1# Copyright 2001-2010 by Vinay Sajip. All Rights Reserved.
2#
3# Permission to use, copy, modify, and distribute this software and its
4# documentation for any purpose and without fee is hereby granted,
5# provided that the above copyright notice appear in all copies and that
6# both that copyright notice and this permission notice appear in
7# supporting documentation, and that the name of Vinay Sajip
8# not be used in advertising or publicity pertaining to distribution
9# of the software without specific, written prior permission.
10# VINAY SAJIP DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
11# ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
12# VINAY SAJIP BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
13# ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
14# IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16
17"""
18Logging package for Python. Based on PEP 282 and comments thereto in
19comp.lang.python, and influenced by Apache's log4j system.
20
21Copyright (C) 2001-2010 Vinay Sajip. All Rights Reserved.
22
23To use, simply 'import logging' and log away!
24"""
25
26import sys, os, time, cStringIO, traceback, warnings, weakref
27
28__all__ = ['BASIC_FORMAT', 'BufferingFormatter', 'CRITICAL', 'DEBUG', 'ERROR',
29           'FATAL', 'FileHandler', 'Filter', 'Formatter', 'Handler', 'INFO',
30           'LogRecord', 'Logger', 'LoggerAdapter', 'NOTSET', 'NullHandler',
31           'StreamHandler', 'WARN', 'WARNING', 'addLevelName', 'basicConfig',
32           'captureWarnings', 'critical', 'debug', 'disable', 'error',
33           'exception', 'fatal', 'getLevelName', 'getLogger', 'getLoggerClass',
34           'info', 'log', 'makeLogRecord', 'setLoggerClass', 'warn', 'warning']
35
36try:
37    import codecs
38except ImportError:
39    codecs = None
40
41try:
42    import thread
43    import threading
44except ImportError:
45    thread = None
46
47__author__  = "Vinay Sajip <vinay_sajip@red-dove.com>"
48__status__  = "production"
49__version__ = "0.5.1.2"
50__date__    = "07 February 2010"
51
52#---------------------------------------------------------------------------
53#   Miscellaneous module data
54#---------------------------------------------------------------------------
55try:
56    unicode
57    _unicode = True
58except NameError:
59    _unicode = False
60
61#
62# _srcfile is used when walking the stack to check when we've got the first
63# caller stack frame.
64#
65if hasattr(sys, 'frozen'): #support for py2exe
66    _srcfile = "logging%s__init__%s" % (os.sep, __file__[-4:])
67elif __file__[-4:].lower() in ['.pyc', '.pyo']:
68    _srcfile = __file__[:-4] + '.py'
69else:
70    _srcfile = __file__
71_srcfile = os.path.normcase(_srcfile)
72
73# next bit filched from 1.5.2's inspect.py
74def currentframe():
75    """Return the frame object for the caller's stack frame."""
76    try:
77        raise Exception
78    except:
79        return sys.exc_info()[2].tb_frame.f_back
80
81if hasattr(sys, '_getframe'): currentframe = lambda: sys._getframe(3)
82# done filching
83
84# _srcfile is only used in conjunction with sys._getframe().
85# To provide compatibility with older versions of Python, set _srcfile
86# to None if _getframe() is not available; this value will prevent
87# findCaller() from being called.
88#if not hasattr(sys, "_getframe"):
89#    _srcfile = None
90
91#
92#_startTime is used as the base when calculating the relative time of events
93#
94_startTime = time.time()
95
96#
97#raiseExceptions is used to see if exceptions during handling should be
98#propagated
99#
100raiseExceptions = 1
101
102#
103# If you don't want threading information in the log, set this to zero
104#
105logThreads = 1
106
107#
108# If you don't want multiprocessing information in the log, set this to zero
109#
110logMultiprocessing = 1
111
112#
113# If you don't want process information in the log, set this to zero
114#
115logProcesses = 1
116
117#---------------------------------------------------------------------------
118#   Level related stuff
119#---------------------------------------------------------------------------
120#
121# Default levels and level names, these can be replaced with any positive set
122# of values having corresponding names. There is a pseudo-level, NOTSET, which
123# is only really there as a lower limit for user-defined levels. Handlers and
124# loggers are initialized with NOTSET so that they will log all messages, even
125# at user-defined levels.
126#
127
128CRITICAL = 50
129FATAL = CRITICAL
130ERROR = 40
131WARNING = 30
132WARN = WARNING
133INFO = 20
134DEBUG = 10
135NOTSET = 0
136
137_levelNames = {
138    CRITICAL : 'CRITICAL',
139    ERROR : 'ERROR',
140    WARNING : 'WARNING',
141    INFO : 'INFO',
142    DEBUG : 'DEBUG',
143    NOTSET : 'NOTSET',
144    'CRITICAL' : CRITICAL,
145    'ERROR' : ERROR,
146    'WARN' : WARNING,
147    'WARNING' : WARNING,
148    'INFO' : INFO,
149    'DEBUG' : DEBUG,
150    'NOTSET' : NOTSET,
151}
152
153def getLevelName(level):
154    """
155    Return the textual representation of logging level 'level'.
156
157    If the level is one of the predefined levels (CRITICAL, ERROR, WARNING,
158    INFO, DEBUG) then you get the corresponding string. If you have
159    associated levels with names using addLevelName then the name you have
160    associated with 'level' is returned.
161
162    If a numeric value corresponding to one of the defined levels is passed
163    in, the corresponding string representation is returned.
164
165    Otherwise, the string "Level %s" % level is returned.
166    """
167    return _levelNames.get(level, ("Level %s" % level))
168
169def addLevelName(level, levelName):
170    """
171    Associate 'levelName' with 'level'.
172
173    This is used when converting levels to text during message formatting.
174    """
175    _acquireLock()
176    try:    #unlikely to cause an exception, but you never know...
177        _levelNames[level] = levelName
178        _levelNames[levelName] = level
179    finally:
180        _releaseLock()
181
182def _checkLevel(level):
183    if isinstance(level, int):
184        rv = level
185    elif str(level) == level:
186        if level not in _levelNames:
187            raise ValueError("Unknown level: %r" % level)
188        rv = _levelNames[level]
189    else:
190        raise TypeError("Level not an integer or a valid string: %r" % level)
191    return rv
192
193#---------------------------------------------------------------------------
194#   Thread-related stuff
195#---------------------------------------------------------------------------
196
197#
198#_lock is used to serialize access to shared data structures in this module.
199#This needs to be an RLock because fileConfig() creates and configures
200#Handlers, and so might arbitrary user threads. Since Handler code updates the
201#shared dictionary _handlers, it needs to acquire the lock. But if configuring,
202#the lock would already have been acquired - so we need an RLock.
203#The same argument applies to Loggers and Manager.loggerDict.
204#
205if thread:
206    _lock = threading.RLock()
207else:
208    _lock = None
209
210def _acquireLock():
211    """
212    Acquire the module-level lock for serializing access to shared data.
213
214    This should be released with _releaseLock().
215    """
216    if _lock:
217        _lock.acquire()
218
219def _releaseLock():
220    """
221    Release the module-level lock acquired by calling _acquireLock().
222    """
223    if _lock:
224        _lock.release()
225
226#---------------------------------------------------------------------------
227#   The logging record
228#---------------------------------------------------------------------------
229
230class LogRecord(object):
231    """
232    A LogRecord instance represents an event being logged.
233
234    LogRecord instances are created every time something is logged. They
235    contain all the information pertinent to the event being logged. The
236    main information passed in is in msg and args, which are combined
237    using str(msg) % args to create the message field of the record. The
238    record also includes information such as when the record was created,
239    the source line where the logging call was made, and any exception
240    information to be logged.
241    """
242    def __init__(self, name, level, pathname, lineno,
243                 msg, args, exc_info, func=None):
244        """
245        Initialize a logging record with interesting information.
246        """
247        ct = time.time()
248        self.name = name
249        self.msg = msg
250        #
251        # The following statement allows passing of a dictionary as a sole
252        # argument, so that you can do something like
253        #  logging.debug("a %(a)d b %(b)s", {'a':1, 'b':2})
254        # Suggested by Stefan Behnel.
255        # Note that without the test for args[0], we get a problem because
256        # during formatting, we test to see if the arg is present using
257        # 'if self.args:'. If the event being logged is e.g. 'Value is %d'
258        # and if the passed arg fails 'if self.args:' then no formatting
259        # is done. For example, logger.warn('Value is %d', 0) would log
260        # 'Value is %d' instead of 'Value is 0'.
261        # For the use case of passing a dictionary, this should not be a
262        # problem.
263        if args and len(args) == 1 and isinstance(args[0], dict) and args[0]:
264            args = args[0]
265        self.args = args
266        self.levelname = getLevelName(level)
267        self.levelno = level
268        self.pathname = pathname
269        try:
270            self.filename = os.path.basename(pathname)
271            self.module = os.path.splitext(self.filename)[0]
272        except (TypeError, ValueError, AttributeError):
273            self.filename = pathname
274            self.module = "Unknown module"
275        self.exc_info = exc_info
276        self.exc_text = None      # used to cache the traceback text
277        self.lineno = lineno
278        self.funcName = func
279        self.created = ct
280        self.msecs = (ct - long(ct)) * 1000
281        self.relativeCreated = (self.created - _startTime) * 1000
282        if logThreads and thread:
283            self.thread = thread.get_ident()
284            self.threadName = threading.current_thread().name
285        else:
286            self.thread = None
287            self.threadName = None
288        if not logMultiprocessing:
289            self.processName = None
290        else:
291            self.processName = 'MainProcess'
292            mp = sys.modules.get('multiprocessing')
293            if mp is not None:
294                # Errors may occur if multiprocessing has not finished loading
295                # yet - e.g. if a custom import hook causes third-party code
296                # to run when multiprocessing calls import. See issue 8200
297                # for an example
298                try:
299                    self.processName = mp.current_process().name
300                except StandardError:
301                    pass
302        if logProcesses and hasattr(os, 'getpid'):
303            self.process = os.getpid()
304        else:
305            self.process = None
306
307    def __str__(self):
308        return '<LogRecord: %s, %s, %s, %s, "%s">'%(self.name, self.levelno,
309            self.pathname, self.lineno, self.msg)
310
311    def getMessage(self):
312        """
313        Return the message for this LogRecord.
314
315        Return the message for this LogRecord after merging any user-supplied
316        arguments with the message.
317        """
318        if not _unicode: #if no unicode support...
319            msg = str(self.msg)
320        else:
321            msg = self.msg
322            if not isinstance(msg, basestring):
323                try:
324                    msg = str(self.msg)
325                except UnicodeError:
326                    msg = self.msg      #Defer encoding till later
327        if self.args:
328            msg = msg % self.args
329        return msg
330
331def makeLogRecord(dict):
332    """
333    Make a LogRecord whose attributes are defined by the specified dictionary,
334    This function is useful for converting a logging event received over
335    a socket connection (which is sent as a dictionary) into a LogRecord
336    instance.
337    """
338    rv = LogRecord(None, None, "", 0, "", (), None, None)
339    rv.__dict__.update(dict)
340    return rv
341
342#---------------------------------------------------------------------------
343#   Formatter classes and functions
344#---------------------------------------------------------------------------
345
346class Formatter(object):
347    """
348    Formatter instances are used to convert a LogRecord to text.
349
350    Formatters need to know how a LogRecord is constructed. They are
351    responsible for converting a LogRecord to (usually) a string which can
352    be interpreted by either a human or an external system. The base Formatter
353    allows a formatting string to be specified. If none is supplied, the
354    default value of "%s(message)\\n" is used.
355
356    The Formatter can be initialized with a format string which makes use of
357    knowledge of the LogRecord attributes - e.g. the default value mentioned
358    above makes use of the fact that the user's message and arguments are pre-
359    formatted into a LogRecord's message attribute. Currently, the useful
360    attributes in a LogRecord are described by:
361
362    %(name)s            Name of the logger (logging channel)
363    %(levelno)s         Numeric logging level for the message (DEBUG, INFO,
364                        WARNING, ERROR, CRITICAL)
365    %(levelname)s       Text logging level for the message ("DEBUG", "INFO",
366                        "WARNING", "ERROR", "CRITICAL")
367    %(pathname)s        Full pathname of the source file where the logging
368                        call was issued (if available)
369    %(filename)s        Filename portion of pathname
370    %(module)s          Module (name portion of filename)
371    %(lineno)d          Source line number where the logging call was issued
372                        (if available)
373    %(funcName)s        Function name
374    %(created)f         Time when the LogRecord was created (time.time()
375                        return value)
376    %(asctime)s         Textual time when the LogRecord was created
377    %(msecs)d           Millisecond portion of the creation time
378    %(relativeCreated)d Time in milliseconds when the LogRecord was created,
379                        relative to the time the logging module was loaded
380                        (typically at application startup time)
381    %(thread)d          Thread ID (if available)
382    %(threadName)s      Thread name (if available)
383    %(process)d         Process ID (if available)
384    %(message)s         The result of record.getMessage(), computed just as
385                        the record is emitted
386    """
387
388    converter = time.localtime
389
390    def __init__(self, fmt=None, datefmt=None):
391        """
392        Initialize the formatter with specified format strings.
393
394        Initialize the formatter either with the specified format string, or a
395        default as described above. Allow for specialized date formatting with
396        the optional datefmt argument (if omitted, you get the ISO8601 format).
397        """
398        if fmt:
399            self._fmt = fmt
400        else:
401            self._fmt = "%(message)s"
402        self.datefmt = datefmt
403
404    def formatTime(self, record, datefmt=None):
405        """
406        Return the creation time of the specified LogRecord as formatted text.
407
408        This method should be called from format() by a formatter which
409        wants to make use of a formatted time. This method can be overridden
410        in formatters to provide for any specific requirement, but the
411        basic behaviour is as follows: if datefmt (a string) is specified,
412        it is used with time.strftime() to format the creation time of the
413        record. Otherwise, the ISO8601 format is used. The resulting
414        string is returned. This function uses a user-configurable function
415        to convert the creation time to a tuple. By default, time.localtime()
416        is used; to change this for a particular formatter instance, set the
417        'converter' attribute to a function with the same signature as
418        time.localtime() or time.gmtime(). To change it for all formatters,
419        for example if you want all logging times to be shown in GMT,
420        set the 'converter' attribute in the Formatter class.
421        """
422        ct = self.converter(record.created)
423        if datefmt:
424            s = time.strftime(datefmt, ct)
425        else:
426            t = time.strftime("%Y-%m-%d %H:%M:%S", ct)
427            s = "%s,%03d" % (t, record.msecs)
428        return s
429
430    def formatException(self, ei):
431        """
432        Format and return the specified exception information as a string.
433
434        This default implementation just uses
435        traceback.print_exception()
436        """
437        sio = cStringIO.StringIO()
438        traceback.print_exception(ei[0], ei[1], ei[2], None, sio)
439        s = sio.getvalue()
440        sio.close()
441        if s[-1:] == "\n":
442            s = s[:-1]
443        return s
444
445    def usesTime(self):
446        """
447        Check if the format uses the creation time of the record.
448        """
449        return self._fmt.find("%(asctime)") >= 0
450
451    def format(self, record):
452        """
453        Format the specified record as text.
454
455        The record's attribute dictionary is used as the operand to a
456        string formatting operation which yields the returned string.
457        Before formatting the dictionary, a couple of preparatory steps
458        are carried out. The message attribute of the record is computed
459        using LogRecord.getMessage(). If the formatting string uses the
460        time (as determined by a call to usesTime(), formatTime() is
461        called to format the event time. If there is exception information,
462        it is formatted using formatException() and appended to the message.
463        """
464        record.message = record.getMessage()
465        if self.usesTime():
466            record.asctime = self.formatTime(record, self.datefmt)
467        s = self._fmt % record.__dict__
468        if record.exc_info:
469            # Cache the traceback text to avoid converting it multiple times
470            # (it's constant anyway)
471            if not record.exc_text:
472                record.exc_text = self.formatException(record.exc_info)
473        if record.exc_text:
474            if s[-1:] != "\n":
475                s = s + "\n"
476            try:
477                s = s + record.exc_text
478            except UnicodeError:
479                # Sometimes filenames have non-ASCII chars, which can lead
480                # to errors when s is Unicode and record.exc_text is str
481                # See issue 8924
482                s = s + record.exc_text.decode(sys.getfilesystemencoding())
483        return s
484
485#
486#   The default formatter to use when no other is specified
487#
488_defaultFormatter = Formatter()
489
490class BufferingFormatter(object):
491    """
492    A formatter suitable for formatting a number of records.
493    """
494    def __init__(self, linefmt=None):
495        """
496        Optionally specify a formatter which will be used to format each
497        individual record.
498        """
499        if linefmt:
500            self.linefmt = linefmt
501        else:
502            self.linefmt = _defaultFormatter
503
504    def formatHeader(self, records):
505        """
506        Return the header string for the specified records.
507        """
508        return ""
509
510    def formatFooter(self, records):
511        """
512        Return the footer string for the specified records.
513        """
514        return ""
515
516    def format(self, records):
517        """
518        Format the specified records and return the result as a string.
519        """
520        rv = ""
521        if len(records) > 0:
522            rv = rv + self.formatHeader(records)
523            for record in records:
524                rv = rv + self.linefmt.format(record)
525            rv = rv + self.formatFooter(records)
526        return rv
527
528#---------------------------------------------------------------------------
529#   Filter classes and functions
530#---------------------------------------------------------------------------
531
532class Filter(object):
533    """
534    Filter instances are used to perform arbitrary filtering of LogRecords.
535
536    Loggers and Handlers can optionally use Filter instances to filter
537    records as desired. The base filter class only allows events which are
538    below a certain point in the logger hierarchy. For example, a filter
539    initialized with "A.B" will allow events logged by loggers "A.B",
540    "A.B.C", "A.B.C.D", "A.B.D" etc. but not "A.BB", "B.A.B" etc. If
541    initialized with the empty string, all events are passed.
542    """
543    def __init__(self, name=''):
544        """
545        Initialize a filter.
546
547        Initialize with the name of the logger which, together with its
548        children, will have its events allowed through the filter. If no
549        name is specified, allow every event.
550        """
551        self.name = name
552        self.nlen = len(name)
553
554    def filter(self, record):
555        """
556        Determine if the specified record is to be logged.
557
558        Is the specified record to be logged? Returns 0 for no, nonzero for
559        yes. If deemed appropriate, the record may be modified in-place.
560        """
561        if self.nlen == 0:
562            return 1
563        elif self.name == record.name:
564            return 1
565        elif record.name.find(self.name, 0, self.nlen) != 0:
566            return 0
567        return (record.name[self.nlen] == ".")
568
569class Filterer(object):
570    """
571    A base class for loggers and handlers which allows them to share
572    common code.
573    """
574    def __init__(self):
575        """
576        Initialize the list of filters to be an empty list.
577        """
578        self.filters = []
579
580    def addFilter(self, filter):
581        """
582        Add the specified filter to this handler.
583        """
584        if not (filter in self.filters):
585            self.filters.append(filter)
586
587    def removeFilter(self, filter):
588        """
589        Remove the specified filter from this handler.
590        """
591        if filter in self.filters:
592            self.filters.remove(filter)
593
594    def filter(self, record):
595        """
596        Determine if a record is loggable by consulting all the filters.
597
598        The default is to allow the record to be logged; any filter can veto
599        this and the record is then dropped. Returns a zero value if a record
600        is to be dropped, else non-zero.
601        """
602        rv = 1
603        for f in self.filters:
604            if not f.filter(record):
605                rv = 0
606                break
607        return rv
608
609#---------------------------------------------------------------------------
610#   Handler classes and functions
611#---------------------------------------------------------------------------
612
613_handlers = weakref.WeakValueDictionary()  #map of handler names to handlers
614_handlerList = [] # added to allow handlers to be removed in reverse of order initialized
615
616def _removeHandlerRef(wr):
617    """
618    Remove a handler reference from the internal cleanup list.
619    """
620    # This function can be called during module teardown, when globals are
621    # set to None. If _acquireLock is None, assume this is the case and do
622    # nothing.
623    if _acquireLock is not None:
624        _acquireLock()
625        try:
626            if wr in _handlerList:
627                _handlerList.remove(wr)
628        finally:
629            _releaseLock()
630
631def _addHandlerRef(handler):
632    """
633    Add a handler to the internal cleanup list using a weak reference.
634    """
635    _acquireLock()
636    try:
637        _handlerList.append(weakref.ref(handler, _removeHandlerRef))
638    finally:
639        _releaseLock()
640
641class Handler(Filterer):
642    """
643    Handler instances dispatch logging events to specific destinations.
644
645    The base handler class. Acts as a placeholder which defines the Handler
646    interface. Handlers can optionally use Formatter instances to format
647    records as desired. By default, no formatter is specified; in this case,
648    the 'raw' message as determined by record.message is logged.
649    """
650    def __init__(self, level=NOTSET):
651        """
652        Initializes the instance - basically setting the formatter to None
653        and the filter list to empty.
654        """
655        Filterer.__init__(self)
656        self._name = None
657        self.level = _checkLevel(level)
658        self.formatter = None
659        # Add the handler to the global _handlerList (for cleanup on shutdown)
660        _addHandlerRef(self)
661        self.createLock()
662
663    def get_name(self):
664        return self._name
665
666    def set_name(self, name):
667        _acquireLock()
668        try:
669            if self._name in _handlers:
670                del _handlers[self._name]
671            self._name = name
672            if name:
673                _handlers[name] = self
674        finally:
675            _releaseLock()
676
677    name = property(get_name, set_name)
678
679    def createLock(self):
680        """
681        Acquire a thread lock for serializing access to the underlying I/O.
682        """
683        if thread:
684            self.lock = threading.RLock()
685        else:
686            self.lock = None
687
688    def acquire(self):
689        """
690        Acquire the I/O thread lock.
691        """
692        if self.lock:
693            self.lock.acquire()
694
695    def release(self):
696        """
697        Release the I/O thread lock.
698        """
699        if self.lock:
700            self.lock.release()
701
702    def setLevel(self, level):
703        """
704        Set the logging level of this handler.
705        """
706        self.level = _checkLevel(level)
707
708    def format(self, record):
709        """
710        Format the specified record.
711
712        If a formatter is set, use it. Otherwise, use the default formatter
713        for the module.
714        """
715        if self.formatter:
716            fmt = self.formatter
717        else:
718            fmt = _defaultFormatter
719        return fmt.format(record)
720
721    def emit(self, record):
722        """
723        Do whatever it takes to actually log the specified logging record.
724
725        This version is intended to be implemented by subclasses and so
726        raises a NotImplementedError.
727        """
728        raise NotImplementedError('emit must be implemented '
729                                  'by Handler subclasses')
730
731    def handle(self, record):
732        """
733        Conditionally emit the specified logging record.
734
735        Emission depends on filters which may have been added to the handler.
736        Wrap the actual emission of the record with acquisition/release of
737        the I/O thread lock. Returns whether the filter passed the record for
738        emission.
739        """
740        rv = self.filter(record)
741        if rv:
742            self.acquire()
743            try:
744                self.emit(record)
745            finally:
746                self.release()
747        return rv
748
749    def setFormatter(self, fmt):
750        """
751        Set the formatter for this handler.
752        """
753        self.formatter = fmt
754
755    def flush(self):
756        """
757        Ensure all logging output has been flushed.
758
759        This version does nothing and is intended to be implemented by
760        subclasses.
761        """
762        pass
763
764    def close(self):
765        """
766        Tidy up any resources used by the handler.
767
768        This version removes the handler from an internal map of handlers,
769        _handlers, which is used for handler lookup by name. Subclasses
770        should ensure that this gets called from overridden close()
771        methods.
772        """
773        #get the module data lock, as we're updating a shared structure.
774        _acquireLock()
775        try:    #unlikely to raise an exception, but you never know...
776            if self._name and self._name in _handlers:
777                del _handlers[self._name]
778        finally:
779            _releaseLock()
780
781    def handleError(self, record):
782        """
783        Handle errors which occur during an emit() call.
784
785        This method should be called from handlers when an exception is
786        encountered during an emit() call. If raiseExceptions is false,
787        exceptions get silently ignored. This is what is mostly wanted
788        for a logging system - most users will not care about errors in
789        the logging system, they are more interested in application errors.
790        You could, however, replace this with a custom handler if you wish.
791        The record which was being processed is passed in to this method.
792        """
793        if raiseExceptions:
794            ei = sys.exc_info()
795            try:
796                traceback.print_exception(ei[0], ei[1], ei[2],
797                                          None, sys.stderr)
798                sys.stderr.write('Logged from file %s, line %s\n' % (
799                                 record.filename, record.lineno))
800            except IOError:
801                pass    # see issue 5971
802            finally:
803                del ei
804
805class StreamHandler(Handler):
806    """
807    A handler class which writes logging records, appropriately formatted,
808    to a stream. Note that this class does not close the stream, as
809    sys.stdout or sys.stderr may be used.
810    """
811
812    def __init__(self, stream=None):
813        """
814        Initialize the handler.
815
816        If stream is not specified, sys.stderr is used.
817        """
818        Handler.__init__(self)
819        if stream is None:
820            stream = sys.stderr
821        self.stream = stream
822
823    def flush(self):
824        """
825        Flushes the stream.
826        """
827        if self.stream and hasattr(self.stream, "flush"):
828            self.stream.flush()
829
830    def emit(self, record):
831        """
832        Emit a record.
833
834        If a formatter is specified, it is used to format the record.
835        The record is then written to the stream with a trailing newline.  If
836        exception information is present, it is formatted using
837        traceback.print_exception and appended to the stream.  If the stream
838        has an 'encoding' attribute, it is used to determine how to do the
839        output to the stream.
840        """
841        try:
842            msg = self.format(record)
843            stream = self.stream
844            fs = "%s\n"
845            if not _unicode: #if no unicode support...
846                stream.write(fs % msg)
847            else:
848                try:
849                    if (isinstance(msg, unicode) and
850                        getattr(stream, 'encoding', None)):
851                        ufs = fs.decode(stream.encoding)
852                        try:
853                            stream.write(ufs % msg)
854                        except UnicodeEncodeError:
855                            #Printing to terminals sometimes fails. For example,
856                            #with an encoding of 'cp1251', the above write will
857                            #work if written to a stream opened or wrapped by
858                            #the codecs module, but fail when writing to a
859                            #terminal even when the codepage is set to cp1251.
860                            #An extra encoding step seems to be needed.
861                            stream.write((ufs % msg).encode(stream.encoding))
862                    else:
863                        stream.write(fs % msg)
864                except UnicodeError:
865                    stream.write(fs % msg.encode("UTF-8"))
866            self.flush()
867        except (KeyboardInterrupt, SystemExit):
868            raise
869        except:
870            self.handleError(record)
871
872class FileHandler(StreamHandler):
873    """
874    A handler class which writes formatted logging records to disk files.
875    """
876    def __init__(self, filename, mode='a', encoding=None, delay=0):
877        """
878        Open the specified file and use it as the stream for logging.
879        """
880        #keep the absolute path, otherwise derived classes which use this
881        #may come a cropper when the current directory changes
882        if codecs is None:
883            encoding = None
884        self.baseFilename = os.path.abspath(filename)
885        self.mode = mode
886        self.encoding = encoding
887        if delay:
888            #We don't open the stream, but we still need to call the
889            #Handler constructor to set level, formatter, lock etc.
890            Handler.__init__(self)
891            self.stream = None
892        else:
893            StreamHandler.__init__(self, self._open())
894
895    def close(self):
896        """
897        Closes the stream.
898        """
899        if self.stream:
900            self.flush()
901            if hasattr(self.stream, "close"):
902                self.stream.close()
903            StreamHandler.close(self)
904            self.stream = None
905
906    def _open(self):
907        """
908        Open the current base file with the (original) mode and encoding.
909        Return the resulting stream.
910        """
911        if self.encoding is None:
912            stream = open(self.baseFilename, self.mode)
913        else:
914            stream = codecs.open(self.baseFilename, self.mode, self.encoding)
915        return stream
916
917    def emit(self, record):
918        """
919        Emit a record.
920
921        If the stream was not opened because 'delay' was specified in the
922        constructor, open it before calling the superclass's emit.
923        """
924        if self.stream is None:
925            self.stream = self._open()
926        StreamHandler.emit(self, record)
927
928#---------------------------------------------------------------------------
929#   Manager classes and functions
930#---------------------------------------------------------------------------
931
932class PlaceHolder(object):
933    """
934    PlaceHolder instances are used in the Manager logger hierarchy to take
935    the place of nodes for which no loggers have been defined. This class is
936    intended for internal use only and not as part of the public API.
937    """
938    def __init__(self, alogger):
939        """
940        Initialize with the specified logger being a child of this placeholder.
941        """
942        #self.loggers = [alogger]
943        self.loggerMap = { alogger : None }
944
945    def append(self, alogger):
946        """
947        Add the specified logger as a child of this placeholder.
948        """
949        #if alogger not in self.loggers:
950        if alogger not in self.loggerMap:
951            #self.loggers.append(alogger)
952            self.loggerMap[alogger] = None
953
954#
955#   Determine which class to use when instantiating loggers.
956#
957_loggerClass = None
958
959def setLoggerClass(klass):
960    """
961    Set the class to be used when instantiating a logger. The class should
962    define __init__() such that only a name argument is required, and the
963    __init__() should call Logger.__init__()
964    """
965    if klass != Logger:
966        if not issubclass(klass, Logger):
967            raise TypeError("logger not derived from logging.Logger: "
968                            + klass.__name__)
969    global _loggerClass
970    _loggerClass = klass
971
972def getLoggerClass():
973    """
974    Return the class to be used when instantiating a logger.
975    """
976
977    return _loggerClass
978
979class Manager(object):
980    """
981    There is [under normal circumstances] just one Manager instance, which
982    holds the hierarchy of loggers.
983    """
984    def __init__(self, rootnode):
985        """
986        Initialize the manager with the root node of the logger hierarchy.
987        """
988        self.root = rootnode
989        self.disable = 0
990        self.emittedNoHandlerWarning = 0
991        self.loggerDict = {}
992        self.loggerClass = None
993
994    def getLogger(self, name):
995        """
996        Get a logger with the specified name (channel name), creating it
997        if it doesn't yet exist. This name is a dot-separated hierarchical
998        name, such as "a", "a.b", "a.b.c" or similar.
999
1000        If a PlaceHolder existed for the specified name [i.e. the logger
1001        didn't exist but a child of it did], replace it with the created
1002        logger and fix up the parent/child references which pointed to the
1003        placeholder to now point to the logger.
1004        """
1005        rv = None
1006        _acquireLock()
1007        try:
1008            if name in self.loggerDict:
1009                rv = self.loggerDict[name]
1010                if isinstance(rv, PlaceHolder):
1011                    ph = rv
1012                    rv = (self.loggerClass or _loggerClass)(name)
1013                    rv.manager = self
1014                    self.loggerDict[name] = rv
1015                    self._fixupChildren(ph, rv)
1016                    self._fixupParents(rv)
1017            else:
1018                rv = (self.loggerClass or _loggerClass)(name)
1019                rv.manager = self
1020                self.loggerDict[name] = rv
1021                self._fixupParents(rv)
1022        finally:
1023            _releaseLock()
1024        return rv
1025
1026    def setLoggerClass(self, klass):
1027        """
1028        Set the class to be used when instantiating a logger with this Manager.
1029        """
1030        if klass != Logger:
1031            if not issubclass(klass, Logger):
1032                raise TypeError("logger not derived from logging.Logger: "
1033                                + klass.__name__)
1034        self.loggerClass = klass
1035
1036    def _fixupParents(self, alogger):
1037        """
1038        Ensure that there are either loggers or placeholders all the way
1039        from the specified logger to the root of the logger hierarchy.
1040        """
1041        name = alogger.name
1042        i = name.rfind(".")
1043        rv = None
1044        while (i > 0) and not rv:
1045            substr = name[:i]
1046            if substr not in self.loggerDict:
1047                self.loggerDict[substr] = PlaceHolder(alogger)
1048            else:
1049                obj = self.loggerDict[substr]
1050                if isinstance(obj, Logger):
1051                    rv = obj
1052                else:
1053                    assert isinstance(obj, PlaceHolder)
1054                    obj.append(alogger)
1055            i = name.rfind(".", 0, i - 1)
1056        if not rv:
1057            rv = self.root
1058        alogger.parent = rv
1059
1060    def _fixupChildren(self, ph, alogger):
1061        """
1062        Ensure that children of the placeholder ph are connected to the
1063        specified logger.
1064        """
1065        name = alogger.name
1066        namelen = len(name)
1067        for c in ph.loggerMap.keys():
1068            #The if means ... if not c.parent.name.startswith(nm)
1069            if c.parent.name[:namelen] != name:
1070                alogger.parent = c.parent
1071                c.parent = alogger
1072
1073#---------------------------------------------------------------------------
1074#   Logger classes and functions
1075#---------------------------------------------------------------------------
1076
1077class Logger(Filterer):
1078    """
1079    Instances of the Logger class represent a single logging channel. A
1080    "logging channel" indicates an area of an application. Exactly how an
1081    "area" is defined is up to the application developer. Since an
1082    application can have any number of areas, logging channels are identified
1083    by a unique string. Application areas can be nested (e.g. an area
1084    of "input processing" might include sub-areas "read CSV files", "read
1085    XLS files" and "read Gnumeric files"). To cater for this natural nesting,
1086    channel names are organized into a namespace hierarchy where levels are
1087    separated by periods, much like the Java or Python package namespace. So
1088    in the instance given above, channel names might be "input" for the upper
1089    level, and "input.csv", "input.xls" and "input.gnu" for the sub-levels.
1090    There is no arbitrary limit to the depth of nesting.
1091    """
1092    def __init__(self, name, level=NOTSET):
1093        """
1094        Initialize the logger with a name and an optional level.
1095        """
1096        Filterer.__init__(self)
1097        self.name = name
1098        self.level = _checkLevel(level)
1099        self.parent = None
1100        self.propagate = 1
1101        self.handlers = []
1102        self.disabled = 0
1103
1104    def setLevel(self, level):
1105        """
1106        Set the logging level of this logger.
1107        """
1108        self.level = _checkLevel(level)
1109
1110    def debug(self, msg, *args, **kwargs):
1111        """
1112        Log 'msg % args' with severity 'DEBUG'.
1113
1114        To pass exception information, use the keyword argument exc_info with
1115        a true value, e.g.
1116
1117        logger.debug("Houston, we have a %s", "thorny problem", exc_info=1)
1118        """
1119        if self.isEnabledFor(DEBUG):
1120            self._log(DEBUG, msg, args, **kwargs)
1121
1122    def info(self, msg, *args, **kwargs):
1123        """
1124        Log 'msg % args' with severity 'INFO'.
1125
1126        To pass exception information, use the keyword argument exc_info with
1127        a true value, e.g.
1128
1129        logger.info("Houston, we have a %s", "interesting problem", exc_info=1)
1130        """
1131        if self.isEnabledFor(INFO):
1132            self._log(INFO, msg, args, **kwargs)
1133
1134    def warning(self, msg, *args, **kwargs):
1135        """
1136        Log 'msg % args' with severity 'WARNING'.
1137
1138        To pass exception information, use the keyword argument exc_info with
1139        a true value, e.g.
1140
1141        logger.warning("Houston, we have a %s", "bit of a problem", exc_info=1)
1142        """
1143        if self.isEnabledFor(WARNING):
1144            self._log(WARNING, msg, args, **kwargs)
1145
1146    warn = warning
1147
1148    def error(self, msg, *args, **kwargs):
1149        """
1150        Log 'msg % args' with severity 'ERROR'.
1151
1152        To pass exception information, use the keyword argument exc_info with
1153        a true value, e.g.
1154
1155        logger.error("Houston, we have a %s", "major problem", exc_info=1)
1156        """
1157        if self.isEnabledFor(ERROR):
1158            self._log(ERROR, msg, args, **kwargs)
1159
1160    def exception(self, msg, *args):
1161        """
1162        Convenience method for logging an ERROR with exception information.
1163        """
1164        self.error(msg, exc_info=1, *args)
1165
1166    def critical(self, msg, *args, **kwargs):
1167        """
1168        Log 'msg % args' with severity 'CRITICAL'.
1169
1170        To pass exception information, use the keyword argument exc_info with
1171        a true value, e.g.
1172
1173        logger.critical("Houston, we have a %s", "major disaster", exc_info=1)
1174        """
1175        if self.isEnabledFor(CRITICAL):
1176            self._log(CRITICAL, msg, args, **kwargs)
1177
1178    fatal = critical
1179
1180    def log(self, level, msg, *args, **kwargs):
1181        """
1182        Log 'msg % args' with the integer severity 'level'.
1183
1184        To pass exception information, use the keyword argument exc_info with
1185        a true value, e.g.
1186
1187        logger.log(level, "We have a %s", "mysterious problem", exc_info=1)
1188        """
1189        if not isinstance(level, int):
1190            if raiseExceptions:
1191                raise TypeError("level must be an integer")
1192            else:
1193                return
1194        if self.isEnabledFor(level):
1195            self._log(level, msg, args, **kwargs)
1196
1197    def findCaller(self):
1198        """
1199        Find the stack frame of the caller so that we can note the source
1200        file name, line number and function name.
1201        """
1202        f = currentframe()
1203        #On some versions of IronPython, currentframe() returns None if
1204        #IronPython isn't run with -X:Frames.
1205        if f is not None:
1206            f = f.f_back
1207        rv = "(unknown file)", 0, "(unknown function)"
1208        while hasattr(f, "f_code"):
1209            co = f.f_code
1210            filename = os.path.normcase(co.co_filename)
1211            if filename == _srcfile:
1212                f = f.f_back
1213                continue
1214            rv = (co.co_filename, f.f_lineno, co.co_name)
1215            break
1216        return rv
1217
1218    def makeRecord(self, name, level, fn, lno, msg, args, exc_info, func=None, extra=None):
1219        """
1220        A factory method which can be overridden in subclasses to create
1221        specialized LogRecords.
1222        """
1223        rv = LogRecord(name, level, fn, lno, msg, args, exc_info, func)
1224        if extra is not None:
1225            for key in extra:
1226                if (key in ["message", "asctime"]) or (key in rv.__dict__):
1227                    raise KeyError("Attempt to overwrite %r in LogRecord" % key)
1228                rv.__dict__[key] = extra[key]
1229        return rv
1230
1231    def _log(self, level, msg, args, exc_info=None, extra=None):
1232        """
1233        Low-level logging routine which creates a LogRecord and then calls
1234        all the handlers of this logger to handle the record.
1235        """
1236        if _srcfile:
1237            #IronPython doesn't track Python frames, so findCaller throws an
1238            #exception on some versions of IronPython. We trap it here so that
1239            #IronPython can use logging.
1240            try:
1241                fn, lno, func = self.findCaller()
1242            except ValueError:
1243                fn, lno, func = "(unknown file)", 0, "(unknown function)"
1244        else:
1245            fn, lno, func = "(unknown file)", 0, "(unknown function)"
1246        if exc_info:
1247            if not isinstance(exc_info, tuple):
1248                exc_info = sys.exc_info()
1249        record = self.makeRecord(self.name, level, fn, lno, msg, args, exc_info, func, extra)
1250        self.handle(record)
1251
1252    def handle(self, record):
1253        """
1254        Call the handlers for the specified record.
1255
1256        This method is used for unpickled records received from a socket, as
1257        well as those created locally. Logger-level filtering is applied.
1258        """
1259        if (not self.disabled) and self.filter(record):
1260            self.callHandlers(record)
1261
1262    def addHandler(self, hdlr):
1263        """
1264        Add the specified handler to this logger.
1265        """
1266        _acquireLock()
1267        try:
1268            if not (hdlr in self.handlers):
1269                self.handlers.append(hdlr)
1270        finally:
1271            _releaseLock()
1272
1273    def removeHandler(self, hdlr):
1274        """
1275        Remove the specified handler from this logger.
1276        """
1277        _acquireLock()
1278        try:
1279            if hdlr in self.handlers:
1280                self.handlers.remove(hdlr)
1281        finally:
1282            _releaseLock()
1283
1284    def callHandlers(self, record):
1285        """
1286        Pass a record to all relevant handlers.
1287
1288        Loop through all handlers for this logger and its parents in the
1289        logger hierarchy. If no handler was found, output a one-off error
1290        message to sys.stderr. Stop searching up the hierarchy whenever a
1291        logger with the "propagate" attribute set to zero is found - that
1292        will be the last logger whose handlers are called.
1293        """
1294        c = self
1295        found = 0
1296        while c:
1297            for hdlr in c.handlers:
1298                found = found + 1
1299                if record.levelno >= hdlr.level:
1300                    hdlr.handle(record)
1301            if not c.propagate:
1302                c = None    #break out
1303            else:
1304                c = c.parent
1305        if (found == 0) and raiseExceptions and not self.manager.emittedNoHandlerWarning:
1306            sys.stderr.write("No handlers could be found for logger"
1307                             " \"%s\"\n" % self.name)
1308            self.manager.emittedNoHandlerWarning = 1
1309
1310    def getEffectiveLevel(self):
1311        """
1312        Get the effective level for this logger.
1313
1314        Loop through this logger and its parents in the logger hierarchy,
1315        looking for a non-zero logging level. Return the first one found.
1316        """
1317        logger = self
1318        while logger:
1319            if logger.level:
1320                return logger.level
1321            logger = logger.parent
1322        return NOTSET
1323
1324    def isEnabledFor(self, level):
1325        """
1326        Is this logger enabled for level 'level'?
1327        """
1328        if self.manager.disable >= level:
1329            return 0
1330        return level >= self.getEffectiveLevel()
1331
1332    def getChild(self, suffix):
1333        """
1334        Get a logger which is a descendant to this one.
1335
1336        This is a convenience method, such that
1337
1338        logging.getLogger('abc').getChild('def.ghi')
1339
1340        is the same as
1341
1342        logging.getLogger('abc.def.ghi')
1343
1344        It's useful, for example, when the parent logger is named using
1345        __name__ rather than a literal string.
1346        """
1347        if self.root is not self:
1348            suffix = '.'.join((self.name, suffix))
1349        return self.manager.getLogger(suffix)
1350
1351class RootLogger(Logger):
1352    """
1353    A root logger is not that different to any other logger, except that
1354    it must have a logging level and there is only one instance of it in
1355    the hierarchy.
1356    """
1357    def __init__(self, level):
1358        """
1359        Initialize the logger with the name "root".
1360        """
1361        Logger.__init__(self, "root", level)
1362
1363_loggerClass = Logger
1364
1365class LoggerAdapter(object):
1366    """
1367    An adapter for loggers which makes it easier to specify contextual
1368    information in logging output.
1369    """
1370
1371    def __init__(self, logger, extra):
1372        """
1373        Initialize the adapter with a logger and a dict-like object which
1374        provides contextual information. This constructor signature allows
1375        easy stacking of LoggerAdapters, if so desired.
1376
1377        You can effectively pass keyword arguments as shown in the
1378        following example:
1379
1380        adapter = LoggerAdapter(someLogger, dict(p1=v1, p2="v2"))
1381        """
1382        self.logger = logger
1383        self.extra = extra
1384
1385    def process(self, msg, kwargs):
1386        """
1387        Process the logging message and keyword arguments passed in to
1388        a logging call to insert contextual information. You can either
1389        manipulate the message itself, the keyword args or both. Return
1390        the message and kwargs modified (or not) to suit your needs.
1391
1392        Normally, you'll only need to override this one method in a
1393        LoggerAdapter subclass for your specific needs.
1394        """
1395        kwargs["extra"] = self.extra
1396        return msg, kwargs
1397
1398    def debug(self, msg, *args, **kwargs):
1399        """
1400        Delegate a debug call to the underlying logger, after adding
1401        contextual information from this adapter instance.
1402        """
1403        msg, kwargs = self.process(msg, kwargs)
1404        self.logger.debug(msg, *args, **kwargs)
1405
1406    def info(self, msg, *args, **kwargs):
1407        """
1408        Delegate an info call to the underlying logger, after adding
1409        contextual information from this adapter instance.
1410        """
1411        msg, kwargs = self.process(msg, kwargs)
1412        self.logger.info(msg, *args, **kwargs)
1413
1414    def warning(self, msg, *args, **kwargs):
1415        """
1416        Delegate a warning call to the underlying logger, after adding
1417        contextual information from this adapter instance.
1418        """
1419        msg, kwargs = self.process(msg, kwargs)
1420        self.logger.warning(msg, *args, **kwargs)
1421
1422    def error(self, msg, *args, **kwargs):
1423        """
1424        Delegate an error call to the underlying logger, after adding
1425        contextual information from this adapter instance.
1426        """
1427        msg, kwargs = self.process(msg, kwargs)
1428        self.logger.error(msg, *args, **kwargs)
1429
1430    def exception(self, msg, *args, **kwargs):
1431        """
1432        Delegate an exception call to the underlying logger, after adding
1433        contextual information from this adapter instance.
1434        """
1435        msg, kwargs = self.process(msg, kwargs)
1436        kwargs["exc_info"] = 1
1437        self.logger.error(msg, *args, **kwargs)
1438
1439    def critical(self, msg, *args, **kwargs):
1440        """
1441        Delegate a critical call to the underlying logger, after adding
1442        contextual information from this adapter instance.
1443        """
1444        msg, kwargs = self.process(msg, kwargs)
1445        self.logger.critical(msg, *args, **kwargs)
1446
1447    def log(self, level, msg, *args, **kwargs):
1448        """
1449        Delegate a log call to the underlying logger, after adding
1450        contextual information from this adapter instance.
1451        """
1452        msg, kwargs = self.process(msg, kwargs)
1453        self.logger.log(level, msg, *args, **kwargs)
1454
1455    def isEnabledFor(self, level):
1456        """
1457        See if the underlying logger is enabled for the specified level.
1458        """
1459        return self.logger.isEnabledFor(level)
1460
1461root = RootLogger(WARNING)
1462Logger.root = root
1463Logger.manager = Manager(Logger.root)
1464
1465#---------------------------------------------------------------------------
1466# Configuration classes and functions
1467#---------------------------------------------------------------------------
1468
1469BASIC_FORMAT = "%(levelname)s:%(name)s:%(message)s"
1470
1471def basicConfig(**kwargs):
1472    """
1473    Do basic configuration for the logging system.
1474
1475    This function does nothing if the root logger already has handlers
1476    configured. It is a convenience method intended for use by simple scripts
1477    to do one-shot configuration of the logging package.
1478
1479    The default behaviour is to create a StreamHandler which writes to
1480    sys.stderr, set a formatter using the BASIC_FORMAT format string, and
1481    add the handler to the root logger.
1482
1483    A number of optional keyword arguments may be specified, which can alter
1484    the default behaviour.
1485
1486    filename  Specifies that a FileHandler be created, using the specified
1487              filename, rather than a StreamHandler.
1488    filemode  Specifies the mode to open the file, if filename is specified
1489              (if filemode is unspecified, it defaults to 'a').
1490    format    Use the specified format string for the handler.
1491    datefmt   Use the specified date/time format.
1492    level     Set the root logger level to the specified level.
1493    stream    Use the specified stream to initialize the StreamHandler. Note
1494              that this argument is incompatible with 'filename' - if both
1495              are present, 'stream' is ignored.
1496
1497    Note that you could specify a stream created using open(filename, mode)
1498    rather than passing the filename and mode in. However, it should be
1499    remembered that StreamHandler does not close its stream (since it may be
1500    using sys.stdout or sys.stderr), whereas FileHandler closes its stream
1501    when the handler is closed.
1502    """
1503    # Add thread safety in case someone mistakenly calls
1504    # basicConfig() from multiple threads
1505    _acquireLock()
1506    try:
1507        if len(root.handlers) == 0:
1508            filename = kwargs.get("filename")
1509            if filename:
1510                mode = kwargs.get("filemode", 'a')
1511                hdlr = FileHandler(filename, mode)
1512            else:
1513                stream = kwargs.get("stream")
1514                hdlr = StreamHandler(stream)
1515            fs = kwargs.get("format", BASIC_FORMAT)
1516            dfs = kwargs.get("datefmt", None)
1517            fmt = Formatter(fs, dfs)
1518            hdlr.setFormatter(fmt)
1519            root.addHandler(hdlr)
1520            level = kwargs.get("level")
1521            if level is not None:
1522                root.setLevel(level)
1523    finally:
1524        _releaseLock()
1525
1526#---------------------------------------------------------------------------
1527# Utility functions at module level.
1528# Basically delegate everything to the root logger.
1529#---------------------------------------------------------------------------
1530
1531def getLogger(name=None):
1532    """
1533    Return a logger with the specified name, creating it if necessary.
1534
1535    If no name is specified, return the root logger.
1536    """
1537    if name:
1538        return Logger.manager.getLogger(name)
1539    else:
1540        return root
1541
1542#def getRootLogger():
1543#    """
1544#    Return the root logger.
1545#
1546#    Note that getLogger('') now does the same thing, so this function is
1547#    deprecated and may disappear in the future.
1548#    """
1549#    return root
1550
1551def critical(msg, *args, **kwargs):
1552    """
1553    Log a message with severity 'CRITICAL' on the root logger.
1554    """
1555    if len(root.handlers) == 0:
1556        basicConfig()
1557    root.critical(msg, *args, **kwargs)
1558
1559fatal = critical
1560
1561def error(msg, *args, **kwargs):
1562    """
1563    Log a message with severity 'ERROR' on the root logger.
1564    """
1565    if len(root.handlers) == 0:
1566        basicConfig()
1567    root.error(msg, *args, **kwargs)
1568
1569def exception(msg, *args):
1570    """
1571    Log a message with severity 'ERROR' on the root logger,
1572    with exception information.
1573    """
1574    error(msg, exc_info=1, *args)
1575
1576def warning(msg, *args, **kwargs):
1577    """
1578    Log a message with severity 'WARNING' on the root logger.
1579    """
1580    if len(root.handlers) == 0:
1581        basicConfig()
1582    root.warning(msg, *args, **kwargs)
1583
1584warn = warning
1585
1586def info(msg, *args, **kwargs):
1587    """
1588    Log a message with severity 'INFO' on the root logger.
1589    """
1590    if len(root.handlers) == 0:
1591        basicConfig()
1592    root.info(msg, *args, **kwargs)
1593
1594def debug(msg, *args, **kwargs):
1595    """
1596    Log a message with severity 'DEBUG' on the root logger.
1597    """
1598    if len(root.handlers) == 0:
1599        basicConfig()
1600    root.debug(msg, *args, **kwargs)
1601
1602def log(level, msg, *args, **kwargs):
1603    """
1604    Log 'msg % args' with the integer severity 'level' on the root logger.
1605    """
1606    if len(root.handlers) == 0:
1607        basicConfig()
1608    root.log(level, msg, *args, **kwargs)
1609
1610def disable(level):
1611    """
1612    Disable all logging calls of severity 'level' and below.
1613    """
1614    root.manager.disable = level
1615
1616def shutdown(handlerList=_handlerList):
1617    """
1618    Perform any cleanup actions in the logging system (e.g. flushing
1619    buffers).
1620
1621    Should be called at application exit.
1622    """
1623    for wr in reversed(handlerList[:]):
1624        #errors might occur, for example, if files are locked
1625        #we just ignore them if raiseExceptions is not set
1626        try:
1627            h = wr()
1628            if h:
1629                try:
1630                    h.acquire()
1631                    h.flush()
1632                    h.close()
1633                except (IOError, ValueError):
1634                    # Ignore errors which might be caused
1635                    # because handlers have been closed but
1636                    # references to them are still around at
1637                    # application exit.
1638                    pass
1639                finally:
1640                    h.release()
1641        except:
1642            if raiseExceptions:
1643                raise
1644            #else, swallow
1645
1646#Let's try and shutdown automatically on application exit...
1647import atexit
1648atexit.register(shutdown)
1649
1650# Null handler
1651
1652class NullHandler(Handler):
1653    """
1654    This handler does nothing. It's intended to be used to avoid the
1655    "No handlers could be found for logger XXX" one-off warning. This is
1656    important for library code, which may contain code to log events. If a user
1657    of the library does not configure logging, the one-off warning might be
1658    produced; to avoid this, the library developer simply needs to instantiate
1659    a NullHandler and add it to the top-level logger of the library module or
1660    package.
1661    """
1662    def handle(self, record):
1663        pass
1664
1665    def emit(self, record):
1666        pass
1667
1668    def createLock(self):
1669        self.lock = None
1670
1671# Warnings integration
1672
1673_warnings_showwarning = None
1674
1675def _showwarning(message, category, filename, lineno, file=None, line=None):
1676    """
1677    Implementation of showwarnings which redirects to logging, which will first
1678    check to see if the file parameter is None. If a file is specified, it will
1679    delegate to the original warnings implementation of showwarning. Otherwise,
1680    it will call warnings.formatwarning and will log the resulting string to a
1681    warnings logger named "py.warnings" with level logging.WARNING.
1682    """
1683    if file is not None:
1684        if _warnings_showwarning is not None:
1685            _warnings_showwarning(message, category, filename, lineno, file, line)
1686    else:
1687        s = warnings.formatwarning(message, category, filename, lineno, line)
1688        logger = getLogger("py.warnings")
1689        if not logger.handlers:
1690            logger.addHandler(NullHandler())
1691        logger.warning("%s", s)
1692
1693def captureWarnings(capture):
1694    """
1695    If capture is true, redirect all warnings to the logging package.
1696    If capture is False, ensure that warnings are not redirected to logging
1697    but to their original destinations.
1698    """
1699    global _warnings_showwarning
1700    if capture:
1701        if _warnings_showwarning is None:
1702            _warnings_showwarning = warnings.showwarning
1703            warnings.showwarning = _showwarning
1704    else:
1705        if _warnings_showwarning is not None:
1706            warnings.showwarning = _warnings_showwarning
1707            _warnings_showwarning = None
1708