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"""Wrapper around HuggingFace APIs.""" | |
from typing import Any, Dict, List, Mapping, Optional | |
from pydantic import BaseModel, Extra, root_validator | |
from langchain.llms.base import LLM | |
from langchain.llms.utils import enforce_stop_tokens | |
from langchain.utils import get_from_dict_or_env | |
DEFAULT_REPO_ID = "gpt2" | |
VALID_TASKS = ("text2text-generation", "text-generation") | |
class HuggingFaceHub(LLM, BaseModel): | |
"""Wrapper around HuggingFaceHub models. | |
To use, you should have the ``huggingface_hub`` python package installed, and the | |
environment variable ``HUGGINGFACEHUB_API_TOKEN`` set with your API token, or pass | |
it as a named parameter to the constructor. | |
Only supports `text-generation` and `text2text-generation` for now. | |
Example: | |
.. code-block:: python | |
from langchain.llms import HuggingFaceHub | |
hf = HuggingFaceHub(repo_id="gpt2", huggingfacehub_api_token="my-api-key") | |
""" | |
client: Any #: :meta private: | |
repo_id: str = DEFAULT_REPO_ID | |
"""Model name to use.""" | |
task: Optional[str] = None | |
"""Task to call the model with. Should be a task that returns `generated_text`.""" | |
model_kwargs: Optional[dict] = None | |
"""Key word arguments to pass to the model.""" | |
huggingfacehub_api_token: Optional[str] = None | |
class Config: | |
"""Configuration for this pydantic object.""" | |
extra = Extra.forbid | |
def validate_environment(cls, values: Dict) -> Dict: | |
"""Validate that api key and python package exists in environment.""" | |
huggingfacehub_api_token = get_from_dict_or_env( | |
values, "huggingfacehub_api_token", "HUGGINGFACEHUB_API_TOKEN" | |
) | |
try: | |
from huggingface_hub.inference_api import InferenceApi | |
repo_id = values["repo_id"] | |
client = InferenceApi( | |
repo_id=repo_id, | |
token=huggingfacehub_api_token, | |
task=values.get("task"), | |
) | |
if client.task not in VALID_TASKS: | |
raise ValueError( | |
f"Got invalid task {client.task}, " | |
f"currently only {VALID_TASKS} are supported" | |
) | |
values["client"] = client | |
except ImportError: | |
raise ValueError( | |
"Could not import huggingface_hub python package. " | |
"Please it install it with `pip install huggingface_hub`." | |
) | |
return values | |
def _identifying_params(self) -> Mapping[str, Any]: | |
"""Get the identifying parameters.""" | |
_model_kwargs = self.model_kwargs or {} | |
return { | |
**{"repo_id": self.repo_id, "task": self.task}, | |
**{"model_kwargs": _model_kwargs}, | |
} | |
def _llm_type(self) -> str: | |
"""Return type of llm.""" | |
return "huggingface_hub" | |
def _call(self, prompt: str, stop: Optional[List[str]] = None) -> str: | |
"""Call out to HuggingFace Hub's inference endpoint. | |
Args: | |
prompt: The prompt to pass into the model. | |
stop: Optional list of stop words to use when generating. | |
Returns: | |
The string generated by the model. | |
Example: | |
.. code-block:: python | |
response = hf("Tell me a joke.") | |
""" | |
_model_kwargs = self.model_kwargs or {} | |
response = self.client(inputs=prompt, params=_model_kwargs) | |
if "error" in response: | |
raise ValueError(f"Error raised by inference API: {response['error']}") | |
if self.client.task == "text-generation": | |
# Text generation return includes the starter text. | |
text = response[0]["generated_text"][len(prompt) :] | |
elif self.client.task == "text2text-generation": | |
text = response[0]["generated_text"] | |
else: | |
raise ValueError( | |
f"Got invalid task {self.client.task}, " | |
f"currently only {VALID_TASKS} are supported" | |
) | |
if stop is not None: | |
# This is a bit hacky, but I can't figure out a better way to enforce | |
# stop tokens when making calls to huggingface_hub. | |
text = enforce_stop_tokens(text, stop) | |
return text | |