logzero

1.7.0 · active · verified Sun Apr 12

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.

Warnings

gotcha logzero 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`.
gotcha When 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)`).
gotcha Functions 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.
gotcha If 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.

Install

pip install logzero Install with pip

Imports

logger
```
from logzero import logger
```
logzero module functions
```
import logzero
logzero.logfile('/path/to/file.log')
```
Many configuration functions like `logfile`, `loglevel`, `json` are typically called as `logzero.function_name()` after `import logzero`.

Quickstart

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}")

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