144 lines
4.5 KiB
Python
144 lines
4.5 KiB
Python
"""Application base class.
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"""
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import logging
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import logging.handlers
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import optparse
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import os
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import sys
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LOG = logging.getLogger(__name__)
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class App(object):
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"""Application base class.
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"""
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NAME = os.path.splitext(os.path.basename(sys.argv[0]))[0]
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CONSOLE_MESSAGE_FORMAT = '%(message)s'
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LOG_FILE_MESSAGE_FORMAT = '[%(asctime)s] %(levelname)-8s %(name)s %(message)s'
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DEFAULT_VERBOSE_LEVEL = 1
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def __init__(self, description, version, command_manager):
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self.command_manager = command_manager
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self.parser = self.build_option_parser(description, version)
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def build_option_parser(self, description, version):
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"""Return an optparse option parser for this application.
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Subclasses may override this method to extend
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the parser with more global options.
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"""
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parser = optparse.OptionParser(
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description=description,
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version='%prog {}'.format(version),
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add_help_option=False,
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)
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parser.disable_interspersed_args()
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parser.add_option(
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'-v', '--verbose',
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action='count',
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dest='verbose_level',
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default=self.DEFAULT_VERBOSE_LEVEL,
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help='Increase verbosity of output. Can be repeated.',
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)
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parser.add_option(
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'-q', '--quiet',
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action='store_const',
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dest='verbose_level',
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const=0,
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help='suppress output except warnings and errors',
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)
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parser.add_option(
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'-h', action='help',
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help="show this help message and exit",
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)
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parser.add_option(
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'--help', action='callback',
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callback=self.show_verbose_help,
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help="show verbose help message and exit",
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)
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parser.add_option(
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'--debug',
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default=False,
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action='store_true',
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help='show tracebacks on errors',
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)
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return parser
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def show_verbose_help(self, *args):
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"""Displays the normal syntax info and a list of available subcommands.
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"""
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self.parser.print_help()
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print('')
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print('Commands:')
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for name, ep in sorted(self.command_manager):
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factory = ep.load()
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cmd = factory(self, None)
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print(' %-13s %s' % (name, cmd.get_description()))
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sys.exit(0)
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def configure_logging(self):
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"""Create logging handlers for any log output.
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"""
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root_logger = logging.getLogger('')
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# Set up logging to a file
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root_logger.setLevel(logging.DEBUG)
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file_handler = logging.handlers.RotatingFileHandler(
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self.NAME + '.log',
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maxBytes=10240,
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backupCount=1,
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)
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formatter = logging.Formatter(self.LOG_FILE_MESSAGE_FORMAT)
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file_handler.setFormatter(formatter)
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root_logger.addHandler(file_handler)
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# Send higher-level messages to the console via stderr
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console = logging.StreamHandler()
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console_level = {0: logging.WARNING,
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1: logging.INFO,
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2: logging.DEBUG,
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}.get(self.options.verbose_level, logging.DEBUG)
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console.setLevel(console_level)
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formatter = logging.Formatter(self.CONSOLE_MESSAGE_FORMAT)
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console.setFormatter(formatter)
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root_logger.addHandler(console)
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return
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def prepare_to_run_command(self, cmd):
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"""Perform any preliminary work needed to run a command.
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"""
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return
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def clean_up(self, cmd, result, err):
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"""Hook run after a command is done to shutdown the app.
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"""
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return
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def run(self, argv):
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"""Equivalent to the main program for the application.
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"""
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if not argv:
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argv = ['-h']
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self.options, remainder = self.parser.parse_args(argv)
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self.configure_logging()
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cmd_factory, cmd_name, sub_argv = self.command_manager.find_command(remainder)
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cmd = cmd_factory(self, self.options)
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err = None
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result = 1
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try:
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self.prepare_to_run_command(cmd)
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cmd_parser = cmd.get_parser(' '.join([self.NAME, cmd_name]))
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parsed_args = cmd_parser.parse_args(sub_argv)
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result = cmd.run(parsed_args)
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except Exception as err:
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if self.options.debug:
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LOG.exception(err)
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raise
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LOG.error(err)
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finally:
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self.clean_up(cmd, result, err)
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return result
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