forked from zaclys/searxng
377 lines
12 KiB
Python
377 lines
12 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-or-later
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# lint: pylint
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"""Configuration class :py:class:`Config` with deep-update, schema validation
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and deprecated names.
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The :py:class:`Config` class implements a configuration that is based on
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structured dictionaries. The configuration schema is defined in a dictionary
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structure and the configuration data is given in a dictionary structure.
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"""
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from __future__ import annotations
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import copy
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import typing
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import logging
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import pathlib
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import pytomlpp as toml
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__all__ = ['Config', 'UNSET', 'SchemaIssue']
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log = logging.getLogger(__name__)
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class FALSE:
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"""Class of ``False`` singelton"""
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# pylint: disable=multiple-statements
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def __init__(self, msg):
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self.msg = msg
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def __bool__(self):
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return False
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def __str__(self):
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return self.msg
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__repr__ = __str__
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UNSET = FALSE('<UNSET>')
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class SchemaIssue(ValueError):
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"""Exception to store and/or raise a message from a schema issue."""
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def __init__(self, level: typing.Literal['warn', 'invalid'], msg: str):
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self.level = level
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super().__init__(msg)
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def __str__(self):
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return f"[cfg schema {self.level}] {self.args[0]}"
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class Config:
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"""Base class used for configuration"""
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UNSET = UNSET
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@classmethod
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def from_toml(cls, schema_file: pathlib.Path, cfg_file: pathlib.Path, deprecated: dict) -> Config:
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# init schema
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log.debug("load schema file: %s", schema_file)
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cfg = cls(cfg_schema=toml.load(schema_file), deprecated=deprecated)
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if not cfg_file.exists():
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log.warning("missing config file: %s", cfg_file)
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return cfg
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# load configuration
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log.debug("load config file: %s", cfg_file)
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try:
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upd_cfg = toml.load(cfg_file)
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except toml.DecodeError as exc:
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msg = str(exc).replace('\t', '').replace('\n', ' ')
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log.error("%s: %s", cfg_file, msg)
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raise
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is_valid, issue_list = cfg.validate(upd_cfg)
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for msg in issue_list:
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log.error(str(msg))
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if not is_valid:
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raise TypeError(f"schema of {cfg_file} is invalid!")
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cfg.update(upd_cfg)
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return cfg
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def __init__(self, cfg_schema: typing.Dict, deprecated: typing.Dict[str, str]):
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"""Construtor of class Config.
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:param cfg_schema: Schema of the configuration
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:param deprecated: dictionary that maps deprecated configuration names to a messages
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These values are needed for validation, see :py:obj:`validate`.
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"""
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self.cfg_schema = cfg_schema
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self.deprecated = deprecated
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self.cfg = copy.deepcopy(cfg_schema)
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def __getitem__(self, key: str):
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return self.get(key)
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def validate(self, cfg: dict):
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"""Validation of dictionary ``cfg`` on :py:obj:`Config.SCHEMA`.
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Validation is done by :py:obj:`validate`."""
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return validate(self.cfg_schema, cfg, self.deprecated)
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def update(self, upd_cfg: dict):
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"""Update this configuration by ``upd_cfg``."""
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dict_deepupdate(self.cfg, upd_cfg)
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def default(self, name: str):
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"""Returns default value of field ``name`` in ``self.cfg_schema``."""
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return value(name, self.cfg_schema)
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def get(self, name: str, default=UNSET, replace=True):
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"""Returns the value to which ``name`` points in the configuration.
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If there is no such ``name`` in the config and the ``default`` is
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:py:obj:`UNSET`, a :py:obj:`KeyError` is raised.
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"""
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parent = self._get_parent_dict(name)
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val = parent.get(name.split('.')[-1], UNSET)
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if val is UNSET:
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if default is UNSET:
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raise KeyError(name)
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val = default
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if replace and isinstance(val, str):
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val = val % self
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return val
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def set(self, name: str, val):
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"""Set the value to which ``name`` points in the configuration.
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If there is no such ``name`` in the config, a :py:obj:`KeyError` is
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raised.
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"""
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parent = self._get_parent_dict(name)
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parent[name.split('.')[-1]] = val
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def _get_parent_dict(self, name):
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parent_name = '.'.join(name.split('.')[:-1])
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if parent_name:
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parent = value(parent_name, self.cfg)
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else:
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parent = self.cfg
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if (parent is UNSET) or (not isinstance(parent, dict)):
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raise KeyError(parent_name)
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return parent
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def path(self, name: str, default=UNSET):
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"""Get a :py:class:`pathlib.Path` object from a config string."""
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val = self.get(name, default)
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if val is UNSET:
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if default is UNSET:
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raise KeyError(name)
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return default
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return pathlib.Path(str(val))
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def pyobj(self, name, default=UNSET):
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"""Get python object refered by full qualiffied name (FQN) in the config
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string."""
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fqn = self.get(name, default)
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if fqn is UNSET:
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if default is UNSET:
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raise KeyError(name)
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return default
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(modulename, name) = str(fqn).rsplit('.', 1)
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m = __import__(modulename, {}, {}, [name], 0)
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return getattr(m, name)
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# working with dictionaries
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def value(name: str, data_dict: dict):
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"""Returns the value to which ``name`` points in the ``dat_dict``.
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.. code: python
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>>> data_dict = {
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"foo": {"bar": 1 },
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"bar": {"foo": 2 },
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"foobar": [1, 2, 3],
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}
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>>> value('foobar', data_dict)
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[1, 2, 3]
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>>> value('foo.bar', data_dict)
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1
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>>> value('foo.bar.xxx', data_dict)
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<UNSET>
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"""
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ret_val = data_dict
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for part in name.split('.'):
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if isinstance(ret_val, dict):
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ret_val = ret_val.get(part, UNSET)
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if ret_val is UNSET:
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break
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return ret_val
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def validate(
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schema_dict: typing.Dict, data_dict: typing.Dict, deprecated: typing.Dict[str, str]
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) -> typing.Tuple[bool, list]:
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"""Deep validation of dictionary in ``data_dict`` against dictionary in
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``schema_dict``. Argument deprecated is a dictionary that maps deprecated
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configuration names to a messages::
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deprecated = {
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"foo.bar" : "config 'foo.bar' is deprecated, use 'bar.foo'",
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"..." : "..."
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}
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The function returns a python tuple ``(is_valid, issue_list)``:
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``is_valid``:
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A bool value indicating ``data_dict`` is valid or not.
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``issue_list``:
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A list of messages (:py:obj:`SchemaIssue`) from the validation::
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[schema warn] data_dict: deprecated 'fontlib.foo': <DEPRECATED['foo.bar']>
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[schema invalid] data_dict: key unknown 'fontlib.foo'
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[schema invalid] data_dict: type mismatch 'fontlib.foo': expected ..., is ...
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If ``schema_dict`` or ``data_dict`` is not a dictionary type a
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:py:obj:`SchemaIssue` is raised.
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"""
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names = []
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is_valid = True
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issue_list = []
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if not isinstance(schema_dict, dict):
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raise SchemaIssue('invalid', "schema_dict is not a dict type")
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if not isinstance(data_dict, dict):
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raise SchemaIssue('invalid', f"data_dict issue{'.'.join(names)} is not a dict type")
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is_valid, issue_list = _validate(names, issue_list, schema_dict, data_dict, deprecated)
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return is_valid, issue_list
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def _validate(
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names: typing.List,
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issue_list: typing.List,
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schema_dict: typing.Dict,
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data_dict: typing.Dict,
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deprecated: typing.Dict[str, str],
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) -> typing.Tuple[bool, typing.List]:
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is_valid = True
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for key, data_value in data_dict.items():
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names.append(key)
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name = '.'.join(names)
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deprecated_msg = deprecated.get(name)
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# print("XXX %s: key %s // data_value: %s" % (name, key, data_value))
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if deprecated_msg:
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issue_list.append(SchemaIssue('warn', f"data_dict '{name}': deprecated - {deprecated_msg}"))
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schema_value = value(name, schema_dict)
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# print("YYY %s: key %s // schema_value: %s" % (name, key, schema_value))
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if schema_value is UNSET:
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if not deprecated_msg:
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issue_list.append(SchemaIssue('invalid', f"data_dict '{name}': key unknown in schema_dict"))
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is_valid = False
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elif type(schema_value) != type(data_value): # pylint: disable=unidiomatic-typecheck
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issue_list.append(
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SchemaIssue(
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'invalid',
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(f"data_dict: type mismatch '{name}':" f" expected {type(schema_value)}, is: {type(data_value)}"),
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)
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)
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is_valid = False
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elif isinstance(data_value, dict):
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_valid, _ = _validate(names, issue_list, schema_dict, data_value, deprecated)
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is_valid = is_valid and _valid
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names.pop()
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return is_valid, issue_list
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def dict_deepupdate(base_dict: dict, upd_dict: dict, names=None):
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"""Deep-update of dictionary in ``base_dict`` by dictionary in ``upd_dict``.
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For each ``upd_key`` & ``upd_val`` pair in ``upd_dict``:
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0. If types of ``base_dict[upd_key]`` and ``upd_val`` do not match raise a
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:py:obj:`TypeError`.
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1. If ``base_dict[upd_key]`` is a dict: recursively deep-update it by ``upd_val``.
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2. If ``base_dict[upd_key]`` not exist: set ``base_dict[upd_key]`` from a
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(deep-) copy of ``upd_val``.
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3. If ``upd_val`` is a list, extend list in ``base_dict[upd_key]`` by the
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list in ``upd_val``.
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4. If ``upd_val`` is a set, update set in ``base_dict[upd_key]`` by set in
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``upd_val``.
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"""
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# pylint: disable=too-many-branches
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if not isinstance(base_dict, dict):
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raise TypeError("argument 'base_dict' is not a ditionary type")
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if not isinstance(upd_dict, dict):
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raise TypeError("argument 'upd_dict' is not a ditionary type")
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if names is None:
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names = []
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for upd_key, upd_val in upd_dict.items():
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# For each upd_key & upd_val pair in upd_dict:
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if isinstance(upd_val, dict):
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if upd_key in base_dict:
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# if base_dict[upd_key] exists, recursively deep-update it
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if not isinstance(base_dict[upd_key], dict):
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raise TypeError(f"type mismatch {'.'.join(names)}: is not a dict type in base_dict")
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dict_deepupdate(
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base_dict[upd_key],
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upd_val,
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names
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+ [
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upd_key,
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],
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)
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else:
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# if base_dict[upd_key] not exist, set base_dict[upd_key] from deepcopy of upd_val
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base_dict[upd_key] = copy.deepcopy(upd_val)
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elif isinstance(upd_val, list):
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if upd_key in base_dict:
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# if base_dict[upd_key] exists, base_dict[up_key] is extended by
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# the list from upd_val
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if not isinstance(base_dict[upd_key], list):
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raise TypeError(f"type mismatch {'.'.join(names)}: is not a list type in base_dict")
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base_dict[upd_key].extend(upd_val)
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else:
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# if base_dict[upd_key] doesn't exists, set base_dict[key] from a deepcopy of the
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# list in upd_val.
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base_dict[upd_key] = copy.deepcopy(upd_val)
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elif isinstance(upd_val, set):
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if upd_key in base_dict:
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# if base_dict[upd_key] exists, base_dict[up_key] is updated by the set in upd_val
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if not isinstance(base_dict[upd_key], set):
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raise TypeError(f"type mismatch {'.'.join(names)}: is not a set type in base_dict")
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base_dict[upd_key].update(upd_val.copy())
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else:
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# if base_dict[upd_key] doesn't exists, set base_dict[upd_key] from a copy of the
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# set in upd_val
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base_dict[upd_key] = upd_val.copy()
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else:
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# for any other type of upd_val replace or add base_dict[upd_key] by a copy
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# of upd_val
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base_dict[upd_key] = copy.copy(upd_val)
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