# structlog **Repository Path**: jingcheng_989/structlog ## Basic Information - **Project Name**: structlog - **Description**: Structured Logging for Python - **Primary Language**: Unknown - **License**: MIT - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2019-09-16 - **Last Updated**: 2024-06-10 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README .. image:: https://www.structlog.org/en/latest/_static/structlog_logo_small.png :alt: structlog Logo :width: 256px :target: https://www.structlog.org/ ============================================ ``structlog``: Structured Logging for Python ============================================ .. image:: https://img.shields.io/pypi/v/structlog.svg :target: https://pypi.org/project/structlog/ :alt: PyPI .. image:: https://readthedocs.org/projects/structlog/badge/?version=stable :target: https://www.structlog.org/en/stable/?badge=stable :alt: Documentation Status .. image:: https://dev.azure.com/the-hynek/structlog/_apis/build/status/hynek.structlog?branchName=master :target: https://dev.azure.com/the-hynek/structlog/_build?definitionId=1 :alt: CI Status .. image:: https://codecov.io/github/hynek/structlog/branch/master/graph/badge.svg :target: https://codecov.io/github/hynek/structlog :alt: Test Coverage .. image:: https://img.shields.io/badge/code%20style-black-000000.svg :target: https://github.com/ambv/black :alt: Code style: black .. -begin-short- ``structlog`` makes logging in Python less painful and more powerful by adding structure to your log entries. It's up to you whether you want ``structlog`` to take care about 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. .. -end-short- Once you feel inspired to try it out, check out our friendly `Getting Started tutorial `_ that also contains detailed installation instructions! .. -begin-spiel- If you prefer videos over reading, check out this DjangoCon Europe 2019 talk by `Markus Holtermann `_: "`Logging Rethought 2: The Actions of Frank Taylor Jr. `_". Easier Logging ============== You can stop writing prose and start thinking in terms of an event that happens in the context of key/value pairs: .. code-block:: pycon >>> from structlog import get_logger >>> log = get_logger() >>> log.info("key_value_logging", out_of_the_box=True, effort=0) 2016-04-20 16:20.13 key_value_logging effort=0 out_of_the_box=True Each log entry is a meaningful dictionary instead of an opaque string now! Data Binding ============ Since log entries are dictionaries, you can start binding and re-binding key/value pairs to your loggers to ensure they are present in every following logging call: .. code-block:: pycon >>> log = log.bind(user="anonymous", some_key=23) >>> log = log.bind(user="hynek", another_key=42) >>> log.info("user.logged_in", happy=True) 2016-04-20 16:20.13 user.logged_in another_key=42 happy=True some_key=23 user='hynek' Powerful Pipelines ================== Each log entry goes through a `processor pipeline `_ that is just a chain of functions that receive a dictionary and return a new dictionary that gets fed into the next function. That allows for simple but powerful data manipulation: .. code-block:: python def timestamper(logger, log_method, event_dict): """Add a timestamp to each log entry.""" event_dict["timestamp"] = time.time() return event_dict There are `plenty of processors `_ for most common tasks coming with ``structlog``: - Collectors of `call stack information `_ ("How did this log entry happen?"), - …and `exceptions `_ ("What happened‽"). - Unicode encoders/decoders. - Flexible `timestamping `_. Formatting ========== ``structlog`` is completely flexible about *how* the resulting log entry is emitted. Since each log entry is a dictionary, it can be formatted to **any** format: - A colorful key/value format for `local development `_, - `JSON `_ for easy parsing, - or some standard format you have parsers for like nginx or Apache httpd. Internally, formatters are processors whose return value (usually a string) is passed into loggers that are responsible for the output of your message. ``structlog`` comes with multiple useful formatters out-of-the-box. Output ====== ``structlog`` is also very flexible with the final output of your log entries: - A **built-in** lightweight printer like in the examples above. Easy to use and fast. - Use the **standard library**'s or **Twisted**'s logging modules for compatibility. In this case ``structlog`` works like a wrapper that formats a string and passes them off into existing systems that won't ever know that ``structlog`` even exists. Or the other way round: ``structlog`` comes with a ``logging`` formatter that allows for processing third party log records. - Don't format it to a string at all! ``structlog`` passes you a dictionary and you can do with it whatever you want. Reported uses cases are sending them out via network or saving them in a database. .. -end-spiel- .. -begin-meta- Getting Help ============ Please use the ``structlog`` tag on `StackOverflow `_ to get help. Answering questions of your fellow developers is also great way to help the project! Project Information =================== ``structlog`` is dual-licensed under `Apache License, version 2 `_ and `MIT `_, available from `PyPI `_, the source code can be found on `GitHub `_, the documentation at https://www.structlog.org/. We collect useful third party extension in `our wiki `_. ``structlog`` targets Python 2.7, 3.5 and newer, and PyPy.