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Diffstat (limited to 'deluge/config.py')
| -rw-r--r-- | deluge/config.py | 568 |
1 files changed, 568 insertions, 0 deletions
diff --git a/deluge/config.py b/deluge/config.py new file mode 100644 index 0000000..c5cb312 --- /dev/null +++ b/deluge/config.py @@ -0,0 +1,568 @@ +# +# Copyright (C) 2008 Andrew Resch <andrewresch@gmail.com> +# +# This file is part of Deluge and is licensed under GNU General Public License 3.0, or later, with +# the additional special exception to link portions of this program with the OpenSSL library. +# See LICENSE for more details. +# + +""" +Deluge Config Module + +This module is used for loading and saving of configuration files.. or anything +really. + +The format of the config file is two json encoded dicts: + +<version dict> +<content dict> + +The version dict contains two keys: file and format. The format version is +controlled by the Config class. It should only be changed when anything below +it is changed directly by the Config class. An example of this would be if we +changed the serializer for the content to something different. + +The config file version is changed by the 'owner' of the config file. This is +to signify that there is a change in the naming of some config keys or something +similar along those lines. + +The content is simply the dict to be saved and will be serialized before being +written. + +Converting + +Since the format of the config could change, there needs to be a way to have +the Config object convert to newer formats. To do this, you will need to +register conversion functions for various versions of the config file. Note that +this can only be done for the 'config file version' and not for the 'format' +version as this will be done internally. + +""" +import json +import logging +import os +import pickle +import shutil +from codecs import getwriter +from tempfile import NamedTemporaryFile + +from deluge.common import JSON_FORMAT, get_default_config_dir + +log = logging.getLogger(__name__) + + +def find_json_objects(text, decoder=json.JSONDecoder()): + """Find json objects in text. + + Args: + text (str): The text to find json objects within. + + Returns: + list: A list of tuples containing start and end locations of json + objects in the text. e.g. [(start, end), ...] + + + """ + objects = [] + offset = 0 + while True: + try: + start = text.index('{', offset) + except ValueError: + break + + try: + __, index = decoder.raw_decode(text[start:]) + except json.decoder.JSONDecodeError: + offset = start + 1 + else: + offset = start + index + objects.append((start, offset)) + + return objects + + +def cast_to_existing_type(value, old_value): + """Attempt to convert new value type to match old value type""" + types_match = isinstance(old_value, (type(None), type(value))) + if value is not None and not types_match: + old_type = type(old_value) + # Skip convert to bytes since requires knowledge of encoding and value should + # be unicode anyway. + if old_type is bytes: + return value + + return old_type(value) + + return value + + +class Config: + """This class is used to access/create/modify config files. + + Args: + filename (str): The config filename. + defaults (dict): The default config values to insert before loading the config file. + config_dir (str): the path to the config directory. + file_version (int): The file format for the default config values when creating + a fresh config. This value should be increased whenever a new migration function is + setup to convert old config files. (default: 1) + log_mask_funcs (dict): A dict of key:function, used to mask sensitive + key values (e.g. passwords) when logging is enabled. + + """ + + def __init__( + self, + filename, + defaults=None, + config_dir=None, + file_version=1, + log_mask_funcs=None, + ): + self.__config = {} + self.__set_functions = {} + self.__change_callbacks = [] + self.__log_mask_funcs = log_mask_funcs if log_mask_funcs else {} + + # These hold the version numbers and they will be set when loaded + self.__version = {'format': 1, 'file': file_version} + + # This will get set with a reactor.callLater whenever a config option + # is set. + self._save_timer = None + + if defaults: + for key, value in defaults.items(): + self.set_item(key, value, default=True) + + # Load the config from file in the config_dir + if config_dir: + self.__config_file = os.path.join(config_dir, filename) + else: + self.__config_file = get_default_config_dir(filename) + + self.load() + + def callLater(self, period, func, *args, **kwargs): # noqa: N802 ignore camelCase + """Wrapper around reactor.callLater for test purpose.""" + from twisted.internet import reactor + + return reactor.callLater(period, func, *args, **kwargs) + + def __contains__(self, item): + return item in self.__config + + def __setitem__(self, key, value): + """See set_item""" + + return self.set_item(key, value) + + def set_item(self, key, value, default=False): + """Sets item 'key' to 'value' in the config dictionary. + + Does not allow changing the item's type unless it is None. + + If the types do not match, it will attempt to convert it to the + set type before raising a ValueError. + + Args: + key (str): Item to change to change. + value (any): The value to change item to, must be same type as what is + currently in the config. + default (optional, bool): When setting a default value skip func or save + callbacks. + + Raises: + ValueError: Raised when the type of value is not the same as what is + currently in the config and it could not convert the value. + + Examples: + >>> config = Config('test.conf') + >>> config['test'] = 5 + >>> config['test'] + 5 + + """ + if isinstance(value, bytes): + value = value.decode() + + if key in self.__config: + try: + value = cast_to_existing_type(value, self.__config[key]) + except ValueError: + log.warning('Value Type "%s" invalid for key: %s', type(value), key) + raise + else: + if self.__config[key] == value: + return + + if log.isEnabledFor(logging.DEBUG): + if key in self.__log_mask_funcs: + value = self.__log_mask_funcs[key](value) + log.debug( + 'Setting key "%s" to: %s (of type: %s)', + key, + value, + type(value), + ) + self.__config[key] = value + + # Skip save or func callbacks if setting default value for keys + if default: + return + + # Run the set_function for this key if any + for func in self.__set_functions.get(key, []): + self.callLater(0, func, key, value) + + try: + + def do_change_callbacks(key, value): + for func in self.__change_callbacks: + func(key, value) + + self.callLater(0, do_change_callbacks, key, value) + except Exception: + pass + + # We set the save_timer for 5 seconds if not already set + if not self._save_timer or not self._save_timer.active(): + self._save_timer = self.callLater(5, self.save) + + def __getitem__(self, key): + """See get_item""" + return self.get_item(key) + + def get_item(self, key): + """Gets the value of item 'key'. + + Args: + key (str): The item for which you want it's value. + + Returns: + any: The value of item 'key'. + + Raises: + ValueError: If 'key' is not in the config dictionary. + + Examples: + >>> config = Config('test.conf', defaults={'test': 5}) + >>> config['test'] + 5 + + """ + return self.__config[key] + + def get(self, key, default=None): + """Gets the value of item 'key' if key is in the config, else default. + + If default is not given, it defaults to None, so that this method + never raises a KeyError. + + Args: + key (str): the item for which you want it's value + default (any): the default value if key is missing + + Returns: + any: The value of item 'key' or default. + + Examples: + >>> config = Config('test.conf', defaults={'test': 5}) + >>> config.get('test', 10) + 5 + >>> config.get('bad_key', 10) + 10 + + """ + try: + return self.get_item(key) + except KeyError: + return default + + def __delitem__(self, key): + """ + See + :meth:`del_item` + """ + self.del_item(key) + + def del_item(self, key): + """Deletes item with a specific key from the configuration. + + Args: + key (str): The item which you wish to delete. + + Raises: + ValueError: If 'key' is not in the config dictionary. + + Examples: + >>> config = Config('test.conf', defaults={'test': 5}) + >>> del config['test'] + + """ + + del self.__config[key] + + # We set the save_timer for 5 seconds if not already set + if not self._save_timer or not self._save_timer.active(): + self._save_timer = self.callLater(5, self.save) + + def register_change_callback(self, callback): + """Registers a callback function for any changed value. + + Will be called when any value is changed in the config dictionary. + + Args: + callback (func): The function to call with parameters: f(key, value). + + Examples: + >>> config = Config('test.conf', defaults={'test': 5}) + >>> def cb(key, value): + ... print key, value + ... + >>> config.register_change_callback(cb) + + """ + self.__change_callbacks.append(callback) + + def register_set_function(self, key, function, apply_now=True): + """Register a function to be called when a config value changes. + + Args: + key (str): The item to monitor for change. + function (func): The function to call when the value changes, f(key, value). + apply_now (bool): If True, the function will be called immediately after it's registered. + + Examples: + >>> config = Config('test.conf', defaults={'test': 5}) + >>> def cb(key, value): + ... print key, value + ... + >>> config.register_set_function('test', cb, apply_now=True) + test 5 + + """ + log.debug('Registering function for %s key..', key) + if key not in self.__set_functions: + self.__set_functions[key] = [] + + self.__set_functions[key].append(function) + + # Run the function now if apply_now is set + if apply_now: + function(key, self.__config[key]) + + def apply_all(self): + """Calls all set functions. + + Examples: + >>> config = Config('test.conf', defaults={'test': 5}) + >>> def cb(key, value): + ... print key, value + ... + >>> config.register_set_function('test', cb, apply_now=False) + >>> config.apply_all() + test 5 + + """ + log.debug('Calling all set functions..') + for key, value in self.__set_functions.items(): + for func in value: + func(key, self.__config[key]) + + def apply_set_functions(self, key): + """Calls set functions for `:param:key`. + + Args: + key (str): the config key + + """ + log.debug('Calling set functions for key %s..', key) + if key in self.__set_functions: + for func in self.__set_functions[key]: + func(key, self.__config[key]) + + def load(self, filename=None): + """Load a config file. + + Args: + filename (str): If None, uses filename set in object initialization + + """ + if not filename: + filename = self.__config_file + + try: + with open(filename, encoding='utf8') as _file: + data = _file.read() + except OSError as ex: + log.warning('Unable to open config file %s: %s', filename, ex) + return + + objects = find_json_objects(data) + + if not len(objects): + # No json objects found, try depickling it + try: + self.__config.update(pickle.loads(data)) + except Exception as ex: + log.exception(ex) + log.warning('Unable to load config file: %s', filename) + elif len(objects) == 1: + start, end = objects[0] + try: + self.__config.update(json.loads(data[start:end])) + except Exception as ex: + log.exception(ex) + log.warning('Unable to load config file: %s', filename) + elif len(objects) == 2: + try: + start, end = objects[0] + self.__version.update(json.loads(data[start:end])) + start, end = objects[1] + self.__config.update(json.loads(data[start:end])) + except Exception as ex: + log.exception(ex) + log.warning('Unable to load config file: %s', filename) + + if not log.isEnabledFor(logging.DEBUG): + return + + config = self.__config + if self.__log_mask_funcs: + config = { + key: self.__log_mask_funcs[key](config[key]) + if key in self.__log_mask_funcs + else config[key] + for key in config + } + + log.debug( + 'Config %s version: %s.%s loaded: %s', + filename, + self.__version['format'], + self.__version['file'], + config, + ) + + def save(self, filename=None): + """Save configuration to disk. + + Args: + filename (str): If None, uses filename set in object initialization + + Returns: + bool: Whether or not the save succeeded. + + """ + if not filename: + filename = self.__config_file + # Check to see if the current config differs from the one on disk + # We will only write a new config file if there is a difference + try: + with open(filename, encoding='utf8') as _file: + data = _file.read() + objects = find_json_objects(data) + start, end = objects[0] + version = json.loads(data[start:end]) + start, end = objects[1] + loaded_data = json.loads(data[start:end]) + if self.__config == loaded_data and self.__version == version: + # The config has not changed so lets just return + if self._save_timer and self._save_timer.active(): + self._save_timer.cancel() + return True + except (OSError, IndexError) as ex: + log.warning('Unable to open config file: %s because: %s', filename, ex) + + # Save the new config and make sure it's written to disk + try: + with NamedTemporaryFile( + prefix=os.path.basename(filename) + '.', delete=False + ) as _file: + filename_tmp = _file.name + log.debug('Saving new config file %s', filename_tmp) + json.dump(self.__version, getwriter('utf8')(_file), **JSON_FORMAT) + json.dump(self.__config, getwriter('utf8')(_file), **JSON_FORMAT) + _file.flush() + os.fsync(_file.fileno()) + except OSError as ex: + log.error('Error writing new config file: %s', ex) + return False + + # Resolve symlinked config files before backing up and saving. + filename = os.path.realpath(filename) + + # Make a backup of the old config + try: + log.debug('Backing up old config file to %s.bak', filename) + shutil.move(filename, filename + '.bak') + except OSError as ex: + log.warning('Unable to backup old config: %s', ex) + + # The new config file has been written successfully, so let's move it over + # the existing one. + try: + log.debug('Moving new config file %s to %s', filename_tmp, filename) + shutil.move(filename_tmp, filename) + except OSError as ex: + log.error('Error moving new config file: %s', ex) + return False + else: + return True + finally: + if self._save_timer and self._save_timer.active(): + self._save_timer.cancel() + + def run_converter(self, input_range, output_version, func): + """Runs a function that will convert file versions. + + Args: + input_range (tuple): (int, int) The range of input versions this function will accept. + output_version (int): The version this function will convert to. + func (func): The function that will do the conversion, it will take the config + dict as an argument and return the augmented dict. + + Raises: + ValueError: If output_version is less than the input_range. + + """ + if output_version in input_range or output_version <= max(input_range): + raise ValueError('output_version needs to be greater than input_range') + + if self.__version['file'] not in input_range: + log.debug( + 'File version %s is not in input_range %s, ignoring converter function..', + self.__version['file'], + input_range, + ) + return + + try: + self.__config = func(self.__config) + except Exception as ex: + log.exception(ex) + log.error( + 'There was an exception try to convert config file %s %s to %s', + self.__config_file, + self.__version['file'], + output_version, + ) + raise ex + else: + self.__version['file'] = output_version + self.save() + + @property + def config_file(self): + return self.__config_file + + @property + def config(self): + """The config dictionary""" + return self.__config + + @config.deleter + def config(self): + return self.save() |