Logging Tree

1.10 · active · verified Fri Apr 17

The `logging-tree` library provides a simple way to introspect and display the logger hierarchy from Python's built-in `logging` module. It helps developers visualize how loggers are configured, including their levels and handlers. The current version is 1.10, with releases occurring periodically to add minor features or address issues.

Common errors

```
ModuleNotFoundError: No module named 'logging_tree'
```
cause The `logging-tree` library is not installed in your Python environment.

fix Run `pip install logging-tree` to install the library.
```
My logging tree output is not appearing in my log file / specific handler output.
```
cause `logging_tree.printout()` by default sends its output directly to standard output (`sys.stdout`), not through the `logging` system's handlers.

fix To redirect the output, use the `file` argument: `from io import StringIO; output = StringIO(); printout(file=output); tree_string = output.getvalue()`.
```
The displayed logging tree only shows 'root' and nothing else, even though my application uses logging.
```
cause While your application may use logging, it might only be using the root logger or loggers that haven't been explicitly retrieved with `logging.getLogger('name')`, or your `printout()` call happens before loggers are fully initialized.

fix Ensure that named loggers are created and active before calling `printout()`. Also, verify that you are indeed defining distinct loggers beyond the root. For example, explicitly call `logging.getLogger('my_app')` at some point in your code.

Warnings

gotcha `printout()` writes to `sys.stdout` by default.
Fix: If you need to capture the output, pass a `file` object to `printout()`, e.g., `printout(file=my_file_object)`, or redirect `sys.stdout`.
gotcha An 'empty' or minimal tree might be displayed if no named loggers are actively used or configured.
Fix: Ensure that your application explicitly retrieves and potentially configures named loggers (e.g., `logging.getLogger('my_app')`) before calling `printout()` to see a detailed tree.
deprecated The `main()` function is deprecated.
Fix: Use `printout()` directly instead of `main()` for displaying the logging tree.

Install

pip install logging-tree Install stable version

Imports

printout
```
from logging_tree import printout
```
This is the primary function for displaying the logging tree.

Quickstart

This example configures a basic logging hierarchy and then uses `logging_tree.printout()` to display the structure of all active loggers, their levels, and handlers.

import logging
from logging_tree import printout

# Configure some loggers to demonstrate the tree
root_logger = logging.getLogger()
root_logger.setLevel(logging.INFO)
root_logger.addHandler(logging.StreamHandler())

app_logger = logging.getLogger('my_app')
app_logger.setLevel(logging.DEBUG)

module_logger = logging.getLogger('my_app.sub_module')
module_logger.setLevel(logging.WARNING)

# Log some messages to ensure loggers are active
root_logger.info('Root logger message')
app_logger.debug('App logger message')
module_logger.warning('Sub-module logger message')

# Display the logging tree
print('\nLogging Tree:')
printout()

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