541 lines
19 KiB
Python
541 lines
19 KiB
Python
import argparse
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import inspect
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import logging
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import re
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import sys
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import app_skellington
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from ._bootstrap import _bootstrap_logger
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from . import app_container
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# If explicit fail is enabled, any command with at least one unknown
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# argument will be rejected entirely. If not enabled, unknown arguments
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# will be ignored.
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EXPLICIT_FAIL_ON_UNKNOWN_ARGS = True
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class CommandTree:
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"""
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Command-line interface to hold a menu of commands. You can register
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commands (functions or methods) in a CommandTree which will generate
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a corresponding argparse.ArgumentParser (and nested SubParsers) that
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map function/method arguments into argparse Parameters. Then, you
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can translate command-line arguments into invoking the function.
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Commands must be registered before being invoked. You create nested
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SubMenu(s). If function parameters have defaults, those will be
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available for override else they use the function defaults.
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Print helpful information:
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./scriptname -h # View tier-0 help and usage doc
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./scriptname [submenu] -h # View submenu help and usage doc
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./scriptname [submenu] [command] -h # View command documentation and parameters
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argparse is finicky about argument placement:
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./scriptname
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[application arguments]
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[submenu] [submenu arguments]
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[command] [command arguments]
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For example,
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./scriptname --option="value" [submenu] [command]
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is different than
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./scriptname [submenu] [command] --option="value"
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in that option is being applied to the application in the first example and
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applied to the refresh_datasets command (under the nhsn command group) in
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the second. In the same way the -h, --help options print different docs
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depending on where the help option was passed.
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"""
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def __init__(self):
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self.root_parser = argparse.ArgumentParser()
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self.submenu_param = None # submenu_param is the variable name
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# of the root submenu argument, i.e. the arg
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# in root_parser which selects the submenu.
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self.entries = {}
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# NOTE(MG) Implementation note:
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# CommandTree uses only one of these internal structures (i.e. mutually exclusive),
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# 'entries' is used when there is a submenu linked to multiple commands.
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# '_cmd_tree_is_single_command' and '_single_command' instead are used
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# when the CommandTree is linked to one and only one command.
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self._cmd_tree_is_single_command = False
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self._single_command = None
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def print_tree(self):
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import pprint
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pprint.pprint(self.entries)
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def add_argument(self, *args, **kwargs):
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"""
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Adds an argument to the root parser.
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"""
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_bootstrap_logger.info('adding argument to root parser: %s and %s', args, kwargs)
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self.root_parser.add_argument(*args, **kwargs)
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def init_submenu(self, param_name, is_required=False):
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"""
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Creates a root-level submenu with no entries. SubMenu node is
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returned which can have submenus and commands attached to it.
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"""
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# Creates an argument as a slot in the underlying argparse.
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subparsers = self.root_parser.add_subparsers(
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dest = param_name,
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metavar = param_name,
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required = is_required
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)
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submenu = SubMenu(self, subparsers, param_name)
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submenu.submenu_path = ''
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submenu.var_name = param_name
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_bootstrap_logger.info('Initialized root-level submenu: Parameter = \'%s\'', param_name)
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self.entries[param_name] = submenu
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self.submenu_param = param_name
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return submenu
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def register_command(
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self, func, cmd_name=None, func_signature=None,
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docstring=None
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):
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"""
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When no submenu functionality is desired, this links a single
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command into underlying argparse options.
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"""
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# begin copy-paste from SubMenu.register_command
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if inspect.isfunction(func):
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# print('func is function')
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pass
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elif inspect.ismethod(func):
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pass
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# print('func is method')
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else:
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raise Exception('bad value passed in for function')
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if not cmd_name:
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# safe try/except
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cmd_name = func.__name__
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if func_signature is None:
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func_signature = inspect.signature(func)
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if docstring is None:
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docstring = func.__doc__
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sig = func_signature
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params = sig.parameters
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# help is displayed next to the command in the submenu enumeration or
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# list of commands:
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help_text = HelpGenerator.generate_help_from_sig(docstring)
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# description is displayed when querying help for the specific command:
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description_text = HelpGenerator.generate_description_from_sig(docstring)
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# end copy-paste from SubMenu.register_command
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# begin copy-paste then editted from SubMenu.register_command
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# For each paramter in the function create an argparse argument in
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# the child ArgumentParser created for this menu entry:
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for key in params:
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if key == 'self':
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continue
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param = params[key]
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if '=' in str(param):
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if param.default is None:
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helptext = 'default provided'
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else:
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helptext = "default = '{}'".format(param.default)
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self.root_parser.add_argument(
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key,
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help=helptext,
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nargs='?',
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default=param.default)
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else:
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helptext = 'required'
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self.root_parser.add_argument(
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key,
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help=helptext)
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# # Wrapper function that instantiates an object and runs a method
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# # on-demand. The object is created, injected with necessary
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# # dependencies or services, and the method is invoked.
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# def func(*args, **kwargs):
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# obj = constructor()
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# return cls_method(obj, *args, **kwargs)
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# Build the CommandEntry structure
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cmd = CommandEntry()
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cmd.argparse_node = self.root_parser
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cmd.cmd_name = cmd_name
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cmd.func_signature = sig
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# cmd.func_ref = None
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cmd.callback = func
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registered_name = cmd_name
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_bootstrap_logger.info('registered command: %s', registered_name)
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# end copy-paste then editted from SubMenu.register_command
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self._cmd_tree_is_single_command = True
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self._single_command = cmd
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self._entries = None
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# def _validate(self):
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# pass
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# # TODO(MG):
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# # subparser can not be empty, needs to have parsers attached
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def parse(self, args=None):
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if args is None:
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args = sys.argv[1:]
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try:
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# on error, prints some argparse error messages:
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pargs, unk = self.root_parser.parse_known_args(args)
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# if len(unk) > 0:
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# _bootstrap_logger.error(
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# 'failed to interpret argument(s) or command-line switch from shell: %s',
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# unk)
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# if EXPLICIT_FAIL_ON_UNKNOWN_ARGS:
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# _bootstrap_logger.warn(
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# 'failed to parse arguments: explicitly failing to be safe')
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# return False, False
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if hasattr(pargs, 'usage'):
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pass
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# print('found usage in app_skellington')
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return pargs, unk, True
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# Note: SystemExit is raised when '-h' argument is supplied.
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except SystemExit as ex:
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return None, None, False
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def run_command(self, args=None):
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args, unk, success = self.parse(args)
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if not success:
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_bootstrap_logger.info('SystemExit: Perhaps user invoked --help')
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return
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if args is False and unk is False:
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_bootstrap_logger.error('failed parsing args')
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return False
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_bootstrap_logger.info('received args from shell: %s', args)
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args = vars(args)
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cmd = self._lookup_command(args)
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if cmd is None:
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print('cmd is None')
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_bootstrap_logger.error('failed to find command')
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return False
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return self._invoke_command(cmd, args)
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def _lookup_command(self, args):
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keys = list(args.keys())
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# In the case there is at-most one command registered in
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# the CommandTree with no SubMenu (submenu will be disabled
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# in this case):
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if self._cmd_tree_is_single_command:
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assert self._cmd_tree_is_single_command is True, 'corrupt data structure in CommandMenu'
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assert self._entries is None, 'corrupt data structure in CommandMenu'
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assert isinstance(self._single_command, CommandEntry), 'corrupt data structure in CommandMenu'
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return self._single_command
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# There is at least one submenu we need to go down:
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else:
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assert self._single_command is None, 'corrupt data structure in CommandMenu'
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assert self._cmd_tree_is_single_command == False, 'corrupt data structure in CommandMenu'
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# Key or variable name used by argparse to store the submenu options
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argparse_param = self.submenu_param # e.g.: submenu_root
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submenu = self.entries[argparse_param]
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while True:
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if argparse_param not in keys:
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print('root menu parameter not found in args:', argparse_param)
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input('<broken>')
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val = args.get(argparse_param)
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_bootstrap_logger.debug('argparse command is \'{}\' = {}'.format(argparse_param, val))
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lookup = submenu.entries.get(val)
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_bootstrap_logger.debug('lookup, entries[{}] = {}'.format(val, lookup))
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# print(submenu.entries)
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# pop value
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del args[argparse_param]
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if isinstance(lookup, SubMenu):
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submenu = lookup
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argparse_param = submenu.var_name
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elif isinstance(lookup, CommandEntry):
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return lookup
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# return self._invoke_command(lookup, args)
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else:
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raise app_container.NoCommandSpecified('No command specified.')
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def _invoke_command(self, cmd, args):
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func = cmd.callback
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sig = cmd.func_signature
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params = sig.parameters
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params = [params[paramname] for paramname in params]
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func_args = []
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for param in params:
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if param.name in args:
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func_args.append(args[param.name])
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_bootstrap_logger.info('function: %s', func)
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_bootstrap_logger.info('function args: %s', func_args)
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return func(*func_args)
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def _get_subparser(self):
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return self.root_parser._subparsers._actions[1]
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class SubMenu:
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def __init__(self, parent, subparsers_obj, name):
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self.parent = parent # Reference to root CommandTree
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self.subparsers_obj = subparsers_obj
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self.name = name
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self.submenu_path = None
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self.entries = {}
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def register_command(
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self, func, cmd_name=None, func_signature=None,
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docstring=None
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):
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"""
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Registers a command as an entry in this submenu. Provided function is
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converted into argparse arguments and made available to the user.
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Arguments
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---------
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func:
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Callback function which will be mapped
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to the submenu entry.
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cmd_name (optional):
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User-facing entry name. By default will be the function name.
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The user will be able to use [cmd_name] [arg, ...] to
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invoke the callback function.
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func_signature: optionally, you can pass in the
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inspect.signature(). If None, will inspect the
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incoming func. Note on internals: This is used
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to pass the function signature of the command
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function while having the callback point to a
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function partial which executes some other code.
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This hook is used to inject dependencies and then
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execute the command function.
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"""
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if inspect.isfunction(func):
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# print('func is function')
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pass
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elif inspect.ismethod(func):
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pass
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# print('func is method')
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else:
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raise Exception('bad value passed in for function')
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if not cmd_name:
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# safe try/except
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cmd_name = func.__name__
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if func_signature is None:
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func_signature = inspect.signature(func)
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if docstring is None:
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docstring = func.__doc__
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sig = func_signature
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params = sig.parameters
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# help is displayed next to the command in the submenu enumeration or
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# list of commands:
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help_text = HelpGenerator.generate_help_from_sig(docstring)
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# description is displayed when querying help for the specific command:
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description_text = HelpGenerator.generate_description_from_sig(docstring)
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# Entry in local argparse._SubParsersAction
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# type = ArgumentParser
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child_node = self.subparsers_obj.add_parser(
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cmd_name, # Note: cmd_name here will be the VALUE
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# passed into the argparse arg VARIABLE NAME
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# created when the SubMenu/argparse.addZ_subparsers()
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# was created.
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help=help_text,
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description=description_text
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)
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# For each paramter in the function create an argparse argument in
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# the child ArgumentParser created for this menu entry:
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for key in params:
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if key == 'self':
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continue
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param = params[key]
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if '=' in str(param):
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if param.default is None:
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helptext = 'default provided'
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else:
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helptext = "default = '{}'".format(param.default)
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child_node.add_argument(
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key,
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help=helptext,
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nargs='?',
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default=param.default)
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else:
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helptext = 'required'
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child_node.add_argument(
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key,
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help=helptext)
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# # Wrapper function that instantiates an object and runs a method
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# # on-demand. The object is created, injected with necessary
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# # dependencies or services, and the method is invoked.
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# def func(*args, **kwargs):
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# obj = constructor()
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# return cls_method(obj, *args, **kwargs)
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# Build the CommandEntry structure
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cmd = CommandEntry()
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cmd.argparse_node = child_node
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cmd.cmd_name = cmd_name
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cmd.func_signature = sig
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# cmd.func_ref = None
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cmd.callback = func
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registered_name = '{}.{}'.format(
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self.submenu_path,
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cmd_name)
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_bootstrap_logger.info('registered command: %s', registered_name)
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self.entries[cmd_name] = cmd
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def create_submenu(
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self, var_name, cmd_entry_name=None, is_required=False
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):
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"""
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Creates a child-submenu.
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Arguments
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---------
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var_name:
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A code-facing argparse parameter used to store the
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value/entry chosen by the user.
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cmd_entry_name:
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A user-facing name used to select created submenu.
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If not provided, the user-facing command name defaults
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to the same name as the code-facing argparse parameter
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is_required:
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Switches if a value must be selected in the created submenu.
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If not, it's an optional positional argument.
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"""
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if cmd_entry_name is None:
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cmd_entry_name = var_name
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# Create an entry in self's submenu:
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# type = ArgumentParser
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entry_node = self.subparsers_obj.add_parser(
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cmd_entry_name,
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help='sub-submenu help',
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description='sub-sub description')
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# Turn entry into a submenu of it's own:
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# type = _SubParsersAction
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subp_node = entry_node.add_subparsers(
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dest = var_name,
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metavar = var_name,
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required = is_required)
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submenu = SubMenu(
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self.parent,
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subp_node,
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cmd_entry_name)
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submenu.var_name = var_name
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submenu.submenu_path = '{}.{}'.format(self.submenu_path, cmd_entry_name)
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submenu_name = submenu.submenu_path
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_bootstrap_logger.info('registered submenu: %s', submenu_name)
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self.entries[cmd_entry_name] = submenu
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return submenu
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def __repr__(self):
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return 'SubMenu({})<{}>'.format(
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self.name,
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','.join(['cmds'])
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)
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class CommandEntry:
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"""
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Structure for a command-entry in the CLI.
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Stores the command-subcommand names, the function signature which contains
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the original parameters of the function-to-be-invoked, a reference to the
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original function, and a callback function wrapper which, by convention,
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instantiates the necessary objects (injecting dependencies, etc.) and
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executes the original function.
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The CLI module has functionality to translate the original function
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arguments into argparse options (creating the documentation also). Similary,
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it can convert from argparse options into a function call.
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"""
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def __init__(self):
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self.argparse_node = None
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self.cmd_name = None # Don't think we need. And needs to be changed
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# from SubMenu
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self.menu_path = None
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self.func_signature = None
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self.func_ref = None
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self.callback = None
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|
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def __repr__(self):
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return 'CommandEntry<{}>'.format(self.cmd_name)
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|
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class HelpGenerator:
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def __init__(self):
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pass
|
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|
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@staticmethod
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def generate_help_from_sig(doctext):
|
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"""
|
|
The 'help' text is displayed next to the command when enumerating
|
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the submenu commands.
|
|
"""
|
|
if doctext == None:
|
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return doctext
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regex = '(.*?)[.?!]'
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match = re.match(regex, doctext, re.MULTILINE | re.DOTALL)
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if match:
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return match.group(1) + '.'
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return doctext
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|
|
@staticmethod
|
|
def generate_description_from_sig(doctext):
|
|
"""
|
|
The 'description' paragraph is provided when the user requests help
|
|
on a specific command.
|
|
"""
|
|
if doctext == None:
|
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return doctext
|
|
regex = '(.*?)[.?!]'
|
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match = re.match(regex, doctext, re.MULTILINE | re.DOTALL)
|
|
if match:
|
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return match.group(1) + '.'
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return doctext
|
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|