304 lines
10 KiB
Python
304 lines
10 KiB
Python
"""Application base class.
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"""
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import argparse
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import codecs
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import locale
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import logging
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import logging.handlers
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import os
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import sys
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from .help import HelpAction, HelpCommand
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from .interactive import InteractiveApp
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# Make sure the cliff library has a logging handler
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# in case the app developer doesn't set up logging.
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# For py26 compat, create a NullHandler
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if hasattr(logging, 'NullHandler'):
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NullHandler = logging.NullHandler
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else:
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class NullHandler(logging.Handler):
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def handle(self, record):
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pass
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def emit(self, record):
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pass
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def createLock(self):
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self.lock = None
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logging.getLogger('cliff').addHandler(NullHandler())
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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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:param description: one-liner explaining the program purpose
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:paramtype description: str
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:param version: application version number
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:paramtype version: str
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:param command_manager: plugin loader
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:paramtype command_manager: cliff.commandmanager.CommandManager
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:param stdin: Standard input stream
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:paramtype stdin: readable I/O stream
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:param stdout: Standard output stream
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:paramtype stdout: writable I/O stream
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:param stderr: Standard error output stream
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:paramtype stderr: writable I/O stream
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:param interactive_app_factory: callable to create an
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interactive application
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:paramtype interactive_app_factory: cliff.interactive.InteractiveApp
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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 = \
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'[%(asctime)s] %(levelname)-8s %(name)s %(message)s'
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DEFAULT_VERBOSE_LEVEL = 1
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DEFAULT_OUTPUT_ENCODING = 'utf-8'
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def __init__(self, description, version, command_manager,
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stdin=None, stdout=None, stderr=None,
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interactive_app_factory=InteractiveApp):
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"""Initialize the application.
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"""
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self.command_manager = command_manager
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self.command_manager.add_command('help', HelpCommand)
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self._set_streams(stdin, stdout, stderr)
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self.interactive_app_factory = interactive_app_factory
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self.parser = self.build_option_parser(description, version)
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self.interactive_mode = False
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self.interpreter = None
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def _set_streams(self, stdin, stdout, stderr):
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locale.setlocale(locale.LC_ALL, '')
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if sys.version_info[:2] == (2, 6):
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# Configure the input and output streams. If a stream is
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# provided, it must be configured correctly by the
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# caller. If not, make sure the versions of the standard
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# streams used by default are wrapped with encodings. This
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# works around a problem with Python 2.6 fixed in 2.7 and
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# later (http://hg.python.org/cpython/rev/e60ef17561dc/).
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lang, encoding = locale.getdefaultlocale()
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encoding = (getattr(sys.stdout, 'encoding', None)
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or encoding
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or self.DEFAULT_OUTPUT_ENCODING
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)
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self.stdin = stdin or codecs.getreader(encoding)(sys.stdin)
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self.stdout = stdout or codecs.getwriter(encoding)(sys.stdout)
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self.stderr = stderr or codecs.getwriter(encoding)(sys.stderr)
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else:
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self.stdin = stdin or sys.stdin
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self.stdout = stdout or sys.stdout
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self.stderr = stderr or sys.stderr
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def build_option_parser(self, description, version,
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argparse_kwargs=None):
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"""Return an argparse 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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:param description: full description of the application
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:paramtype description: str
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:param version: version number for the application
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:paramtype version: str
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:param argparse_kwargs: extra keyword argument passed to the
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ArgumentParser constructor
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:paramtype extra_kwargs: dict
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"""
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argparse_kwargs = argparse_kwargs or {}
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parser = argparse.ArgumentParser(
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description=description,
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add_help=False,
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**argparse_kwargs
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)
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parser.add_argument(
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'--version',
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action='version',
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version='%(prog)s {0}'.format(version),
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)
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parser.add_argument(
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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_argument(
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'--log-file',
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action='store',
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default=None,
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help='Specify a file to log output. Disabled by default.',
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)
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parser.add_argument(
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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_argument(
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'-h', '--help',
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action=HelpAction,
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nargs=0,
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default=self, # tricky
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help="show this help message and exit",
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)
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parser.add_argument(
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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 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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root_logger.setLevel(logging.DEBUG)
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# Set up logging to a file
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if self.options.log_file:
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file_handler = logging.FileHandler(
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filename=self.options.log_file,
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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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# Always send higher-level messages to the console via stderr
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console = logging.StreamHandler(self.stderr)
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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 run(self, argv):
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"""Equivalent to the main program for the application.
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:param argv: input arguments and options
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:paramtype argv: list of str
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"""
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try:
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self.options, remainder = self.parser.parse_known_args(argv)
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self.configure_logging()
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self.interactive_mode = not remainder
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self.initialize_app(remainder)
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except Exception as err:
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if hasattr(self, 'options'):
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debug = self.options.debug
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else:
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debug = True
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if debug:
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LOG.exception(err)
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raise
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else:
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LOG.error(err)
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return 1
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result = 1
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if self.interactive_mode:
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result = self.interact()
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else:
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result = self.run_subcommand(remainder)
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return result
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# FIXME(dhellmann): Consider moving these command handling methods
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# to a separate class.
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def initialize_app(self, argv):
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"""Hook for subclasses to take global initialization action
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after the arguments are parsed but before a command is run.
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Invoked only once, even in interactive mode.
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:param argv: List of arguments, including the subcommand to run.
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Empty for interactive mode.
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"""
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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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:param cmd: command processor being invoked
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:paramtype cmd: cliff.command.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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:param cmd: command processor being invoked
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:paramtype cmd: cliff.command.Command
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:param result: return value of cmd
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:paramtype result: int
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:param err: exception or None
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:paramtype err: Exception
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"""
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return
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def interact(self):
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self.interpreter = self.interactive_app_factory(self,
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self.command_manager,
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self.stdin,
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self.stdout,
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)
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self.interpreter.cmdloop()
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return 0
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def run_subcommand(self, argv):
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try:
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subcommand = self.command_manager.find_command(argv)
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except ValueError as err:
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if self.options.debug:
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LOG.exception(err)
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else:
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LOG.error(err)
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return 2
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cmd_factory, cmd_name, sub_argv = subcommand
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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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full_name = (cmd_name
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if self.interactive_mode
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else ' '.join([self.NAME, cmd_name])
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)
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cmd_parser = cmd.get_parser(full_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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else:
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LOG.error(err)
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try:
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self.clean_up(cmd, result, err)
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except Exception as err2:
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if self.options.debug:
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LOG.exception(err2)
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else:
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LOG.error('Could not clean up: %s', err2)
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if self.options.debug:
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raise
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else:
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try:
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self.clean_up(cmd, result, None)
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except Exception as err3:
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if self.options.debug:
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LOG.exception(err3)
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else:
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LOG.error('Could not clean up: %s', err3)
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return result
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