srne-mqtt/srnemqtt/config.py

# -*- coding: utf-8 -*-
import importlib
import os
from time import sleep
from typing import Any, Dict, List, Optional, Type

import yaml

from .consumers import BaseConsumer
from .interfaces import BaseInterface


def get_consumer(name: str) -> Optional[Type[BaseConsumer]]:
    mod_name, cls_name = name.rsplit(".", 1)

    mod = importlib.import_module(f".consumers.{mod_name}", package=__package__)

    # print(mod)
    # print(dir(mod))
    res = getattr(mod, cls_name)
    assert issubclass(res, BaseConsumer)

    return res


def get_config() -> Dict[str, Any]:
    with open("config.yaml", "r") as fh:
        conf: dict = yaml.safe_load(fh)
        conf.setdefault("consumers", {})

        return conf


def write_config(conf: Dict[str, Any]):
    with open(".config.yaml~writing", "w") as fh:
        yaml.safe_dump(conf, fh, indent=2, encoding="utf-8")
    os.rename(".config.yaml~writing", "config.yaml")


def get_consumers(conf: Optional[Dict[str, Any]] = None) -> List[BaseConsumer]:
    if conf is None:
        conf = get_config()

    consumers = []
    for name, consumer_config in conf["consumers"].items():
        # print(name, consumer_config)
        mod = get_consumer(name)
        if mod:
            # print(mod)
            consumers.append(mod(consumer_config))

    write_config(conf)
    return consumers


def _get_interface(name: str) -> Type[BaseInterface]:
    mod_name, cls_name = name.rsplit(".", 1)

    mod = importlib.import_module(f".interfaces.{mod_name}", package=__package__)

    res = getattr(mod, cls_name)
    assert issubclass(res, BaseInterface)

    return res


def get_interface(conf: Optional[Dict[str, Any]] = None) -> BaseInterface:
    if conf is None:
        conf = get_config()

    name = conf["interface"]["name"]
    params = conf["interface"].get("params", {})

    mod = _get_interface(name)
    assert mod

    return mod(**params)


if __name__ == "__main__":
    conf = get_config()

    consumers = get_consumers(conf)

    try:
        while True:
            for consumer in consumers:
                consumer.poll()
                sleep(1)
    except (KeyboardInterrupt, SystemExit, Exception) as e:
        for consumer in consumers:
            consumer.exit()

        if type(e) is not KeyboardInterrupt:
            raise

        write_config(conf)