epydoc.log

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      1  # epydoc -- Logging
      2  #
      3  # Copyright (C) 2005 Edward Loper
      4  # Author: Edward Loper <edloper@loper.org>
      5  # URL: <http://epydoc.sf.net>
      6  #
      7  # $Id: log.py 1488 2007-02-14 00:34:27Z edloper $
      8
      9  """
     10  Functions used to report messages and progress updates to the user.
     11  These functions are delegated to zero or more registered L{Logger}
     12  objects, which are responsible for actually presenting the information
     13  to the user.  Different interfaces are free to create and register
     14  their own C{Logger}s, allowing them to present this information in the
     15  manner that is best suited to each interface.
     16
     17  @note: I considered using the standard C{logging} package to provide
     18  this functionality.  However, I found that it would be too difficult
     19  to get that package to provide the behavior I want (esp. with respect
     20  to progress displays; but also with respect to message blocks).
     21
     22  @group Message Severity Levels: DEBUG, INFO, WARNING, ERROR, FATAL
     23  """
     24  __docformat__ = 'epytext en'
     25
     26  import sys, os
     27
     28  DEBUG = 10
     29  INFO = 20
     30  DOCSTRING_WARNING = 25
     31  WARNING = 30
     32  ERROR = 40
     33  FATAL = 40
     34
     35  ######################################################################
     36  # Logger Base Class
     37  ######################################################################
     38 -class Logger:
     39      """
     40      An abstract base class that defines the interface for X{loggers},
     41      which are used by epydoc to report information back to the user.
     42      Loggers are responsible for tracking two types of information:
     43
     44          - Messages, such as warnings and errors.
     45          - Progress on the current task.
     46
     47      This abstract class allows the command-line interface and the
     48      graphical interface to each present this information to the user
     49      in the way that's most natural for each interface.  To set up a
     50      logger, create a subclass of C{Logger} that overrides all methods,
     51      and register it using L{register_logger}.
     52      """
     53      #////////////////////////////////////////////////////////////
     54      # Messages
     55      #////////////////////////////////////////////////////////////
     56
     57 -    def log(self, level, message):
     58          """
     59          Display a message.
     60
     61          @param message: The message string to display.  C{message} may
     62          contain newlines, but does not need to end in a newline.
     63          @param level: An integer value indicating the severity of the
     64          message.
     65          """
     66
     67 -    def close(self):
     68          """
     69          Perform any tasks needed to close this logger.
     70          """
     71
     72      #////////////////////////////////////////////////////////////
     73      # Message blocks
     74      #////////////////////////////////////////////////////////////
     75
     76 -    def start_block(self, header):
     77          """
     78          Start a new message block.  Any calls to L{info()},
     79          L{warning()}, or L{error()} that occur between a call to
     80          C{start_block} and a corresponding call to C{end_block} will
     81          be grouped together, and displayed with a common header.
     82          C{start_block} can be called multiple times (to form nested
     83          blocks), but every call to C{start_block} I{must} be balanced
     84          by a call to C{end_block}.
     85          """
     86
     87 -    def end_block(self):
     88          """
     89          End a warning block.  See L{start_block} for details.
     90          """
     91
     92      #////////////////////////////////////////////////////////////
     93      # Progress bar
     94      #////////////////////////////////////////////////////////////
     95
     96 -    def start_progress(self, header=None):
     97          """
     98          Begin displaying progress for a new task.  C{header} is a
     99          description of the task for which progress is being reported.
    100          Each call to C{start_progress} must be followed by a call to
    101          C{end_progress} (with no intervening calls to
    102          C{start_progress}).
    103          """
    104
    105 -    def end_progress(self):
    106          """
    107          Finish off the display of progress for the current task.  See
    108          L{start_progress} for more information.
    109          """
    110
    111 -    def progress(self, percent, message=''):
    112          """
    113          Update the progress display.
    114
    115          @param percent: A float from 0.0 to 1.0, indicating how much
    116              progress has been made.
    117          @param message: A message indicating the most recent action
    118              that contributed towards that progress.
    119          """
    120
    121 -class SimpleLogger(Logger):
    122 -    def __init__(self, threshold=WARNING):
    123          self.threshold = threshold
    124 -    def log(self, level, message):
    125          if level >= self.threshold: print message
    126
    127  ######################################################################
    128  # Logger Registry
    129  ######################################################################
    130
    131  _loggers = []
    132  """
    133  The list of registered logging functions.
    134  """
    135
    136 -def register_logger(logger):
    137      """
    138      Register a logger.  Each call to one of the logging functions
    139      defined by this module will be delegated to each registered
    140      logger.
    141      """
    142      _loggers.append(logger)
    143
    144 -def remove_logger(logger):
    145      _loggers.remove(logger)
    146
    147  ######################################################################
    148  # Logging Functions
    149  ######################################################################
    150  # The following methods all just delegate to the corresponding
    151  # methods in the Logger class (above) for each registered logger.
    152
    153 -def fatal(*messages):
    154      """Display the given fatal message."""
    155      message = ' '.join(['%s' % (m,) for m in messages])
    156      for logger in _loggers: logger.log(FATAL, message)
    157
    158 -def error(*messages):
    159      """Display the given error message."""
    160      message = ' '.join(['%s' % (m,) for m in messages])
    161      for logger in _loggers: logger.log(ERROR, message)
    162
    163 -def warning(*messages):
    164      """Display the given warning message."""
    165      message = ' '.join(['%s' % (m,) for m in messages])
    166      for logger in _loggers: logger.log(WARNING, message)
    167
    168 -def docstring_warning(*messages):
    169      """Display the given docstring warning message."""
    170      message = ' '.join(['%s' % (m,) for m in messages])
    171      for logger in _loggers: logger.log(DOCSTRING_WARNING, message)
    172
    173 -def info(*messages):
    174      """Display the given informational message."""
    175      message = ' '.join(['%s' % (m,) for m in messages])
    176      for logger in _loggers: logger.log(INFO, message)
    177
    178 -def debug(*messages):
    179      """Display the given debugging message."""
    180      message = ' '.join(['%s' % (m,) for m in messages])
    181      for logger in _loggers: logger.log(DEBUG, message)
    182
    183 -def start_block(header):
    184      for logger in _loggers: logger.start_block(header)
    185  start_block.__doc__ = Logger.start_block.__doc__
    186
    187 -def end_block():
    188      for logger in _loggers: logger.end_block()
    189  end_block.__doc__ = Logger.end_block.__doc__
    190
    191 -def start_progress(header=None):
    192      for logger in _loggers: logger.start_progress(header)
    193  start_progress.__doc__ = Logger.start_progress.__doc__
    194
    195 -def end_progress():
    196      for logger in _loggers: logger.end_progress()
    197  end_progress.__doc__ = Logger.end_progress.__doc__
    198
    199 -def progress(percent, message=''):
    200      for logger in _loggers: logger.progress(percent, '%s' % message)
    201  progress.__doc__ = Logger.progress.__doc__
    202
    203 -def close():
    204      for logger in _loggers: logger.close()
    205