baseimage-tutorial-framework/tfw/logging.py

# pylint: disable=bad-whitespace
from datetime import datetime
from typing import TextIO, Union
from dataclasses import dataclass
from traceback import format_exception
from logging import DEBUG, getLogger, Handler, Formatter, Filter


class Color:
    RED     = '\033[31m'
    GREEN   = '\033[32m'
    YELLOW  = '\033[33m'
    BLUE    = '\033[34m'
    CYAN    = '\033[36m'
    WHITE   = '\033[37m'
    RESET   = '\033[0m'


@dataclass
class Log:
    stream: Union[str, TextIO]
    formatter: Formatter


class Logger:
    def __init__(self, logs, level=DEBUG):
        self.root_logger = getLogger()
        self.old_level = self.root_logger.level
        self.new_level = level
        self.handlers = []
        for log in logs:
            handler = LogHandler(log.stream)
            handler.setFormatter(log.formatter)
            self.handlers.append(handler)

    def start(self):
        self.root_logger.setLevel(self.new_level)
        for handler in self.handlers:
            self.root_logger.addHandler(handler)

    def stop(self):
        self.root_logger.setLevel(self.old_level)
        for handler in self.handlers:
            handler.close()
            self.root_logger.removeHandler(handler)


class LogHandler(Handler):
    def __init__(self, stream):
        if isinstance(stream, str):
            self.stream = open(stream, 'a+')
            self.close_stream = True
        else:
            self.stream = stream
            self.close_stream = False
        super().__init__()

    def emit(self, record):
        entry = self.format(record)
        self.stream.write(entry+'\n')
        self.stream.flush()

    def close(self):
        if self.close_stream:
            self.stream.close()

class LogFormatter(Formatter):
    severity_to_color = {
        'CRITICAL' : Color.RED,
        'ERROR'    : Color.RED,
        'WARNING'  : Color.YELLOW,
        'INFO'     : Color.GREEN,
        'DEBUG'    : Color.BLUE,
        'NOTSET'   : Color.CYAN
    }

    def __init__(self, limit):
        self.limit = limit
        super().__init__()

    def format(self, record):
        time = datetime.utcfromtimestamp(record.created).strftime('%H:%M:%S')
        if record.args:
            tuple_args = (record.args,) if isinstance(record.args, dict) else record.args
            clean_args = tuple((self.trim(arg) for arg in tuple_args))
            message = record.msg % clean_args
        else:
            message = record.msg
        trace = '\n'+''.join(format_exception(*record.exc_info)) if record.exc_info else ''

        return (f'[{Color.WHITE}{time}{Color.RESET}|>'
                f'{self.severity_to_color[record.levelname]}{record.module}:'
                f'{record.levelname.lower()}{Color.RESET}] {message}{trace}')

    def trim(self, value):
        if isinstance(value, dict):
            return {k: self.trim(v) for k, v in value.items()}
        if isinstance(value, str):
            value_str = str(value)
            return value_str if len(value_str) <= self.limit else f'{value_str[:self.limit]}...'
        return value


class VerboseLogFormatter(Formatter):
    def format(self, record):  # pylint: disable=no-self-use
        date = datetime.utcfromtimestamp(record.created).strftime('%H:%M:%S')
        if record.args:
            message = record.msg % record.args
        else:
            message = record.msg
        trace = '\n'+''.join(format_exception(*record.exc_info)) if record.exc_info else ''

        return (f'[{date}|>{record.module}:{record.levelname.lower()}] '
                f'{message}{trace}')


class WhitelistFilter(Filter):
    def __init__(self, names):
        self.names = names
        super().__init__()

    def filter(self, record):
        return record.module in self.names


class BlacklistFilter(Filter):
    def __init__(self, names):
        self.names = names
        super().__init__()

    def filter(self, record):
        return record.module not in self.names