Package: privex-loghelper
Python Log HelperPython Log Helperis a small class designed to simplify the use of the built-in Python Logging Module.It has no dependencies, and should be compatible with most versions of Python 2.x and 3.x (though we still recommend a minimum of 3.4).It was originally created byChris (Someguy123)for use in personal Python projects,
as well as for use in projects developed atPrivex Inc.If this project has helped you, considergrabbing a VPS or Dedicated Server from Privex- prices start at as little as 8 USD/mo (we take cryptocurrency!)LicensePython Log Helperwas created byPrivex Inc. of Belize City, and licensed under the X11/MIT License.
See the fileLICENSEfor the license text.TL;DR; license:We offer no warranty. You can copy it, modify it, use it in projects with a different license, and even in commercial (paid for) software.The most important rule is - youMUSTkeep the original license text visible (seeLICENSE) in any copies.ContributingWe're happy to accept pull requests, no matter how small.Please make sure any changes you make meet these basic requirements:No additional dependencies. We want LogHelper to be lightweight and painless to install.Any code taken from other projects should be compatible with the MIT LicenseThis is a new project, and as such, supporting Python versions prior to 3.4 is very low priority.However, we're happy to accept PRs to improve compatibility with older versions of Python, as long as it doesn't:drastically increase the complexity of the codeOR cause problems for those on newer versions of Python.InstallationDownload and install from PyPi using pipPython 3pip3installprivex-loghelperPython 2pipinstallprivex-loghelper(Alternative) Manual install from GitOption 1 - Use pip to install straight from Githubpip3installgit+https://github.com/Privex/python-loghelperOption 2 - Clone and install manually# Clone the repository from Githubgitclonehttps://github.com/Privex/python-loghelpercdpython-loghelper# RECOMMENDED INSTALL METHOD# Use pip to install the source codepip3install.# ALTERNATIVE INSTALL METHOD# If you don't have pip, or have issues with installing using it, then you can use setuptools instead.python3setup.pyinstallUsageThe code is very well documented, you can find out all usage documentation inLogHelper.py.All functions are type annotated, with detailed pydoc block comments. If you're using a Python optimised IDE such asPyCharmit should
offer code completion and help when using the package.Basic usageThe most basic usage is to simply initialise the class with no parameters, and attach a
file handler to send log output to a file.# Import the classfromprivex.loghelperimportLogHelper# The first param is logger_name - a hierarchical dot-separated name to organise loggers.# If it's not specified, or is None, it will use the root logger (which will affect some# third-party packages that don't have their own logging settings)lh=LogHelper('mylogger')# Log to a file called test.log in the current directorylh.add_file_handler('test.log')# Grab the logger instancelog=lh.get_logger()# Now let's log 'hello world' to the file.log.info('hello world')After running the above,test.logshould contain:2018-12-05 22:05:18,915 root         INFO     hello worldCopying your logging config to other logger namesThird party packages often use their own logging instance names. To make it easy for you to copy your settings
to other instances, you can use thecopy_logger(name)method.# Set up logging for your app, log anything >=INFOlh=LogHelper('myapp',handler_level=logging.INFO)# Log to a file called test.log in the current directory (note: absolute path is better)lh.add_file_handler('test.log')# Now copy your logging level, handlers, and formatting to the logger privex.jsonrpclh.copy_logger('privex.jsonrpc')# You can specify multiple logger names as positional arguments. All specified loggers will# have their handlers replaced with yours, and have their logging level set to match.lh.copy_logger('example.app','otherexample')After copying your settings onto a named logger, all logging using that logger should use your specified handlers,
and your log level.This covers modules that access the logger vialogging.getLogger('loggername'), as well as via Python Logging wrappers
such as privex-loghelper.Splitting error and debug logs into different filesSomething that can make it easier to sift through logs, is to split your normal debug logs from warnings and errors.Using the standardloggingmodule, this could take 10 lines of code, and is highly repetitive.With the Python Log Helper, it's just a few lines.# Import the classfromprivex.loghelperimportLogHelper# Import logging to be able to specify the verbosity levelsimportlogging# The global level (kwarg `level`) defaults to DEBUG, but the default handler level is only INFO.# You can specify handler_level to change that.# To help prevent conflicts from other python packages which use the root ('') logger, you should set a custom# logger name.lh=LogHelper(logger_name='my_app',handler_level=logging.DEBUG)# Log messages that are DEBUG (default handler and global logging level) or higher to `debug.log`lh.add_file_handler('debug.log')# Log only WARNING or above to `error.log`lh.add_file_handler('error.log',level=logging.WARNING)# Grab the logger instancelog=lh.get_logger()# To test that logs are being sent to the correct files, let's try an `info`, a `warning` and an `error` log message.log.info('something normal is happening')log.warning('something strange is happening')log.error('something VERY BAD is happening')After running the above Python script, you should see the following log files:debug.log2018-12-05 22:10:25,253 root         INFO        something normal is happening
2018-12-05 22:10:25,254 root         WARNING     something strange is happening
2018-12-05 22:10:25,256 root         ERROR       something VERY BAD is happeningerror.log2018-12-05 22:10:25,254 root         WARNING     something strange is happening
2018-12-05 22:10:25,256 root         ERROR       something VERY BAD is happeningAs you can see, thedebug.logsaved all of the messages, whileerror.logonly saved the warning and the error.Log RotationYou can also have painless log rotation, without the need for something likelogrotated.The LogHelper class has a functionadd_timed_file_handlerwhich wrapslogging.handler.TimedRotatingFileHandler.Simply specify the type of interval (when) to rotate with, how often it should rotate (interval), and how many intervals you
would like to keep before deleting older ones (backups). Setbackupsto 0 if you don't want it to delete older logs.For more information oninterval,whenandbackups,
seethe official logging docsBy default, logs are rotated once (interval=1) per day (when='D'), and removed after 14 days (backups=14).# Import the classfromprivex.loghelperimportLogHelper# Using sleep to simulate time passingfromtimeimportsleeplh=LogHelper()# Log to a file called test.log in the current directory# Rotate the log every minute, and only keep up to 60 minutes of logslh.add_timed_file_handler('test.log',when='M',interval=1,backups=60)# Grab the logger instancelog=lh.get_logger()# Now let's log 'hello world' to the file.log.info('hello world')log.info('hello world 2')sleep(60)log.info('hello world 3')We can now see it's generated two timestamped logs, since the interval was set to 1 minute.$ls-l-rw-r--r--1userusers585Dec22:58test.log.2018-12-05_22-58-rw-r--r--1userusers585Dec22:59test.log.2018-12-05_22-59

$cattest.log.2018-12-05_22-582018-12-0522:58:24,600rootINFOhelloworld2018-12-0522:58:24,743rootINFOhelloworld2$cattest.log.2018-12-05_22-592018-12-0522:59:25,512rootINFOhelloworld3Concurrent Log RotationFor applications with concurrency like those built on modern Django, you may need to use ConcurrentLogHandler for the logs to work correctly,
if you want to use this, you'll need to install the package with the concurrent extra like so:pip3install'privex-loghelper[concurrent]'Or if this doesn't work, install ConcurrentLogHandler by hand:pip3installConcurrentLogHandlerNow you may passconcurrent=Trueto theadd_timed_file_handlermethod, to use ConcurrentLogHandler instead of the standard one:lh.add_timed_file_handler('test.log',when='M',interval=1,backups=60,concurrent=True)Thanks for reading!If this project has helped you, considergrabbing a VPS or Dedicated Server from Privex- prices start at as little as US$8/mo (we take cryptocurrency!)