Getting Serious with Loguru: Real-World Configuration

Written by: Marlon Colca
Posted on 02 May 2025 - 5 months ago
python logging loguru

Now it's time to take logging seriously

After your first logger.info("Hello world"), it’s time to take logging seriously.
In this post, we’ll cover how to configure rotation, retention, compression, and how to combine console + file logging effectively for real-world use cases.

🚀 Basic Loguru Setup

from loguru import logger

logger.add("app.log")
logger.info("Starting the application")

But that doesn’t scale. In production, you need to control:

• How large your logs can grow.

• How long to keep them.

• How to archive them.

• Where to send them.

📦 Log Rotation

logger.add("app.log", rotation="10 MB")

Or rotate daily:

logger.add("app.log", rotation="00:00")  # Every midnight

🧹 Log Retention

Automatically delete old logs:

logger.add("app.log", rotation="10 MB", retention="7 days")

Or keep just the last 5 files:

logger.add("app.log", rotation="10 MB", retention=5)

🗜️ Compression

If you’re storing logs, compress them to save space:

logger.add("app.log", rotation="100 MB", retention="10 days", compression="zip")

Also supports "gz", "tar", etc.

🎯 Logging Levels per Output

Send different log levels to different outputs:

logger.add(sys.stderr, level="INFO")        # Only INFO+ to console
logger.add("debug.log", level="DEBUG")      # Full details to file

🧪 Full Setup Example

from loguru import logger
import sys

logger.remove()  # Clear default handlers

logger.add(
    "app.log",
    rotation="10 MB",
    retention="10 days",
    compression="zip",
    level="DEBUG"
)

logger.add(sys.stderr, level="INFO")

🧠 Pro Tip: Environment-Based Config

import os

level = "DEBUG" if os.getenv("ENV") == "dev" else "INFO"

logger.add("app.log", level=level, rotation="5 MB", retention="7 days")

✅ Conclusion

Loguru makes it easy to set up a production-grade logging system in just a few lines. You get power and simplicity, without the headache of configuring the standard logging module.

🔜 Coming up next

👉 Structured logging with Loguru for ELK and other observability tools

🔜 Coming up next

Structured Logging with Loguru: JSON for Observability Tools

When you're sending logs to ELK, Datadog, or any log aggregator, plain text isn't enough.

03 May 2025 - 5 months ago