83 lines
3.1 KiB
Python
83 lines
3.1 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, Optional, Tuple, Type, Union
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from freqtrade import OperationalException
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logger = logging.getLogger(__name__)
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class IResolver(object):
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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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type_name = "Unknown"
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@staticmethod
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def _get_valid_object(object_type, module_path: Path,
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object_name: str) -> Optional[Type[Any]]:
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"""
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Returns the first object with matching object_type and object_name in the path given.
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:param object_type: object_type (class)
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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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:return: class or None
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"""
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# Generate spec based on absolute path
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spec = importlib.util.spec_from_file_location('unknown', str(module_path))
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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) 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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valid_objects_gen = (
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obj for name, obj in inspect.getmembers(module, inspect.isclass)
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if object_name == name and object_type in obj.__bases__
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)
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return next(valid_objects_gen, None)
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@classmethod
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def _search_object(self, directory: Path, object_type, object_name: str,
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kwargs: dict = {}) -> 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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:return: object instance
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"""
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logger.debug("Searching for %s %s in '%s'", object_type.__name__, object_name, directory)
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objs = []
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for entry in directory.iterdir():
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# Only consider python files
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if not str(entry).endswith('.py'):
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logger.debug('Ignoring %s', entry)
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continue
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module_path = Path.resolve(directory.joinpath(entry))
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obj = IResolver._get_valid_object(
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object_type, module_path, object_name
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)
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if obj:
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objs.append((obj, module_path))
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if len(objs) == 0:
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return (None, None)
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elif len(objs) == 1:
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obj, module_path = objs[0]
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return (obj(**kwargs), module_path)
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else:
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raise OperationalException(
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f"Cannot resolve object: found more than one objects of type "
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f"`{self.type_name}` with name `{object_name}`. "
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"Use unique names for custom strategies, hyperopts and other custom objects "
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"so that Freqtrade can be able to resolve them. "
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f"Found in modules: {[str(m) for (_, m) in objs]}")
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