Mini Shell

# -*- coding: utf-8 -*-

# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2019 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT
import logging
import typing

T = typing.TypeVar('T')

logger = logging.getLogger("cloudlinux-summary")


class StatisticsDict(dict):
    """
    Special class to store all metrics before sending it
    """

    # a few values which should be return if we can't collect statistic for something module
    DEFAULT_RESULTS = {
        "str": "-42",
        "int": -42,
        "float": -42.0,
        "str_list": ["-42"],
        "int_list": [-42],
        "int_dict": {
            "-42": -42,
        },
        "float_dict": {
            "-42": -42.0,
        },
        "str_dict": {
            "-42": "-42",
        },
        # Special default result.
        # Only for collecting of statistics about client's rpm packages
        "rpm_stat_list": [],
    }

    def evaluate_safe(
            self,
            func: typing.Callable[..., T],
            log_message: str | None
    ) -> tuple[bool, T]:
        """
        Method for catching any exceptions while calling the passed function,
        logging them and returning None and success flag if an exception has been encountered.
        Returns a formatted result of the function call otherwise.

        :param func:
            function that should be called
        :param log_message:
            if given, it will be logged as exception message.
        """
        try:
            result = func()
        except Exception as err:
            if log_message:
                logger.exception(
                    '%s. Exception: "%s"',
                    log_message,
                    err,
                )
            return False, None

        return True, result

    def add_metric(
            self,
            func: typing.Callable[..., T],
            type_of_result: str,
            name_of_metric: str,
            log_message: str | None
    ) -> None:
        """
        Calls `evaluate_safe` and saves the result from it
        in the metric dictionary.

        :param log_message:
            if given, it will be logged as exception message.
        See method `evaluate_safe` for more details.
        """

        success, result = self.evaluate_safe(
            func,
            log_message,
        )

        if not success:
            result = self.DEFAULT_RESULTS[type_of_result]

        self[name_of_metric] = result