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			378 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			378 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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from typing import Any
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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) -> Any:
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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: Any = UNSET, replace: bool = True) -> Any:
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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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