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# Copyright 2022 VyOS maintainers and contributors <maintainers@vyos.io>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library. If not, see <http://www.gnu.org/licenses/>.
import re
import sys
import typing
class Error(Exception):
""" Any error that makes requested operation impossible to complete
for reasons unrelated to the user input or script logic.
"""
pass
class UnconfiguredSubsystem(Error):
""" Requested operation is valid, but cannot be completed
because corresponding subsystem is not configured and running.
"""
pass
class DataUnavailable(Error):
""" Requested operation is valid, but cannot be completed
because data for it is not available.
This error MAY be treated as temporary because such issues
are often caused by transient events such as service restarts.
"""
pass
class PermissionDenied(Error):
""" Requested operation is valid, but the caller has no permission
to perform it.
"""
pass
def _is_op_mode_function_name(name):
if re.match(r"^(show|clear|reset|restart)", name):
return True
else:
return False
def _is_show(name):
if re.match(r"^show", name):
return True
else:
return False
def _get_op_mode_functions(module):
from inspect import getmembers, isfunction
# Get all functions in that module
funcs = getmembers(module, isfunction)
# getmembers returns (name, func) tuples
funcs = list(filter(lambda ft: _is_op_mode_function_name(ft[0]), funcs))
funcs_dict = {}
for (name, thunk) in funcs:
funcs_dict[name] = thunk
return funcs_dict
def _is_optional_type(t):
# Optional[t] is internally an alias for Union[t, NoneType]
# and there's no easy way to get union members it seems
if (type(t) == typing._UnionGenericAlias):
if (len(t.__args__) == 2):
if t.__args__[1] == type(None):
return True
return False
def _get_arg_type(t):
""" Returns the type itself if it's a primitive type,
or the "real" type of typing.Optional
Doesn't work with anything else at the moment!
"""
if _is_optional_type(t):
return t.__args__[0]
else:
return t
def run(module):
from argparse import ArgumentParser
functions = _get_op_mode_functions(module)
parser = ArgumentParser()
subparsers = parser.add_subparsers(dest="subcommand")
for function_name in functions:
subparser = subparsers.add_parser(function_name, help=functions[function_name].__doc__)
type_hints = typing.get_type_hints(functions[function_name])
if 'return' in type_hints:
del type_hints['return']
for opt in type_hints:
th = type_hints[opt]
if _get_arg_type(th) == bool:
subparser.add_argument(f"--{opt}", action='store_true')
else:
if _is_optional_type(th):
subparser.add_argument(f"--{opt}", type=_get_arg_type(th), default=None)
else:
subparser.add_argument(f"--{opt}", type=_get_arg_type(th), required=True)
# Get options as a dict rather than a namespace,
# so that we can modify it and pack for passing to functions
args = vars(parser.parse_args())
if not args["subcommand"]:
print("Subcommand required!")
parser.print_usage()
sys.exit(1)
function_name = args["subcommand"]
func = functions[function_name]
# Remove the subcommand from the arguments,
# it would cause an extra argument error when we pass the dict to a function
del args["subcommand"]
# Show commands must always get the "raw" argument,
# but other commands (clear/reset/restart) should not,
# because they produce no output and it makes no sense for them.
if ("raw" not in args) and _is_show(function_name):
args["raw"] = False
if re.match(r"^show", function_name):
# Show commands are slightly special:
# they may return human-formatted output
# or a raw dict that we need to serialize in JSON for printing
res = func(**args)
if not args["raw"]:
return res
else:
from json import dumps
return dumps(res, indent=4)
else:
# Other functions should not return anything,
# although they may print their own warnings or status messages
func(**args)
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