backup-tool/app/logger.py

"""This module contains the logging module."""
from typing import Union
from pathlib import Path
from datetime import datetime
import sys


class Logger:
    """A logger class that logs, ya get the point."""

    LOG_LEVELS = [
        "debug",
        "info",
        "warning",
        "error",
        "critical",
    ]
    """The log levels' names.

    When used as arguments, the counting starts at 1
    instead of 0.
    """

    def __init__(
        self,
        log_file: Union[Path, str] = None,
        append: bool = True,
        stdout: bool = True,
        log_level: int = 3,
    ):
        """Initialize a new Logger object.

        Args:
            log_file: path to a log file. If any of the folders within the log
                file's path don't exist, they will get created. If no value is
                specified, no log file is created.
            append: wether or not to append to the existing file or overwrite
                it. If False, the original file gets deleted during init.
            stdout: wether or not to log to stdout as well
            log_level: the minimum level to log
        """
        self.log_file = Path(log_file) if log_file else None
        self.stdout = stdout
        self.log_level = log_level

        # Remove the original log file
        if not append:
            self.log_file.unlink(missing_ok=True)

    def custom(self, message: str, header: str = None):
        """Log a message given a header and a message.

        If a header is provided (aka truthy), the final form of the messsage
        wil be:

            `[YYYY-MM-DD HH:MM:SS][header] message`

        Otherwise, it's just:

            `[YYYY-MM-DD HH:MM:SS] message`

        Args:
            message: the message to display
            header: the header to add to the message
        """
        timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")
        log_message = f"[{timestamp}] {message}\n"

        if header:
            log_message = f"[{timestamp}][{header}] {message}\n"

        if self.log_file:
            self.log_file.write_text(log_message)

        if self.stdout:
            sys.stdout.write(log_message)

    def log(self, level: int, message: str):
        """Log a message with a specific level.

        Args:
            level: log level (index in the LOG_LEVELS variable)
            message: the message to log
        """
        if level < self.log_level:
            return

        level_name = self.LOG_LEVELS[level - 1].upper()
        self.custom(level_name, message)

    def debug(self, message: str):
        """Log a debug message."""
        self.log(1, message)

    def info(self, message: str):
        """Log an info message."""
        self.log(2, message)

    def warning(self, message: str):
        """Log a warning message."""
        self.log(3, message)

    def error(self, message: str):
        """Log an error message."""
        self.log(4, message)

    def critical(self, message: str):
        """Log a critical message."""
        self.log(5, message)