Viewing file: _config.py (3.48 KB) -rw-r--r-- Select action/file-type: (+) | (+) | (+) | Code (+) | Session (+) | (+) | SDB (+) | (+) | (+) | (+) | (+) | (+) |
import configparser import dataclasses from dataclasses import dataclass from pathlib import Path from typing import Callable from typing import ClassVar from typing import Optional from typing import Union
from .helpers import make_path
class ConfigError(BaseException): pass
class MissingConfig(ConfigError): pass
class MissingConfigSection(ConfigError): pass
class MissingConfigItem(ConfigError): pass
class ConfigValueTypeError(ConfigError): pass
class _GetterDispatch: def __init__(self, initialdata, default_getter: Callable): self.default_getter = default_getter self.data = initialdata
def get_fn_for_type(self, type_): return self.data.get(type_, self.default_getter)
def get_typed_value(self, type_, name): get_fn = self.get_fn_for_type(type_) return get_fn(name)
def _parse_cfg_file(filespec: Union[Path, str]): cfg = configparser.ConfigParser() try: filepath = make_path(filespec, check_exists=True) except FileNotFoundError as e: raise MissingConfig(f"No config file found at {filespec}") from e else: with open(filepath, encoding="utf-8") as f: cfg.read_file(f) return cfg
def _build_getter(cfg_obj, cfg_section, method, converter=None): def caller(option, **kwargs): try: rv = getattr(cfg_obj, method)(cfg_section, option, **kwargs) except configparser.NoSectionError as nse: raise MissingConfigSection( f"No config section named {cfg_section}" ) from nse except configparser.NoOptionError as noe: raise MissingConfigItem(f"No config item for {option}") from noe except ValueError as ve: # ConfigParser.getboolean, .getint, .getfloat raise ValueError # on bad types raise ConfigValueTypeError( f"Wrong value type for {option}" ) from ve else: if converter: try: rv = converter(rv) except Exception as e: raise ConfigValueTypeError( f"Wrong value type for {option}" ) from e return rv
return caller
def _build_getter_dispatch(cfg_obj, cfg_section, converters=None): converters = converters or {}
default_getter = _build_getter(cfg_obj, cfg_section, "get")
# support ConfigParser builtins getters = { int: _build_getter(cfg_obj, cfg_section, "getint"), bool: _build_getter(cfg_obj, cfg_section, "getboolean"), float: _build_getter(cfg_obj, cfg_section, "getfloat"), str: default_getter, }
# use ConfigParser.get and convert value getters.update( { type_: _build_getter( cfg_obj, cfg_section, "get", converter=converter_fn ) for type_, converter_fn in converters.items() } )
return _GetterDispatch(getters, default_getter)
@dataclass class ReadsCfg: section_header: ClassVar[str] converters: ClassVar[Optional[dict]] = None
@classmethod def from_cfg_file(cls, filespec: Union[Path, str]): cfg = _parse_cfg_file(filespec) dispatch = _build_getter_dispatch( cfg, cls.section_header, converters=cls.converters ) kwargs = { field.name: dispatch.get_typed_value(field.type, field.name) for field in dataclasses.fields(cls) } return cls(**kwargs)
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