peft/config.py

# Copyright 2023-present the HuggingFace Inc. team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import inspect
import json
import os
from dataclasses import asdict, dataclass, field
from typing import Dict, Optional, Union

from huggingface_hub import hf_hub_download
from transformers.utils import PushToHubMixin

from .utils import CONFIG_NAME, PeftType, TaskType


@dataclass
class PeftConfigMixin(PushToHubMixin):
    r"""
    This is the base configuration class for PEFT adapter models. It contains all the methods that are common to all
    PEFT adapter models. This class inherits from [`~transformers.utils.PushToHubMixin`] which contains the methods to
    push your model to the Hub. The method `save_pretrained` will save the configuration of your adapter model in a
    directory. The method `from_pretrained` will load the configuration of your adapter model from a directory.

    Args:
        peft_type (Union[[`~peft.utils.config.PeftType`], `str`]): The type of Peft method to use.
    """

    peft_type: Optional[PeftType] = field(default=None, metadata={"help": "The type of PEFT model."})
    auto_mapping: Optional[dict] = field(
        default=None, metadata={"help": "An auto mapping dict to help retrieve the base model class if needed."}
    )

    def to_dict(self) -> Dict:
        r"""
        Returns the configuration for your adapter model as a dictionary.
        """
        return asdict(self)

    def save_pretrained(self, save_directory: str, **kwargs) -> None:
        r"""
        This method saves the configuration of your adapter model in a directory.

        Args:
            save_directory (`str`):
                The directory where the configuration will be saved.
            kwargs (additional keyword arguments, *optional*):
                Additional keyword arguments passed along to the [`~transformers.utils.PushToHubMixin.push_to_hub`]
                method.
        """
        if os.path.isfile(save_directory):
            raise AssertionError(f"Provided path ({save_directory}) should be a directory, not a file")

        os.makedirs(save_directory, exist_ok=True)
        auto_mapping_dict = kwargs.pop("auto_mapping_dict", None)

        output_dict = asdict(self)
        # converting set type to list
        for key, value in output_dict.items():
            if isinstance(value, set):
                output_dict[key] = list(value)

        output_path = os.path.join(save_directory, CONFIG_NAME)

        # Add auto mapping details for custom models.
        if auto_mapping_dict is not None:
            output_dict["auto_mapping"] = auto_mapping_dict

        # save it
        with open(output_path, "w") as writer:
            writer.write(json.dumps(output_dict, indent=2, sort_keys=True))

    @classmethod
    def from_peft_type(cls, **kwargs):
        r"""
        This method loads the configuration of your adapter model from a set of kwargs.

        The appropriate configuration type is determined by the `peft_type` argument. If `peft_type` is not provided,
        the calling class type is instantiated.

        Args:
            kwargs (configuration keyword arguments):
                Keyword arguments passed along to the configuration initialization.
        """
        # Avoid circular dependency .. TODO: fix this with a larger refactor
        from peft.mapping import PEFT_TYPE_TO_CONFIG_MAPPING

        # TODO: this hack is needed to fix the following issue (on commit 702f937):
        # if someone saves a default config and loads it back with `PeftConfig` class it yields to
        # not loading the correct config class.

        # from peft import AdaLoraConfig, PeftConfig
        # peft_config = AdaLoraConfig()
        # print(peft_config)
        # >>> AdaLoraConfig(peft_type=<PeftType.ADALORA: 'ADALORA'>, auto_mapping=None, base_model_name_or_path=None,
        # revision=None, task_type=None, inference_mode=False, r=8, target_modules=None, lora_alpha=8, lora_dropout=0.0, ...
        #
        # peft_config.save_pretrained("./test_config")
        # peft_config = PeftConfig.from_pretrained("./test_config")
        # print(peft_config)
        # >>> PeftConfig(peft_type='ADALORA', auto_mapping=None, base_model_name_or_path=None, revision=None, task_type=None, inference_mode=False)

        if "peft_type" in kwargs:
            peft_type = kwargs["peft_type"]
            config_cls = PEFT_TYPE_TO_CONFIG_MAPPING[peft_type]
        else:
            config_cls = cls

        return config_cls(**kwargs)

    @classmethod
    def from_pretrained(cls, pretrained_model_name_or_path: str, subfolder: Optional[str] = None, **kwargs):
        r"""
        This method loads the configuration of your adapter model from a directory.

        Args:
            pretrained_model_name_or_path (`str`):
                The directory or the Hub repository id where the configuration is saved.
            kwargs (additional keyword arguments, *optional*):
                Additional keyword arguments passed along to the child class initialization.
        """
        path = (
            os.path.join(pretrained_model_name_or_path, subfolder)
            if subfolder is not None
            else pretrained_model_name_or_path
        )

        hf_hub_download_kwargs, class_kwargs, _ = cls._split_kwargs(kwargs)

        if os.path.isfile(os.path.join(path, CONFIG_NAME)):
            config_file = os.path.join(path, CONFIG_NAME)
        else:
            try:
                config_file = hf_hub_download(
                    pretrained_model_name_or_path, CONFIG_NAME, subfolder=subfolder, **hf_hub_download_kwargs
                )
            except Exception as exc:
                raise ValueError(f"Can't find '{CONFIG_NAME}' at '{pretrained_model_name_or_path}'") from exc

        loaded_attributes = cls.from_json_file(config_file)
        kwargs = {**class_kwargs, **loaded_attributes}
        return cls.from_peft_type(**kwargs)

    @classmethod
    def from_json_file(cls, path_json_file: str, **kwargs):
        r"""
        Loads a configuration file from a json file.

        Args:
            path_json_file (`str`):
                The path to the json file.
        """
        with open(path_json_file) as file:
            json_object = json.load(file)

        return json_object

    @classmethod
    def _split_kwargs(cls, kwargs):
        hf_hub_download_kwargs = {}
        class_kwargs = {}
        other_kwargs = {}

        for key, value in kwargs.items():
            if key in inspect.signature(hf_hub_download).parameters:
                hf_hub_download_kwargs[key] = value
            elif key in list(cls.__annotations__):
                class_kwargs[key] = value
            else:
                other_kwargs[key] = value

        return hf_hub_download_kwargs, class_kwargs, other_kwargs

    @classmethod
    def _get_peft_type(
        cls,
        model_id: str,
        **hf_hub_download_kwargs,
    ):
        subfolder = hf_hub_download_kwargs.get("subfolder", None)

        path = os.path.join(model_id, subfolder) if subfolder is not None else model_id

        if os.path.isfile(os.path.join(path, CONFIG_NAME)):
            config_file = os.path.join(path, CONFIG_NAME)
        else:
            try:
                config_file = hf_hub_download(
                    model_id,
                    CONFIG_NAME,
                    **hf_hub_download_kwargs,
                )
            except Exception:
                raise ValueError(f"Can't find '{CONFIG_NAME}' at '{model_id}'")

        loaded_attributes = cls.from_json_file(config_file)
        return loaded_attributes["peft_type"]

    @property
    def is_prompt_learning(self) -> bool:
        r"""
        Utility method to check if the configuration is for prompt learning.
        """
        return False

    @property
    def is_adaption_prompt(self) -> bool:
        """Return True if this is an adaption prompt config."""
        return False


@dataclass
class PeftConfig(PeftConfigMixin):
    """
    This is the base configuration class to store the configuration of a [`PeftModel`].

    Args:
        peft_type (Union[[`~peft.utils.config.PeftType`], `str`]): The type of Peft method to use.
        task_type (Union[[`~peft.utils.config.TaskType`], `str`]): The type of task to perform.
        inference_mode (`bool`, defaults to `False`): Whether to use the Peft model in inference mode.
    """

    base_model_name_or_path: Optional[str] = field(
        default=None, metadata={"help": "The name of the base model to use."}
    )
    revision: Optional[str] = field(default=None, metadata={"help": "The specific model version to use."})
    peft_type: Optional[Union[str, PeftType]] = field(default=None, metadata={"help": "Peft type"})
    task_type: Optional[Union[str, TaskType]] = field(default=None, metadata={"help": "Task type"})
    inference_mode: bool = field(default=False, metadata={"help": "Whether to use inference mode"})


@dataclass
class PromptLearningConfig(PeftConfig):
    """
    This is the base configuration class to store the configuration of [`PrefixTuning`], [`PromptEncoder`], or
    [`PromptTuning`].

    Args:
        num_virtual_tokens (`int`): The number of virtual tokens to use.
        token_dim (`int`): The hidden embedding dimension of the base transformer model.
        num_transformer_submodules (`int`): The number of transformer submodules in the base transformer model.
        num_attention_heads (`int`): The number of attention heads in the base transformer model.
        num_layers (`int`): The number of layers in the base transformer model.
    """

    num_virtual_tokens: int = field(default=None, metadata={"help": "Number of virtual tokens"})
    token_dim: int = field(
        default=None, metadata={"help": "The hidden embedding dimension of the base transformer model"}
    )
    num_transformer_submodules: Optional[int] = field(
        default=None, metadata={"help": "Number of transformer submodules"}
    )
    num_attention_heads: Optional[int] = field(default=None, metadata={"help": "Number of attention heads"})
    num_layers: Optional[int] = field(default=None, metadata={"help": "Number of transformer layers"})

    @property
    def is_prompt_learning(self) -> bool:
        r"""
        Utility method to check if the configuration is for prompt learning.
        """
        return True