
            return self.callback(*vals)
        except StandardError:
            pass


def parse_param_spec(spec):
    """
    Parse a param spec into to (name, kw).

    The ``spec`` string determines the param name, whether the param is
    required, and whether the param is multivalue according the following
    syntax:

    ======  =====  ========  ==========
    Spec    Name   Required  Multivalue
    ======  =====  ========  ==========
    'var'   'var'  True      False
    'var?'  'var'  False     False
    'var*'  'var'  False     True
    'var+'  'var'  True      True
    ======  =====  ========  ==========

    For example,

    >>> parse_param_spec('login')
    ('login', {'required': True, 'multivalue': False})
    >>> parse_param_spec('gecos?')
    ('gecos', {'required': False, 'multivalue': False})
    >>> parse_param_spec('telephone_numbers*')
    ('telephone_numbers', {'required': False, 'multivalue': True})
    >>> parse_param_spec('group+')
    ('group', {'required': True, 'multivalue': True})

    :param spec: A spec string.
    """
    if type(spec) is not str:
        raise_TypeError(spec, str, 'spec')
    if len(spec) < 2:
        raise ValueError(
            'param spec must be at least 2 characters; got %r' % spec
        )
    _map = {
        '?': dict(required=False, multivalue=False),
        '*': dict(required=False, multivalue=True),
        '+': dict(required=True, multivalue=True),
    }
    end = spec[-1]
    if end in _map:
        return (spec[:-1], _map[end])
    return (spec, dict(required=True, multivalue=False))


class Param(plugable.ReadOnly):
    """
    A parameter accepted by a `Command`.

    ============  =================  ==================
    Keyword       Type               Default
    ============  =================  ==================
    type          ipa_type.Type      ipa_type.Unicode()
    doc           str                ''
    required      bool               True
    multivalue    bool               False
    primary_key   bool               False
    normalize     callable           None
    default       same as type.type  None
    default_from  callable           None
    ============  =================  ==================
    """
    __nones = (None, '', tuple(), [])
    __defaults = dict(
        type=ipa_types.Unicode(),
        doc='',
        required=True,
        multivalue=False,
        primary_key=False,
        normalize=None,
        default=None,
        default_from=None,
        rules=tuple(),
    )

    def __init__(self, name, **override):
        if not ('required' in override or 'multivalue' in override):
            (name, kw_from_spec) = parse_param_spec(name)
            override.update(kw_from_spec)
        kw = dict(self.__defaults)
        if not set(kw).issuperset(override):
            extra = sorted(set(override) - set(kw))
            raise TypeError(
                'Param.__init__() takes no such kwargs: %s' % ', '.join(extra)
            )
        kw.update(override)
        self.__kw = kw
        self.name = check_name(name)
        self.type = self.__check_isinstance(ipa_types.Type, 'type')
        self.doc = self.__check_type(str, 'doc')
        self.required = self.__check_type(bool, 'required')
        self.multivalue = self.__check_type(bool, 'multivalue')
        self.default = kw['default']
        df = kw['default_from']
        if callable(df) and not isinstance(df, DefaultFrom):
            df = DefaultFrom(df)
        self.default_from = check_type(df, DefaultFrom, 'default_from',
            allow_none=True
        )
        self.__normalize = kw['normalize']
        self.rules = self.__check_type(tuple, 'rules')
        self.all_rules = (self.type.validate,) + self.rules
        self.primary_key = self.__check_type(bool, 'primary_key')
        lock(self)

    def __clone__(self, **override):
        """
        Return a new `Param` instance similar to this one.
        """
        kw = dict(self.__kw)
        kw.update(override)
        return self.__class__(self.name, **kw)

    def __check_type(self, type_, name, allow_none=False):
        value = self.__kw[name]
        return check_type(value, type_, name, allow_none)

    def __check_isinstance(self, type_, name, allow_none=False):
        value = self.__kw[name]
        return check_isinstance(value, type_, name, allow_none)

    def __dispatch(self, value, scalar):
        """
        Helper method used by `normalize` and `convert`.
        """
        if value in self.__nones:
            return
        if self.multivalue:
            if type(value) in (tuple, list):
                return tuple(
                    scalar(v, i) for (i, v) in enumerate(value)
                )
            return (scalar(value, 0),) # tuple
        return scalar(value)

    def __normalize_scalar(self, value, index=None):
        """
        Normalize a scalar value.

        This method is called once with each value in multivalue.
        """
        if not isinstance(value, basestring):
            return value
        try:
            return self.__normalize(value)
        except StandardError:
            return value

    def normalize(self, value):
        """
        Normalize ``value`` using normalize callback.

        If this `Param` instance does not have a normalize callback,
        ``value`` is returned unchanged.

        If this `Param` instance has a normalize callback and ``value`` is
        a basestring, the normalize callback is called and its return value
        is returned.

        If ``value`` is not a basestring, or if an exception is caught
        when calling the normalize callback, ``value`` is returned unchanged.

        :param value: A proposed value for this parameter.
        """
        if self.__normalize is None:
            return value
        return self.__dispatch(value, self.__normalize_scalar)

    def __convert_scalar(self, value, index=None):
        """
        Convert a scalar value.

        This method is called once with each value in multivalue.
        """
        if value in self.__nones:
            return
        converted = self.type(value)
        if converted is None:
            raise errors.ConversionError(
                self.name, value, self.type, index=index
            )
        return converted

    def convert(self, value):
        """
        Convert/coerce ``value`` to Python type for this `Param`.

        If ``value`` can not be converted, ConversionError is raised, which
        is as subclass of ValidationError.

        If ``value`` is None, conversion is not attempted and None is
        returned.

        :param value: A proposed value for this parameter.
        """
        return self.__dispatch(value, self.__convert_scalar)

    def __validate_scalar(self, value, index=None):
        """
        Validate a scalar value.

        This method is called once with each value in multivalue.
        """
        if type(value) is not self.type.type:
            raise_TypeError(value, self.type.type, 'value')
        for rule in self.rules:
            error = rule(value)
            if error is not None:
                raise errors.RuleError(
                    self.name, value, error, rule, index=index
                )

    def validate(self, value):
        """
        Check validity of a value.

        Each validation rule is called in turn and if any returns and error,
        RuleError is raised, which is a subclass of ValidationError.

        :param value: A proposed value for this parameter.
        """
        if value is None:
            if self.required:
                raise errors.RequirementError(self.name)
            return
        if self.multivalue:
            if type(value) is not tuple:
                raise_TypeError(value, tuple, 'value')
            for (i, v) in enumerate(value):
                self.__validate_scalar(v, i)
        else:
            self.__validate_scalar(value)

    def get_default(self, **kw):
        """
        Return a default value for this parameter.

        If this `Param` instance does not have a default_from() callback, this
        method always returns the static Param.default instance attribute.

        On the other hand, if this `Param` instance has a default_from()
        callback, the callback is called and its return value is returned
        (assuming that value is not None).

        If the default_from() callback returns None, or if an exception is
        caught when calling the default_from() callback, the static
        Param.default instance attribute is returned.

        :param kw: Optional keyword arguments to pass to default_from().
        """
        if self.default_from is not None:
            default = self.default_from(**kw)
            if default is not None:
                try:
                    return self.convert(self.normalize(default))
                except errors.ValidationError:
                    return None
        return self.default

    def get_values(self):
        if self.type.name in ('Enum', 'CallbackEnum'):
            return self.type.values
        return tuple()

    def __call__(self, value, **kw):
        if value in self.__nones:
            value = self.get_default(**kw)
        else:
            value = self.convert(self.normalize(value))
        self.validate(value)
        return value

    def __repr__(self):
        return '%s(%r, %s())' % (
            self.__class__.__name__,
            self.name,
            self.type.name,
        )


def create_param(spec):
    """
    Create a `Param` instance from a param spec.

    If ``spec`` is a `Param` instance, ``spec`` is returned unchanged.

    If ``spec`` is an str instance, then ``spec`` is parsed and an
    appropriate `Param` instance is created and returned.

    See `parse_param_spec` for the definition of the spec syntax.

    :param spec: A spec string or a `Param` instance.
    """
    if type(spec) is Param:
        return spec
    if type(spec) is not str:
        raise TypeError(
            'create_param() takes %r or %r; got %r' % (str, Param, spec)
        )
    return Param(spec)


class Command(plugable.Plugin):
    """
    A public IPA atomic operation.

    All plugins that subclass from `Command` will be automatically available
    as a CLI command and as an XML-RPC method.

    Plugins that subclass from Command are registered in the ``api.Command``
    namespace. For example:

    >>> api = plugable.API(Command)
    >>> class my_command(Command):
    ...     pass
    ...
    >>> api.register(my_command)
    >>> api.finalize()
    >>> list(api.Command)
    ['my_command']
    >>> api.Command.my_command
    PluginProxy(Command, __main__.my_command())
    """

    __public__ = frozenset((
        'get_default',
        'convert',
        'normalize',
        'validate',
        'execute',
        '__call__',
        'args',
        'options',
        'params',
        'args_to_kw',
        'kw_to_args',
    ))
    takes_options = tuple()
    takes_args = tuple()
    args = None
    options = None
    params = None

    def __call__(self, *args, **kw):
        """
        Perform validation and then execute the command.

        If not in a server context, the call will be forwarded over
        XML-RPC and the executed an the nearest IPA server.
        """
        if len(args) > 0:
            arg_kw = self.args_to_kw(*args)
            assert set(arg_kw).intersection(kw) == set()
            kw.update(arg_kw)
        kw = self.normalize(**kw)
        kw = self.convert(**kw)
        kw.update(self.get_default(**kw))
        self.validate(**kw)
        args = tuple(kw.pop(name) for name in self.args)
        return self.run(*args, **kw)

    def args_to_kw(self, *values):
        """
        Map positional into keyword arguments.
        """
        if self.max_args is not None and len(values) > self.max_args:
            if self.max_args == 0:
                raise errors.ArgumentError(self, 'takes no arguments')
            if self.max_args == 1:
                raise errors.ArgumentError(self, 'takes at most 1 argument')
            raise errors.ArgumentError(self,
                'takes at most %d arguments' % len(self.args)
            )
        return dict(self.__args_to_kw_iter(values))

    def __args_to_kw_iter(self, values):
        """
        Generator used by `Command.args_to_kw` method.
        """
        multivalue = False
        for (i, arg) in enumerate(self.args()):
            assert not multivalue
            if len(values) > i:
                if arg.multivalue:
                    multivalue = True
                    yield (arg.name, values[i:])
                else:
                    yield (arg.name, values[i])
            else:
                break

    def kw_to_args(self, **kw):
        """
        Map keyword into positional arguments.
        """
        return tuple(kw.get(name, None) for name in self.args)

    def normalize(self, **kw):
        """
        Return a dictionary of normalized values.

        For example:

        >>> class my_command(Command):
        ...     takes_options = (
        ...         Param('first', normalize=lambda value: value.lower()),
        ...         Param('last'),
        ...     )
        ...
        >>> c = my_command()
        >>> c.finalize()
        >>> c.normalize(first='JOHN', last='DOE')
        {'last': 'DOE', 'first': 'john'}
        """
        return dict(
            (k, self.params[k].normalize(v)) for (k, v) in kw.iteritems()
        )

    def convert(self, **kw):
        """
        Return a dictionary of values converted to correct type.

        >>> from ipalib import ipa_types
        >>> class my_command(Command):
        ...     takes_args = (
        ...         Param('one', type=ipa_types.Int()),
        ...         'two',
        ...     )
        ...
        >>> c = my_command()
        >>> c.finalize()
        >>> c.convert(one=1, two=2)
        {'two': u'2', 'one': 1}
        """
        return dict(
            (k, self.params[k].convert(v)) for (k, v) in kw.iteritems()
        )

    def get_default(self, **kw):
        """
        Return a dictionary of defaults for all missing required values.

        For example:

        >>> class my_command(Command):
        ...     takes_args = [Param('color', default='Red')]
        ...
        >>> c = my_command()
        >>> c.finalize()
        >>> c.get_default()
        {'color': 'Red'}
        >>> c.get_default(color='Yellow')
        {}
        """
        return dict(self.__get_default_iter(kw))

    def __get_default_iter(self, kw):
        """
        Generator method used by `Command.get_default`.
        """
        for param in self.params():
            if param.required and kw.get(param.name, None) is None:
                yield (param.name, param.get_default(**kw))

    def validate(self, **kw):
        """
        Validate all values.

        If any value fails the validation, `ipalib.errors.ValidationError`
        (or a subclass thereof) will be raised.
        """
        for param in self.params():
            value = kw.get(param.name, None)
            if value is not None:
                param.validate(value)
            elif param.required:
                raise errors.RequirementError(param.name)

    def run(self, *args, **kw):
        """
        Dispatch to `Command.execute` or `Command.forward`.

        If running in a server context, `Command.execute` is called and the
        actually work this command performs is executed locally.

        If running in a non-server context, `Command.forward` is called,
        which forwards this call over XML-RPC to the exact same command
        on the nearest IPA server and the actual work this command
        performs is executed remotely.
        """
        if self.api.env.server_context:
            target = self.execute
        else:
            target = self.forward
        object.__setattr__(self, 'run', target)
        return target(*args, **kw)

    def execute(self, *args, **kw):
        """
        Perform the actual work this command does.

        This method should be implemented only against functionality
        in self.api.Backend.  For example, a hypothetical
        user_add.execute() might be implemented like this:

        >>> class user_add(Command):
        ...     def execute(self, **kw):
        ...         return self.api.Backend.ldap.add(**kw)
        ...
        """
        raise NotImplementedError('%s.execute()' % self.name)

    def forward(self, *args, **kw):
        """
        Forward call over XML-RPC to this same command on server.
        """
        return self.api.Backend.xmlrpc.forward_call(self.name, *args, **kw)

    def finalize(self):
        """
        Finalize plugin initialization.

        This method creates the ``args``, ``options``, and ``params``
        namespaces.  This is not done in `Command.__init__` because
        subclasses (like `crud.Add`) might need to access other plugins
        loaded in self.api to determine what their custom `Command.get_args`
        and `Command.get_options` methods should yield.
        """
        self.args = plugable.NameSpace(self.__create_args(), sort=False)
        if len(self.args) == 0 or not self.args[-1].multivalue:
            self.max_args = len(self.args)
        else:
            self.max_args = None
        self.options = plugable.NameSpace(
            (create_param(spec) for spec in self.get_options()),
            sort=False
        )
        self.params = plugable.NameSpace(
            tuple(self.args()) + tuple(self.options()), sort=False
        )
        super(Command, self).finalize()

    def get_args(self):
        """
        Return iterable with arguments for Command.args namespace.

        Subclasses can override this to customize how the arguments
        are determined.  For an example of why this can be useful,
        see `ipalib.crud.Mod`.
        """
        return self.takes_args

    def get_options(self):
        """
        Return iterable with options for Command.options namespace.

        Subclasses can override this to customize how the options
        are determined.  For an example of why this can be useful,
        see `ipalib.crud.Mod`.
        """
        return self.takes_options

    def __create_args(self):
        """
        Generator used to create args namespace.
        """
        optional = False
        multivalue = False
        for arg in self.get_args():
            arg = create_param(arg)
            if optional and arg.required:
                raise ValueError(
                    '%s: required argument after optional' % arg.name
                )
            if multivalue:
                raise ValueError(
                    '%s: only final argument can be multivalue' % arg.name
                )
            if not arg.required:
                optional = True
            if arg.multivalue:
                multivalue = True
            yield arg


class Object(plugable.Plugin):
    __public__ = frozenset((
        'backend',
        'methods',
        'properties',
        'params',
        'primary_key',
        'params_minus_pk',
    ))
    backend = None
    methods = None
    properties = None
    params = None
    primary_key = None
    params_minus_pk = None

    # Can override in subclasses:
    backend_name = None
    takes_params = tuple()

    def set_api(self, api):
        super(Object, self).set_api(api)
        self.methods = plugable.NameSpace(
            self.__get_attrs('Method'), sort=False
        )
        self.properties = plugable.NameSpace(
            self.__get_attrs('Property'), sort=False
        )
        self.params = plugable.NameSpace(
            self.__get_params(), sort=False
        )
        pkeys = filter(lambda p: p.primary_key, self.params())
        if len(pkeys) > 1:
            raise ValueError(
                '%s (Object) has multiple primary keys: %s' % (
                    self.name,
                    ', '.join(p.name for p in pkeys),
                )
            )
        if len(pkeys) == 1:
            self.primary_key = pkeys[0]
            self.params_minus_pk = plugable.NameSpace(
                filter(lambda p: not p.primary_key, self.params()), sort=False
            )

        if 'Backend' in self.api and self.backend_name in self.api.Backend:
            self.backend = self.api.Backend[self.backend_name]

    def __get_attrs(self, name):
        if name not in self.api:
            return
        namespace = self.api[name]
        assert type(namespace) is plugable.NameSpace
        for proxy in namespace(): # Equivalent to dict.itervalues()
            if proxy.obj_name == self.name:
                yield proxy.__clone__('attr_name')

    def __get_params(self):
        props = self.properties.__todict__()


context:
space:
mode: