tiramisu/tiramisu/config.py

# -*- coding: utf-8 -*-
"pretty small and local configuration management tool"
# Copyright (C) 2012 Team tiramisu (see AUTHORS for all contributors)
#
# 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# The original `Config` design model is unproudly borrowed from
# the rough pypy's guys: http://codespeak.net/svn/pypy/dist/pypy/config/
# the whole pypy projet is under MIT licence
# ____________________________________________________________
from copy import copy
from tiramisu.error import (PropertiesOptionError, ConfigError, NotFoundError,
    AmbigousOptionError, ConflictConfigError, NoMatchingOptionFound,
    MandatoryError, MethodCallError, NoValueReturned)
from tiramisu.option import (OptionDescription, Option, SymLinkOption,
    group_types, Multi, apply_requires)

# ______________________________________________________________________
# generic owner. 'default' is the general config owner after init time
default_owner = 'user'

# ____________________________________________________________
class Config(object):
    "main configuration management entry"
    #properties attribute: the name of a property enables this property
    _cfgimpl_properties = ['hidden', 'disabled']
    _cfgimpl_permissive = []
    #mandatory means: a mandatory option has to have a value that is not None
    _cfgimpl_mandatory = True
    _cfgimpl_frozen = True
    #enables validation function for options if set
    _cfgimpl_validator = False
    _cfgimpl_owner = default_owner
    _cfgimpl_toplevel = None

    def __init__(self, descr, parent=None):
        """ Configuration option management master class
        :param descr: describes the configuration schema
        :type descr: an instance of ``option.OptionDescription``
        :param parent: is None if the ``Config`` is root parent Config otherwise
        :type parent: ``Config``
        """
        self._cfgimpl_descr = descr
        self._cfgimpl_value_owners = {}
        self._cfgimpl_parent = parent
        "`Config()` indeed is in charge of the `Option()`'s values"
        self._cfgimpl_values = {}
        self._cfgimpl_previous_values = {}
        "warnings are a great idea, let's make up a better use of it"
        self._cfgimpl_warnings = []
        self._cfgimpl_toplevel = self._cfgimpl_get_toplevel()
        '`freeze()` allows us to carry out this calculation again if necessary'
        self._cfgimpl_frozen = self._cfgimpl_toplevel._cfgimpl_frozen
        self._cfgimpl_build()

    def _validate_duplicates(self, children):
        """duplicates Option names in the schema
        :type children: list of `Option` or `OptionDescription`
        """
        duplicates = []
        for dup in children:
            if dup._name not in duplicates:
                duplicates.append(dup._name)
            else:
                raise ConflictConfigError('duplicate option name: '
                    '{0}'.format(dup._name))

    def _cfgimpl_build(self):
        """
        - builds the config object from the schema
        - settles various default values for options
        """
        self._validate_duplicates(self._cfgimpl_descr._children)
        for child in self._cfgimpl_descr._children:
            if isinstance(child, Option):
                if child.is_multi():
                    childdef = Multi(copy(child.getdefault()), config=self,
                                     child=child)
                    self._cfgimpl_values[child._name] = childdef
                    self._cfgimpl_previous_values[child._name] = list(childdef)
                else:
                    childdef = child.getdefault()
                    self._cfgimpl_values[child._name] = childdef
                    self._cfgimpl_previous_values[child._name] = childdef
                self._cfgimpl_value_owners[child._name] = 'default'
            elif isinstance(child, OptionDescription):
                self._validate_duplicates(child._children)
                self._cfgimpl_values[child._name] = Config(child, parent=self)
#        self.override(overrides)

    def cfgimpl_set_permissive(self, permissive):
        if not isinstance(permissive, list):
            raise TypeError('permissive must be a list')
        self._cfgimpl_permissive = permissive

    def cfgimpl_update(self):
        """dynamically adds `Option()` or `OptionDescription()`
        """
        # FIXME this is an update for new options in the schema only
        # see the update_child() method of the descr object
        for child in self._cfgimpl_descr._children:
            if isinstance(child, Option):
                if child._name not in self._cfgimpl_values:
                    if child.is_multi():
                        self._cfgimpl_values[child._name] = Multi(
                                copy(child.getdefault()), config=self, child=child)
                    else:
                        self._cfgimpl_values[child._name] = copy(child.getdefault())
                    self._cfgimpl_value_owners[child._name] = 'default'
            elif isinstance(child, OptionDescription):
                if child._name not in self._cfgimpl_values:
                    self._cfgimpl_values[child._name] = Config(child, parent=self)

    def cfgimpl_set_owner(self, owner):
        ":param owner: sets the default value for owner at the Config level"
        self._cfgimpl_owner = owner
        for child in self._cfgimpl_descr._children:
            if isinstance(child, OptionDescription):
                self._cfgimpl_values[child._name].cfgimpl_set_owner(owner)
    # ____________________________________________________________
    # properties methods
    def _cfgimpl_has_properties(self):
        "has properties means the Config's properties attribute is not empty"
        return bool(len(self._cfgimpl_properties))

    def _cfgimpl_has_property(self, propname):
        """has property propname in the Config's properties attribute
        :param property: string wich is the name of the property"""
        return propname in self._cfgimpl_properties

    def cfgimpl_enable_property(self, propname):
        "puts property propname in the Config's properties attribute"
        if self._cfgimpl_parent != None:
            raise MethodCallError("this method root_hide() shall not be"
                                  "used with non-root Config() object")
        if propname not in self._cfgimpl_properties:
            self._cfgimpl_properties.append(propname)

    def cfgimpl_disable_property(self, propname):
        "deletes property propname in the Config's properties attribute"
        if self._cfgimpl_parent != None:
            raise MethodCallError("this method root_hide() shall not be"
                                  "used with non-root Config() object")
        if self._cfgimpl_has_property(propname):
            self._cfgimpl_properties.remove(propname)
    # ____________________________________________________________
    # attribute methods
    def __setattr__(self, name, value):
        "attribute notation mechanism for the setting of the value of an option"
        if name.startswith('_cfgimpl_'):
            self.__dict__[name] = value
            return
        if '.' in name:
            homeconfig, name = self._cfgimpl_get_home_by_path(name)
            return setattr(homeconfig, name, value)
        if type(getattr(self._cfgimpl_descr, name)) != SymLinkOption:
            self._validate(name, getattr(self._cfgimpl_descr, name))
        self.setoption(name, value, self._cfgimpl_owner)

    def _validate(self, name, opt_or_descr, permissive=False):
        "validation for the setattr and the getattr"
        apply_requires(opt_or_descr, self)
        if not isinstance(opt_or_descr, Option) and \
                not isinstance(opt_or_descr, OptionDescription):
            raise TypeError('Unexpected object: {0}'.format(repr(opt_or_descr)))
        properties = copy(opt_or_descr.properties)
        for proper in copy(properties):
            if not self._cfgimpl_toplevel._cfgimpl_has_property(proper):
                properties.remove(proper)
        if permissive:
            for perm in self._cfgimpl_toplevel._cfgimpl_permissive:
                if perm in properties:
                    properties.remove(perm)
        if properties != []:
            raise PropertiesOptionError("trying to access"
                    " to an option named: {0} with properties"
                    " {1}".format(name, str(properties)),
                    properties)

    def _is_empty(self, opt):
        "convenience method to know if an option is empty"
        if (not opt.is_multi() and self._cfgimpl_values[opt._name] == None) or \
            (opt.is_multi() and (self._cfgimpl_values[opt._name] == [] or \
                None in self._cfgimpl_values[opt._name])):
            return True
        return False

    def _test_mandatory(self, path, opt):
        # mandatory options
        homeconfig = self._cfgimpl_get_toplevel()
        mandatory = homeconfig._cfgimpl_mandatory
        if opt.is_mandatory() and mandatory:
            if self._is_empty(opt) and \
                    opt.is_empty_by_default():
                raise MandatoryError("option: {0} is mandatory "
                                      "and shall have a value".format(path))

    def __getattr__(self, name):
        return self._getattr(name)

    def _getattr(self, name, permissive=False):
        """
        attribute notation mechanism for accessing the value of an option
        :param name: attribute name
        :param permissive: permissive doesn't raise some property error
        (see ``_cfgimpl_permissive``)
        :return: option's value if name is an option name, OptionDescription
        otherwise
        """
        # attribute access by passing a path,
        # for instance getattr(self, "creole.general.family.adresse_ip_eth0")
        if '.' in name:
            homeconfig, name = self._cfgimpl_get_home_by_path(name)
            return homeconfig._getattr(name, permissive)
        opt_or_descr = getattr(self._cfgimpl_descr, name)
        # symlink options
        if type(opt_or_descr) == SymLinkOption:
            return getattr(self, opt_or_descr.path)
        if name not in self._cfgimpl_values:
            raise AttributeError("%s object has no attribute %s" %
                                 (self.__class__, name))
        self._validate(name, opt_or_descr, permissive)
        # special attributes
        if name.startswith('_cfgimpl_'):
            # if it were in __dict__ it would have been found already
            return self.__dict__[name]
            raise AttributeError("%s object has no attribute %s" %
                                 (self.__class__, name))
        if not isinstance(opt_or_descr, OptionDescription):
            # options with callbacks (fill or auto)
            if opt_or_descr.has_callback():
                value = self._cfgimpl_values[name]
                if (not opt_or_descr.is_frozen() or \
                        not opt_or_descr.is_forced_on_freeze()) and \
                        not opt_or_descr.is_default_owner(self):
                    if opt_or_descr.is_multi():
                        if None not in value:
                            return value
                    else:
                        return value
                rootconfig = self._cfgimpl_get_toplevel()
                try:
                    result = opt_or_descr.getcallback_value(rootconfig)
                except NoValueReturned, err:
                    pass
                else:
                    if opt_or_descr.is_multi():
                        if not isinstance(result, list):
                            result = [result]
                        _result = Multi(result, value.config, value.child)
                    else:
                        # this result **shall not** be a list
                        if isinstance(result, list):
                            raise ConfigError('invalid calculated value returned'
                                ' for option {0} : shall not be a list'.format(name))
                        _result = result
                    if _result != None and not opt_or_descr.validate(_result,
                                rootconfig._cfgimpl_validator):
                        raise ConfigError('invalid calculated value returned'
                            ' for option {0}'.format(name))
                    self._cfgimpl_values[name] = _result
                    self._cfgimpl_value_owners[name] = 'default'
            self._test_mandatory(name, opt_or_descr)
            # frozen and force default
            if not opt_or_descr.has_callback() and opt_or_descr.is_forced_on_freeze():
                return opt_or_descr.getdefault()

        return self._cfgimpl_values[name]

    def unwrap_from_name(self, name):
        """convenience method to extract and Option() object from the Config()
        **and it is slow**: it recursively searches into the namespaces

        :returns: Option()
        """
        paths = self.getpaths(allpaths=True)
        opts = dict([(path, self.unwrap_from_path(path)) for path in paths])
        all_paths = [p.split(".") for p in self.getpaths()]
        for pth in all_paths:
            if name in pth:
                return opts[".".join(pth)]
        raise NotFoundError("name: {0} not found".format(name))

    def unwrap_from_path(self, path):
        """convenience method to extract and Option() object from the Config()
        and it is **fast**: finds the option directly in the appropriate
        namespace

        :returns: Option()
        """
        if '.' in path:
            homeconfig, path = self._cfgimpl_get_home_by_path(path)
            return getattr(homeconfig._cfgimpl_descr, path)
        return getattr(self._cfgimpl_descr, path)

    #def __delattr__(self, name):
    #    "if you use delattr you are responsible for all bad things happening"
    #    if name.startswith('_cfgimpl_'):
    #        del self.__dict__[name]
    #        return
    #    self._cfgimpl_value_owners[name] = 'default'
    #    opt = getattr(self._cfgimpl_descr, name)
    #    if isinstance(opt, OptionDescription):
    #        raise AttributeError("can't option subgroup")
    #    self._cfgimpl_values[name] = getattr(opt, 'default', None)

    def setoption(self, name, value, who=None):
        """effectively modifies the value of an Option()
        (typically called by the __setattr__)

        :param who: is an owner's name
        who is **not necessarily** a owner, because it cannot be a list
        :type who: string
        """
        child = getattr(self._cfgimpl_descr, name)
        if type(child) != SymLinkOption:
            if who == None:
                who = self._cfgimpl_owner
            if child.is_multi():
                if type(value) != Multi:
                    if type(value) == list:
                        value = Multi(value, self, child)
                    else:
                        raise ConfigError("invalid value for option:"
                                   " {0} that is set to multi".format(name))
            child.setoption(self, value, who)
            child.setowner(self, who)
        else:
            homeconfig = self._cfgimpl_get_toplevel()
            child.setoption(homeconfig, value, who)

    def set(self, **kwargs):
        """
        "do what I mean"-interface to option setting. Searches all paths
        starting from that config for matches of the optional arguments
        and sets the found option if the match is not ambiguous.
        :param kwargs: dict of name strings to values.
        """
        all_paths = [p.split(".") for p in self.getpaths(allpaths=True)]
        for key, value in kwargs.iteritems():
            key_p = key.split('.')
            candidates = [p for p in all_paths if p[-len(key_p):] == key_p]
            if len(candidates) == 1:
                name = '.'.join(candidates[0])
                homeconfig, name = self._cfgimpl_get_home_by_path(name)
                try:
                    getattr(homeconfig, name)
                except MandatoryError:
                    pass
                except Exception, e:
                    raise e # HiddenOptionError or DisabledOptionError
                homeconfig.setoption(name, value, self._cfgimpl_owner)
            elif len(candidates) > 1:
                raise AmbigousOptionError(
                    'more than one option that ends with %s' % (key, ))
            else:
                raise NoMatchingOptionFound(
                    'there is no option that matches %s'
                    ' or the option is hidden or disabled'% (key, ))

    def get(self, name):
        """
        same as a find_first() method in a config that has identical names
        that is : Returns the first item of an option named 'name'

        much like the attribute access way, except that
        the search for the option is performed recursively in the whole
        configuration tree.
        **carefull**: very slow !

        :returns: option value.
        """
        paths = self.getpaths(allpaths=True)
        pathsvalues = []
        for path in paths:
            pathname = path.split('.')[-1]
            if pathname == name:
                try:
                    value = getattr(self, path)
                    return value
                except Exception, e:
                    raise e
        raise NotFoundError("option {0} not found in config".format(name))

    def _cfgimpl_get_home_by_path(self, path):
        """:returns: tuple (config, name)"""
        path = path.split('.')
        for step in path[:-1]:
            self = getattr(self, step)
        return self, path[-1]

    def _cfgimpl_get_toplevel(self):
        ":returns: root config"
        while self._cfgimpl_parent is not None:
            self = self._cfgimpl_parent
        return self

    def _cfgimpl_get_path(self):
        "the path in the attribute access meaning."
        subpath = []
        obj = self
        while obj._cfgimpl_parent is not None:
            subpath.insert(0, obj._cfgimpl_descr._name)
            obj = obj._cfgimpl_parent
        return ".".join(subpath)
    # ______________________________________________________________________
    def cfgimpl_previous_value(self, path):
        "stores the previous value"
        home, name = self._cfgimpl_get_home_by_path(path)
        return home._cfgimpl_previous_values[name]

    def get_previous_value(self, name):
        "for the time being, only the previous Option's value is accessible"
        return self._cfgimpl_previous_values[name]
    # ______________________________________________________________________
    def add_warning(self, warning):
        "Config implements its own warning pile. Could be useful"
        self._cfgimpl_get_toplevel()._cfgimpl_warnings.append(warning)

    def get_warnings(self):
        "Config implements its own warning pile"
        return self._cfgimpl_get_toplevel()._cfgimpl_warnings
    # ____________________________________________________________
    # Config()'s status
    def cfgimpl_freeze(self):
        "cannot modify the frozen `Option`'s"
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_frozen = True
        self._cfgimpl_frozen = True

    def cfgimpl_unfreeze(self):
        "can modify the Options that are frozen"
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_frozen = False
        self._cfgimpl_frozen = False

    def is_frozen(self):
        "freeze flag at Config level"
        rootconfig = self._cfgimpl_get_toplevel()
        return rootconfig._cfgimpl_frozen

    def cfgimpl_read_only(self):
        "convenience method to freeze, hidde and disable"
        self.cfgimpl_freeze()
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig.cfgimpl_disable_property('hidden')
        rootconfig.cfgimpl_enable_property('disabled')
        rootconfig._cfgimpl_mandatory = True
        rootconfig._cfgimpl_validator = True

    def cfgimpl_read_write(self):
        "convenience method to freeze, hidde and disable"
        self.cfgimpl_freeze()
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig.cfgimpl_enable_property('hidden')
        rootconfig.cfgimpl_enable_property('disabled')
        rootconfig._cfgimpl_mandatory = False

    def cfgimpl_non_mandatory(self):
        """mandatory at the Config level means that the Config raises an error
        if a mandatory option is found"""
        if self._cfgimpl_parent != None:
            raise MethodCallError("this method root_mandatory shall"
                                  " not be used with non-root Confit() object")
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_mandatory = False

    def cfgimpl_mandatory(self):
        """mandatory at the Config level means that the Config raises an error
        if a mandatory option is found"""
        if self._cfgimpl_parent != None:
            raise MethodCallError("this method root_mandatory shall"
                                  " not be used with non-root Confit() object")
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_mandatory = True

    def is_mandatory(self):
        "all mandatory Options shall have a value"
        rootconfig = self._cfgimpl_get_toplevel()
        return rootconfig._cfgimpl_mandatory
    # ____________________________________________________________
    def getkey(self):
        return self._cfgimpl_descr.getkey(self)

    def __hash__(self):
        return hash(self.getkey())

    def __eq__(self, other):
        "Config comparison"
        return self.getkey() == other.getkey()

    def __ne__(self, other):
        "Config comparison"
        return not self == other
    # ______________________________________________________________________
    def __iter__(self):
        "iteration only on Options (not OptionDescriptions)"
        for child in self._cfgimpl_descr._children:
            if isinstance(child, Option):
                try:
                    yield child._name, getattr(self, child._name)
                except:
                    pass # option with properties

    def iter_groups(self, group_type=None):
        "iteration on OptionDescriptions"
        if group_type == None:
            groups = group_types
        else:
            if group_type not in group_types:
                raise TypeError("Unknown group_type: {0}".format(group_type))
            groups = [group_type]
        for child in self._cfgimpl_descr._children:
            if isinstance(child, OptionDescription):
                try:
                    if child.get_group_type() in groups:
                        yield child._name, getattr(self, child._name)
                except:
                    pass # hidden, disabled option
    # ______________________________________________________________________
    def __str__(self, indent=""):
        "Config's string representation"
        lines = []
        children = [(child._name, child)
                    for child in self._cfgimpl_descr._children]
        children.sort()
        for name, child in children:
            if self._cfgimpl_value_owners.get(name, None) == 'default':
                continue
            value = getattr(self, name)
            if isinstance(value, Config):
                substr = value.__str__(indent + "    ")
            else:
                substr = "%s    %s = %s" % (indent, name, value)
            if substr:
                lines.append(substr)
        if indent and not lines:
            return ''   # hide subgroups with all default values
        lines.insert(0, "%s[%s]" % (indent, self._cfgimpl_descr._name,))
        return '\n'.join(lines)

    def getpaths(self, include_groups=False, allpaths=False, mandatory=False):
        """returns a list of all paths in self, recursively, taking care of
        the context of properties (hidden/disabled)

        :param include_groups: if true, OptionDescription are included
        :param allpaths: all the options (event the properties protected ones)
        :param mandatory: includes the mandatory options
        :returns: list of all paths
        """
        paths = []
        for path in self._cfgimpl_descr.getpaths(include_groups=include_groups):
            try:
                value = getattr(self, path)

            except MandatoryError:
                if mandatory or allpaths:
                    paths.append(path)
            except PropertiesOptionError:
                if allpaths:
                    paths.append(path) # option which have properties added
            else:
                 paths.append(path)
        return paths

    def _find(self, bytype, byname, byvalue, byattrs, first):
        """
            :param first: return only one option if True, a list otherwise
        """
        def _filter_by_attrs():
            if byattrs is None:
                return True
            for key, value in byattrs.items():
                if not hasattr(option, key):
                    return False
                else:
                    if getattr(option, key) != value:
                        return False
                    else:
                        continue
            return True
        def _filter_by_name():
            if byname is None:
                return True
            pathname = path.split('.')[-1]
            if pathname == byname:
                return True
            else:
                return False
        def _filter_by_value():
            if byvalue is None:
                return True
            try:
                value = getattr(self, path)
                if value == byvalue:
                    return True
            except Exception, e: # a property restricts the acces to value
                pass
            return False
        def _filter_by_type():
            if bytype is None:
                return True
            if isinstance(option, bytype):
                return True
            return False

        find_results = []
        paths = self.getpaths(allpaths=True)
        for path in paths:
            option = self.unwrap_from_path(path)
            if not _filter_by_name():
                continue
            if not _filter_by_value():
                continue
            if not _filter_by_type():
                continue
            if not _filter_by_attrs():
                continue
            if first:
                return option
            else:
                find_results.append(option)
        if first:
            return None
        else:
            return find_results

    def find(self, bytype=None, byname=None, byvalue=None, byattrs=None):
        """
            finds a list of options recursively in the config

            :param bytype: Option class (BoolOption, StrOption, ...)
            :param byname: filter by Option._name
            :param byvalue: filter by the option's value
            :param byattrs: dict of option attributes (default, callback...)
            :returns: list of matching Option objects
        """
        return self._find(bytype, byname, byvalue, byattrs, first=False)

    def find_first(self, bytype=None, byname=None, byvalue=None, byattrs=None):
        """
            finds an option recursively in the config

            :param bytype: Option class (BoolOption, StrOption, ...)
            :param byname: filter by Option._name
            :param byvalue: filter by the option's value
            :param byattrs: dict of option attributes (default, callback...)
            :returns: list of matching Option objects
        """
        return self._find(bytype, byname, byvalue, byattrs, first=True)

def make_dict(config, flatten=False):
    """export the whole config into a `dict`
    :returns: dict of Option's name (or path) and values"""
    paths = config.getpaths()
    pathsvalues = []
    for path in paths:
        if flatten:
            pathname = path.split('.')[-1]
        else:
            pathname = path
        try:
            value = getattr(config, path)
            pathsvalues.append((pathname, value))
        except:
            pass # this just a hidden or disabled option
    options = dict(pathsvalues)
    return options

def mandatory_warnings(config):
    """convenience function to trace Options that are mandatory and
    where no value has been set

    :returns: generator of mandatory Option's path
    """
    mandatory = config._cfgimpl_get_toplevel()._cfgimpl_mandatory
    config._cfgimpl_get_toplevel()._cfgimpl_mandatory = True
    for path in config._cfgimpl_descr.getpaths(include_groups=True):
        try:
            value = config._getattr(path, permissive=True)
        except MandatoryError:
            yield path
        except PropertiesOptionError:
            pass
    config._cfgimpl_get_toplevel()._cfgimpl_mandatory = mandatory