/usr/lib/python3/dist-packages/cement/core/controller.py is in python3-cement 2.10.0-1.
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import re
import textwrap
import argparse
from ..core import exc, interface, handler
from ..utils.misc import minimal_logger
LOG = minimal_logger(__name__)
def controller_validator(klass, obj):
"""
Validates a handler implementation against the IController interface.
"""
members = [
'_setup',
'_dispatch',
]
meta = [
'label',
'interface',
'config_section',
'config_defaults',
'stacked_on',
'stacked_type',
]
interface.validate(IController, obj, members, meta=meta)
# also check _meta.arguments values
errmsg = "Controller arguments must be a list of tuples. I.e. " + \
"[ (['-f', '--foo'], dict(action='store')), ]"
if obj._meta.arguments is not None:
if type(obj._meta.arguments) is not list:
raise exc.InterfaceError(errmsg)
for item in obj._meta.arguments:
if type(item) is not tuple:
raise exc.InterfaceError(errmsg)
if type(item[0]) is not list:
raise exc.InterfaceError(errmsg)
if type(item[1]) is not dict:
raise exc.InterfaceError(errmsg)
if not obj._meta.label == 'base' and obj._meta.stacked_on is None:
errmsg = "Controller `%s` is not stacked anywhere!" % \
obj.__class__.__name__
raise exc.InterfaceError(errmsg)
if not obj._meta.label == 'base' and \
obj._meta.stacked_type not in ['nested', 'embedded']:
raise exc.InterfaceError(
"Controller '%s' " % obj._meta.label +
"has an unknown stacked type of '%s'." %
obj._meta.stacked_type
)
class IController(interface.Interface):
"""
This class defines the Controller Handler Interface. Classes that
implement this handler must provide the methods and attributes defined
below.
Implementations do *not* subclass from interfaces.
Usage:
.. code-block:: python
from cement.core import controller
class MyBaseController(controller.CementBaseController):
class Meta:
interface = controller.IController
...
"""
# pylint: disable=W0232, C0111, R0903
class IMeta:
"""Interface meta-data."""
#: The string identifier of the interface.
label = 'controller'
#: The interface validator function.
validator = controller_validator
# Must be provided by the implementation
Meta = interface.Attribute('Handler meta-data')
def _setup(app_obj):
"""
The _setup function is after application initialization and after it
is determined that this controller was requested via command line
arguments. Meaning, a controllers _setup() function is only called
right before it's _dispatch() function is called to execute a command.
Must 'setup' the handler object making it ready for the framework
or the application to make further calls to it.
:param app_obj: The application object.
:returns: ``None``
"""
def _dispatch(self):
"""
Reads the application object's data to dispatch a command from this
controller. For example, reading self.app.pargs to determine what
command was passed, and then executing that command function.
Note that Cement does *not* parse arguments when calling _dispatch()
on a controller, as it expects the controller to handle parsing
arguments (I.e. self.app.args.parse()).
:returns: Returns the result of the executed controller function,
or ``None`` if no controller function is called.
"""
class expose(object):
"""
Used to expose controller functions to be listed as commands, and to
decorate the function with Meta data for the argument parser.
:param help: Help text to display for that command.
:type help: str
:param hide: Whether the command should be visible.
:type hide: boolean
:param aliases: Aliases to this command.
:param aliases_only: Whether to only display the aliases (not the label).
This is useful for situations where you have obscure function names
which you do not want displayed. Effecively, if there are aliases and
`aliases_only` is True, then aliases[0] will appear as the actual
command/function label.
:type aliases: ``list``
Usage:
.. code-block:: python
from cement.core.controller import CementBaseController, expose
class MyAppBaseController(CementBaseController):
class Meta:
label = 'base'
@expose(hide=True, aliases=['run'])
def default(self):
print("In MyAppBaseController.default()")
@expose()
def my_command(self):
print("In MyAppBaseController.my_command()")
"""
# pylint: disable=W0622
def __init__(self, help='', hide=False, aliases=[], aliases_only=False):
self.hide = hide
self.help = help
self.aliases = aliases
self.aliases_only = aliases_only
def __call__(self, func):
metadict = {}
metadict['label'] = re.sub('_', '-', func.__name__)
metadict['func_name'] = func.__name__
metadict['exposed'] = True
metadict['hide'] = self.hide
metadict['help'] = self.help or func.__doc__
metadict['aliases'] = self.aliases
metadict['aliases_only'] = self.aliases_only
metadict['controller'] = None # added by the controller
func.__cement_meta__ = metadict
return func
# pylint: disable=R0921
class CementBaseController(handler.CementBaseHandler):
"""
This is an implementation of the
`IControllerHandler <#cement.core.controller.IController>`_ interface, but
as a base class that application controllers `should` subclass from.
Registering it directly as a handler is useless.
NOTE: This handler **requires** that the applications 'arg_handler' be
argparse. If using an alternative argument handler you will need to
write your own controller base class.
NOTE: This the initial default implementation of CementBaseController. In
the future it will be replaced by CementBaseController2, therefore using
CementBaseController2 is recommended for new development.
Usage:
.. code-block:: python
from cement.core.controller import CementBaseController
class MyAppBaseController(CementBaseController):
class Meta:
label = 'base'
description = 'MyApp is awesome'
config_defaults = dict()
arguments = []
epilog = "This is the text at the bottom of --help."
# ...
class MyStackedController(CementBaseController):
class Meta:
label = 'second_controller'
aliases = ['sec', 'secondary']
stacked_on = 'base'
stacked_type = 'embedded'
# ...
"""
class Meta:
"""
Controller meta-data (can be passed as keyword arguments to the parent
class).
"""
interface = IController
"""The interface this class implements."""
label = None
"""The string identifier for the controller."""
aliases = []
"""
A list of aliases for the controller. Will be treated like
command/function aliases for non-stacked controllers. For example:
``myapp <controller_label> --help`` is the same as
``myapp <controller_alias> --help``.
"""
aliases_only = False
"""
When set to True, the controller label will not be displayed at
command line, only the aliases will. Effectively, aliases[0] will
appear as the label. This feature is useful for the situation Where
you might want two controllers to have the same label when stacked
on top of separate controllers. For example, 'myapp users list' and
'myapp servers list' where 'list' is a stacked controller, not a
function.
"""
description = None
"""The description shown at the top of '--help'. Default: None"""
config_section = None
"""
A config [section] to merge config_defaults into. Cement will default
to controller.<label> if None is set.
"""
config_defaults = {}
"""
Configuration defaults (type: dict) that are merged into the
applications config object for the config_section mentioned above.
"""
arguments = []
"""
Arguments to pass to the argument_handler. The format is a list
of tuples whos items are a ( list, dict ). Meaning:
``[ ( ['-f', '--foo'], dict(dest='foo', help='foo option') ), ]``
This is equivelant to manually adding each argument to the argument
parser as in the following example:
``parser.add_argument(['-f', '--foo'], help='foo option', dest='foo')``
"""
stacked_on = 'base'
"""
A label of another controller to 'stack' commands/arguments on top of.
"""
stacked_type = 'embedded'
"""
Whether to `embed` commands and arguments within the parent controller
or to simply `nest` the controller under the parent controller (making
it a sub-sub-command). Must be one of `['embedded', 'nested']` only
if `stacked_on` is not `None`.
"""
hide = False
"""Whether or not to hide the controller entirely."""
epilog = None
"""
The text that is displayed at the bottom when '--help' is passed.
"""
usage = None
"""
The text that is displayed at the top when '--help' is passed.
Although the default is `None`, Cement will set this to a generic
usage based on the `prog`, `controller` name, etc if nothing else is
passed.
"""
argument_formatter = argparse.RawDescriptionHelpFormatter
"""
The argument formatter class to use to display --help output.
"""
default_func = 'default'
"""
Function to call if no sub-command is passed. Note that this can
**not** start with an ``_`` due to backward compatibility restraints
in how Cement discovers and maps commands.
"""
def __init__(self, *args, **kw):
super(CementBaseController, self).__init__(*args, **kw)
self.app = None
self._commands = {} # used to store collected commands
self._visible_commands = [] # used to sort visible command labels
self._arguments = [] # used to store collected arguments
self._dispatch_map = {} # used to map commands/aliases to controller
self._dispatch_command = None # set during _parse_args()
def _setup(self, app_obj):
"""
See `IController._setup() <#cement.core.cache.IController._setup>`_.
"""
super(CementBaseController, self)._setup(app_obj)
if getattr(self._meta, 'description', None) is None:
self._meta.description = "%s Controller" % \
self._meta.label.capitalize()
self.app = app_obj
def _collect(self):
LOG.debug("collecting arguments/commands for %s" % self)
arguments = []
commands = []
# process my arguments and commands first
arguments = list(self._meta.arguments)
for member in dir(self.__class__):
if member.startswith('_'):
continue
try:
func = getattr(self.__class__, member).__cement_meta__
except AttributeError:
continue
else:
func['controller'] = self
commands.append(func)
# process stacked controllers second for commands and args
for contr in self.app.handler.list('controller'):
# don't include self here
if contr == self.__class__:
continue
contr = contr()
contr._setup(self.app)
if contr._meta.stacked_on == self._meta.label:
if contr._meta.stacked_type == 'embedded':
contr_arguments, contr_commands = contr._collect()
for arg in contr_arguments:
arguments.append(arg)
for func in contr_commands:
commands.append(func)
elif contr._meta.stacked_type == 'nested':
metadict = {}
metadict['label'] = re.sub('_', '-', contr._meta.label)
metadict['func_name'] = '_dispatch'
metadict['exposed'] = True
metadict['hide'] = contr._meta.hide
metadict['help'] = contr._meta.description
metadict['aliases'] = contr._meta.aliases
metadict['aliases_only'] = contr._meta.aliases_only
metadict['controller'] = contr
commands.append(metadict)
return (arguments, commands)
def _process_arguments(self):
for _arg, _kw in self._arguments:
try:
self.app.args.add_argument(*_arg, **_kw)
except argparse.ArgumentError as e:
raise exc.FrameworkError(e.__str__())
def _process_commands(self):
self._dispatch_map = {}
self._visible_commands = []
for cmd in self._commands:
# process command labels
if cmd['label'] in self._dispatch_map.keys():
raise exc.FrameworkError(
"Duplicate command named '%s' " % cmd['label'] +
"found in controller '%s'" % cmd['controller']
)
self._dispatch_map[cmd['label']] = cmd
if not cmd['hide']:
self._visible_commands.append(cmd['label'])
# process command aliases
for alias in cmd['aliases']:
if alias in self._dispatch_map.keys():
raise exc.FrameworkError(
"The alias '%s' of the " % alias +
"'%s' controller collides " % cmd['controller'] +
"with a command or alias of the same name."
)
self._dispatch_map[alias] = cmd
self._visible_commands.sort()
def _get_dispatch_command(self):
default_func_key = re.sub('_', '-', self._meta.default_func)
if (len(self.app.argv) <= 0) or (self.app.argv[0].startswith('-')):
# if no command is passed, then use default
if default_func_key in self._dispatch_map.keys():
self._dispatch_command = self._dispatch_map[default_func_key]
elif self.app.argv[0] in self._dispatch_map.keys():
self._dispatch_command = self._dispatch_map[self.app.argv[0]]
self.app.argv.pop(0)
else:
# check for default again (will get here if command line has
# positional arguments that don't start with a -)
if default_func_key in self._dispatch_map.keys():
self._dispatch_command = self._dispatch_map[default_func_key]
def _parse_args(self):
self.app.args.description = self._help_text
self.app.args.usage = self._usage_text
self.app.args.formatter_class = self._meta.argument_formatter
self.app._parse_args()
def _dispatch(self):
"""
Takes the remaining arguments from self.app.argv and parses for a
command to dispatch, and if so... dispatches it.
"""
if hasattr(self._meta, 'epilog'):
if self._meta.epilog is not None:
self.app.args.epilog = self._meta.epilog
self._arguments, self._commands = self._collect()
self._process_commands()
self._get_dispatch_command()
if self._dispatch_command:
if self._dispatch_command['func_name'] == '_dispatch':
func = getattr(self._dispatch_command['controller'],
'_dispatch')
return func()
else:
self._process_arguments()
self._parse_args()
func = getattr(self._dispatch_command['controller'],
self._dispatch_command['func_name'])
return func()
else:
self._process_arguments()
self._parse_args()
@property
def _usage_text(self):
"""Returns the usage text displayed when ``--help`` is passed."""
if self._meta.usage is not None:
return self._meta.usage
txt = "%s (sub-commands ...) [options ...] {arguments ...}" % \
self.app.args.prog
return txt
@property
def _help_text(self):
"""Returns the help text displayed when '--help' is passed."""
cmd_txt = ''
for label in self._visible_commands:
cmd = self._dispatch_map[label]
if len(cmd['aliases']) > 0 and cmd['aliases_only']:
if len(cmd['aliases']) > 1:
first = cmd['aliases'].pop(0)
cmd_txt = cmd_txt + " %s (aliases: %s)\n" % \
(first, ', '.join(cmd['aliases']))
else:
cmd_txt = cmd_txt + " %s\n" % cmd['aliases'][0]
elif len(cmd['aliases']) > 0:
cmd_txt = cmd_txt + " %s (aliases: %s)\n" % \
(label, ', '.join(cmd['aliases']))
else:
cmd_txt = cmd_txt + " %s\n" % label
if cmd['help']:
cmd_txt = cmd_txt + " %s\n\n" % cmd['help']
else:
cmd_txt = cmd_txt + "\n"
if len(cmd_txt) > 0:
txt = '''%s
commands:
%s
''' % (self._meta.description, cmd_txt)
else:
txt = self._meta.description
return textwrap.dedent(txt)
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