src/engine_discovery.py - master - keorlov/aichess

src/engine_discovery.py
71 строка2 KB
Konstantin Orlov
wip
06 июн 2026, 13:19
06 июн 2026, 13:19cb645b7
"""Auto-discovery of chess engines from the engines/ directory.

Each subdirectory under ``engines_dir`` that contains an ``engine.py`` with a
``choose_move(fen: str) -> str`` callable is treated as a valid engine.

Discovery performs only an AST-level check (no execution) so engines with
side effects at import time are not run during tournament startup. The match
runner will surface real import / call errors when the engine is actually
invoked.

Returns a dictionary mapping engine name -> absolute file path of engine.py.
"""

import ast
import os
from typing import Dict


def discover_engines(engines_dir: str) -> Dict[str, str]:
    """Scan ``engines_dir`` and return {engine_name: engine_file_path}.

    Engines with broken engine.py files are still included (the match
    runner handles import failures), but a warning is printed.
    """

    engines: Dict[str, str] = {}

    if not os.path.isdir(engines_dir):
        return engines

    engines_dir = os.path.abspath(engines_dir)

    for entry in sorted(os.listdir(engines_dir)):
        engine_path = os.path.join(engines_dir, entry)
        if not os.path.isdir(engine_path):
            continue

        engine_file = os.path.join(engine_path, "engine.py")
        if not os.path.isfile(engine_file):
            continue

        engines[entry] = engine_file

        _validate_engine_ast(entry, engine_file)

    return engines


def _validate_engine_ast(name: str, engine_file: str):
    """AST-level check that the engine defines a ``choose_move`` function.

    No code is executed. If the file is unparseable or doesn't define
    ``choose_move``, a warning is printed but the engine is still listed —
    the match runner will surface the real failure when it tries to import
    the module.
    """
    try:
        with open(engine_file, "r", encoding="utf-8") as f:
            source = f.read()
        tree = ast.parse(source, filename=engine_file)
    except SyntaxError as e:
        print(f"Warning: {name} engine.py has a syntax error: {e}")
        return
    except OSError as e:
        print(f"Warning: {name} engine.py could not be read: {e}")
        return

    for node in ast.walk(tree):
        if isinstance(node, (ast.FunctionDef, ast.AsyncFunctionDef)) and node.name == "choose_move":
            return
    print(f"Warning: {name} engine.py has no choose_move function")