text: # Copyright 2001-2016 by Vinay Sajip. All Rights Reserved.
  #
  # Permission to use, copy, modify, and distribute this software and its
  # documentation for any purpose and without fee is hereby granted,
  # provided that the above copyright notice appear in all copies and that
  # both that copyright notice and this permission notice appear in
  # supporting documentation, and that the name of Vinay Sajip
  # not be used in advertising or publicity pertaining to distribution
  # of the software without specific, written prior permission.
  # VINAY SAJIP DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
  # ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
  # VINAY SAJIP BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
  # ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
  # IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  
  """
  Additional handlers for the logging package for Python. The core package is
  based on PEP 282 and comments thereto in comp.lang.python.
  
  Copyright (C) 2001-2016 Vinay Sajip. All Rights Reserved.
  
  To use, simply 'import logging.handlers' and log away!
  """
  
  import logging, socket, os, pickle, struct, time, re
  from stat import ST_DEV, ST_INO, ST_MTIME
  import queue
  import threading
  import copy
  
  #
  # Some constants...
  #
  
  DEFAULT_TCP_LOGGING_PORT    = 9020
  DEFAULT_UDP_LOGGING_PORT    = 9021
  DEFAULT_HTTP_LOGGING_PORT   = 9022
  DEFAULT_SOAP_LOGGING_PORT   = 9023
  SYSLOG_UDP_PORT             = 514
  SYSLOG_TCP_PORT             = 514
  
  _MIDNIGHT = 24 * 60 * 60  # number of seconds in a day
  
  class BaseRotatingHandler(logging.FileHandler):
      """
      Base class for handlers that rotate log files at a certain point.
      Not meant to be instantiated directly.  Instead, use RotatingFileHandler
      or TimedRotatingFileHandler.
      """
      def __init__(self, filename, mode, encoding=None, delay=False, errors=None):
          """
          Use the specified filename for streamed logging
          """
          logging.FileHandler.__init__(self, filename, mode=mode,
                                       encoding=encoding, delay=delay,
                                       errors=errors)
          self.mode = mode
          self.encoding = encoding
          self.errors = errors
          self.namer = None
          self.rotator = None
  
      def emit(self, record):
          """
          Emit a record.
  
          Output the record to the file, catering for rollover as described
          in doRollover().
          """
          try:
              if self.shouldRollover(record):
                  self.doRollover()
              logging.FileHandler.emit(self, record)
          except Exception:
              self.handleError(record)
  
      def rotation_filename(self, default_name):
          """
          Modify the filename of a log file when rotating.
  
          This is provided so that a custom filename can be provided.
  
          The default implementation calls the 'namer' attribute of the
          handler, if it's callable, passing the default name to
          it. If the attribute isn't callable (the default is None), the name
          is returned unchanged.
  
          :param default_name: The default name for the log file.
          """
          if not callable(self.namer):
              result = default_name
          else:
              result = self.namer(default_name)
          return result
  
      def rotate(self, source, dest):
          """
          When rotating, rotate the current log.
  
          The default implementation calls the 'rotator' attribute of the
          handler, if it's callable, passing the source and dest arguments to
          it. If the attribute isn't callable (the default is None), the source
          is simply renamed to the destination.
  
          :param source: The source filename. This is normally the base
                         filename, e.g. 'test.log'
          :param dest:   The destination filename. This is normally
                         what the source is rotated to, e.g. 'test.log.1'.
          """
          if not callable(self.rotator):
              # Issue 18940: A file may not have been created if delay is True.
              if os.path.exists(source):
                  os.rename(source, dest)
          else:
              self.rotator(source, dest)
  
  class RotatingFileHandler(BaseRotatingHandler):
      """
      Handler for logging to a set of files, which switches from one file
      to the next when the current file reaches a certain size.
      """
      def __init__(self, filename, mode='a', maxBytes=0, backupCount=0,
                   encoding=None, delay=False, errors=None):
          """
          Open the specified file and use it as the stream for logging.
  
          By default, the file grows indefinitely. You can specify particular
          values of maxBytes and backupCount to allow the file to rollover at
          a predetermined size.
  
          Rollover occurs whenever the current log file is nearly maxBytes in
          length. If backupCount is >= 1, the system will successively create
          new files with the same pathname as the base file, but with extensions
          ".1", ".2" etc. appended to it. For example, with a backupCount of 5
          and a base file name of "app.log", you would get "app.log",
          "app.log.1", "app.log.2", ... through to "app.log.5". The file being
          written to is always "app.log" - when it gets filled up, it is closed
          and renamed to "app.log.1", and if files "app.log.1", "app.log.2" etc.
          exist, then they are renamed to "app.log.2", "app.log.3" etc.
          respectively.
  
          If maxBytes is zero, rollover never occurs.
          """
          # If rotation/rollover is wanted, it doesn't make sense to use another
          # mode. If for example 'w' were specified, then if there were multiple
          # runs of the calling application, the logs from previous runs would be
          # lost if the 'w' is respected, because the log file would be truncated
          # on each run.
          if maxBytes > 0:
              mode = 'a'
          BaseRotatingHandler.__init__(self, filename, mode, encoding=encoding,
                                       delay=delay, errors=errors)
          self.maxBytes = maxBytes
          self.backupCount = backupCount
  
      def doRollover(self):
          """
          Do a rollover, as described in __init__().
          """
          if self.stream:
              self.stream.close()
              self.stream = None
          if self.backupCount > 0:
              for i in range(self.backupCount - 1, 0, -1):
                  sfn = self.rotation_filename("%s.%d" % (self.baseFilename, i))
                  dfn = self.rotation_filename("%s.%d" % (self.baseFilename,
                                                          i + 1))
                  if os.path.exists(sfn):
                      if os.path.exists(dfn):
                          os.remove(dfn)
                      os.rename(sfn, dfn)
              dfn = self.rotation_filename(self.baseFilename + ".1")
              if os.path.exists(dfn):
                  os.remove(dfn)
              self.rotate(self.baseFilename, dfn)
          if not self.delay:
              self.stream = self._open()
  
      def shouldRollover(self, record):
          """
          Determine if rollover should occur.
  
          Basically, see if the supplied record would cause the file to exceed
          the size limit we have.
          """
          if self.stream is None:                 # delay was set...
              self.stream = self._open()
          if self.maxBytes > 0:                   # are we rolling over?
              msg = "%s\n" % self.format(record)
              self.stream.seek(0, 2)  #due to non-posix-compliant Windows feature
              if self.stream.tell() + len(msg) >= self.maxBytes:
                  return 1
          return 0
  
  class TimedRotatingFileHandler(BaseRotatingHandler):
      """
      Handler for logging to a file, rotating the log file at certain timed
      intervals.
  
      If backupCount is > 0, when rollover is done, no more than backupCount
      files are kept - the oldest ones are deleted.
      """
      def __init__(self, filename, when='h', interval=1, backupCount=0,
                   encoding=None, delay=False, utc=False, atTime=None,
                   errors=None):
          BaseRotatingHandler.__init__(self, filename, 'a', encoding=encoding,
                                       delay=delay, errors=errors)
          self.when = when.upper()
          self.backupCount = backupCount
          self.utc = utc
          self.atTime = atTime
          # Calculate the real rollover interval, which is just the number of
          # seconds between rollovers.  Also set the filename suffix used when
          # a rollover occurs.  Current 'when' events supported:
          # S - Seconds
          # M - Minutes
          # H - Hours
          # D - Days
          # midnight - roll over at midnight
          # W{0-6} - roll over on a certain day; 0 - Monday
          #
          # Case of the 'when' specifier is not important; lower or upper case
          # will work.
          if self.when == 'S':
              self.interval = 1 # one second
              self.suffix = "%Y-%m-%d_%H-%M-%S"
              self.extMatch = r"^\d{4}-\d{2}-\d{2}_\d{2}-\d{2}-\d{2}(\.\w+)?$"
          elif self.when == 'M':
              self.interval = 60 # one minute
              self.suffix = "%Y-%m-%d_%H-%M"
              self.extMatch = r"^\d{4}-\d{2}-\d{2}_\d{2}-\d{2}(\.\w+)?$"
          elif self.when == 'H':
              self.interval = 60 * 60 # one hour
              self.suffix = "%Y-%m-%d_%H"
              self.extMatch = r"^\d{4}-\d{2}-\d{2}_\d{2}(\.\w+)?$"
          elif self.when == 'D' or self.when == 'MIDNIGHT':
              self.interval = 60 * 60 * 24 # one day
              self.suffix = "%Y-%m-%d"
              self.extMatch = r"^\d{4}-\d{2}-\d{2}(\.\w+)?$"
          elif self.when.startswith('W'):
              self.interval = 60 * 60 * 24 * 7 # one week
              if len(self.when) != 2:
                  raise ValueError("You must specify a day for weekly rollover from 0 to 6 (0 is Monday): %s" % self.when)
              if self.when[1] < '0' or self.when[1] > '6':
                  raise ValueError("Invalid day specified for weekly rollover: %s" % self.when)
              self.dayOfWeek = int(self.when[1])
              self.suffix = "%Y-%m-%d"
              self.extMatch = r"^\d{4}-\d{2}-\d{2}(\.\w+)?$"
          else:
              raise ValueError("Invalid rollover interval specified: %s" % self.when)
  
          self.extMatch = re.compile(self.extMatch, re.ASCII)
          self.interval = self.interval * interval # multiply by units requested
          # The following line added because the filename passed in could be a
          # path object (see Issue #27493), but self.baseFilename will be a string
          filename = self.baseFilename
          if os.path.exists(filename):
              t = os.stat(filename)[ST_MTIME]
          else:
              t = int(time.time())
          self.rolloverAt = self.computeRollover(t)
  
      def computeRollover(self, currentTime):
          """
          Work out the rollover time based on the specified time.
          """
          result = currentTime + self.interval
          # If we are rolling over at midnight or weekly, then the interval is already known.
          # What we need to figure out is WHEN the next interval is.  In other words,
          # if you are rolling over at midnight, then your base interval is 1 day,
          # but you want to start that one day clock at midnight, not now.  So, we
          # have to fudge the rolloverAt value in order to trigger the first rollover
          # at the right time.  After that, the regular interval will take care of
          # the rest.  Note that this code doesn't care about leap seconds. :)
          if self.when == 'MIDNIGHT' or self.when.startswith('W'):
              # This could be done with less code, but I wanted it to be clear
              if self.utc:
                  t = time.gmtime(currentTime)
              else:
                  t = time.localtime(currentTime)
              currentHour = t[3]
              currentMinute = t[4]
              currentSecond = t[5]
              currentDay = t[6]
              # r is the number of seconds left between now and the next rotation
              if self.atTime is None:
                  rotate_ts = _MIDNIGHT
              else:
                  rotate_ts = ((self.atTime.hour * 60 + self.atTime.minute)*60 +
                      self.atTime.second)
  
              r = rotate_ts - ((currentHour * 60 + currentMinute) * 60 +
                  currentSecond)
              if r < 0:
                  # Rotate time is before the current time (for example when
                  # self.rotateAt is 13:45 and it now 14:15), rotation is
                  # tomorrow.
                  r += _MIDNIGHT
                  currentDay = (currentDay + 1) % 7
              result = currentTime + r
              # If we are rolling over on a certain day, add in the number of days until
              # the next rollover, but offset by 1 since we just calculated the time
              # until the next day starts.  There are three cases:
              # Case 1) The day to rollover is today; in this case, do nothing
              # Case 2) The day to rollover is further in the interval (i.e., today is
              #         day 2 (Wednesday) and rollover is on day 6 (Sunday).  Days to
              #         next rollover is simply 6 - 2 - 1, or 3.
              # Case 3) The day to rollover is behind us in the interval (i.e., today
              #         is day 5 (Saturday) and rollover is on day 3 (Thursday).
              #         Days to rollover is 6 - 5 + 3, or 4.  In this case, it's the
              #         number of days left in the current week (1) plus the number
              #         of days in the next week until the rollover day (3).
              # The calculations described in 2) and 3) above need to have a day added.
              # This is because the above time calculation takes us to midnight on this
              # day, i.e. the start of the next day.
              if self.when.startswith('W'):
                  day = currentDay # 0 is Monday
                  if day != self.dayOfWeek:
                      if day < self.dayOfWeek:
                          daysToWait = self.dayOfWeek - day
                      else:
                          daysToWait = 6 - day + self.dayOfWeek + 1
                      newRolloverAt = result + (daysToWait * (60 * 60 * 24))
                      if not self.utc:
                          dstNow = t[-1]
                          dstAtRollover = time.localtime(newRolloverAt)[-1]
                          if dstNow != dstAtRollover:
                              if not dstNow:  # DST kicks in before next rollover, so we need to deduct an hour
                                  addend = -3600
                              else:           # DST bows out before next rollover, so we need to add an hour
                                  addend = 3600
                              newRolloverAt += addend
                      result = newRolloverAt
          return result
  
      def shouldRollover(self, record):
          """
          Determine if rollover should occur.
  
          record is not used, as we are just comparing times, but it is needed so
          the method signatures are the same
          """
          t = int(time.time())
          if t >= self.rolloverAt:
              return 1
          return 0
  
      def getFilesToDelete(self):
          """
          Determine the files to delete when rolling over.
  
          More specific than the earlier method, which just used glob.glob().
          """
          dirName, baseName = os.path.split(self.baseFilename)
          fileNames = os.listdir(dirName)
          result = []
          prefix = baseName + "."
          plen = len(prefix)
          for fileName in fileNames:
              if fileName[:plen] == prefix:
                  suffix = fileName[plen:]
                  if self.extMatch.match(suffix):
                      result.append(os.path.join(dirName, fileName))
          if len(result) < self.backupCount:
              result = []
          else:
              result.sort()
              result = result[:len(result) - self.backupCount]
          return result
  
      def doRollover(self):
          """
          do a rollover; in this case, a date/time stamp is appended to the filename
          when the rollover happens.  However, you want the file to be named for the
          start of the interval, not the current time.  If there is a backup count,
          then we have to get a list of matching filenames, sort them and remove
          the one with the oldest suffix.
          """
          if self.stream:
              self.stream.close()
              self.stream = None
          # get the time that this sequence started at and make it a TimeTuple
          currentTime = int(time.time())
          dstNow = time.localtime(currentTime)[-1]
          t = self.rolloverAt - self.interval
          if self.utc:
              timeTuple = time.gmtime(t)
          else:
              timeTuple = time.localtime(t)
              dstThen = timeTuple[-1]
              if dstNow != dstThen:
                  if dstNow:
                      addend = 3600
                  else:
                      addend = -3600
                  timeTuple = time.localtime(t + addend)
          dfn = self.rotation_filename(self.baseFilename + "." +
                                       time.strftime(self.suffix, timeTuple))
          if os.path.exists(dfn):
              os.remove(dfn)
          self.rotate(self.baseFilename, dfn)
          if self.backupCount > 0:
              for s in self.getFilesToDelete():
                  os.remove(s)
          if not self.delay:
              self.stream = self._open()
          newRolloverAt = self.computeRollover(currentTime)
          while newRolloverAt <= currentTime:
              newRolloverAt = newRolloverAt + self.interval
          #If DST changes and midnight or weekly rollover, adjust for this.
          if (self.when == 'MIDNIGHT' or self.when.startswith('W')) and not self.utc:
              dstAtRollover = time.localtime(newRolloverAt)[-1]
              if dstNow != dstAtRollover:
                  if not dstNow:  # DST kicks in before next rollover, so we need to deduct an hour
                      addend = -3600
                  else:           # DST bows out before next rollover, so we need to add an hour
                      addend = 3600
                  newRolloverAt += addend
          self.rolloverAt = newRolloverAt
  
  class WatchedFileHandler(logging.FileHandler):
      """
      A handler for logging to a file, which watches the file
      to see if it has changed while in use. This can happen because of
      usage of programs such as newsyslog and logrotate which perform
      log file rotation. This handler, intended for use under Unix,
      watches the file to see if it has changed since the last emit.
      (A file has changed if its device or inode have changed.)
      If it has changed, the old file stream is closed, and the file
      opened to get a new stream.
  
      This handler is not appropriate for use under Windows, because
      under Windows open files cannot be moved or renamed - logging
      opens the files with exclusive locks - and so there is no need
      for such a handler. Furthermore, ST_INO is not supported under
      Windows; stat always returns zero for this value.
  
      This handler is based on a suggestion and patch by Chad J.
      Schroeder.
      """
      def __init__(self, filename, mode='a', encoding=None, delay=False,
                   errors=None):
          logging.FileHandler.__init__(self, filename, mode=mode,
                                       encoding=encoding, delay=delay,
                                       errors=errors)
          self.dev, self.ino = -1, -1
          self._statstream()
  
      def _statstream(self):
          if self.stream:
              sres = os.fstat(self.stream.fileno())
              self.dev, self.ino = sres[ST_DEV], sres[ST_INO]
  
      def reopenIfNeeded(self):
          """
          Reopen log file if needed.
  
          Checks if the underlying file has changed, and if it
          has, close the old stream and reopen the file to get the
          current stream.
          """
          # Reduce the chance of race conditions by stat'ing by path only
          # once and then fstat'ing our new fd if we opened a new log stream.
          # See issue #14632: Thanks to John Mulligan for the problem report
          # and patch.
          try:
              # stat the file by path, checking for existence
              sres = os.stat(self.baseFilename)
          except FileNotFoundError:
              sres = None
          # compare file system stat with that of our stream file handle
          if not sres or sres[ST_DEV] != self.dev or sres[ST_INO] != self.ino:
              if self.stream is not None:
                  # we have an open file handle, clean it up
                  self.stream.flush()
                  self.stream.close()
                  self.stream = None  # See Issue #21742: _open () might fail.
                  # open a new file handle and get new stat info from that fd
                  self.stream = self._open()
                  self._statstream()
  
      def emit(self, record):
          """
          Emit a record.
  
          If underlying file has changed, reopen the file before emitting the
          record to it.
          """
          self.reopenIfNeeded()
          logging.FileHandler.emit(self, record)
  
  
  class SocketHandler(logging.Handler):
      """
      A handler class which writes logging records, in pickle format, to
      a streaming socket. The socket is kept open across logging calls.
      If the peer resets it, an attempt is made to reconnect on the next call.
      The pickle which is sent is that of the LogRecord's attribute dictionary
      (__dict__), so that the receiver does not need to have the logging module
      installed in order to process the logging event.
  
      To unpickle the record at the receiving end into a LogRecord, use the
      makeLogRecord function.
      """
  
      def __init__(self, host, port):
          """
          Initializes the handler with a specific host address and port.
  
          When the attribute *closeOnError* is set to True - if a socket error
          occurs, the socket is silently closed and then reopened on the next
          logging call.
          """
          logging.Handler.__init__(self)
          self.host = host
          self.port = port
          if port is None:
              self.address = host
          else:
              self.address = (host, port)
          self.sock = None
          self.closeOnError = False
          self.retryTime = None
          #
          # Exponential backoff parameters.
          #
          self.retryStart = 1.0
          self.retryMax = 30.0
          self.retryFactor = 2.0
  
      def makeSocket(self, timeout=1):
          """
          A factory method which allows subclasses to define the precise
          type of socket they want.
          """
          if self.port is not None:
              result = socket.create_connection(self.address, timeout=timeout)
          else:
              result = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
              result.settimeout(timeout)
              try:
                  result.connect(self.address)
              except OSError:
                  result.close()  # Issue 19182
                  raise
          return result
  
      def createSocket(self):
          """
          Try to create a socket, using an exponential backoff with
          a max retry time. Thanks to Robert Olson for the original patch
          (SF #815911) which has been slightly refactored.
          """
          now = time.time()
          # Either retryTime is None, in which case this
          # is the first time back after a disconnect, or
          # we've waited long enough.
          if self.retryTime is None:
              attempt = True
          else:
              attempt = (now >= self.retryTime)
          if attempt:
              try:
                  self.sock = self.makeSocket()
                  self.retryTime = None # next time, no delay before trying
              except OSError:
                  #Creation failed, so set the retry time and return.
                  if self.retryTime is None:
                      self.retryPeriod = self.retryStart
                  else:
                      self.retryPeriod = self.retryPeriod * self.retryFactor
                      if self.retryPeriod > self.retryMax:
                          self.retryPeriod = self.retryMax
                  self.retryTime = now + self.retryPeriod
  
      def send(self, s):
          """
          Send a pickled string to the socket.
  
          This function allows for partial sends which can happen when the
          network is busy.
          """
          if self.sock is None:
              self.createSocket()
          #self.sock can be None either because we haven't reached the retry
          #time yet, or because we have reached the retry time and retried,
          #but are still unable to connect.
          if self.sock:
              try:
                  self.sock.sendall(s)
              except OSError: #pragma: no cover
                  self.sock.close()
                  self.sock = None  # so we can call createSocket next time
  
      def makePickle(self, record):
          """
          Pickles the record in binary format with a length prefix, and
          returns it ready for transmission across the socket.
          """
          ei = record.exc_info
          if ei:
              # just to get traceback text into record.exc_text ...
              dummy = self.format(record)
          # See issue #14436: If msg or args are objects, they may not be
          # available on the receiving end. So we convert the msg % args
          # to a string, save it as msg and zap the args.
          d = dict(record.__dict__)
          d['msg'] = record.getMessage()
          d['args'] = None
          d['exc_info'] = None
          # Issue #25685: delete 'message' if present: redundant with 'msg'
          d.pop('message', None)
          s = pickle.dumps(d, 1)
          slen = struct.pack(">L", len(s))
          return slen + s
  
      def handleError(self, record):
          """
          Handle an error during logging.
  
          An error has occurred during logging. Most likely cause -
          connection lost. Close the socket so that we can retry on the
          next event.
          """
          if self.closeOnError and self.sock:
              self.sock.close()
              self.sock = None        #try to reconnect next time
          else:
              logging.Handler.handleError(self, record)
  
      def emit(self, record):
          """
          Emit a record.
  
          Pickles the record and writes it to the socket in binary format.
          If there is an error with the socket, silently drop the packet.
          If there was a problem with the socket, re-establishes the
          socket.
          """
          try:
              s = self.makePickle(record)
              self.send(s)
          except Exception:
              self.handleError(record)
  
      def close(self):
          """
          Closes the socket.
          """
          self.acquire()
          try:
              sock = self.sock
              if sock:
                  self.sock = None
                  sock.close()
              logging.Handler.close(self)
          finally:
              self.release()
  
  class DatagramHandler(SocketHandler):
      """
      A handler class which writes logging records, in pickle format, to
      a datagram socket.  The pickle which is sent is that of the LogRecord's
      attribute dictionary (__dict__), so that the receiver does not need to
      have the logging module installed in order to process the logging event.
  
      To unpickle the record at the receiving end into a LogRecord, use the
      makeLogRecord function.
  
      """
      def __init__(self, host, port):
          """
          Initializes the handler with a specific host address and port.
          """
          SocketHandler.__init__(self, host, port)
          self.closeOnError = False
  
      def makeSocket(self):
          """
          The factory method of SocketHandler is here overridden to create
          a UDP socket (SOCK_DGRAM).
          """
          if self.port is None:
              family = socket.AF_UNIX
          else:
              family = socket.AF_INET
          s = socket.socket(family, socket.SOCK_DGRAM)
          return s
  
      def send(self, s):
          """
          Send a pickled string to a socket.
  
          This function no longer allows for partial sends which can happen
          when the network is busy - UDP does not guarantee delivery and
          can deliver packets out of sequence.
          """
          if self.sock is None:
              self.createSocket()
          self.sock.sendto(s, self.address)
  
  class SysLogHandler(logging.Handler):
      """
      A handler class which sends formatted logging records to a syslog
      server. Based on Sam Rushing's syslog module:
      http://www.nightmare.com/squirl/python-ext/misc/syslog.py
      Contributed by Nicolas Untz (after which minor refactoring changes
      have been made).
      """
  
      # from <linux/sys/syslog.h>:
      # ======================================================================
      # priorities/facilities are encoded into a single 32-bit quantity, where
      # the bottom 3 bits are the priority (0-7) and the top 28 bits are the
      # facility (0-big number). Both the priorities and the facilities map
      # roughly one-to-one to strings in the syslogd(8) source code.  This
      # mapping is included in this file.
      #
      # priorities (these are ordered)
  
      LOG_EMERG     = 0       #  system is unusable
      LOG_ALERT     = 1       #  action must be taken immediately
      LOG_CRIT      = 2       #  critical conditions
      LOG_ERR       = 3       #  error conditions
      LOG_WARNING   = 4       #  warning conditions
      LOG_NOTICE    = 5       #  normal but significant condition
      LOG_INFO      = 6       #  informational
      LOG_DEBUG     = 7       #  debug-level messages
  
      #  facility codes
      LOG_KERN      = 0       #  kernel messages
      LOG_USER      = 1       #  random user-level messages
      LOG_MAIL      = 2       #  mail system
      LOG_DAEMON    = 3       #  system daemons
      LOG_AUTH      = 4       #  security/authorization messages
      LOG_SYSLOG    = 5       #  messages generated internally by syslogd
      LOG_LPR       = 6       #  line printer subsystem
      LOG_NEWS      = 7       #  network news subsystem
      LOG_UUCP      = 8       #  UUCP subsystem
      LOG_CRON      = 9       #  clock daemon
      LOG_AUTHPRIV  = 10      #  security/authorization messages (private)
      LOG_FTP       = 11      #  FTP daemon
  
      #  other codes through 15 reserved for system use
      LOG_LOCAL0    = 16      #  reserved for local use
      LOG_LOCAL1    = 17      #  reserved for local use
      LOG_LOCAL2    = 18      #  reserved for local use
      LOG_LOCAL3    = 19      #  reserved for local use
      LOG_LOCAL4    = 20      #  reserved for local use
      LOG_LOCAL5    = 21      #  reserved for local use
      LOG_LOCAL6    = 22      #  reserved for local use
      LOG_LOCAL7    = 23      #  reserved for local use
  
      priority_names = {
          "alert":    LOG_ALERT,
          "crit":     LOG_CRIT,
          "critical": LOG_CRIT,
          "debug":    LOG_DEBUG,
          "emerg":    LOG_EMERG,
          "err":      LOG_ERR,
          "error":    LOG_ERR,        #  DEPRECATED
          "info":     LOG_INFO,
          "notice":   LOG_NOTICE,
          "panic":    LOG_EMERG,      #  DEPRECATED
          "warn":     LOG_WARNING,    #  DEPRECATED
          "warning":  LOG_WARNING,
          }
  
      facility_names = {
          "auth":     LOG_AUTH,
          "authpriv": LOG_AUTHPRIV,
          "cron":     LOG_CRON,
          "daemon":   LOG_DAEMON,
          "ftp":      LOG_FTP,
          "kern":     LOG_KERN,
          "lpr":      LOG_LPR,
          "mail":     LOG_MAIL,
          "news":     LOG_NEWS,
          "security": LOG_AUTH,       #  DEPRECATED
          "syslog":   LOG_SYSLOG,
          "user":     LOG_USER,
          "uucp":     LOG_UUCP,
          "local0":   LOG_LOCAL0,
          "local1":   LOG_LOCAL1,
          "local2":   LOG_LOCAL2,
          "local3":   LOG_LOCAL3,
          "local4":   LOG_LOCAL4,
          "local5":   LOG_LOCAL5,
          "local6":   LOG_LOCAL6,
          "local7":   LOG_LOCAL7,
          }
  
      #The map below appears to be trivially lowercasing the key. However,
      #there's more to it than meets the eye - in some locales, lowercasing
      #gives unexpected results. See SF #1524081: in the Turkish locale,
      #"INFO".lower() != "info"
      priority_map = {
          "DEBUG" : "debug",
          "INFO" : "info",
          "WARNING" : "warning",
          "ERROR" : "error",
          "CRITICAL" : "critical"
      }
  
      def __init__(self, address=('localhost', SYSLOG_UDP_PORT),
                   facility=LOG_USER, socktype=None):
          """
          Initialize a handler.
  
          If address is specified as a string, a UNIX socket is used. To log to a
          local syslogd, "SysLogHandler(address="/dev/log")" can be used.
          If facility is not specified, LOG_USER is used. If socktype is
          specified as socket.SOCK_DGRAM or socket.SOCK_STREAM, that specific
          socket type will be used. For Unix sockets, you can also specify a
          socktype of None, in which case socket.SOCK_DGRAM will be used, falling
          back to socket.SOCK_STREAM.
          """
          logging.Handler.__init__(self)
  
          self.address = address
          self.facility = facility
          self.socktype = socktype
  
          if isinstance(address, str):
              self.unixsocket = True
              # Syslog server may be unavailable during handler initialisation.
              # C's openlog() function also ignores connection errors.
              # Moreover, we ignore these errors while logging, so it not worse
              # to ignore it also here.
              try:
                  self._connect_unixsocket(address)
              except OSError:
                  pass
          else:
              self.unixsocket = False
              if socktype is None:
                  socktype = socket.SOCK_DGRAM
              host, port = address
              ress = socket.getaddrinfo(host, port, 0, socktype)
              if not ress:
                  raise OSError("getaddrinfo returns an empty list")
              for res in ress:
                  af, socktype, proto, _, sa = res
                  err = sock = None
                  try:
                      sock = socket.socket(af, socktype, proto)
                      if socktype == socket.SOCK_STREAM:
                          sock.connect(sa)
                      break
                  except OSError as exc:
                      err = exc
                      if sock is not None:
                          sock.close()
              if err is not None:
                  raise err
              self.socket = sock
              self.socktype = socktype
  
      def _connect_unixsocket(self, address):
          use_socktype = self.socktype
          if use_socktype is None:
              use_socktype = socket.SOCK_DGRAM
          self.socket = socket.socket(socket.AF_UNIX, use_socktype)
          try:
              self.socket.connect(address)
              # it worked, so set self.socktype to the used type
              self.socktype = use_socktype
          except OSError:
              self.socket.close()
              if self.socktype is not None:
                  # user didn't specify falling back, so fail
                  raise
              use_socktype = socket.SOCK_STREAM
              self.socket = socket.socket(socket.AF_UNIX, use_socktype)
              try:
                  self.socket.connect(address)
                  # it worked, so set self.socktype to the used type
                  self.socktype = use_socktype
              except OSError:
                  self.socket.close()
                  raise
  
      def encodePriority(self, facility, priority):
          """
          Encode the facility and priority. You can pass in strings or
          integers - if strings are passed, the facility_names and
          priority_names mapping dictionaries are used to convert them to
          integers.
          """
          if isinstance(facility, str):
              facility = self.facility_names[facility]
          if isinstance(priority, str):
              priority = self.priority_names[priority]
          return (facility << 3) | priority
  
      def close(self):
          """
          Closes the socket.
          """
          self.acquire()
          try:
              self.socket.close()
              logging.Handler.close(self)
          finally:
              self.release()
  
      def mapPriority(self, levelName):
          """
          Map a logging level name to a key in the priority_names map.
          This is useful in two scenarios: when custom levels are being
          used, and in the case where you can't do a straightforward
          mapping by lowercasing the logging level name because of locale-
          specific issues (see SF #1524081).
          """
          return self.priority_map.get(levelName, "warning")
  
      ident = ''          # prepended to all messages
      append_nul = True   # some old syslog daemons expect a NUL terminator
  
      def emit(self, record):
          """
          Emit a record.
  
          The record is formatted, and then sent to the syslog server. If
          exception information is present, it is NOT sent to the server.
          """
          try:
              msg = self.format(record)
              if self.ident:
                  msg = self.ident + msg
              if self.append_nul:
                  msg += '\000'
  
              # We need to convert record level to lowercase, maybe this will
              # change in the future.
              prio = '<%d>' % self.encodePriority(self.facility,
                                                  self.mapPriority(record.levelname))
              prio = prio.encode('utf-8')
              # Message is a string. Convert to bytes as required by RFC 5424
              msg = msg.encode('utf-8')
              msg = prio + msg
              if self.unixsocket:
                  try:
                      self.socket.send(msg)
                  except OSError:
                      self.socket.close()
                      self._connect_unixsocket(self.address)
                      self.socket.send(msg)
              elif self.socktype == socket.SOCK_DGRAM:
                  self.socket.sendto(msg, self.address)
              else:
                  self.socket.sendall(msg)
          except Exception:
              self.handleError(record)
  
  class SMTPHandler(logging.Handler):
      """
      A handler class which sends an SMTP email for each logging event.
      """
      def __init__(self, mailhost, fromaddr, toaddrs, subject,
                   credentials=None, secure=None, timeout=5.0):
          """
          Initialize the handler.
  
          Initialize the instance with the from and to addresses and subject
          line of the email. To specify a non-standard SMTP port, use the
          (host, port) tuple format for the mailhost argument. To specify
          authentication credentials, supply a (username, password) tuple
          for the credentials argument. To specify the use of a secure
          protocol (TLS), pass in a tuple for the secure argument. This will
          only be used when authentication credentials are supplied. The tuple
          will be either an empty tuple, or a single-value tuple with the name
          of a keyfile, or a 2-value tuple with the names of the keyfile and
          certificate file. (This tuple is passed to the `starttls` method).
          A timeout in seconds can be specified for the SMTP connection (the
          default is one second).
          """
          logging.Handler.__init__(self)
          if isinstance(mailhost, (list, tuple)):
              self.mailhost, self.mailport = mailhost
          else:
              self.mailhost, self.mailport = mailhost, None
          if isinstance(credentials, (list, tuple)):
              self.username, self.password = credentials
          else:
              self.username = None
          self.fromaddr = fromaddr
          if isinstance(toaddrs, str):
              toaddrs = [toaddrs]
          self.toaddrs = toaddrs
          self.subject = subject
          self.secure = secure
          self.timeout = timeout
  
      def getSubject(self, record):
          """
          Determine the subject for the email.
  
          If you want to specify a subject line which is record-dependent,
          override this method.
          """
          return self.subject
  
      def emit(self, record):
          """
          Emit a record.
  
          Format the record and send it to the specified addressees.
          """
          try:
              import smtplib
              from email.message import EmailMessage
              import email.utils
  
              port = self.mailport
              if not port:
                  port = smtplib.SMTP_PORT
              smtp = smtplib.SMTP(self.mailhost, port, timeout=self.timeout)
              msg = EmailMessage()
              msg['From'] = self.fromaddr
              msg['To'] = ','.join(self.toaddrs)
              msg['Subject'] = self.getSubject(record)
              msg['Date'] = email.utils.localtime()
              msg.set_content(self.format(record))
              if self.username:
                  if self.secure is not None:
                      smtp.ehlo()
                      smtp.starttls(*self.secure)
                      smtp.ehlo()
                  smtp.login(self.username, self.password)
              smtp.send_message(msg)
              smtp.quit()
          except Exception:
              self.handleError(record)
  
  class NTEventLogHandler(logging.Handler):
      """
      A handler class which sends events to the NT Event Log. Adds a
      registry entry for the specified application name. If no dllname is
      provided, win32service.pyd (which contains some basic message
      placeholders) is used. Note that use of these placeholders will make
      your event logs big, as the entire message source is held in the log.
      If you want slimmer logs, you have to pass in the name of your own DLL
      which contains the message definitions you want to use in the event log.
      """
      def __init__(self, appname, dllname=None, logtype="Application"):
          logging.Handler.__init__(self)
          try:
              import win32evtlogutil, win32evtlog
              self.appname = appname
              self._welu = win32evtlogutil
              if not dllname:
                  dllname = os.path.split(self._welu.__file__)
                  dllname = os.path.split(dllname[0])
                  dllname = os.path.join(dllname[0], r'win32service.pyd')
              self.dllname = dllname
              self.logtype = logtype
              self._welu.AddSourceToRegistry(appname, dllname, logtype)
              self.deftype = win32evtlog.EVENTLOG_ERROR_TYPE
              self.typemap = {
                  logging.DEBUG   : win32evtlog.EVENTLOG_INFORMATION_TYPE,
                  logging.INFO    : win32evtlog.EVENTLOG_INFORMATION_TYPE,
                  logging.WARNING : win32evtlog.EVENTLOG_WARNING_TYPE,
                  logging.ERROR   : win32evtlog.EVENTLOG_ERROR_TYPE,
                  logging.CRITICAL: win32evtlog.EVENTLOG_ERROR_TYPE,
           }
          except ImportError:
              print("The Python Win32 extensions for NT (service, event "\
                          "logging) appear not to be available.")
              self._welu = None
  
      def getMessageID(self, record):
          """
          Return the message ID for the event record. If you are using your
          own messages, you could do this by having the msg passed to the
          logger being an ID rather than a formatting string. Then, in here,
          you could use a dictionary lookup to get the message ID. This
          version returns 1, which is the base message ID in win32service.pyd.
          """
          return 1
  
      def getEventCategory(self, record):
          """
          Return the event category for the record.
  
          Override this if you want to specify your own categories. This version
          returns 0.
          """
          return 0
  
      def getEventType(self, record):
          """
          Return the event type for the record.
  
          Override this if you want to specify your own types. This version does
          a mapping using the handler's typemap attribute, which is set up in
          __init__() to a dictionary which contains mappings for DEBUG, INFO,
          WARNING, ERROR and CRITICAL. If you are using your own levels you will
          either need to override this method or place a suitable dictionary in
          the handler's typemap attribute.
          """
          return self.typemap.get(record.levelno, self.deftype)
  
      def emit(self, record):
          """
          Emit a record.
  
          Determine the message ID, event category and event type. Then
          log the message in the NT event log.
          """
          if self._welu:
              try:
                  id = self.getMessageID(record)
                  cat = self.getEventCategory(record)
                  type = self.getEventType(record)
                  msg = self.format(record)
                  self._welu.ReportEvent(self.appname, id, cat, type, [msg])
              except Exception:
                  self.handleError(record)
  
      def close(self):
          """
          Clean up this handler.
  
          You can remove the application name from the registry as a
          source of event log entries. However, if you do this, you will
          not be able to see the events as you intended in the Event Log
          Viewer - it needs to be able to access the registry to get the
          DLL name.
          """
          #self._welu.RemoveSourceFromRegistry(self.appname, self.logtype)
          logging.Handler.close(self)
  
  class HTTPHandler(logging.Handler):
      """
      A class which sends records to a Web server, using either GET or
      POST semantics.
      """
      def __init__(self, host, url, method="GET", secure=False, credentials=None,
                   context=None):
          """
          Initialize the instance with the host, the request URL, and the method
          ("GET" or "POST")
          """
          logging.Handler.__init__(self)
          method = method.upper()
          if method not in ["GET", "POST"]:
              raise ValueError("method must be GET or POST")
          if not secure and context is not None:
              raise ValueError("context parameter only makes sense "
                               "with secure=True")
          self.host = host
          self.url = url
          self.method = method
          self.secure = secure
          self.credentials = credentials
          self.context = context
  
      def mapLogRecord(self, record):
          """
          Default implementation of mapping the log record into a dict
          that is sent as the CGI data. Overwrite in your class.
          Contributed by Franz Glasner.
          """
          return record.__dict__
  
      def emit(self, record):
          """
          Emit a record.
  
          Send the record to the Web server as a percent-encoded dictionary
          """
          try:
              import http.client, urllib.parse
              host = self.host
              if self.secure:
                  h = http.client.HTTPSConnection(host, context=self.context)
              else:
                  h = http.client.HTTPConnection(host)
              url = self.url
              data = urllib.parse.urlencode(self.mapLogRecord(record))
              if self.method == "GET":
                  if (url.find('?') >= 0):
                      sep = '&'
                  else:
                      sep = '?'
                  url = url + "%c%s" % (sep, data)
              h.putrequest(self.method, url)
              # support multiple hosts on one IP address...
              # need to strip optional :port from host, if present
              i = host.find(":")
              if i >= 0:
                  host = host[:i]
              # See issue #30904: putrequest call above already adds this header
              # on Python 3.x.
              # h.putheader("Host", host)
              if self.method == "POST":
                  h.putheader("Content-type",
                              "application/x-www-form-urlencoded")
                  h.putheader("Content-length", str(len(data)))
              if self.credentials:
                  import base64
                  s = ('%s:%s' % self.credentials).encode('utf-8')
                  s = 'Basic ' + base64.b64encode(s).strip().decode('ascii')
                  h.putheader('Authorization', s)
              h.endheaders()
              if self.method == "POST":
                  h.send(data.encode('utf-8'))
              h.getresponse()    #can't do anything with the result
          except Exception:
              self.handleError(record)
  
  class BufferingHandler(logging.Handler):
      """
    A handler class which buffers logging records in memory. Whenever each
    record is added to the buffer, a check is made to see if the buffer should
    be flushed. If it should, then flush() is expected to do what's needed.
      """
      def __init__(self, capacity):
          """
          Initialize the handler with the buffer size.
          """
          logging.Handler.__init__(self)
          self.capacity = capacity
          self.buffer = []
  
      def shouldFlush(self, record):
          """
          Should the handler flush its buffer?
  
          Returns true if the buffer is up to capacity. This method can be
          overridden to implement custom flushing strategies.
          """
          return (len(self.buffer) >= self.capacity)
  
      def emit(self, record):
          """
          Emit a record.
  
          Append the record. If shouldFlush() tells us to, call flush() to process
          the buffer.
          """
          self.buffer.append(record)
          if self.shouldFlush(record):
              self.flush()
  
      def flush(self):
          """
          Override to implement custom flushing behaviour.
  
          This version just zaps the buffer to empty.
          """
          self.acquire()
          try:
              self.buffer = []
          finally:
              self.release()
  
      def close(self):
          """
          Close the handler.
  
          This version just flushes and chains to the parent class' close().
          """
          try:
              self.flush()
          finally:
              logging.Handler.close(self)
  
  class MemoryHandler(BufferingHandler):
      """
      A handler class which buffers logging records in memory, periodically
      flushing them to a target handler. Flushing occurs whenever the buffer
      is full, or when an event of a certain severity or greater is seen.
      """
      def __init__(self, capacity, flushLevel=logging.ERROR, target=None,
                   flushOnClose=True):
          """
          Initialize the handler with the buffer size, the level at which
          flushing should occur and an optional target.
  
          Note that without a target being set either here or via setTarget(),
          a MemoryHandler is no use to anyone!
  
          The ``flushOnClose`` argument is ``True`` for backward compatibility
          reasons - the old behaviour is that when the handler is closed, the
          buffer is flushed, even if the flush level hasn't been exceeded nor the
          capacity exceeded. To prevent this, set ``flushOnClose`` to ``False``.
          """
          BufferingHandler.__init__(self, capacity)
          self.flushLevel = flushLevel
          self.target = target
          # See Issue #26559 for why this has been added
          self.flushOnClose = flushOnClose
  
      def shouldFlush(self, record):
          """
          Check for buffer full or a record at the flushLevel or higher.
          """
          return (len(self.buffer) >= self.capacity) or \
                  (record.levelno >= self.flushLevel)
  
      def setTarget(self, target):
          """
          Set the target handler for this handler.
          """
          self.target = target
  
      def flush(self):
          """
          For a MemoryHandler, flushing means just sending the buffered
          records to the target, if there is one. Override if you want
          different behaviour.
  
          The record buffer is also cleared by this operation.
          """
          self.acquire()
          try:
              if self.target:
                  for record in self.buffer:
                      self.target.handle(record)
                  self.buffer = []
          finally:
              self.release()
  
      def close(self):
          """
          Flush, if appropriately configured, set the target to None and lose the
          buffer.
          """
          try:
              if self.flushOnClose:
                  self.flush()
          finally:
              self.acquire()
              try:
                  self.target = None
                  BufferingHandler.close(self)
              finally:
                  self.release()
  
  
  class QueueHandler(logging.Handler):
      """
      This handler sends events to a queue. Typically, it would be used together
      with a multiprocessing Queue to centralise logging to file in one process
      (in a multi-process application), so as to avoid file write contention
      between processes.
  
      This code is new in Python 3.2, but this class can be copy pasted into
      user code for use with earlier Python versions.
      """
  
      def __init__(self, queue):
          """
          Initialise an instance, using the passed queue.
          """
          logging.Handler.__init__(self)
          self.queue = queue
  
      def enqueue(self, record):
          """
          Enqueue a record.
  
          The base implementation uses put_nowait. You may want to override
          this method if you want to use blocking, timeouts or custom queue
          implementations.
          """
          self.queue.put_nowait(record)
  
      def prepare(self, record):
          """
          Prepares a record for queuing. The object returned by this method is
          enqueued.
  
          The base implementation formats the record to merge the message
          and arguments, and removes unpickleable items from the record
          in-place.
  
          You might want to override this method if you want to convert
          the record to a dict or JSON string, or send a modified copy
          of the record while leaving the original intact.
          """
          # The format operation gets traceback text into record.exc_text
          # (if there's exception data), and also returns the formatted
          # message. We can then use this to replace the original
          # msg + args, as these might be unpickleable. We also zap the
          # exc_info and exc_text attributes, as they are no longer
          # needed and, if not None, will typically not be pickleable.
          msg = self.format(record)
          # bpo-35726: make copy of record to avoid affecting other handlers in the chain.
          record = copy.copy(record)
          record.message = msg
          record.msg = msg
          record.args = None
          record.exc_info = None
          record.exc_text = None
          return record
  
      def emit(self, record):
          """
          Emit a record.
  
          Writes the LogRecord to the queue, preparing it for pickling first.
          """
          try:
              self.enqueue(self.prepare(record))
          except Exception:
              self.handleError(record)
  
  
  class QueueListener(object):
      """
      This class implements an internal threaded listener which watches for
      LogRecords being added to a queue, removes them and passes them to a
      list of handlers for processing.
      """
      _sentinel = None
  
      def __init__(self, queue, *handlers, respect_handler_level=False):
          """
          Initialise an instance with the specified queue and
          handlers.
          """
          self.queue = queue
          self.handlers = handlers
          self._thread = None
          self.respect_handler_level = respect_handler_level
  
      def dequeue(self, block):
          """
          Dequeue a record and return it, optionally blocking.
  
          The base implementation uses get. You may want to override this method
          if you want to use timeouts or work with custom queue implementations.
          """
          return self.queue.get(block)
  
      def start(self):
          """
          Start the listener.
  
          This starts up a background thread to monitor the queue for
          LogRecords to process.
          """
          self._thread = t = threading.Thread(target=self._monitor)
          t.daemon = True
          t.start()
  
      def prepare(self, record):
          """
          Prepare a record for handling.
  
          This method just returns the passed-in record. You may want to
          override this method if you need to do any custom marshalling or
          manipulation of the record before passing it to the handlers.
          """
          return record
  
      def handle(self, record):
          """
          Handle a record.
  
          This just loops through the handlers offering them the record
          to handle.
          """
          record = self.prepare(record)
          for handler in self.handlers:
              if not self.respect_handler_level:
                  process = True
              else:
                  process = record.levelno >= handler.level
              if process:
                  handler.handle(record)
  
      def _monitor(self):
          """
          Monitor the queue for records, and ask the handler
          to deal with them.
  
          This method runs on a separate, internal thread.
          The thread will terminate if it sees a sentinel object in the queue.
          """
          q = self.queue
          has_task_done = hasattr(q, 'task_done')
          while True:
              try:
                  record = self.dequeue(True)
                  if record is self._sentinel:
                      if has_task_done:
                          q.task_done()
                      break
                  self.handle(record)
                  if has_task_done:
                      q.task_done()
              except queue.Empty:
                  break
  
      def enqueue_sentinel(self):
          """
          This is used to enqueue the sentinel record.
  
          The base implementation uses put_nowait. You may want to override this
          method if you want to use timeouts or work with custom queue
          implementations.
          """
          self.queue.put_nowait(self._sentinel)
  
      def stop(self):
          """
          Stop the listener.
  
          This asks the thread to terminate, and then waits for it to do so.
          Note that if you don't call this before your application exits, there
          may be some records still left on the queue, which won't be processed.
          """
          self.enqueue_sentinel()
          self._thread.join()
          self._thread = None
  