imgcreate/debug.py

   1 #
   2 # debug.py: Helper routines for debugging
   3 #
   4 # Copyright 2008, Red Hat  Inc.
   5 #
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; version 2 of the License.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU Library General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program; if not, write to the Free Software
  17 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18 #
  19
  20 import logging
  21 import logging.handlers
  22 import optparse
  23 import sys
  24
  25
  26 def handle_logging(option, opt, val, parser, logger, level):
  27     if level < logger.level:
  28         logger.setLevel(level)
  29
  30 def handle_logfile(option, opt, val, parser, logger, stream):
  31     try:
  32         logfile = logging.FileHandler(val,"a")
  33     except IOError, e:
  34         raise optparse.OptionValueError("Cannot open file '%s' : %s" %
  35                                         (val, e.strerror))
  36
  37
  38     logger.removeHandler(stream)
  39     logger.addHandler(logfile)
  40
  41 def setup_logging(parser = None):
  42     """Set up the root logger and add logging options.
  43
  44     Set up the root logger so only warning/error messages are logged to stderr
  45     by default.
  46
  47     Also, optionally, add --debug, --verbose and --logfile command line options
  48     to the supplied option parser, allowing the root logger configuration to be
  49     modified by the user.
  50
  51     Note, to avoid possible namespace clashes, setup_logging() will only ever
  52     add these three options. No new options will be added in the future.
  53
  54     parser -- an optparse.OptionParser instance, or None
  55
  56     """
  57     logger = logging.getLogger()
  58
  59     logger.setLevel(logging.WARN)
  60
  61     stream = logging.StreamHandler(sys.stderr)
  62
  63     logger.addHandler(stream)
  64
  65     if parser is None:
  66         return
  67
  68     group = optparse.OptionGroup(parser, "Debugging options",
  69                                  "These options control the output of logging information during image creation")
  70
  71     group.add_option("-d", "--debug",
  72                      action = "callback", callback = handle_logging,
  73                      callback_args = (logger, logging.DEBUG),
  74                      help = "Output debugging information")
  75
  76     group.add_option("-v", "--verbose",
  77                      action = "callback", callback = handle_logging,
  78                      callback_args = (logger, logging.INFO),
  79                      help = "Output verbose progress information")
  80
  81     group.add_option("", "--logfile", type="string",
  82                      action = "callback", callback = handle_logfile,
  83                      callback_args = (logger, stream),
  84                      help = "Save debug information to FILE", metavar = "FILE")
  85
  86     parser.add_option_group(group)