liveBook · Manning

getLogger

As explained in Python How-To

getLogger is a function in Python's logging module that returns the named logger associated with a logging hierarchy.

Need one consistent logger across a module or application? Call logging.getLogger(name) instead of constructing Logger directly. The named logger can be retrieved from multiple places, configured once, and reused throughout the application. section 12.1.1

logger_good = logging.getLogger("task_app")

Retrieve a named logger with logging.getLogger rather than creating a Logger instance directly. section 12.1.1

For a module-level logger, use logging.getLogger(__name__). The module’s __name__ supplies its name, giving each module an identifiable logger while preserving shared retrieval for that name. section 12.1.1 section 12.1.5

Prefer getLogger because it:

  • Returns the same named logger when called repeatedly. section 12.1.1
  • Avoids separately configuring multiple distinct Logger instances for the same module. section 12.1.1
  • Works with handlers, logging levels, and formatted records configured for the logger. section 12.6

Avoid duplicate handlers

Repeated setup can attach multiple file handlers to the same logger and produce duplicate records. Check whether the logger has handlers before adding one; existing handlers can also be removed through the logger’s handlers list. section 12.1.5

How Python How-To covers it

How deep it goes
Explains shared identity, module naming, and handler implications, but defers detailed logging configuration.
Examples
Uses named logger snippets, repeated identity assertions, logging.getLogger(__name__), and a duplicate-handler troubleshooting exercise.
What it assumes
Assumes basic Python modules and objects while teaching logger creation and module-level naming directly.
What you can do after
Apply it via Python’s logging module to create consistent module-level and application-level loggers.
How it connects
Connects getLogger with the Logger class, module names, handlers, logging levels, and formatted log records.
Cover of Python How-To
liveBookmanning.com
Read Python How-To on liveBook Get the book at manning.com

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Python How-To. The section links point to the parts of the book it draws on.