Why Loguru Beats Python’s Built‑in Logging: A Hands‑On Guide

Introduction

Loguru: a more elegant logging solution!

loguru

is a simple yet powerful third‑party logging library for Python that adds useful features to the standard logger, reducing the pain of Python logging.

1. Why use Loguru

Simple and convenient way to output the logs you need.

When writing Python scripts you often need logs to debug issues and record important information.

The built‑in logging module requires manual handler/formatter configuration, which can be cumbersome.

import logging
logger = logging.getLogger('xxx')
handler = logging.StreamHandler()
formatter = logging.Formatter('%(asctime)s %(name)-12s %(levelname)-8s %(message)s')
handler.setFormatter(formatter)
logger.addHandler(handler)
logger.setLevel(logging.DEBUG)
logger.debug('This is a %s', 'test')

Loguru works out of the box without such initialization.

# pip install loguru

2. Features

Key advantages of Loguru.

Ready‑to‑use, no setup required.

No explicit initialization; just import and use.

Easy file rotation, retention, compression.

Elegant string formatting.

Exception catching in threads or main thread.

Customizable log level styles.

Async‑compatible and thread‑/process‑safe.

Lazy evaluation.

Suitable for scripts and libraries.

Full compatibility with the standard logging module.

Improved datetime handling.

3. Quick start

Common Loguru operations.

from loguru import logger
logger.debug("That's it, beautiful and simple logging!")

Adding a handler:

logger.add(sys.stderr,
    format="{time} {level} {message}",
    filter="my_module",
    level="INFO")

File rotation and retention:

logger.add("file_{time}.log")
logger.add("file_{time}.log", rotation="500 MB")
logger.add("file_{time}.log", rotation="12:00")
logger.add("file_{time}.log", rotation="1 week")
logger.add("file_X.log", retention="10 days")
logger.add("file_Y.log", compression="zip")

Lazy evaluation:

logger.opt(lazy=True).debug("If sink level <= DEBUG: {x}", x=lambda: expensive_function(2**64))

Custom log level:

new_level = logger.level("SNAKY", no=38, color="<yellow>", icon="🐍")
logger.log("SNAKY", "Here we go!")

4. Important details

add() parameters and removal.

sink

can be a file path, file object, stream, another logging handler, or a custom callable.

Calling remove(id) disables the previously added sink.

trace = logger.add('runtime.log')
logger.debug('this is a debug message')
logger.remove(trace)
logger.debug('this is another debug message')

Integration with Flask (example omitted for brevity).