patrick_logger.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""patrick_logger.py is a simple multi-verbosity-level logger for when the
standard library module is way more than needed. Several of my scripts
depend on this module.

This script is copyright 2017-2020 by Patrick Mooney. It is licensed under
GPL v3+ at your option. No guarantees or representations of fitness or
warranties apply. This is free software; you're getting more than you paid
for. More info in the file LICENSE.md.
"""


from __future__ import print_function

import datetime
import os
import sys

import text_handling        # https://github.com/patrick-brian-mooney/python-personal-library/


# Can set the starting level above zero explicitly when debugging.
verbosity_level = 0


class Logger(object):
    "An abstract logger class that encapsulates settings and behavior."
    def __init__(self, name="default logger", logfile_paths=None):
        """Set up the logger object. If LOGFILE_PATHS is specified, a log file is opened
        and kept at each location in the list.
        """
        self.width = text_handling.terminal_width()
        self.name = name
        self.output_destinations = [ sys.stdout ]
        if logfile_paths is None:
            self.logfile_paths = [][:]
        elif isinstance(logfile_paths, (list, tuple)):
            self.logfile_paths = logfile_paths
        else:
            self.logfile_paths = [ logfile_paths ]
        for logfile_path in self.logfile_paths:
            new_log_file = open(logfile_path, mode='wt', buffering=1)
            self.output_destinations += [ new_log_file ]
            new_log_file.write('Hello, traveler. This is the beginning of a log file called: "%s".\n' % self.name)
            new_log_file.write('Some basic system info about the host machine: %s\n' % str(os.uname()))
            new_log_file.write('This log was begun %s\n\n\n\n' % datetime.datetime.now().strftime('%A, %d %B %Y at %H:%M'))
            self.width = -1

    def __del__(self):
        """Clean up. More specifically: close any open files that aren't standard
        streams.
        """
        if sys is not None:
            for dest in self.output_destinations:
                if dest not in [sys.stdout, sys.stderr, sys.stdin]:
                    dest.close()

    def log_it(self, message, minimum_level=1):
        """Add a message to the log if the current verbosity_level is at least the minimum_level of the message.
        """
        if verbosity_level >= 6:    # set verbosity to at least 6 to get this message output in the debug log
            self.log_it("\nDEBUGGING: function log_it() called", 1)
        if verbosity_level >= minimum_level:
            for dest in self.output_destinations:
                print('\n'.join(text_handling._get_wrapped_lines(message)), file=dest)

the_logger = Logger()


def log_it(message, minimum_level=1):
    """Convenience function to wrap the automatically created default Logger object."""
    the_logger.log_it(message, minimum_level)