124 lines
4.3 KiB
Python
124 lines
4.3 KiB
Python
# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""Discover and lookup command plugins.
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"""
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import inspect
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import logging
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import pkg_resources
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LOG = logging.getLogger(__name__)
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class EntryPointWrapper(object):
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"""Wrap up a command class already imported to make it look like a plugin.
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"""
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def __init__(self, name, command_class):
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self.name = name
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self.command_class = command_class
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def load(self, require=False):
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return self.command_class
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class CommandManager(object):
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"""Discovers commands and handles lookup based on argv data.
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:param namespace: String containing the setuptools entrypoint namespace
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for the plugins to be loaded. For example,
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``'cliff.formatter.list'``.
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:param convert_underscores: Whether cliff should convert underscores to
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spaces in entry_point commands.
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"""
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def __init__(self, namespace, convert_underscores=True):
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self.commands = {}
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self._legacy = {}
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self.namespace = namespace
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self.convert_underscores = convert_underscores
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self._load_commands()
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def _load_commands(self):
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# NOTE(jamielennox): kept for compatibility.
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if self.namespace:
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self.load_commands(self.namespace)
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def load_commands(self, namespace):
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"""Load all the commands from an entrypoint"""
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for ep in pkg_resources.iter_entry_points(namespace):
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LOG.debug('found command %r', ep.name)
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cmd_name = (ep.name.replace('_', ' ')
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if self.convert_underscores
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else ep.name)
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self.commands[cmd_name] = ep
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return
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def __iter__(self):
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return iter(self.commands.items())
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def add_command(self, name, command_class):
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self.commands[name] = EntryPointWrapper(name, command_class)
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def add_legacy_command(self, old_name, new_name):
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"""Map an old command name to the new name.
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:param old_name: The old command name.
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:type old_name: str
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:param new_name: The new command name.
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:type new_name: str
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"""
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self._legacy[old_name] = new_name
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def find_command(self, argv):
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"""Given an argument list, find a command and
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return the processor and any remaining arguments.
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"""
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start = self._get_last_possible_command_index(argv)
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for i in range(start, 0, -1):
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name = ' '.join(argv[:i])
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search_args = argv[i:]
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# The legacy command handling may modify name, so remember
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# the value we actually found in argv so we can return it.
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return_name = name
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# Convert the legacy command name to its new name.
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if name in self._legacy:
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name = self._legacy[name]
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if name in self.commands:
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cmd_ep = self.commands[name]
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if hasattr(cmd_ep, 'resolve'):
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cmd_factory = cmd_ep.resolve()
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else:
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# NOTE(dhellmann): Some fake classes don't take
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# require as an argument. Yay?
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arg_spec = inspect.getargspec(cmd_ep.load)
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if 'require' in arg_spec[0]:
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cmd_factory = cmd_ep.load(require=False)
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else:
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cmd_factory = cmd_ep.load()
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return (cmd_factory, return_name, search_args)
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else:
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raise ValueError('Unknown command %r' %
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(argv,))
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def _get_last_possible_command_index(self, argv):
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"""Returns the index after the last argument
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in argv that can be a command word
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"""
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for i, arg in enumerate(argv):
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if arg.startswith('-'):
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return i
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return len(argv)
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