errorlog.py

import os
import sys
import logging

from   pathlib import Path


_loggers = dict()

def get_logger(level=None, path=None, timestamps=False):
    '''
    Returns a logger, which can be used like logger.info('some message') etc.

    INPUTS: level ... None --> use environment variable
                      otherwise string like 'DEBUG', 'INFO', 'WARNING', 'ERROR', 'FATAL', 'CRITICAL'

            path  ... None --> do not log to disk
                      otherwise string of where to save all log messages (identical console printouts will also happen)

            timestamps ... boolean, to turn on inclusion of timestamps in log messages

    OUTPUTS: logger instance
    '''
    if level == 'DEBUG':
        loglevel = logging.DEBUG
    
    elif level == 'INFO':
        loglevel = logging.INFO
    
    elif level == 'WARN' or level == 'WARNING':
        loglevel = logging.WARNING
    
    elif level == 'ERROR':
        loglevel = logging.ERROR
    
    elif level == 'FATAL' or level == 'CRITICAL':
        loglevel = logging.CRITICAL
    
    else:
        raise ValueError('Unknown log level {}; should be DEBUG/INFO/WARNING/ERROR/CRITICAL'.format(level))

    if level not in _loggers:
        logger = logging.getLogger('lumfn.'+level)
        logger.setLevel(loglevel)

        #- handler and formatter code adapted from
        #- https://docs.python.org/3/howto/logging.html#configuring-logging

        # create console handler and set level to debug
        ch = logging.StreamHandler()
        ch.setLevel(loglevel)

        # optionally create file handler, similarly
        if path:
            fh = logging.FileHandler(filename=path, mode='a', encoding='utf-8')
            fh.setLevel(loglevel)
        else:
            fh = None

        # create formatter
        kwargs = {'fmt': '%(levelname)s:%(filename)s:%(lineno)s:%(funcName)s:%(message)s'}
        if timestamps:
            kwargs['fmt'] = '%(asctime)s:' + kwargs['fmt']
            kwargs['datefmt'] = '%Y %m %d %H:%M:%S:%z'

        formatter = logging.Formatter(**kwargs)

        # add formatter to ch
        ch.setFormatter(formatter)
        if fh:
            fh.setFormatter(formatter)

        # add handlers to logger
        logger.addHandler(ch)
        if fh:
            logger.addHandler(fh)

        _loggers[level] = logger

    return  _loggers[level]

errorlog_path = '{}/errors/errorlog.txt'.format(os.environ['GOLD_DIR'])
errorlog_dir  = os.path.dirname(errorlog_path) 

Path(errorlog_dir).mkdir(parents=True, exist_ok=True)

errorlog      = get_logger(level='DEBUG', path=errorlog_path, timestamps=True)

def handle_exception(exc_type, exc_value, exc_traceback):
    if issubclass(exc_type, KeyboardInterrupt):
        sys.__excepthook__(exc_type, exc_value, exc_traceback)
        return

    with open(errorlog_path, 'a') as fh:
        fh.write('\n\n**********************************************************************************\n')

    errorlog.error('ERROR', exc_info=(exc_type, exc_value, exc_traceback))

    with open(errorlog_path, 'a') as fh:
        fh.write('\n\n**********************************************************************************\n')

    print(f'ERROR:  logged at {errorlog_path}')


sys.excepthook = handle_exception


if __name__ == '__main__':
    raise  RuntimeError('Failed to findfile')