logging_extras

A collection of useful logging tools for Python 3.

Installation

The majority of the tools in this library require no additional dependencies. To install the library with the base functionality use the following command.

pip install logging-extras

To use the MQTT* classes, install the library with the following command.

pip install logging-extras[mqtt]

Tools

• MQTThandler - A logging handler that publishes logs to an MQTT broker.
• RelativeTimeFilter - A logging filter that adds a relative time to the log record.
• DiffTimeFilter - A logging filter that adds a time difference to the log record.
• TieredFormatter - A logging formatter that allows for different formatting based on the log level.
• log_function_call - A decorator that logs the arguments and return value of a function call.

Upcomming tools:

• MQTTSubscriber - A logging listener that subscribes to an MQTT broker and logs messages.

Examples

MQTThandler

import logging

from paho.mqtt.client import Client
from logger_extras import MQTTConfig, MQTThandler

handler = MQTThandler(
    host="localhost",
    topic="logs",
    append_logger_name=True,
)
handler.setFormatter(logging.Formatter("%(levelname)s - %(message)s)"))

logger = logging.getLogger(__name__)
logger.addHandler(handler)
logger.setLevel(logging.INFO)

logger.info("Hello World!")

# This will publish the following message to the MQTT broker on the topic "logs/__main__":
# {
#   "timestamp": 1690226241.740354,
#   "message": "INFO - Hello World!",
#   "raw_message": "Hello World!",
#   "level": "INFO", "name": "__main__"
# }

RelativeTimeFilter

import logging
from time import sleep

from logger_extras import RelativeTimeFilter

handler = logging.StreamHandler()
relative_time_filter = RelativeTimeFilter()
handler.addFilter(relative_time_filter)
handler.setFormatter(logging.Formatter("%(reltime).3f - %(message)s"))

logger = logging.getLogger(__name__)
logger.addHandler(handler)
logger.setLevel(logging.INFO)

logger.info("Hello World!")
sleep(2)
logger.info("Hello World!")
relative_time_filter.reset_time_reference()
sleep(1)
logger.info("Hello World!")

# This will log the following:
# 0:00:00 - Hello World!
# 0:00:02 - Hello World!
# 0:00:01 - Hello World!

DiffTimeFilter

import logging
from time import sleep

from logger_extras import DiffTimeFilter

handler = logging.StreamHandler()
handler.addFilter(DiffTimeFilter())
handler.setFormatter(logging.Formatter("%(difftime).3f - %(message)s"))

logger = logging.getLogger(__name__)
logger.addHandler(handler)
logger.setLevel(logging.INFO)

logger.info("Hello World!")
sleep(2)
logger.info("Hello World!")
sleep(1)
logger.info("Hello World!")

# This will log the following:
# 0:00:00 - Hello World!
# 0:00:02 - Hello World!
# 0:00:01 - Hello World!

TieredFormatter

import logging

from logger_extras import TieredFormatter

handler = logging.StreamHandler()
handler.setFormatter(
    TieredFormatter(
        fmt="%(levelname)s - %(message)s",
        level_fmts={
            logging.DEBUG: "%(levelname)s - %(funcName)s:%(lineno)d - %(message)s",
            logging.INFO: "%(message)s",
        },
        datefmt=None,
        style="%",
        validate=True,
    )
)

logger = logging.getLogger(__name__)
logger.addHandler(handler)
logger.setLevel(logging.INFO)

logger.debug("Hello World!")
logger.info("Hello World!")
logger.warning("Hello World!")
logger.error("Hello World!")
logger.critical("Hello World!")

# This will log the following:
# DEBUG - __main__:19 - Hello World!
# Hello World!
# WARNING - Hello World!
# ERROR - Hello World!
# CRITICAL - Hello World!

log_function_call

from logger_extras import log_function_call

@log_function_call(level=logging.INFO)
def add(a, b):
    return a + b

_ = add(1, 2)
# This will log the following:
# 2021-08-03 12:00:00,000 - INFO - Calling __main__.add(a=1, b=2)
# 2021-08-03 12:00:00,000 - INFO - '__main__.add' returned 3