logging Module

print is fine when you're poking at a script in front of you. The moment code runs unattended, in a container, on a server, or as a scheduled job, you need something with levels, destinations, structured output, and a way to turn the noise up or down without redeploying. That's the job of the logging module in the standard library. This lesson covers why print falls apart, the five log levels and when to use each, the logger hierarchy, the four-piece pipeline that every log message flows through, how to configure logging cleanly with dictConfig, structured and JSON output, how to log exceptions properly, and the small performance trap of f-strings inside log calls.