wai-logging

Simple helper library for logging.

Installation

From PyPI:

pip install wai_logging

From Github:

pip install git+https://github.com/waikato-datamining/wai-logging.git

Methods

The following helper methods are available:

• init_logging - initializes the logging with a default level, which can be overridden with an environment variable
• set_logging_level - sets the logging level of a logging.Logger instance
• str_to_logging_level - turns a string logging level into a logging module one, used by init_logging and set_logging_level
• add_logging_level - adds an option for the logging level to an argparse.ArgumentParser instance
• add_logger_name - adds an option for a custom name for a logger to an argparse.ArgumentParser instance

Usage

Below are some examples on how to use the aforementioned methods and what the output may look like.

Example 1

The following logging setup only outputs on stderr using a simple format without timestamps:

from wai.logging import init_logging, LOGGING_INFO, set_logging_level
import logging

init_logging(LOGGING_INFO)
logger = logging.getLogger("my.test")
set_logging_level(logger, LOGGING_INFO)
logger.debug("debugging output")
logger.info("info output")
logger.warning("warning output")

The output:

INFO:my.test:info output
WARNING:my.test:warning output

Example 2

This configuration uses timestamps in its output (log_format; see format strings) and logs to a file as well (filename):

from wai.logging import init_logging, LOGGING_INFO, set_logging_level, TIMESTAMP_LOG_FORMAT
import logging

init_logging(LOGGING_INFO, filename="./out.log", log_format=TIMESTAMP_LOG_FORMAT)
logger = logging.getLogger("my.test")
set_logging_level(logger, LOGGING_INFO)
logger.debug("debugging output")
logger.info("info output")
logger.warning("warning output")

The output:

2025-01-14 09:25:22,837 - INFO - my.test - info output
2025-01-14 09:25:22,837 - WARNING - my.test - warning output

Example 3

The following setup uses a rotating file handler and keeps a maximum of three backups (backupCount; log files get a numeric suffix like .1). A rotation is initiated when the process is restarted and the log file exceeds 100 bytes (maxBytes).

from wai.logging import init_logging, LOGGING_INFO, set_logging_level
import logging.handlers

init_logging(LOGGING_INFO, handlers=[
    logging.StreamHandler(), 
    logging.handlers.RotatingFileHandler(filename="./out.log", backupCount=3, maxBytes=100)])
logger = logging.getLogger("my.test")
set_logging_level(logger, LOGGING_INFO)
logger.debug("debugging output")
logger.info("info output")
logger.warning("warning output")

The output:

INFO:my.test:info output
WARNING:my.test:warning output