76cf68deed
StrategyResolver.load_strategy would fail if any error outside of (ModuleNotFoundError, SyntaxError, ImportError, NameError) is thrown. This change makes it raise an OperationalException when that happens. This will potentially be beneficial to people who use StrategyResolver.load_strategy outside of the FT directories.
187 lines
7.4 KiB
Python
187 lines
7.4 KiB
Python
# pragma pylint: disable=attribute-defined-outside-init
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"""
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This module load custom objects
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"""
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import importlib.util
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import inspect
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import logging
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from pathlib import Path
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from typing import Any, Dict, Iterator, List, Optional, Tuple, Type, Union
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from freqtrade.exceptions import OperationalException
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logger = logging.getLogger(__name__)
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class IResolver:
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"""
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This class contains all the logic to load custom classes
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"""
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# Childclasses need to override this
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object_type: Type[Any]
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object_type_str: str
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user_subdir: Optional[str] = None
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initial_search_path: Optional[Path]
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@classmethod
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def build_search_paths(cls, config: Dict[str, Any], user_subdir: Optional[str] = None,
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extra_dir: Optional[str] = None) -> List[Path]:
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abs_paths: List[Path] = []
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if cls.initial_search_path:
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abs_paths.append(cls.initial_search_path)
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if user_subdir:
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abs_paths.insert(0, config['user_data_dir'].joinpath(user_subdir))
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if extra_dir:
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# Add extra directory to the top of the search paths
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abs_paths.insert(0, Path(extra_dir).resolve())
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return abs_paths
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@classmethod
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def _get_valid_object(cls, module_path: Path, object_name: Optional[str],
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enum_failed: bool = False) -> Iterator[Any]:
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"""
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Generator returning objects with matching object_type and object_name in the path given.
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:param module_path: absolute path to the module
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:param object_name: Class name of the object
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:param enum_failed: If True, will return None for modules which fail.
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Otherwise, failing modules are skipped.
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:return: generator containing tuple of matching objects
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Tuple format: [Object, source]
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"""
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# Generate spec based on absolute path
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# Pass object_name as first argument to have logging print a reasonable name.
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spec = importlib.util.spec_from_file_location(object_name or "", str(module_path))
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if not spec:
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return iter([None])
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module = importlib.util.module_from_spec(spec)
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try:
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spec.loader.exec_module(module) # type: ignore # importlib does not use typehints
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except (ModuleNotFoundError, SyntaxError, ImportError, NameError) as err:
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# Catch errors in case a specific module is not installed
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logger.warning(f"Could not import {module_path} due to '{err}'")
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if enum_failed:
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return iter([None])
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except Exception as e:
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raise OperationalException(f"Error loading {module_path}: {e}") from e
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valid_objects_gen = (
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(obj, inspect.getsource(module)) for
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name, obj in inspect.getmembers(
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module, inspect.isclass) if ((object_name is None or object_name == name)
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and issubclass(obj, cls.object_type)
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and obj is not cls.object_type)
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)
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return valid_objects_gen
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@classmethod
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def _search_object(cls, directory: Path, *, object_name: str, add_source: bool = False
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) -> Union[Tuple[Any, Path], Tuple[None, None]]:
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"""
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Search for the objectname in the given directory
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:param directory: relative or absolute directory path
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:param object_name: ClassName of the object to load
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:return: object class
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"""
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logger.debug(f"Searching for {cls.object_type.__name__} {object_name} in '{directory}'")
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for entry in directory.iterdir():
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# Only consider python files
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if entry.suffix != '.py':
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logger.debug('Ignoring %s', entry)
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continue
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if entry.is_symlink() and not entry.is_file():
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logger.debug('Ignoring broken symlink %s', entry)
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continue
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module_path = entry.resolve()
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obj = next(cls._get_valid_object(module_path, object_name), None)
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if obj:
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obj[0].__file__ = str(entry)
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if add_source:
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obj[0].__source__ = obj[1]
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return (obj[0], module_path)
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return (None, None)
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@classmethod
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def _load_object(cls, paths: List[Path], *, object_name: str, add_source: bool = False,
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kwargs: dict = {}) -> Optional[Any]:
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"""
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Try to load object from path list.
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"""
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for _path in paths:
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try:
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(module, module_path) = cls._search_object(directory=_path,
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object_name=object_name,
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add_source=add_source)
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if module:
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logger.info(
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f"Using resolved {cls.object_type.__name__.lower()[1:]} {object_name} "
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f"from '{module_path}'...")
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return module(**kwargs)
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except FileNotFoundError:
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logger.warning('Path "%s" does not exist.', _path.resolve())
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return None
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@classmethod
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def load_object(cls, object_name: str, config: dict, *, kwargs: dict,
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extra_dir: Optional[str] = None) -> Any:
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"""
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Search and loads the specified object as configured in hte child class.
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:param object_name: name of the module to import
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:param config: configuration dictionary
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:param extra_dir: additional directory to search for the given pairlist
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:raises: OperationalException if the class is invalid or does not exist.
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:return: Object instance or None
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"""
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abs_paths = cls.build_search_paths(config,
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user_subdir=cls.user_subdir,
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extra_dir=extra_dir)
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found_object = cls._load_object(paths=abs_paths, object_name=object_name,
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kwargs=kwargs)
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if found_object:
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return found_object
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raise OperationalException(
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f"Impossible to load {cls.object_type_str} '{object_name}'. This class does not exist "
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"or contains Python code errors."
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)
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@classmethod
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def search_all_objects(cls, directory: Path,
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enum_failed: bool) -> List[Dict[str, Any]]:
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"""
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Searches a directory for valid objects
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:param directory: Path to search
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:param enum_failed: If True, will return None for modules which fail.
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Otherwise, failing modules are skipped.
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:return: List of dicts containing 'name', 'class' and 'location' entries
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"""
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logger.debug(f"Searching for {cls.object_type.__name__} '{directory}'")
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objects = []
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for entry in directory.iterdir():
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# Only consider python files
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if entry.suffix != '.py':
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logger.debug('Ignoring %s', entry)
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continue
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module_path = entry.resolve()
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logger.debug(f"Path {module_path}")
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for obj in cls._get_valid_object(module_path, object_name=None,
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enum_failed=enum_failed):
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objects.append(
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{'name': obj[0].__name__ if obj is not None else '',
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'class': obj[0] if obj is not None else None,
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'location': entry,
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})
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return objects
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