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 patternsreferences/loguru.md- loguru patterns