c0f1a1352b
For our use case we only need to be able to override a value, not set defaults so this simplifies everything.
151 lines
4.5 KiB
Python
151 lines
4.5 KiB
Python
import argparse
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import collections
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import os
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import sys
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class _ParserError(Exception):
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pass
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class _HelpError(Exception):
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pass
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class _ArgumentParser(argparse.ArgumentParser):
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def error(self, message):
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raise _ParserError(message)
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class _HelpAction(argparse.Action):
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def __init__(self, option_strings, dest=None, help=None):
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super(_HelpAction, self).__init__(
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option_strings=option_strings,
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dest=dest or argparse.SUPPRESS,
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default=argparse.SUPPRESS,
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nargs=0,
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help=help)
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def __call__(self, parser, namespace, values, option_string=None):
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raise _HelpError()
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class Command(object):
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def __init__(self):
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self._children = collections.OrderedDict()
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self._arguments = []
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self._overrides = {}
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def _build(self):
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actions = []
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parser = _ArgumentParser(add_help=False)
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parser.register('action', 'help', _HelpAction)
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for args, kwargs in self._arguments:
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actions.append(parser.add_argument(*args, **kwargs))
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parser.add_argument('_args', nargs=argparse.REMAINDER,
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help=argparse.SUPPRESS)
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return parser, actions
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def add_child(self, name, command):
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self._children[name] = command
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def add_argument(self, *args, **kwargs):
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self._arguments.append((args, kwargs))
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def set(self, **kwargs):
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self._overrides.update(kwargs)
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def exit(self, status_code=0, message=None, usage=None):
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print '\n\n'.join(m for m in (usage, message) if m)
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sys.exit(status_code)
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def format_usage(self, prog=None):
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actions = self._build()[1]
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prog = prog or os.path.basename(sys.argv[0])
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return self._usage(actions, prog) + '\n'
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def _usage(self, actions, prog):
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formatter = argparse.HelpFormatter(prog)
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formatter.add_usage(None, actions, [])
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return formatter.format_help().strip()
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def format_help(self, prog=None):
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actions = self._build()[1]
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prog = prog or os.path.basename(sys.argv[0])
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formatter = argparse.HelpFormatter(prog)
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formatter.add_usage(None, actions, [])
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if self.__doc__:
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formatter.add_text(self.__doc__)
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if actions:
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formatter.add_text('OPTIONS:')
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formatter.start_section(None)
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formatter.add_arguments(actions)
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formatter.end_section()
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subhelp = []
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for name, child in self._children.items():
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child._subhelp(name, subhelp)
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if subhelp:
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formatter.add_text('COMMANDS:')
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subhelp.insert(0, '')
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return formatter.format_help() + '\n'.join(subhelp)
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def _subhelp(self, name, result):
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actions = self._build()[1]
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if self.__doc__ or actions:
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formatter = argparse.HelpFormatter(name)
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formatter.add_usage(None, actions, [], '')
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formatter.start_section(None)
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formatter.add_text(self.__doc__)
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formatter.start_section(None)
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formatter.add_arguments(actions)
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formatter.end_section()
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formatter.end_section()
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result.append(formatter.format_help())
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for childname, child in self._children.items():
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child._subhelp(' '.join((name, childname)), result)
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def parse(self, args, prog=None):
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prog = prog or os.path.basename(sys.argv[0])
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try:
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return self._parse(
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args, argparse.Namespace(), self._overrides.copy(), prog)
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except _HelpError:
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self.exit(0, self.format_help(prog))
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def _parse(self, args, namespace, overrides, prog):
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overrides.update(self._overrides)
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parser, actions = self._build()
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try:
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result = parser.parse_args(args, namespace)
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except _ParserError as e:
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self.exit(1, e.message, self._usage(actions, prog))
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if not result._args:
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for attr, value in overrides.items():
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setattr(result, attr, value)
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delattr(result, '_args')
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result.command = self
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return result
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child = result._args.pop(0)
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if child not in self._children:
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usage = self._usage(actions, prog)
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self.exit(1, 'unrecognized command: %s' % child, usage)
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return self._children[child]._parse(
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result._args, result, overrides, ' '.join([prog, child]))
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def run(self, *args, **kwargs):
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raise NotImplementedError
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