issue_log.py

# log_issue.py
"""
We want logging the output of a heavy_task function when the log level is debug.
The problem appears when we use info level and the whole process is being
affected by our debug log statement.


main : reproduce the problem
main_lazy : has the solution.

"""
import logging
from time import sleep


def heavy_task():
    """Consume time and returna a value.

    The generic goal of this function is to process a lot of info and return
    human readable output.
    """
    sleep(3)
    return 3


def main():
    """Reproduce the problem"""

    for i in range(3):
        logging.info("%s", i)
        logging.debug("%s", heavy_task())


# ----------------------------------------------------------------------------
# alternative

class LazyfyStr(object):
    # Taken from https://stackoverflow.com/a/52359695
    __slots__ = 'fn', 'args'

    def __init__(self, fn, *args):
        self.fn = fn
        self.args = args

    def __str__(self):
        return str(self.fn(*self.args))


def main_lazy():
    """Solution"""

    for i in range(3):
        logging.info("%s", i)
        logging.debug("%s", LazyfyStr(heavy_task))


# ----------------------------------------------------------------------------
# execution


if __name__ == "__main__":
    import sys
    logging.basicConfig(level=logging.INFO)

    try:
        lazy = sys.argv[1].lower() == "lazy"
    except IndexError:
        lazy = False

    if lazy:
        logging.info("Running lazy mode")
        main_lazy()
    else:
        logging.info("Running standar mode")
        main()