39_logging.md

39. Logging

Source: src/csharp_to_python_learning/concepts/08_concurrency_and_systems/topic_39_logging.py

What C# developers usually expect C# developers usually expect explicit type declarations, predictable object lifetimes, and compile-time guidance.

C# example Simple equivalent:

Console.WriteLine("INFO service started");

Advanced equivalent:

Console.WriteLine("billing WARNING quota low");

Simple Python example from this file

import logging

logging.basicConfig(level=logging.INFO, format="%(levelname)s %(message)s")
logging.info("service started")

Advanced Python example from this file

import logging

logger = logging.getLogger("billing")
handler = logging.StreamHandler()
handler.setFormatter(logging.Formatter("%(name)s %(levelname)s %(message)s"))
logger.addHandler(handler)
logger.setLevel(logging.WARNING)
logger.warning("quota low")

Python equivalent Python approaches this concept with less ceremony: Structured, leveled logging is the production replacement for print debugging. You still keep production discipline through tests, typing, and tooling.

Detailed explanation for C# developers Structured, leveled logging is the production replacement for print debugging. In practice, combine this with logging, tests, and type hints so the flexibility does not turn into ambiguity. Prefer small functions, clear data boundaries, and explicit contracts where behavior matters.

Common mistakes for C# developers

1. Assuming C# defaults apply directly in Logging without checking Python runtime behavior.
2. Skipping tests because dynamic code feels simpler at first; regressions grow quickly without guardrails.

Exercises

1. Rewrite one recent C# snippet in Python using this concept: Logging.
2. Add input validation, type hints, and one pytest test for the rewritten snippet.

Expected output

• INFO service started
• billing WARNING quota low