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