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# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""Discover and lookup command plugins.
"""
import logging
import stevedore
from . import utils
LOG = logging.getLogger(__name__)
def _get_commands_by_partial_name(args, commands):
n = len(args)
candidates = []
for command_name in commands:
command_parts = command_name.split()
if len(command_parts) != n:
continue
if all(command_parts[i].startswith(args[i]) for i in range(n)):
candidates.append(command_name)
return candidates
class EntryPointWrapper(object):
"""Wrap up a command class already imported to make it look like a plugin.
"""
def __init__(self, name, command_class):
self.name = name
self.command_class = command_class
def load(self, require=False):
return self.command_class
class CommandManager(object):
"""Discovers commands and handles lookup based on argv data.
:param namespace: String containing the entrypoint namespace for the
plugins to be loaded. For example, ``'cliff.formatter.list'``.
:param convert_underscores: Whether cliff should convert underscores to
spaces in entry_point commands.
"""
def __init__(self, namespace, convert_underscores=True):
self.commands = {}
self._legacy = {}
self.namespace = namespace
self.convert_underscores = convert_underscores
self.group_list = []
self._load_commands()
def _load_commands(self):
# NOTE(jamielennox): kept for compatibility.
if self.namespace:
self.load_commands(self.namespace)
def load_commands(self, namespace):
"""Load all the commands from an entrypoint"""
self.group_list.append(namespace)
for ep in stevedore.ExtensionManager(namespace):
LOG.debug('found command %r', ep.name)
cmd_name = (ep.name.replace('_', ' ')
if self.convert_underscores
else ep.name)
self.commands[cmd_name] = ep.entry_point
return
def __iter__(self):
return iter(self.commands.items())
def add_command(self, name, command_class):
self.commands[name] = EntryPointWrapper(name, command_class)
def add_legacy_command(self, old_name, new_name):
"""Map an old command name to the new name.
:param old_name: The old command name.
:type old_name: str
:param new_name: The new command name.
:type new_name: str
"""
self._legacy[old_name] = new_name
def find_command(self, argv):
"""Given an argument list, find a command and
return the processor and any remaining arguments.
"""
start = self._get_last_possible_command_index(argv)
for i in range(start, 0, -1):
name = ' '.join(argv[:i])
search_args = argv[i:]
# The legacy command handling may modify name, so remember
# the value we actually found in argv so we can return it.
return_name = name
# Convert the legacy command name to its new name.
if name in self._legacy:
name = self._legacy[name]
found = None
if name in self.commands:
found = name
else:
candidates = _get_commands_by_partial_name(
argv[:i], self.commands)
if len(candidates) == 1:
found = candidates[0]
if found:
cmd_ep = self.commands[found]
if hasattr(cmd_ep, 'resolve'):
cmd_factory = cmd_ep.resolve()
else:
# NOTE(dhellmann): Some fake classes don't take
# require as an argument. Yay?
arg_spec = utils.getargspec(cmd_ep.load)
if 'require' in arg_spec[0]:
cmd_factory = cmd_ep.load(require=False)
else:
cmd_factory = cmd_ep.load()
return (cmd_factory, return_name, search_args)
else:
raise ValueError('Unknown command %r' %
(argv,))
def _get_last_possible_command_index(self, argv):
"""Returns the index after the last argument
in argv that can be a command word
"""
for i, arg in enumerate(argv):
if arg.startswith('-'):
return i
return len(argv)
def add_command_group(self, group=None):
"""Adds another group of command entrypoints"""
if group:
self.load_commands(group)
def get_command_groups(self):
"""Returns a list of the loaded command groups"""
return self.group_list
def get_command_names(self, group=None):
"""Returns a list of commands loaded for the specified group"""
group_list = []
if group is not None:
for ep in stevedore.ExtensionManager(group):
cmd_name = (
ep.name.replace('_', ' ')
if self.convert_underscores
else ep.name
)
group_list.append(cmd_name)
return group_list
return list(self.commands.keys())
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