janet/janet/__init__.py

import abc
import logging
from dataclasses import dataclass
from typing import Any, Callable, Optional, Sequence

logger = logging.getLogger('janet')


@dataclass
class Device:
    identifiers: Sequence[str]
    available: bool

    name: str
    manufacturer: Optional[str] = None
    model: Optional[str] = None
    sw_version: Optional[str] = None
    kind: Optional[str] = None


class Channel:
    def __init__(self):
        self._listeners = set()

    def put(self, source: Device, entity: Any) -> None:
        remove = set()
        for listener in self._listeners:
            try:
                if listener(source, entity):
                    remove.add(listener)
            except IOError as ex:
                logger.warning(f'Listener raised {ex}, removing', exc_info=ex)
                remove.add(listener)
            except Exception as ex:
                logger.error(f'Listener raised fatal exception {ex}, removing',
                             exc_info=ex)
                remove.add(listener)

        self._listeners ^= remove

    def listen(self, listener: Callable[[Device, Any], None]) -> None:
        self._listeners.add(listener)


class Publisher(abc.ABC):
    @abc.abstractmethod
    def publish(self,
                device: Device,
                entity: Any,
                setter: Optional[Callable] = None):
        pass