| 15 | """An option that can be set using an environment variable of the same name""" |
| 16 | |
| 17 | def __init__( |
| 18 | self, |
| 19 | name: str, |
| 20 | default: _O = UNDEFINED, |
| 21 | mutable: bool = True, |
| 22 | parent: Option[_O] | None = None, |
| 23 | validator: Callable[[Any], _O] = lambda x: cast(_O, x), |
| 24 | ) -> None: |
| 25 | self._name = name |
| 26 | self._mutable = mutable |
| 27 | self._validator = validator |
| 28 | self._subscribers: list[Callable[[_O], None]] = [] |
| 29 | |
| 30 | if name in os.environ: |
| 31 | self._current = validator(os.environ[name]) |
| 32 | |
| 33 | if parent is not None: |
| 34 | if not (parent.mutable and self.mutable): |
| 35 | raise TypeError("Parent and child options must be mutable") |
| 36 | self._default = parent.default |
| 37 | parent.subscribe(self.set_current) |
| 38 | elif default is not UNDEFINED: |
| 39 | self._default = default |
| 40 | else: |
| 41 | raise TypeError("Must specify either a default or a parent option") |
| 42 | |
| 43 | logger.debug(f"{self._name}={self.current}") |
| 44 | |
| 45 | @property |
| 46 | def name(self) -> str: |