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| -rw-r--r-- | python/vyos/configdiff.py | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/python/vyos/configdiff.py b/python/vyos/configdiff.py new file mode 100644 index 000000000..b79893507 --- /dev/null +++ b/python/vyos/configdiff.py @@ -0,0 +1,249 @@ +# Copyright 2020 VyOS maintainers and contributors <maintainers@vyos.io> +# +# This library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. +# +# This library 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 +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public License +# along with this library. If not, see <http://www.gnu.org/licenses/>. + +from enum import IntFlag, auto + +from vyos.config import Config +from vyos.configdict import dict_merge +from vyos.util import get_sub_dict, mangle_dict_keys +from vyos.xml import defaults + +class ConfigDiffError(Exception): + """ + Raised on config dict access errors, for example, calling get_value on + a non-leaf node. + """ + pass + +def enum_to_key(e): + return e.name.lower() + +class Diff(IntFlag): + MERGE = auto() + DELETE = auto() + ADD = auto() + STABLE = auto() + +requires_effective = [enum_to_key(Diff.DELETE)] +target_defaults = [enum_to_key(Diff.MERGE)] + +def _key_sets_from_dicts(session_dict, effective_dict): + session_keys = list(session_dict) + effective_keys = list(effective_dict) + + ret = {} + stable_keys = [k for k in session_keys if k in effective_keys] + + ret[enum_to_key(Diff.MERGE)] = session_keys + ret[enum_to_key(Diff.DELETE)] = [k for k in effective_keys if k not in stable_keys] + ret[enum_to_key(Diff.ADD)] = [k for k in session_keys if k not in stable_keys] + ret[enum_to_key(Diff.STABLE)] = stable_keys + + return ret + +def _dict_from_key_set(key_set, d): + # This will always be applied to a key_set obtained from a get_sub_dict, + # hence there is no possibility of KeyError, as get_sub_dict guarantees + # a return type of dict + ret = {k: d[k] for k in key_set} + + return ret + +def get_config_diff(config, key_mangling=None): + """ + Check type and return ConfigDiff instance. + """ + if not config or not isinstance(config, Config): + raise TypeError("argument must me a Config instance") + if key_mangling and not (isinstance(key_mangling, tuple) and \ + (len(key_mangling) == 2) and \ + isinstance(key_mangling[0], str) and \ + isinstance(key_mangling[1], str)): + raise ValueError("key_mangling must be a tuple of two strings") + + return ConfigDiff(config, key_mangling) + +class ConfigDiff(object): + """ + The class of config changes as represented by comparison between the + session config dict and the effective config dict. + """ + def __init__(self, config, key_mangling=None): + self._level = config.get_level() + self._session_config_dict = config.get_cached_dict() + self._effective_config_dict = config.get_cached_dict(effective=True) + self._key_mangling = key_mangling + + # mirrored from Config; allow path arguments relative to level + def _make_path(self, path): + if isinstance(path, str): + path = path.split() + elif isinstance(path, list): + pass + else: + raise TypeError("Path must be a whitespace-separated string or a list") + + ret = self._level + path + return ret + + def set_level(self, path): + """ + Set the *edit level*, that is, a relative config dict path. + Once set, all operations will be relative to this path, + for example, after ``set_level("system")``, calling + ``get_value("name-server")`` is equivalent to calling + ``get_value("system name-server")`` without ``set_level``. + + Args: + path (str|list): relative config path + """ + if isinstance(path, str): + if path: + self._level = path.split() + else: + self._level = [] + elif isinstance(path, list): + self._level = path.copy() + else: + raise TypeError("Level path must be either a whitespace-separated string or a list") + + def get_level(self): + """ + Gets the current edit level. + + Returns: + str: current edit level + """ + ret = self._level.copy() + return ret + + def _mangle_dict_keys(self, config_dict): + config_dict = mangle_dict_keys(config_dict, self._key_mangling[0], + self._key_mangling[1]) + return config_dict + + def get_child_nodes_diff(self, path=[], expand_nodes=Diff(0), no_defaults=False): + """ + Args: + path (str|list): config path + expand_nodes=Diff(0): bit mask of enum indicating for which nodes + to provide full dict; for example, Diff.MERGE + will expand dict['merge'] into dict under + value + no_detaults=False: if expand_nodes & Diff.MERGE, do not merge default + values to ret['merge'] + + Returns: dict of lists, representing differences between session + and effective config, under path + dict['merge'] = session config values + dict['delete'] = effective config values, not in session + dict['add'] = session config values, not in effective + dict['stable'] = config values in both session and effective + """ + session_dict = get_sub_dict(self._session_config_dict, + self._make_path(path), get_first_key=True) + effective_dict = get_sub_dict(self._effective_config_dict, + self._make_path(path), get_first_key=True) + + ret = _key_sets_from_dicts(session_dict, effective_dict) + + if not expand_nodes: + return ret + + for e in Diff: + if expand_nodes & e: + k = enum_to_key(e) + if k in requires_effective: + ret[k] = _dict_from_key_set(ret[k], effective_dict) + else: + ret[k] = _dict_from_key_set(ret[k], session_dict) + + if self._key_mangling: + ret[k] = self._mangle_dict_keys(ret[k]) + + if k in target_defaults and not no_defaults: + default_values = defaults(self._make_path(path)) + ret[k] = dict_merge(default_values, ret[k]) + + return ret + + def get_node_diff(self, path=[], expand_nodes=Diff(0), no_defaults=False): + """ + Args: + path (str|list): config path + expand_nodes=Diff(0): bit mask of enum indicating for which nodes + to provide full dict; for example, Diff.MERGE + will expand dict['merge'] into dict under + value + no_detaults=False: if expand_nodes & Diff.MERGE, do not merge default + values to ret['merge'] + + Returns: dict of lists, representing differences between session + and effective config, at path + dict['merge'] = session config values + dict['delete'] = effective config values, not in session + dict['add'] = session config values, not in effective + dict['stable'] = config values in both session and effective + """ + session_dict = get_sub_dict(self._session_config_dict, self._make_path(path)) + effective_dict = get_sub_dict(self._effective_config_dict, self._make_path(path)) + + ret = _key_sets_from_dicts(session_dict, effective_dict) + + if not expand_nodes: + return ret + + for e in Diff: + if expand_nodes & e: + k = enum_to_key(e) + if k in requires_effective: + ret[k] = _dict_from_key_set(ret[k], effective_dict) + else: + ret[k] = _dict_from_key_set(ret[k], session_dict) + + if self._key_mangling: + ret[k] = self._mangle_dict_keys(ret[k]) + + if k in target_defaults and not no_defaults: + default_values = defaults(self._make_path(path)) + ret[k] = dict_merge(default_values, ret[k]) + + return ret + + def get_value_diff(self, path=[]): + """ + Args: + path (str|list): config path + + Returns: (new, old) tuple of values in session config/effective config + """ + # one should properly use is_leaf as check; for the moment we will + # deduce from type, which will not catch call on non-leaf node if None + new_value_dict = get_sub_dict(self._session_config_dict, self._make_path(path)) + old_value_dict = get_sub_dict(self._effective_config_dict, self._make_path(path)) + + new_value = None + old_value = None + if new_value_dict: + new_value = next(iter(new_value_dict.values())) + if old_value_dict: + old_value = next(iter(old_value_dict.values())) + + if new_value and isinstance(new_value, dict): + raise ConfigDiffError("get_value_changed called on non-leaf node") + if old_value and isinstance(old_value, dict): + raise ConfigDiffError("get_value_changed called on non-leaf node") + + return new_value, old_value |