logzero

Robust and effective logging for Python 2 and 3.

• Documentation: https://logzero.readthedocs.io
• GitHub: https://github.com/metachris/logzero

Features

• Easy logging to console and/or (rotating) file.
• Provides a fully configured standard Python logger object.
• JSON logging (with integrated python-json-logger)
• Pretty formatting, including level-specific colors in the console.
• No dependencies
• Windows color output supported by colorama
• Robust against str/bytes encoding problems, works with all kinds of character encodings and special characters.
• Multiple loggers can write to the same logfile (also across multiple Python files and processes).
• Global default logger with logzero.logger and custom loggers with logzero.setup_logger(..).
• Compatible with Python 2 and 3.
• All contained in a single file.
• Licensed under the MIT license.
• Heavily inspired by the Tornado web framework.

Installation:

python -m pip install logzero

Example Usage

from logzero import logger

logger.debug("hello")
logger.info("info")
logger.warning("warn")
logger.error("error")

# This is how you'd log an exception
try:
    raise Exception("this is a demo exception")
except Exception as e:
    logger.exception(e)

# JSON logging
import logzero
logzero.json()

logger.info("JSON test")

# Start writing into a logfile
logzero.logfile("/tmp/logzero-demo.log")

# Set a minimum loglevel
logzero.loglevel(logzero.WARNING)

This is the output:

Note: You can find more examples in the documentation: https://logzero.readthedocs.io

JSON logging

JSON logging can be enabled for the default logger with logzero.json(), or with setup_logger(json=True) for custom loggers:

>>> logzero.json()
>>> logger.info("test")
{"asctime": "2020-10-21 10:42:45,808", "filename": "<stdin>", "funcName": "<module>", "levelname": "INFO", "levelno": 20, "lineno": 1, "module": "<stdin>", "message": "test", "name": "logzero_default", "pathname": "<stdin>", "process": 76179, "processName": "MainProcess", "threadName": "MainThread"}

>>> my_logger = setup_logger(json=True)
>>> my_logger.info("test")
{"asctime": "2020-10-21 10:42:45,808", "filename": "<stdin>", "funcName": "<module>", "levelname": "INFO", "levelno": 20, "lineno": 1, "module": "<stdin>", "message": "test", "name": "logzero_default", "pathname": "<stdin>", "process": 76179, "processName": "MainProcess", "threadName": "MainThread"}

The logged JSON object has these fields:

{
  "asctime": "2020-10-21 10:43:40,765",
  "filename": "test.py",
  "funcName": "test_this",
  "levelname": "INFO",
  "levelno": 20,
  "lineno": 9,
  "module": "test",
  "message": "info",
  "name": "logzero",
  "pathname": "_tests/test.py",
  "process": 76204,
  "processName": "MainProcess",
  "threadName": "MainThread"
}

Exceptions logged with logger.exception(e) have these additional JSON fields:

{
  "levelname": "ERROR",
  "levelno": 40,
  "message": "this is a demo exception",
  "exc_info": "Traceback (most recent call last):\n  File \"_tests/test.py\", line 15, in test_this\n    raise Exception(\"this is a demo exception\")\nException: this is a demo exception"
}

Take a look at the documentation for more information and examples:

• Documentation: https://logzero.readthedocs.io.

Installation

Install logzero with pip:

python -m pip install logzero

Here's how you setup a virtualenv and download and run the demo:

# Create and activate a virtualenv in ./venv/
python3 -m venv venv
. venv/bin/activate

# Install logzero
python -m pip install logzero

# Download and run demo.py
wget https://raw.githubusercontent.com/metachris/logzero/master/examples/demo.py
python demo.py

If you don't have pip installed, this Python installation guide can guide you through the process.

Alternatively, if you use the Anaconda distribution:

$ conda config --add channels conda-forge
$ conda install logzero

You can also install logzero from the public Github repo:

$ git clone https://github.com/metachris/logzero.git
$ cd logzero
$ python setup.py install

Contributors

• Chris Hager
• carlodr
• Brian Lenz
• David Martin
• Zakaria Zajac (creator of python-json-logger)

Development

Getting started

$ git clone https://github.com/metachris/logzero.git
$ cd logzero

# Activate virtualenv
$ python3 -m venv venv
$ . venv/bin/activate

# Install main and dev dependencies
$ pip install -e .
$ pip install -r requirements_dev.txt

# Run the tests
$ make test

# Run the linter
$ make lint

# Generate the docs (will auto-open in Chrome)
$ make docs

# You can enable watching mode to automatically rebuild on changes:
$ make servedocs

To test with Python 2.7, you can use Docker:

docker run --rm -it -v /Users/chris/stream/logzero:/mnt python:2.7 /bin/bash

Now you have a shell with the current directory mounted into /mnt/ inside the container.

Notes

• pytest is the test runner
• CI is run with Github actions.
• Download stats: https://pepy.tech/project/logzero

Changelog

See the changelog here: https://github.com/metachris/logzero/blob/master/HISTORY.md

Feedback

All kinds of feedback and contributions are welcome.

• Create an issue
• Create a pull request
• @metachris

History

1.6.5 (2021-03-17)

• Export loglevels directly (you can use eg. logzero.DEBUG instead of logging.DEBUG)
• setup_default_logger use backupCount
• Update dependencies
• PRs: (386)[https://github.com/metachris/logzero/pull/386]

1.6.3 (2020-11-15)

• JSON logging with UTF-8 enabled by default (PR 357)

1.6.0 (1.6.2) (2020-10-29)

• JSON logging support (PR 344)
• Ability to easily change colors (#82)
• Allow creating a root logger (#342)
• Bugfix: file logging with lower loglevel than stream (PR 338)
• Running tests with Python up to 3.9
• Dependency updates

1.5.0 (2018-03-07)

• logzero.syslog(..) (PR 83)

1.4.0 (2018-03-02)

• Allow Disabling stderr Output (PR 83)

1.3.0 (2017-07-19)

• Color output now works in Windows (supported by colorama)

1.2.1 (2017-07-09)

• Logfiles with custom loglevels (eg. stream handler with DEBUG and file handler with ERROR).

1.2.0 (2017-07-05)

• Way better API for configuring the default logger with logzero.loglevel(..), logzero.logfile(..), etc.
• Built-in rotating logfile support.

import logging
import logzero
from logzero import logger

# This log message goes to the console
logger.debug("hello")

# Set a minimum log level
logzero.loglevel(logging.INFO)

# Set a logfile (all future log messages are also saved there)
logzero.logfile("/tmp/logfile.log")

# Set a rotating logfile (replaces the previous logfile handler)
logzero.logfile("/tmp/rotating-logfile.log", maxBytes=1000000, backupCount=3)

# Disable logging to a file
logzero.logfile(None)

# Set a custom formatter
formatter = logging.Formatter('%(name)s - %(asctime)-15s - %(levelname)s: %(message)s');
logzero.formatter(formatter)

# Log some variables
logger.info("var1: %s, var2: %s", var1, var2)

1.1.2 (2017-07-04)

• Better reconfiguration of handlers, doesn't remove custom handlers anymore

1.1.0 (2017-07-03)

• Bugfix: Disabled color logging to logfile

1.1.0 (2017-07-02)

• Global default logger instance (logzero.logger)
• Ability to reconfigure the default logger with (logzero.setup_default_logger(..))
• More tests
• More documentation

1.0.0 (2017-06-27)

• Cleanup and documentation

0.2.0 (2017-06-12)

• Working logzero package with code and tests

0.1.0 (2017-06-12)

• First release on PyPI.