tiramisu/config.py

# -*- coding: utf-8 -*-
"pretty small and local configuration management tool"
# Copyright (C) 2012 Team tiramisu (see README 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 gus of pypy: pypy: http://codespeak.net/svn/pypy/dist/pypy/config/
# the whole pypy projet is under MIT licence
# ____________________________________________________________
from error import (HiddenOptionError, ConfigError, NotFoundError, 
                AmbigousOptionError, ConflictConfigError, NoMatchingOptionFound, 
                            SpecialOwnersError, MandatoryError, MethodCallError, 
                                           DisabledOptionError, ModeOptionError)
from option import (OptionDescription, Option, SymLinkOption, group_types, 
                                                          apply_requires, modes)
import autolib
from autolib import special_owners, special_owner_factory
# ____________________________________________________________
class Config(object):
    _cfgimpl_hidden = True
    _cfgimpl_disabled = True
    _cfgimpl_mandatory = True
    _cfgimpl_frozen = False
    _cfgimpl_owner = "user"
    _cfgimpl_toplevel = None
    _cfgimpl_mode = 'normal'
    
    def __init__(self, descr, parent=None, **overrides):
        self._cfgimpl_descr = descr
        self._cfgimpl_value_owners = {}
        self._cfgimpl_parent = parent
        # `Config()` indeed supports the configuration `Option()`'s values...
        self._cfgimpl_values = {}
        self._cfgimpl_previous_values = {}
        # XXX 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(overrides)

    def _validate_duplicates(self, children):
        duplicates = []
        for dup in children:
            if dup._name not in duplicates:
                duplicates.append(dup._name)
            else:
                raise ConflictConfigError('duplicate option name: <%s>' % \
                                                                      dup._name)

    def _cfgimpl_build(self, overrides):
        self._validate_duplicates(self._cfgimpl_descr._children)
        for child in self._cfgimpl_descr._children:
            if isinstance(child, Option):
                self._cfgimpl_values[child._name] = child.getdefault()
                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_update(self):
        "dynamically adds `Option()` or `OptionDescription()`"
        # Nothing is static. Everything evolve.
        # 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:
                    self._cfgimpl_values[child._name] = 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 override(self, overrides):
        for name, value in overrides.iteritems():
            homeconfig, name = self._cfgimpl_get_home_by_path(name)
            #  if there are special_owners, impossible to override
            if homeconfig._cfgimpl_value_owners[name] in special_owners:
                raise SpecialOwnersError("cannot override option: {0} because "
                                            "of its special owner".format(name))
            homeconfig.setoption(name, value, 'default')

    def cfgimpl_set_owner(self, owner):
        self._cfgimpl_owner = owner
        for child in self._cfgimpl_descr._children:
            if isinstance(child, OptionDescription):
                self._cfgimpl_values[child._name].cfgimpl_set_owner(owner)
    # ____________________________________________________________
    def cfgimpl_hide(self):
        if self._cfgimpl_parent != None:
            raise MethodCallError("this method root_hide() shall not be"
                                           "used with non-root Config() object") 
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_hidden = True

    def cfgimpl_show(self):
        if self._cfgimpl_parent != None:
            raise MethodCallError("this method root_hide() shall not be"
                                           "used with non-root Config() object") 
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_hidden = False
    # ____________________________________________________________
    def cfgimpl_disable(self):
        if self._cfgimpl_parent != None:
            raise MethodCallError("this method root_hide() shall not be"
                                           "used with non-root Confit() object") 
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_disabled = True

    def cfgimpl_enable(self):
        if self._cfgimpl_parent != None:
            raise MethodCallError("this method root_hide() shall not be"
                                           "used with non-root Confit() object") 
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_disabled = False
    # ____________________________________________________________
    def __setattr__(self, name, value):
        if '.' in name:
            homeconfig, name = self._cfgimpl_get_home_by_path(name)
            return setattr(homeconfig, name, value)

        if name.startswith('_cfgimpl_'):
            self.__dict__[name] = value
            return
        if self._cfgimpl_frozen and getattr(self, name) != value:
            raise TypeError("trying to change a value in a frozen config"
                                                ": {0} {1}".format(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):
        if not type(opt_or_descr) == OptionDescription:
            apply_requires(opt_or_descr, self) 
            # hidden options
            if self._cfgimpl_toplevel._cfgimpl_hidden and \
                (opt_or_descr._is_hidden() or self._cfgimpl_descr._is_hidden()):
                raise HiddenOptionError("trying to access to a hidden option:"
                                                           " {0}".format(name))
            # disabled options
            if self._cfgimpl_toplevel._cfgimpl_disabled and \
            (opt_or_descr._is_disabled() or self._cfgimpl_descr._is_disabled()):
                raise DisabledOptionError("this option is disabled:"
                                                            " {0}".format(name))
            # expert options 
            # XXX currently doesn't look at the group, is it really necessary ?
            if self._cfgimpl_toplevel._cfgimpl_mode != 'normal':
                if opt_or_descr.get_mode() != 'normal':
                    raise ModeOptionError("this option's mode is not normal:"
                                                            " {0}".format(name))
        if type(opt_or_descr) == OptionDescription:
            apply_requires(opt_or_descr, self) 

    def __getattr__(self, name):
        # 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 getattr(homeconfig, name)
        opt_or_descr = getattr(self._cfgimpl_descr, name)
        # symlink options 
        if type(opt_or_descr) == SymLinkOption:
            return getattr(self, opt_or_descr.path)
        self._validate(name, opt_or_descr)
        # 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 name not in self._cfgimpl_values:
            raise AttributeError("%s object has no attribute %s" %
                                 (self.__class__, name))
        if name in self._cfgimpl_value_owners:
            owner = self._cfgimpl_value_owners[name]
            # special owners
            if owner in special_owners:
                return special_owner_factory(name, owner, 
                                              default=opt_or_descr.getdefault(),
                                            callback=opt_or_descr.getcallback(),
                                            config=self)
        # mandatory options
        if not isinstance(opt_or_descr, OptionDescription):
            homeconfig = self._cfgimpl_get_toplevel()
            mandatory = homeconfig._cfgimpl_mandatory
            if opt_or_descr.is_mandatory() and mandatory:
                if self._cfgimpl_values[name] == None\
                  and opt_or_descr.getdefault() == None:
                    raise MandatoryError("option: {0} is mandatory " 
                                          "and shall have a value".format(name))
        return self._cfgimpl_values[name]

    def __dir__(self):
        #from_type = dir(type(self))
        from_dict = list(self.__dict__)
        extras = list(self._cfgimpl_values)
        return sorted(set(extras + from_dict))

    def unwrap_from_name(self, name):
        # didn't have to stoop so low: `self.get()` must be the proper method
        # **and it is slow**: it recursively searches into the namespaces
        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):
        # didn't have to stoop so low, `geattr(self, path)` is much better
        # **fast**: finds the option directly in the appropriate namespace
        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):
        if who == None:
            who == self._cfgimpl_owner
        child = getattr(self._cfgimpl_descr, name)
        if type(child) != SymLinkOption:
            if name not in self._cfgimpl_values:
                raise AttributeError('unknown option %s' % (name,))
            # special owners, a value with a owner *auto* cannot be changed
            oldowner = self._cfgimpl_value_owners[child._name]
            if oldowner == 'auto':
                if who == 'auto':
                    raise ConflictConfigError('cannot override value to %s for '
                                          'option %s' % (value, name))
            if oldowner == who:
                oldvalue = getattr(self, name)
                if oldvalue == value: #or who in ("default",):
                    return
            child.setoption(self, value, who)
            # if the value owner is 'auto', set the option to hidden 
            if who == 'auto':
                if not child._is_hidden():
                    child.hide()
            self._cfgimpl_value_owners[name] = who
        else:
            homeconfig = self._cfgimpl_get_toplevel()
            child.setoption(homeconfig, value, who)

    def set(self, **kwargs):
        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):
        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):
        while self._cfgimpl_parent is not None:
            self = self._cfgimpl_parent
        return self

    def add_warning(self, warning):
        self._cfgimpl_get_toplevel()._cfgimpl_warnings.append(warning)

    def get_warnings(self):
        return self._cfgimpl_get_toplevel()._cfgimpl_warnings
    # ____________________________________________________________
    # freeze and read-write statuses
    def cfgimpl_freeze(self):
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_frozen = True
        self._cfgimpl_frozen = True

    def cfgimpl_unfreeze(self):
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_frozen = False
        self._cfgimpl_frozen = False

    def is_frozen(self):
        # it should be the same value as self._cfgimpl_frozen...
        rootconfig = self._cfgimpl_get_toplevel()
        return rootconfig.__dict__['_cfgimpl_frozen']

    def cfgimpl_read_only(self):
        # hung up on freeze, hidden and disabled concepts 
        self.cfgimpl_freeze()
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_hidden = False
        rootconfig._cfgimpl_disabled = True
        rootconfig._cfgimpl_mandatory = True

    def cfgimpl_set_mode(self, mode):
        # normal or expert mode
        rootconfig = self._cfgimpl_get_toplevel()
        if mode not in modes:
            raise ConfigError("mode {0} not available".format(mode))
        rootconfig._cfgimpl_mode = mode
    
    def cfgimpl_read_write(self):
        # hung up on freeze, hidden and disabled concepts
        self.cfgimpl_unfreeze()
        rootconfig = self._cfgimpl_get_toplevel()
        rootconfig._cfgimpl_hidden = True
        rootconfig._cfgimpl_disabled = False
        rootconfig._cfgimpl_mandatory = False
    # ____________________________________________________________
    def getkey(self):
        return self._cfgimpl_descr.getkey(self)

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

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

    def __ne__(self, other):
        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 # hidden, disabled option group

    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=""):
        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):
        """returns a list of all paths in self, recursively, taking care of 
        the context (hidden/disabled)
        """
        paths = []
        for path in self._cfgimpl_descr.getpaths(include_groups=include_groups):
            try: 
                value = getattr(self, path)
            except Exception, e:
                if not allpaths:
                    pass # hidden or disabled option
                else:
                    paths.append(path) # hidden or disabled option added
            else:
                paths.append(path)
        return paths 
        
def make_dict(config, flatten=False):
    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
# ____________________________________________________________