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Diffstat (limited to 'src/leap/common/config/baseconfig.py')
| -rw-r--r-- | src/leap/common/config/baseconfig.py | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/src/leap/common/config/baseconfig.py b/src/leap/common/config/baseconfig.py new file mode 100644 index 0000000..edb9b24 --- /dev/null +++ b/src/leap/common/config/baseconfig.py @@ -0,0 +1,186 @@ +# -*- coding: utf-8 -*- +# baseconfig.py +# Copyright (C) 2013 LEAP +# +# 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 3 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, see <http://www.gnu.org/licenses/>. + +""" +Implements the abstract base class for configuration +""" + +import copy +import logging +import functools +import os + +from abc import ABCMeta, abstractmethod + +from leap.common.check import leap_assert +from leap.common.files import mkdir_p +from leap.common.config.pluggableconfig import PluggableConfig +from leap.common.config.prefixers import get_platform_prefixer + +logger = logging.getLogger(__name__) + + +class BaseConfig: + """ + Abstract base class for any JSON based configuration + """ + + __metaclass__ = ABCMeta + + """ + Standalone is a class wide parameter + + @param standalone: if True it will return the prefix for a + standalone application. Otherwise, it will return the system + default for configuration storage. + @type standalone: bool + """ + standalone = False + + def __init__(self): + self._data = {} + self._config_checker = None + + @abstractmethod + def _get_spec(self): + """ + Returns the spec object for the specific configuration + """ + return None + + def _safe_get_value(self, key): + """ + Tries to return a value only if the config has already been loaded + + @rtype: depends on the config structure, dict, str, array, int + @return: returns the value for the specified key in the config + """ + leap_assert(self._config_checker, "Load the config first") + return self._config_checker.config[key] + + def get_path_prefix(self): + """ + Returns the platform dependant path prefixer + + """ + return get_platform_prefixer().get_path_prefix( + standalone=self.standalone) + + def loaded(self): + """ + Returns True if the configuration has been already + loaded. False otherwise + """ + return self._config_checker is not None + + def save(self, path_list): + """ + Saves the current configuration to disk + + @param path_list: list of components that form the relative + path to configuration. The absolute path will be calculated + depending on the platform. + @type path_list: list + + @return: True if saved to disk correctly, False otherwise + """ + config_path = os.path.join(self.get_path_prefix(), *(path_list[:-1])) + mkdir_p(config_path) + + try: + self._config_checker.serialize(os.path.join(config_path, + path_list[-1])) + except Exception as e: + logger.warning("%s" % (e,)) + raise + return True + + def load(self, path="", data=None, mtime=None): + """ + Loads the configuration from disk + + @type path: str + @param path: relative path to configuration. The absolute path + will be calculated depending on the platform + + @return: True if loaded from disk correctly, False otherwise + """ + + config_path = os.path.join(self.get_path_prefix(), + path) + + self._config_checker = PluggableConfig(format="json") + self._config_checker.options = copy.deepcopy(self._get_spec()) + + try: + if data is None: + self._config_checker.load(fromfile=config_path, mtime=mtime) + else: + self._config_checker.load(data, mtime=mtime) + except Exception as e: + logger.warning("Something went wrong while loading " + + "the config from %s\n%s" % (config_path, e)) + self._config_checker = None + return False + return True + + +class LocalizedKey(object): + """ + Decorator used for keys that are localized in a configuration + """ + + def __init__(self, func, **kwargs): + self._func = func + + def __call__(self, instance, lang="en"): + """ + Tries to return the string for the specified language, otherwise + informs the problem and returns an empty string + + @param lang: language code + @type lang: str + + @return: localized value from the possible values returned by + self._func + """ + descriptions = self._func(instance) + description_lang = "" + config_lang = "en" + for key in descriptions.keys(): + if lang.startswith(key): + config_lang = key + break + + description_lang = descriptions[config_lang] + return description_lang + + def __get__(self, instance, instancetype): + """ + Implement the descriptor protocol to make decorating instance + method possible. + """ + # Return a partial function with the first argument is the instance + # of the class decorated. + return functools.partial(self.__call__, instance) + +if __name__ == "__main__": + try: + config = BaseConfig() # should throw TypeError for _get_spec + except Exception as e: + assert isinstance(e, TypeError), "Something went wrong" + print "Abstract BaseConfig class is working as expected" |