logzero

library1.7.0pypypi✓ verified 22d ago

logzero is a Python library (version 1.7.0) that provides robust and effective logging for both Python 2 and 3. It simplifies logging to the console with pretty, level-specific colored output and supports logging to rotating files. The library also includes built-in JSON logging capabilities, aiming for a low-boilerplate approach to standard Python logging. Its release cadence is generally stable with occasional updates.

observability

pip install logzero

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · LOGZERO

logzero

observabilitypythonv1.7.0

Install

1.6s avg

Import

69ms

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.7.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.072s · 17.9MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.6s · import 0.066s · 18MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

logger

✓ from logzero import logger

logzero module functions

✓ import logzero logzero.logfile('/path/to/file.log')

✗ from logzero import logfile # While possible, direct import of module-level functions is less common than importing 'logger' and accessing functions via 'logzero.' prefix.

Many configuration functions like `logfile`, `loglevel`, `json` are typically called as `logzero.function_name()` after `import logzero`.

This quickstart demonstrates basic console and rotating file logging, setting a global log level, and handling exceptions with `logger.exception()`.

from logzero import logger, logfile import os # Configure a logfile that rotates after 1MB, keeping 3 backups log_file_path = os.path.join(os.getcwd(), "app.log") logfile(log_file_path, maxBytes=1_000_000, backupCount=3) # Set the global minimum log level to INFO logger.setLevel(os.environ.get('LOG_LEVEL', 'INFO')) logger.debug("This is a debug message - won't show with INFO level.") logger.info("Application started successfully.") logger.warning("Disk space is getting low.") try: 1 / 0 except ZeroDivisionError as e: logger.exception(f"An error occurred: {e}")

Debug

Known issues

gotchalogzero outputs all log messages to `stderr` by default, not `stdout`. Users expecting `print()`-like behavior to `stdout` might find their logs redirected, requiring explicit redirection if they want `stdout` for other application output.

fix

Be aware that log output goes to stderr. If you need it in stdout, you might need to redirect stderr to stdout at the shell level, or configure a custom handler to explicitly output to `sys.stdout`.

affects: All versions

gotchaWhen using `logzero.logfile()`, the default parameters `maxBytes=0` and `backupCount=0` disable log file rotation. This means log files will grow indefinitely unless these parameters are explicitly configured to enable rotation.

fix

Always set `maxBytes` and `backupCount` to non-zero values when calling `logzero.logfile()` if log file rotation is desired (e.g., `logzero.logfile('/path/to/app.log', maxBytes=1_000_000, backupCount=3)`).

affects: All versions

gotchaFunctions like `logzero.loglevel()`, `logzero.logfile()`, and `logzero.formatter()` globally reconfigure the *default* `logzero.logger` instance and all its internal handlers. This can unintentionally affect logging behavior across different modules or parts of a larger application if not managed carefully.

fix

For specific logging configurations in different parts of your application, use `logzero.setup_logger(name=...)` to create isolated logger instances instead of relying solely on the global `logzero.logger` and its module-level configuration functions.

affects: All versions

gotchaIf a custom formatter (set via `logzero.formatter()`) includes ANSI color codes and is applied to file handlers without stripping them, log files may contain these escape sequences, making them harder to read in plain text editors.

fix

When using custom formatters for file logging, ensure that color codes are either removed from the format string or handled by a custom `Formatter` class that strips them for file output, or configure separate formatters for stream and file handlers.

affects: All versions

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'logzero'

The logzero library has not been installed in your Python environment or is not accessible within your current project's interpreter.

fix

Install the logzero library using pip: `pip install logzero`

AttributeError: 'Logger' object has no attribute 'WARNING'

You are attempting to call a log level method (e.g., `warning`, `info`, `debug`) using its uppercase constant name (e.g., `WARNING`, `INFO`, `DEBUG`) instead of its lowercase method name.

fix

Use the lowercase method for logging levels: `logger.warning("This is a warning")`

logzero log file not rotating / growing indefinitely

By default, `logzero.logfile()` creates a file that grows indefinitely (no rotation) unless `maxBytes` and `backupCount` parameters are explicitly set.

fix

Configure log rotation by specifying `maxBytes` and `backupCount` when calling `logzero.logfile()`: `logzero.logfile("/tmp/rotating-logfile.log", maxBytes=1e6, backupCount=3)`

logzero output to console and file simultaneously, how to disable console output?

By default, logzero logs to both the console (specifically stderr) and any configured log file. Developers often want to disable console output when logging to a file.

fix

Disable the default stderr logger when setting up the logger: `logger = logzero.setup_default_logger(disableStderrLogger=True)` or `logzero.logfile("your.log", disableStderrLogger=True)` if you are just using `logzero.logfile()`.

Upgrade

Version history

1.7.0latest on PyPI · released Mar 17, 2021

Audit

Dependencies

python-json-loggeroptionalUsed for JSON logging functionality (logzero.json() or setup_logger(json=True)).

coloramaoptionalEnables colored console output on Windows systems.

Agent activity

21 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/metachris/logzero ↗

packagehttps://pypi.org/project/logzero/ ↗

homepagehttps://logzero.readthedocs.io ↗