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# Copyright (C) 2013-2014 Red Hat, Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
# The views and conclusions contained in the software and documentation are
# those of the authors and should not be interpreted as representing official
# policies, either expressed or implied, of the FreeBSD Project.
#
# Authors: Michal Minar <miminar@redhat.com>
#
"""
Manager module for direct subcommands of lmi metacommand. Most of them are
loaded from entry_points of installed python eggs.
"""
import pkg_resources
from lmi.scripts.common import Configuration
from lmi.scripts.common import errors
from lmi.scripts.common import get_logger
from lmi.scripts.common.command import base
from lmi.scripts.common.command import util
LOG = get_logger(__name__)
class _CustomCommandWrapper(object):
"""
Provide an interface mocking an entry_point object for custom commands
added by lmi metacommand application.
:param name: (``str``) Name of command.
:param cmd_class: (``LmiBaseCommand``) Factory for custom commands.
"""
def __init__(self, name, cmd_class):
if not isinstance(name, basestring):
raise TypeError("name must be a string")
if not issubclass(cmd_class, base.LmiBaseCommand):
raise TypeError("cmd_class must be a LmiBaseCommand")
self._name = name
self._cmd_class = cmd_class
@property
def name(self):
""" Return command name. """
return self._name
def load(self):
""" Return command class. """
return self._cmd_class
class CommandManager(object):
"""
Manager of direct subcommands of lmi metacommand. It manages commands
registered with entry_points under particular namespace installed by
python eggs. Custom commands may also be added.
:param namespace: (``str``) Namespace, where commands are registered.
For example ``lmi.scripts.cmd``.
"""
def __init__(self, namespace=None):
if namespace is not None and not isinstance(namespace, basestring):
raise TypeError("namespace must be a string")
if namespace is None:
namespace = Configuration.get_instance().get_safe(
"Main", "CommandNamespace")
self._namespace = namespace
self._commands = {}
self._load_commands()
@property
def command_names(self):
""" Returns list of command names. """
return self._commands.keys()
def __len__(self):
return len(self._commands)
def __iter__(self):
""" Yields command names. """
return iter(self._commands)
def __getitem__(self, cmd_name):
""" Gets command factory for name. """
return self.find_command(cmd_name)
def _load_commands(self):
""" Loads commands from entry points under provided namespace. """
def _add_entry_point(epoint):
"""
Convenience function taking an entry point, making some name
checks and adding it to registered commands.
"""
if not util.RE_COMMAND_NAME.match(epoint.name):
LOG().error('Invalid command name: %s, ignoring.', epoint.name)
return
if epoint.name in self._commands:
LOG().warn('Command "%s" already registered, ignoring.',
epoint.name)
else:
LOG().debug('Found registered command "%s".', epoint.name)
self._commands[epoint.name] = epoint
for entry_point in pkg_resources.iter_entry_points(self._namespace):
if isinstance(entry_point, dict):
for epoint in entry_point.values():
_add_entry_point(epoint)
else:
_add_entry_point(entry_point)
def add_command(self, name, cmd_class):
"""
Registers custom command. May be used for example for *help* command.
:param name: (``str``) Name of command.
:param cmd_class: (``LmiBaseCommand``) Factory for commands.
"""
if not isinstance(name, basestring):
raise TypeError("name must be a string")
if not issubclass(cmd_class, base.LmiBaseCommand):
raise TypeError("cmd_class must be a LmiBaseCommand")
if not util.RE_COMMAND_NAME.match(name):
raise errors.LmiCommandInvalidName(
cmd_class.__module__, cmd_class.__class__.__name__, name)
if name in self._commands:
LOG().warn('Command "%s" already managed, overwriting with "%s:%s".',
name, cmd_class.__module__, cmd_class.__name__)
self._commands[name] = _CustomCommandWrapper(name, cmd_class)
def find_command(self, cmd_name):
"""
Loads a command associated with given name and returns it.
:param cmd_name: (``str``) Name of command to load.
:rtype: (``LmiBaseCommand``) Factory for commands.
"""
try:
return self._commands[cmd_name].load()
except KeyError:
raise errors.LmiCommandNotFound(cmd_name)
except ImportError as err:
LOG().debug('Failed to import command "%s".', cmd_name, exc_info=err)
raise errors.LmiCommandImportError(
cmd_name, self._commands[cmd_name].module_name, err)
def reload_commands(self, keep_custom=True):
"""
Flushes all commands and reloads entry points.
:param keep_custom: (``bool``) Custom commands -- not loaded from
entry points -- are preserved.
"""
if keep_custom:
keep = { n: c for n, c in self._commands.items()
if isinstance(c, _CustomCommandWrapper)}
else:
keep = {}
self._commands = {}
self._load_commands()
self._commands.update(keep)
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