Twiggy A more Pythonic logger
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Python logging logger system logging Pythonic logger

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A more Pythonic logger Twiggy is an early-stage project to build a more Pythonic logging package.Usage:Make display work:>>> import sys; sys.stderr = sys.stdoutSetup is simpleIn your main.py:>>> import twiggy>>> twiggy.quick_setup()Logging Messages>>> from twiggy import *Main interface is the the magic log:>>> log #doctest:+ELLIPSIS< twiggy.Logger.Logger object at 0x... >It works out of the box, using standard levels:>>> log.debug('You may not care')DEBUG:You may not care>>> log.error('OMFG! Pants on fire!')ERROR:OMFG! Pants on fire!It supports a variety of format strings, defaulting to new-style:>>> log.info('I wear {0} on my {where}', 'pants', where='legs')INFO:I wear pants on my legsOld style works fine though:>>> log.options(style='percent').info('I like %s', "bikes")INFO:I like bikesAs do templates:>>> log.options(style='dollar').info('$what kill', what='Cars')INFO:Cars killYou can name your loggers:>>> mylog = log.name('alfredo')>>> mylog.debug('hello')DEBUG:alfredo:helloBut the name has no relation to the object; it's just for human use:>>> mylog is log.name('alfredo')FalseEmitting MessagesEmitters are loosely coupled:>>> twiggy.emitters #doctest:+ELLIPSIS{'*': < twiggy.Emitter.Emitter object at 0x... >}You can set a min_level on Emitters:>>> twiggy.emitters.min_level = twiggy.Levels.INFO>>> log.debug("Help, help I'm being suppressed")>>> log.info("I'm not quite dead yet")INFO:I'm not quite dead yetYou can filter on regexes, or with arbitrary functions:>>> twiggy.emitters.filter = ".*pants.*">>> log.info("Got my {0} on", "pants")INFO:Got my pants on>>> log.info("Got my {0} on", "shirt")Let's reset all that:>>> twiggy.emitters.filter = True>>> twiggy.emitters.min_level = twiggy.Levels.DEBUGBetter outputNewlines are suppressed by default; that can be turned off per-message:>>> log.info('user\ninput\nannoys\nus')INFO:user\ninput\nannoys\nus>>> log.options(suppress_newlines=False).info('we\ndeal')INFO:wedealExceptions are prefixed. Can also pass exc_info. Use '\n' as a prefix to fold into a single line:>>> try:... 1/0... except:... log.trace('error').warning('oh noes') #doctest:+ELLIPSISWARNING:oh noesTRACE Traceback (most recent call last):TRACE File "< doctest notes.txt >", line 2, in TRACE 1/0TRACE ZeroDivisionError: integer division or modulo by zeroMethod ChainingI like this chained style a lot.>>> log.name('benito').info('hi there')INFO:benito:hi thereIt makes structured logging easy:>>> log.fields(paths=42).info('Going for a walk')INFO:paths=42:Going for a walkShort cut. Great for runtime statistics gathering.>>> log.struct(paths=42, dolphins='thankful')INFO:dolphins=thankful:paths=42:Partial binding can be useful for webapps:>>> per_request_log = log.fields(request_id='12345')>>> per_request_log.fields(rows=100, user='frank').info('frobnicating database')INFO:request_id=12345:rows=100:user=frank:frobnicating database>>> per_request_log.fields(bytes=5678).info('sending page over tubes')INFO:bytes=5678:request_id=12345:sending page over tubesChained style is awesome:>>> log.name('donjuan').fields(pants='sexy').info("hello, {who} want to {what}?", who='ladies', what='dance')INFO:donjuan:pants=sexy:hello, ladies want to dance?Dynamic!Any functions in args/fields are called and the value substitued:>>> import os>>> from twiggy.lib import thread_name>>> thread_name()'MainThread'>>> log.fields(pid=os.getpid).info("I'm in thread {0}", thread_name) #doctest:+ELLIPSISINFO:pid=1076:I'm in thread MainThreadThis can be useful with partially-bound loggers, which let's us do some cool stuff:>>> class ThreadTracker(object):... def __init__(self, obj):... self.__obj = obj... # a partially bound logger... self.__log = log.name("tracker").fields(obj_id=id(obj), thread=thread_name)... self.__log.debug("started tracking")... def __getattr__(self, attr):... self.__log.debug("accessed {0}", attr)... return getattr(self.__obj, attr)...>>> class Bunch(object):... pass...>>> foo = Bunch()>>> foo.bar = 42>>> tracked = ThreadTracker(foo)DEBUG:tracker:obj_id=14063980:thread=MainThread:started tracking>>> tracked.barDEBUG:tracker:obj_id=14063980:thread=MainThread:accessed bar42>>> import threading>>> t=threading.Thread(target = lambda: tracked.bar * 2, name = "TheDoubler")>>> t.start()DEBUG:tracker:obj_id=14063980:thread=TheDoubler:accessed barIf you really want to log a callable, repr() it or wrap it in lambda.OptimizationsAs an optimization, a min_level can be set on loggers:>>> mylog.min_level = twiggy.Levels.INFO>>> mylog.info("You see this")INFO:alfredo:You see this>>> mylog.debug("This is hidden")They also take a filter that operates on format_spec. The use case is efficiently shutting off specific messages in a library which is doing something stupid:>>> mylog.filter = lambda s: "shenanigans" not in s>>> mylog.info("Starting silliness")INFO:alfredo:Starting silliness>>> for i in xrange(3): # for large values of 3... mylog.info("I call shenanigans!")>>> mylog.info("End silliness")INFO:alfredo:End silliness Requirements: · Python

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