logging_with_decorator.py

import abc
import functools
import json
import time
import uuid
from dataclasses import asdict
from dataclasses import dataclass
from logging import INFO
from logging import Logger
from logging import basicConfig
from logging import getLogger
from typing import Callable
from typing import Dict


# interface definition
class Describable(metaclass=abc.ABCMeta):
    @abc.abstractmethod
    def describe(self) -> Dict:
        raise NotImplementedError()


# decorator
def observe(logger: Logger):
    def decorator(func: Callable) -> Callable:
        @functools.wraps(func)
        def decorated(self: Describable, *args, **kwargs):
            l: Logger = logger.getChild(self.__class__.__name__).getChild(func.__name__)
            transaction_id: str = str(uuid.uuid4())
            l.info(json.dumps({
                "transaction_id": transaction_id,
                "type": "start",
                "logged_at": time.time_ns(),
                "name": "{0}.{1}".format(
                    self.__class__.__name__,
                    func.__name__
                ),
                "description": self.describe()
            }))
            try:
                res = func(self, *args, **kwargs)

            finally:
                l.info(json.dumps({
                    "transaction_id": transaction_id,
                    "type": "end",
                    "logged_at": time.time_ns(),
                    "name": "{0}.{1}".format(
                        self.__class__.__name__,
                        func.__name__
                    ),
                    "description": self.describe()
                }))

            return res

        return decorated

    return decorator


# class definition
_logger: Logger = getLogger(__name__)


@dataclass(frozen=True)
class Value(Describable):
    __value: str

    def describe(self) -> Dict:
        return asdict(self)

    @observe(logger=_logger)
    def get_value(self):
        return self.__value


# class use case
if __name__ == "__main__":
    basicConfig(level=INFO)
    v: Value = Value("hello")
    print(v.get_value())