Project: structlog

structlog is the production-ready logging solution for Python:

• Simple: Everything is about functions that take and return dictionaries – all hidden behind familiar APIs.
• Powerful: Functions and dictionaries aren’t just simple but also powerful. structlog leaves you in control.
• Fast: structlog is not hamstrung by designs of yore. Its flexibility comes not at the price of performance.

Thanks to its flexible design, you choose whether you want structlog to take care of the output of your log entries or whether you prefer to forward them to an existing logging system like the standard library's logging module.

The output format is just as flexible and structlog comes with support for JSON, logfmt, as well as pretty console output out-of-the-box:

Sponsors

structlog would not be possible without our amazing sponsors. Especially those generously supporting us at the The Organization tier and higher:

Please consider joining them to help make structlog’s maintenance more sustainable!

structlog has been successfully used in production at every scale since 2013, while embracing cutting-edge technologies like asyncio, context variables, or type hints as they emerged. Its paradigms proved influential enough to help design structured logging packages across ecosystems.

Project Links

• Get Help (use the structlog tag on Stack Overflow)
• PyPI
• GitHub
• Documentation
• Changelog
• Third-party Extensions

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Release Information

Added

• The colorful development logger is now even more configurable! Choose freely your colors and the order of the key-value pairs! Implement your own formatters for certain keys!

  Implementing the output on top of the new columns API has changed the default very slightly, but shouldn't be noticeable. #577

• Async log methods (those starting with an a) now also support the collection of callsite information using structlog.processors.CallsiteParameterAdder. #565

Changed

• structlog.stdlib.recreate_defaults() now also adds structlog.stdlib.add_logger_name to the processors. Check out the updated screenshot!

Fixed

• The return value from get_logger() (a BoundLoggerLazyProxy) now passes isinstance-checks against structlog.typing.BindableLogger on Python 3.12. #561

• structlog.threadlocal.tmp_bind() now also works with BoundLoggerLazyProxy (in other words: before anything is bound to a bound logger).

• stdlib: ProcessorFormatter can now be told to not render the log record message using getMessage and just str(record.msg) instead. #550

• stdlib: structlog.stdlib.BoundLogger.exception()'s handling ofLogRecord.exc_info is now set consistent with logging. #571 #572

Full Changelog →

Credits

structlog is written and maintained by Hynek Schlawack. The idea of bound loggers is inspired by previous work by Jean-Paul Calderone and David Reid.

The development is kindly supported by my employer Variomedia AG, structlog’s Tidelift subscribers, and all my amazing GitHub Sponsors.

The logs-loving beaver logo has been contributed by Lynn Root.