122 lines
3.8 KiB
Python
122 lines
3.8 KiB
Python
"""CLI dispatcher — builds parser trees from command dataclasses."""
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from __future__ import annotations
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import logging
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from argparse import ArgumentDefaultsHelpFormatter, ArgumentParser
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from typing import Any, Dict, List, Optional, Type
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from byteb4rb1e.utils.argparse.command import CLICommand
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class CLI:
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"""Composable CLI built from a tree of Command dataclasses.
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Recursively bootstraps an argparse parser hierarchy and tracks
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dest names so ``run()`` can dispatch to the correct leaf command
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without dest chaining in the caller.
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Usage::
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cli = CLI(prog="repository", description="...")
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cli.bootstrap([MirrorCommand, IndexCommand])
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cli.run()
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"""
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def __init__(
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self,
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prog: Optional[str] = None,
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description: str = "",
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) -> None:
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kwargs = {} # type: Dict[str, Any]
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if prog:
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kwargs["prog"] = prog
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if description:
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kwargs["description"] = description
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kwargs.setdefault(
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"formatter_class", ArgumentDefaultsHelpFormatter,
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)
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self.parser = ArgumentParser(**kwargs)
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self._dests = [] # type: List[str]
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self._commands = {} # type: Dict[str, Command]
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def add_arguments(self, parser: ArgumentParser) -> None:
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"""Add global arguments to the root parser."""
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parser.add_argument(
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"-v", "--verbose", action="count", default=0,
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help="Increase verbosity (-v for INFO, -vv for DEBUG)",
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)
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def bootstrap(
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self,
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commands: List[Type[Command]],
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) -> None:
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"""Build the parser tree from a list of top-level commands."""
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self.add_arguments(self.parser)
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dest = "command"
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self._dests.append(dest)
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sub = self.parser.add_subparsers(dest=dest)
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for cmd_cls in commands:
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self._add(sub, cmd_cls, prefix="")
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def _add(
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self,
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subparsers: Any,
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cmd_cls: Type[Command],
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prefix: str,
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) -> None:
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"""Recursively add a command and its subcommands."""
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cmd = cmd_cls()
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parser = subparsers.add_parser(
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cmd.name,
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formatter_class=ArgumentDefaultsHelpFormatter,
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**cmd.parser_kwargs(),
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)
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cmd.add_arguments(parser)
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key = "%s.%s" % (prefix, cmd.name) if prefix else cmd.name
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self._commands[key] = cmd
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if cmd._subcommands:
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dest = "%s_command" % cmd.name
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self._dests.append(dest)
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child_sub = parser.add_subparsers(dest=dest)
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for sc_cls in cmd._subcommands:
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self._add(child_sub, sc_cls, prefix=key)
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def _resolve(self, args: Any) -> Optional[Command]:
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"""Walk dest chain to find the leaf command."""
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parts = [] # type: List[str]
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for dest in self._dests:
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val = getattr(args, dest, None)
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if val is None:
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continue
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parts.append(val)
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if not parts:
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return None
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key = ".".join(parts)
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return self._commands.get(key)
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@staticmethod
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def _setup_logging(verbosity: int) -> None:
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if verbosity >= 2:
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level = logging.DEBUG
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elif verbosity >= 1:
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level = logging.INFO
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else:
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level = logging.WARNING
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logging.basicConfig(
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level=level,
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format="%(asctime)s [%(levelname)s] %(message)s",
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handlers=[logging.StreamHandler()],
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)
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def run(self) -> None:
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"""Parse args and dispatch to the leaf command."""
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args = self.parser.parse_args()
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self._setup_logging(getattr(args, "verbose", 0))
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cmd = self._resolve(args)
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if cmd is None:
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self.parser.print_help()
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raise SystemExit(1)
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raise SystemExit(cmd.execute(args))
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