import logging
import random
import sys

MIN_LENGTH = 5
FIRST_LETTER = 'a'
MESSAGES = ['ant', 'antler', 'bear', 'berry']

logger = logging.getLogger('filter.test') # use root default of WARNING
logger.addHandler(logging.NullHandler()) # we don't want emission of messages to be measured

def lengthFilterFunction(record):
    return len(record.getMessage()) > MIN_LENGTH

class FirstLetterFilter(object):
    
    def filter(self, record):
        message = record.getMessage()
        return message and message[0].lower() == FIRST_LETTER


allowed = ['none', 'all']

def arg_error_exit():
    print(f'use one of {allowed} as an argument, followed by # of log messages to create')
    sys.exit(1)

def main():
    if len(sys.argv) < 3:
        arg_error_exit()
    try:
        option = allowed.index(sys.argv[1].lower())  # 0 (none) is falsy, 1 (all) is truthy
    except:
        arg_error_exit()
    if option:
        _ = logging.Filter('filter')  # should be applied automatically by namespace rules
        logger.addFilter(lengthFilterFunction)
        logger.addFilter(FirstLetterFilter())
    num_messages = int(sys.argv[2])
    random.seed(420)
    numeric_msg = (True, False)
    for i in range(num_messages):
        if random.choice(numeric_msg):
            logger.warning('Number %s', i)
        else:
            logger.warning(random.choice(MESSAGES))

if __name__ == '__main__':
    main()