logfmter 0.0.1

A Python package which supports global logfmt formatted logging.

Python Logfmter

A Python package which supports global logfmt formatted logging.

Install

$ pip install logfmter

Usage

Before integrating this library, you should be familiar with Python's logging functionality. I recommend reading the Basic Logging Tutorial.

This package exposes a single Logfmter class that can be integrated into the standard library logging system similar to any logging.Formatter.

The provided formatter will logfmt encode all logs. Key value pairs are provided via the extra keyword argument or by passing a dictionary as the log message.

Basic

import logging
from logfmter import Logfmter

handler = logging.StreamHandler(sys.stderr)
handler.setFormatter(Logfmter())

logger = logging.getLogger()
logger.addHandler(handler)

logger.error("hello", extra={"alpha": 1}) # at=ERROR msg=hello alpha=1
logger.error({"token": "Hello, World!"}) # at=ERROR token="Hello, World!"

Customize

You can subclass the formatter to change its behavior.

import logging
from logfmter import Logfmter


class CustomLogfmter(Logfmter):
    """
    Provide a custom logfmt formatter which formats
    booleans as "yes" or "no" strings.
    """

    @classmethod
    def format_value(cls, value):
        if isinstance(value, bool):
            return "yes" if value else "no"

	return super().format_value(value)

handler = logging.StreamHandler(sys.stderr)
handler.setFormatter(CustomLogfmter())

logger = logging.getLogger()
logger.addHandler(handler)

logger.error({"example": True}) # at=ERROR example=yes

Development

Required Software

Refer to the links provided below to install these development dependencies:

• direnv
• git
• pyenv

Getting Started

Setup

$ <runtimes.txt xargs -n 1 pyenv install -s
$ direnv allow
$ pip install -r requirements/dev.txt
$ pre-commit install
$ pip install -e .

Tests

Run the test suite against the active python environment.

$ pytest

Run the test suite against the active python environment and watch the codebase for any changes.

$ ptw

Run the test suite against all supported python versions.

$ tox

Publishing

Build

$ python -m build

Upload

$ twine upload dist/*