Source code for langchain_community.llms.vertexai

from __future__ import annotations

from concurrent.futures import Executor, ThreadPoolExecutor
from typing import TYPE_CHECKING, Any, ClassVar, Dict, Iterator, List, Optional, Union

from langchain_core._api.deprecation import deprecated
from langchain_core.callbacks.manager import (
    AsyncCallbackManagerForLLMRun,
    CallbackManagerForLLMRun,
)
from langchain_core.language_models.llms import BaseLLM
from langchain_core.outputs import Generation, GenerationChunk, LLMResult
from langchain_core.pydantic_v1 import BaseModel, Field, root_validator

from langchain_community.utilities.vertexai import (
    create_retry_decorator,
    get_client_info,
    init_vertexai,
    raise_vertex_import_error,
)

if TYPE_CHECKING:
    from google.cloud.aiplatform.gapic import (
        PredictionServiceAsyncClient,
        PredictionServiceClient,
    )
    from google.cloud.aiplatform.models import Prediction
    from google.protobuf.struct_pb2 import Value
    from vertexai.language_models._language_models import (
        TextGenerationResponse,
        _LanguageModel,
    )
    from vertexai.preview.generative_models import Image

# This is for backwards compatibility
# We can remove after `langchain` stops importing it
_response_to_generation = None
completion_with_retry = None
stream_completion_with_retry = None


[docs]def is_codey_model(model_name: str) -> bool: """Return True if the model name is a Codey model.""" return "code" in model_name
[docs]def is_gemini_model(model_name: str) -> bool: """Return True if the model name is a Gemini model.""" return model_name is not None and "gemini" in model_name
[docs]def completion_with_retry( # type: ignore[no-redef] llm: VertexAI, prompt: List[Union[str, "Image"]], stream: bool = False, is_gemini: bool = False, run_manager: Optional[CallbackManagerForLLMRun] = None, **kwargs: Any, ) -> Any: """Use tenacity to retry the completion call.""" retry_decorator = create_retry_decorator(llm, run_manager=run_manager) @retry_decorator def _completion_with_retry( prompt: List[Union[str, "Image"]], is_gemini: bool = False, **kwargs: Any ) -> Any: if is_gemini: return llm.client.generate_content( prompt, stream=stream, generation_config=kwargs ) else: if stream: return llm.client.predict_streaming(prompt[0], **kwargs) return llm.client.predict(prompt[0], **kwargs) return _completion_with_retry(prompt, is_gemini, **kwargs)
[docs]async def acompletion_with_retry( llm: VertexAI, prompt: str, is_gemini: bool = False, run_manager: Optional[AsyncCallbackManagerForLLMRun] = None, **kwargs: Any, ) -> Any: """Use tenacity to retry the completion call.""" retry_decorator = create_retry_decorator(llm, run_manager=run_manager) @retry_decorator async def _acompletion_with_retry( prompt: str, is_gemini: bool = False, **kwargs: Any ) -> Any: if is_gemini: return await llm.client.generate_content_async( prompt, generation_config=kwargs ) return await llm.client.predict_async(prompt, **kwargs) return await _acompletion_with_retry(prompt, is_gemini, **kwargs)
class _VertexAIBase(BaseModel): project: Optional[str] = None "The default GCP project to use when making Vertex API calls." location: str = "us-central1" "The default location to use when making API calls." request_parallelism: int = 5 "The amount of parallelism allowed for requests issued to VertexAI models. " "Default is 5." max_retries: int = 6 """The maximum number of retries to make when generating.""" task_executor: ClassVar[Optional[Executor]] = Field(default=None, exclude=True) stop: Optional[List[str]] = None "Optional list of stop words to use when generating." model_name: Optional[str] = None "Underlying model name." @classmethod def _get_task_executor(cls, request_parallelism: int = 5) -> Executor: if cls.task_executor is None: cls.task_executor = ThreadPoolExecutor(max_workers=request_parallelism) return cls.task_executor class _VertexAICommon(_VertexAIBase): client: "_LanguageModel" = None #: :meta private: client_preview: "_LanguageModel" = None #: :meta private: model_name: str "Underlying model name." temperature: float = 0.0 "Sampling temperature, it controls the degree of randomness in token selection." max_output_tokens: int = 128 "Token limit determines the maximum amount of text output from one prompt." top_p: float = 0.95 "Tokens are selected from most probable to least until the sum of their " "probabilities equals the top-p value. Top-p is ignored for Codey models." top_k: int = 40 "How the model selects tokens for output, the next token is selected from " "among the top-k most probable tokens. Top-k is ignored for Codey models." credentials: Any = Field(default=None, exclude=True) "The default custom credentials (google.auth.credentials.Credentials) to use " "when making API calls. If not provided, credentials will be ascertained from " "the environment." n: int = 1 """How many completions to generate for each prompt.""" streaming: bool = False """Whether to stream the results or not.""" @property def _llm_type(self) -> str: return "vertexai" @property def is_codey_model(self) -> bool: return is_codey_model(self.model_name) @property def _is_gemini_model(self) -> bool: return is_gemini_model(self.model_name) @property def _identifying_params(self) -> Dict[str, Any]: """Gets the identifying parameters.""" return {**{"model_name": self.model_name}, **self._default_params} @property def _default_params(self) -> Dict[str, Any]: params = { "temperature": self.temperature, "max_output_tokens": self.max_output_tokens, "candidate_count": self.n, } if not self.is_codey_model: params.update( { "top_k": self.top_k, "top_p": self.top_p, } ) return params @classmethod def _try_init_vertexai(cls, values: Dict) -> None: allowed_params = ["project", "location", "credentials"] params = {k: v for k, v in values.items() if k in allowed_params} init_vertexai(**params) return None def _prepare_params( self, stop: Optional[List[str]] = None, stream: bool = False, **kwargs: Any, ) -> dict: stop_sequences = stop or self.stop params_mapping = {"n": "candidate_count"} params = {params_mapping.get(k, k): v for k, v in kwargs.items()} params = {**self._default_params, "stop_sequences": stop_sequences, **params} if stream or self.streaming: params.pop("candidate_count") return params
[docs]@deprecated( since="0.0.12", removal="0.3.0", alternative_import="langchain_google_vertexai.VertexAI", ) class VertexAI(_VertexAICommon, BaseLLM): """Google Vertex AI large language models.""" model_name: str = "text-bison" "The name of the Vertex AI large language model." tuned_model_name: Optional[str] = None "The name of a tuned model. If provided, model_name is ignored."
[docs] @classmethod def is_lc_serializable(self) -> bool: return True
[docs] @classmethod def get_lc_namespace(cls) -> List[str]: """Get the namespace of the langchain object.""" return ["langchain", "llms", "vertexai"]
@root_validator() def validate_environment(cls, values: Dict) -> Dict: """Validate that the python package exists in environment.""" tuned_model_name = values.get("tuned_model_name") model_name = values["model_name"] is_gemini = is_gemini_model(values["model_name"]) cls._try_init_vertexai(values) try: from vertexai.language_models import ( CodeGenerationModel, TextGenerationModel, ) from vertexai.preview.language_models import ( CodeGenerationModel as PreviewCodeGenerationModel, ) from vertexai.preview.language_models import ( TextGenerationModel as PreviewTextGenerationModel, ) if is_gemini: from vertexai.preview.generative_models import ( GenerativeModel, ) if is_codey_model(model_name): model_cls = CodeGenerationModel preview_model_cls = PreviewCodeGenerationModel elif is_gemini: model_cls = GenerativeModel preview_model_cls = GenerativeModel else: model_cls = TextGenerationModel preview_model_cls = PreviewTextGenerationModel if tuned_model_name: values["client"] = model_cls.get_tuned_model(tuned_model_name) values["client_preview"] = preview_model_cls.get_tuned_model( tuned_model_name ) else: if is_gemini: values["client"] = model_cls(model_name=model_name) values["client_preview"] = preview_model_cls(model_name=model_name) else: values["client"] = model_cls.from_pretrained(model_name) values["client_preview"] = preview_model_cls.from_pretrained( model_name ) except ImportError: raise_vertex_import_error() if values["streaming"] and values["n"] > 1: raise ValueError("Only one candidate can be generated with streaming!") return values
[docs] def get_num_tokens(self, text: str) -> int: """Get the number of tokens present in the text. Useful for checking if an input will fit in a model's context window. Args: text: The string input to tokenize. Returns: The integer number of tokens in the text. """ try: result = self.client_preview.count_tokens([text]) except AttributeError: raise_vertex_import_error() return result.total_tokens
def _response_to_generation( self, response: TextGenerationResponse ) -> GenerationChunk: """Converts a stream response to a generation chunk.""" try: generation_info = { "is_blocked": response.is_blocked, "safety_attributes": response.safety_attributes, } except Exception: generation_info = None return GenerationChunk(text=response.text, generation_info=generation_info) def _generate( self, prompts: List[str], stop: Optional[List[str]] = None, run_manager: Optional[CallbackManagerForLLMRun] = None, stream: Optional[bool] = None, **kwargs: Any, ) -> LLMResult: should_stream = stream if stream is not None else self.streaming params = self._prepare_params(stop=stop, stream=should_stream, **kwargs) generations: List[List[Generation]] = [] for prompt in prompts: if should_stream: generation = GenerationChunk(text="") for chunk in self._stream( prompt, stop=stop, run_manager=run_manager, **kwargs ): generation += chunk generations.append([generation]) else: res = completion_with_retry( # type: ignore[misc] self, [prompt], stream=should_stream, is_gemini=self._is_gemini_model, run_manager=run_manager, **params, ) generations.append( [self._response_to_generation(r) for r in res.candidates] ) return LLMResult(generations=generations) async def _agenerate( self, prompts: List[str], stop: Optional[List[str]] = None, run_manager: Optional[AsyncCallbackManagerForLLMRun] = None, **kwargs: Any, ) -> LLMResult: params = self._prepare_params(stop=stop, **kwargs) generations = [] for prompt in prompts: res = await acompletion_with_retry( self, prompt, is_gemini=self._is_gemini_model, run_manager=run_manager, **params, ) generations.append( [self._response_to_generation(r) for r in res.candidates] ) return LLMResult(generations=generations) # type: ignore[arg-type] def _stream( self, prompt: str, stop: Optional[List[str]] = None, run_manager: Optional[CallbackManagerForLLMRun] = None, **kwargs: Any, ) -> Iterator[GenerationChunk]: params = self._prepare_params(stop=stop, stream=True, **kwargs) for stream_resp in completion_with_retry( # type: ignore[misc] self, [prompt], stream=True, is_gemini=self._is_gemini_model, run_manager=run_manager, **params, ): chunk = self._response_to_generation(stream_resp) if run_manager: run_manager.on_llm_new_token( chunk.text, chunk=chunk, verbose=self.verbose, ) yield chunk
[docs]@deprecated( since="0.0.12", removal="0.3.0", alternative_import="langchain_google_vertexai.VertexAIModelGarden", ) class VertexAIModelGarden(_VertexAIBase, BaseLLM): """Vertex AI Model Garden large language models.""" client: "PredictionServiceClient" = None #: :meta private: async_client: "PredictionServiceAsyncClient" = None #: :meta private: endpoint_id: str "A name of an endpoint where the model has been deployed." allowed_model_args: Optional[List[str]] = None "Allowed optional args to be passed to the model." prompt_arg: str = "prompt" result_arg: Optional[str] = "generated_text" "Set result_arg to None if output of the model is expected to be a string." "Otherwise, if it's a dict, provided an argument that contains the result." @root_validator() def validate_environment(cls, values: Dict) -> Dict: """Validate that the python package exists in environment.""" try: from google.api_core.client_options import ClientOptions from google.cloud.aiplatform.gapic import ( PredictionServiceAsyncClient, PredictionServiceClient, ) except ImportError: raise_vertex_import_error() if not values["project"]: raise ValueError( "A GCP project should be provided to run inference on Model Garden!" ) client_options = ClientOptions( api_endpoint=f"{values['location']}-aiplatform.googleapis.com" ) client_info = get_client_info(module="vertex-ai-model-garden") values["client"] = PredictionServiceClient( client_options=client_options, client_info=client_info ) values["async_client"] = PredictionServiceAsyncClient( client_options=client_options, client_info=client_info ) return values @property def endpoint_path(self) -> str: return self.client.endpoint_path( project=self.project, location=self.location, endpoint=self.endpoint_id, ) @property def _llm_type(self) -> str: return "vertexai_model_garden" def _prepare_request(self, prompts: List[str], **kwargs: Any) -> List["Value"]: try: from google.protobuf import json_format from google.protobuf.struct_pb2 import Value except ImportError: raise ImportError( "protobuf package not found, please install it with" " `pip install protobuf`" ) instances = [] for prompt in prompts: if self.allowed_model_args: instance = { k: v for k, v in kwargs.items() if k in self.allowed_model_args } else: instance = {} instance[self.prompt_arg] = prompt instances.append(instance) predict_instances = [ json_format.ParseDict(instance_dict, Value()) for instance_dict in instances ] return predict_instances def _generate( self, prompts: List[str], stop: Optional[List[str]] = None, run_manager: Optional[CallbackManagerForLLMRun] = None, **kwargs: Any, ) -> LLMResult: """Run the LLM on the given prompt and input.""" instances = self._prepare_request(prompts, **kwargs) response = self.client.predict(endpoint=self.endpoint_path, instances=instances) return self._parse_response(response) def _parse_response(self, predictions: "Prediction") -> LLMResult: generations: List[List[Generation]] = [] for result in predictions.predictions: generations.append( [ Generation(text=self._parse_prediction(prediction)) for prediction in result ] ) return LLMResult(generations=generations) def _parse_prediction(self, prediction: Any) -> str: if isinstance(prediction, str): return prediction if self.result_arg: try: return prediction[self.result_arg] except KeyError: if isinstance(prediction, str): error_desc = ( "Provided non-None `result_arg` (result_arg=" f"{self.result_arg}). But got prediction of type " f"{type(prediction)} instead of dict. Most probably, you" "need to set `result_arg=None` during VertexAIModelGarden " "initialization." ) raise ValueError(error_desc) else: raise ValueError(f"{self.result_arg} key not found in prediction!") return prediction async def _agenerate( self, prompts: List[str], stop: Optional[List[str]] = None, run_manager: Optional[AsyncCallbackManagerForLLMRun] = None, **kwargs: Any, ) -> LLMResult: """Run the LLM on the given prompt and input.""" instances = self._prepare_request(prompts, **kwargs) response = await self.async_client.predict( endpoint=self.endpoint_path, instances=instances ) return self._parse_response(response)