Python Logging

Overview

Choose the logging system based on project needs. Core principle: stdlib logging for libraries and ecosystem integration, loguru for fast, simple app/CLI logging.

Quick Reference

Need Use

Library or long-lived service stdlib logging

Simple app or CLI loguru

Integrations (Sentry/OTel) stdlib logging

Decision Rules

Use stdlib logging when:

• Building a reusable library

• You need handler hierarchies or integration with ops tooling

Use loguru when:

• You want minimal setup and readable output

• You are building a small app or CLI

Example

Stdlib logger setup:

import logging

logging.basicConfig(level=logging.INFO) logger = logging.getLogger(name) logger.info("App started")

Common Mistakes

• Forcing loguru in a reusable library.

• Mixing two logging systems without a clear boundary.

Red Flags

• Logging recommendations with no rationale for library vs app use.

References

• references/logging.md

• stdlib logging patterns

• references/loguru.md

• loguru patterns