logging-extras 0.3.0b0
Python logging extensions
License: MIT
Keywords: python logging logger handler custom config dictconfig yaml

LOGGING EXTRAS
===============

A collection of various python logging extensions.

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Documentation
-------------
[https://logging-extras.readthedocs.io/en/latest/](https://logging-extras.readthedocs.io/en/latest/)

Installation
------------

Install [logging-extras](https://pypi.org/project/logging-extras/) using pip

    pip install logging-extras

Alternatively, download the latest binary or source package from [github](https://github.com/zobayer1/logging-extras/releases)

Install wheel package with `pip`:

    pip install logging_extras-{tags}.whl

Install source package as editable:

    tar -xf logging-extras-{tags}.tar.gz
    cd logging-extras-{tags}
    pip install -e .

Please refer to documentation pages for available modules.

Module Index
============

config.YAMLConfig
-----------------

YAMLConfig class can be used for loading YAML files with custom tags. This class adds a custom envvar tag to native YAML parser which is used to evaluate environment variables. Supports one or more environment variables in the form of `${VARNAME}` or `${VARNAME:DEFAULT}` within a string. If no default value is specified, empty string is used. Default values can only be treated as plain strings. YAMLConfig can also expand `~` or `~username` just like shells do, either directly hardcoded in YAML file or passed through environment variables.

### Example configuration:

File: **logging.yaml**
```
version: 1
formatters:
  simple:
    format: '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
handlers:
  console:
    class: logging.StreamHandler
    formatter: simple
    stream: ext://sys.stdout
  file_handler:
    class: logging.FileHandler
    filename: ${LOGGING_ROOT:.}/${LOG_FILENAME}
    formatter: simple
loggers:
  test_logger:
    level: DEBUG
    handlers:
      - file_handler
    propagate: no
root:
  level: NOTSET
  handlers:
    - console
```

**Note:** Ignore the backslashes as markdown must display those escape characters.

### Example Usage

File: **test_logger.py**
```
import logging
from logging_.config import YAMLConfig

with open("logging.yaml", "r") as config_file:
    YAMLConfig(config_file.read(), silent=True)

# alternatively, you can use
# YAMLConfig.from_file("logging.yaml", silent=True)

logger = logging.getLogger("test_logger")

logger.debug("This is a debug log")
logger.info("This is an info log")
logger.warning("This is an warning log")
logger.error("This is an error log")
logger.critical("This is a critical log")
```

**Note:** An (optional) explicit `silent=True` flag must be set to suppress any file or parsing related exceptions to be thrown.

handlers.QueueListenerHandler
-----------------------------

A simple `QueueHandler` subclass implementation utilizing `QueueListener` for configured handlers. This is helpful for detaching the logger handlers from the main threads, which reduces the risk of getting blocked, for example, when using slower handlers such as smtp, file, or socket handlers.

### Example configuration:

File: **logging.yaml**
```
version: 1
objects:
  queue:
    class: queue.Queue
    maxsize: 1000
formatters:
  simple:
    format: '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
handlers:
  console:
    class: logging.StreamHandler
    formatter: simple
    stream: ext://sys.stdout
  file_handler:
    class: logging.FileHandler
    filename: test_logger.log
    formatter: simple
  queue_handler:
    class: logging_.handlers.QueueListenerHandler
    handlers:
      - cfg://handlers.console
      - cfg://handlers.file_handler
    queue: cfg://objects.queue
loggers:
  test_logger:
    level: DEBUG
    handlers:
      - queue_handler
    propagate: no
root:
  level: NOTSET
  handlers:
    - console
```

**Note:** A queue object must be passed since the handler does not set a default queue implementation. Set `maxsize: -1` to make the queue unlimited.

### Example Usage

File: **test_logger.py**
```
import logging.config
import yaml

with open("logging.yaml", "r") as config_file:
    logging_config = yaml.safe_load(config_file.read())
    logging.config.dictConfig(logging_config)

logger = logging.getLogger("test_logger")

logger.debug("This is a debug log")
logger.info("This is an info log")
logger.warning("This is an warning log")
logger.error("This is an error log")
logger.critical("This is a critical log")
```

Development
===========

Additional development and documentation dependencies can be installed using extras. It is recommended to use a virtualenv.

### Use Pre-Commit Hooks

Install pre-commit hooks and dependencies:

    pip install pre-commit
    pre-commit install
    pre-commit autoupdate
    pre-commit run --all-files

### Run Tests

Run tests from the source with Pytest:

    pip install -e .[dev]
    pytest -s

### Generate Documentation

Generate documentation from the source with Sphinx:

    pip install -e .[doc]
    cd docs
    mkdir -p _static _templates
    make html
    python -m http.server --directory build/html

### No `requirements.txt` File

This is a python library package that is compatible with a wide range of Python versions. It does not make much sense to pin dependency versions in a traditional `requirements.txt` file. Instead, this project utilizes modern python packaging paradigms with `pyproject.toml` and `setup.cfg` files. However, sometimes some IDEs (i.e. PyCharm) cannot resolve dependencies without a `requirements.txt` file. To generate a `requirements.txt` file, simply run the following command within your venv:

    pip freeze > requirements.txt

### Create Distribution Packages

To create a source and wheel distribution, run:

    git clone git@github.com:zobayer1/logging-extras.git
    python -m pip install wheel
    python setup.py clean sdist bdist_wheel

**Note:** This project uses `setuptools-scm` to generate build versions from git tags. Build system will raise errors if you are trying to build packages outside a git repo.