Logging in Python

A breezy guide to using Python's built-in support for logging. The guide covers general concepts relevant to logging, logging APIs in Python and how to use them, and good practices, gotchas, and performance considerations associated with these APIs. Logging is an integral part of most modern apps. Almost all programming platforms provide built-in logging support with copious documentation. However, using logging APIs well takes some effort as one has to read the documentation and experiment with code samples. This guide is an attempt to reduce this effort and help developers to quickly be productive with logging API offered by Python's logging module. The guide is intended to supplement the reference documentation of Python's logging module. Python has offered built-in support for logging since version 2.3. This support includes library APIs for common concepts and tasks that are specific to logging and language-agnostic. This chapter introduces these concepts and tasks as realized and supported in Python’s logging library. The book contains a three-part guide. The first part introduces concepts and terms pertaining to logging in a programming language-agnostic manner. The second part describes how various elements of Python's logging module support these concepts and terms. This part covers both the API used for logging and the support for configuring the logging library. The third part discusses good practices and gotchas to consider when using Python's logging module. It also presents some performance considerations to keep in mind when using the logging module. To keep the guide short and respect the readers' time, I have tried to limit the presentation to definitions, rationale, samples, recommendations, and explanations, where necessary. When more details are warranted and are available in abundance elsewhere, links to such references are provided.