logzy 0.1.2

A tool for converting f-strings in log functions to lazy-logging

Introduction

ALPHA SOFTWARE: Use at your own risk. Carefully vet the suggestions.

logzy is a linter / fixer that ensures Python log message arguments are in lazy-logging format. This is recommended so that arguments to the log messages are only rendered if they're emitted. Performance regressions can be occur if objects are being rendered even if the log message isn't being emitted.

For example:

import logging

log = logging.getLogger()

user = "root"

# Bad
log.warning(f"Login failed for {user}")

# Good
log.warning("Login failed for %s", user)

You may have seen tools like pylint complain about logging-fstring-interpolation, logging-format-interpolation, or logging-not-lazy.

Installation

pip install logzy

Usage

Since logzy only works on f-strings right now, you probably want to convert everything to an f-string first using a tool like flynt or pyupgrade

TODO

• Make quote character intelligent
  • Check for any quote chars inside message string
  • Make the default configurable on the command line
• logging.log(level, f"{message}")
• Non f-string parameters to log functions (ie .format() or %)
• Untested f-strings:
  • Multiline f-string
  • Nested f-string