Mini Shell

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

# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2021 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT

from dataclasses import dataclass
from typing import Optional

from xray import gettext as _
from .constants import fpm_stat_storage, fpm_reload_timeout
from .exceptions import XRayError
from .utils import dbm_storage, timestamp


@dataclass
class FPMReloadController:
    """
    Class to control the frequency of FPM service reloading
    """
    fpm_service: str

    @property
    def latest_reload(self) -> Optional[int]:
        """
        Get the timestamp of latest reload of FPM service
        """
        try:
            with dbm_storage(fpm_stat_storage) as _fpm_reload_stat:
                try:
                    return int(_fpm_reload_stat[self.fpm_service].decode())
                except KeyError:
                    return None
        except RuntimeError as e:
            raise XRayError(
                _('Failed to get the timestamp of latest FPM reload: %s') % str(e),
                flag='warning')

    def save_latest_reload(self):
        """
        Save the timestamp of latest reload of FPM service
        """
        try:
            # save timestamp of latest reload of corresponding service
            with dbm_storage(fpm_stat_storage) as _fpm_reload_stat:
                _fpm_reload_stat[self.fpm_service] = str(timestamp())
        except RuntimeError as e:
            raise XRayError(
                _('Failed to save the timestamp of latest FPM reload %s, but main operation executed') % str(e),
                flag='warning')

    def delta(self) -> float:
        """
        Get the time delta between current time and saved timestamp
        """
        try:
            # we store timestamp in seconds,
            # but timeout -- fpm_reload_timeout -- in minutes
            return (timestamp() - self.latest_reload) / 60
        except (TypeError, XRayError):
            # 1 hour,
            # big enough for non-blocking flow in case of unexpected errors
            return 60.0

    def restrict(self) -> bool:
        """
        Check if FPM reload should be blocked
        """
        return self.delta() <= fpm_reload_timeout