uologging 0.7.0

Auto-Configuration solution for Python built-in logging.

uologging is a solution for configuring Python's built-in logging module.

Enable console logging

Simply call init_console_logging() to initializing Python's root logger to log to console:

In general, you will want to specify your package name. Omiting the package name will result in ANY python code you depend on logging (as well as your own code).

# Inadvisable: Enable logging for ALL python packages/modules
uologging.init_console_logging()

To enable logging within your package only, you can optionally provide your package name as an argument.

The handy invocation of __name__.split('.')[0] will provide your package's name from anywhere within your package.

# Best Practice: Enable logging only for your package.
my_package_name = __name__.split('.')[0]
uologging.init_console_logging(my_package_name)

Enable (Linux) syslog logging

Similarly, call init_syslog_logging():

# Best Practice: Enable logging for your python package
my_package_name = __name__.split('.')[0]
uologging.init_syslog_logging(my_package_name)

# Inadvisable: Enable logging for ALL python packages/modules
uologging.init_syslog_logging()

Set Logging Verbosity

Per Python logging suggestion: WARNING, ERROR, and CRITICAL messages are all logged by default.

If you are interested in seeing the DEBUG and INFO log messages, you'll need to update the logging verbosity in your application. We provide the method set_logging_verbosity() for this purpose. Higher number means more logging.

Choices are [0,2]. Default is 0. Default will captures WARNING, ERROR, and CRITICAL logs. Provide 1 to also capture INFO logs. Provide 2 to also capture DEBUG logs.

# Enable maximum logging for your python package
my_package_name = __name__.split('.')[0]
uologging.set_logging_verbosity(2, args.verbosity_flag, my_package_name)

# Enable maximum logging for ALL python packages/modules
uologging.set_logging_verbosity(2)

argparse 'verbosity flag'

For CLI tools, we provide an integration with argparse to set the logging verbosity. This integration enables the tool's user to add -vv at the command-line for maximum logging verbosity.

-v will enable INFO messages, but not DEBUG.

The verbosity_flag can be gathered via argparse using add_verbosity_flag(parser):

import uologging
import argparse

parser = argparse.ArgumentParser()
uologging.add_verbosity_flag(parser)

args = parser.parse_args(['-vv'])
# args.verbosity_flag == 2

Now, simply call set_logging_verbosity() with args.verbosity_flag for your package:

my_package_name = __name__.split('.')[0]
uologging.set_logging_verbosity(args.verbosity_flag, my_package_name)

Alternately, if you are comfortable with argparse 'Parent parsers', you can integrate with argparse using use get_default_parser() as a parent parser.

# Alternate 'Parent parser' argparse integration
parser = argparse.ArgumentParser(parents=[
    uologging.get_default_parser(),
])

Example: Configuring CLI tool with console & syslog logging

Let's imagine you have a package "examplepkg" with a CLI tool in the "mytool" module.

# my_cli_tool.py
import argparse
import uologging

# Parse CLI arguments, '-vv' will result in maximum logging verbosity.
parser = argparse.ArgumentParser()
uologging.add_verbosity_flag(parser)
args = parser.parse_args()

# Initialize logging
my_package_name = __name__.split('.')[0]
uologging.init_console_logging(my_package_name)
uologging.init_syslog_logging(my_package_name)
uologging.set_logging_verbosity(args.verbosity_flag, my_package_name)

Logging messages format

The formatting for log messages is specified in the (private) uologging._logging_format variable.

Here are a couple of lines showing what you can expect your logs to looks like:

2022-01-07 15:40:09 DEBUG    Some simle message for you [hello.py:10]
2022-01-07 15:40:09 DEBUG    Finished: example.hello:hello((),{}) [hello.py:10] 
2022-01-07 15:40:09 DEBUG    example.hello:hello((),{}) execution time: 0.00 sec [hello.py:10] 

Tracing a function

There is a simple trace decorator you can use in your python modules to log the 'execution time' of any of your functions.

The trace decorator logs at DEBUG severity. So, call set_logging_verbosity(>=2) to see the trace messages in your logs.

# hello.py
import logging
import uologging

logger = logging.getLogger(__name__)

@uologging.trace(logger)
def hello():
    print('hello!')

hello()

Expect the following messages to be logged:

2022-01-07 15:40:09 DEBUG    Starting: example.hello:hello((),{}) [hello.py:10]
hello!
2022-01-07 15:40:09 DEBUG    Finished: example.hello:hello((),{}) [hello.py:10] 
2022-01-07 15:40:09 DEBUG    example.hello:hello((),{}) execution time: 0.00 sec [hello.py:10] 

logging Best Practices

Use the Python logging package per the following best practices:

1. logger = logging.getLogger(__name__) to get the logger for each module/script.
2. Then, use logger.debug(), logger.info(), logger.warning(), etc to add tracing to your Python modules/scripts.

Example

A trivial example demonstrating best practices:

# hello.py
import logging

logger = logging.getLogger(__name__)

def hello():
    logger.debug('About to say "hello!"')
    print('hello!')
    logger.debug('Said "hello!"')