Source code for langchain.chains.loading
"""Functionality for loading chains."""
import json
from pathlib import Path
from typing import Any, Union
import yaml
from langchain.chains.api.base import APIChain
from langchain.chains.base import Chain
from langchain.chains.combine_documents.map_reduce import MapReduceDocumentsChain
from langchain.chains.combine_documents.map_rerank import MapRerankDocumentsChain
from langchain.chains.combine_documents.refine import RefineDocumentsChain
from langchain.chains.combine_documents.stuff import StuffDocumentsChain
from langchain.chains.hyde.base import HypotheticalDocumentEmbedder
from langchain.chains.llm import LLMChain
from langchain.chains.llm_bash.base import LLMBashChain
from langchain.chains.llm_checker.base import LLMCheckerChain
from langchain.chains.llm_math.base import LLMMathChain
from langchain.chains.llm_requests import LLMRequestsChain
from langchain.chains.pal.base import PALChain
from langchain.chains.qa_with_sources.base import QAWithSourcesChain
from langchain.chains.qa_with_sources.vector_db import VectorDBQAWithSourcesChain
from langchain.chains.retrieval_qa.base import VectorDBQA
from langchain.chains.sql_database.base import SQLDatabaseChain
from langchain.llms.loading import load_llm, load_llm_from_config
from langchain.prompts.loading import load_prompt, load_prompt_from_config
from langchain.utilities.loading import try_load_from_hub
URL_BASE = "https://raw.githubusercontent.com/hwchase17/langchain-hub/master/chains/"
def _load_llm_chain(config: dict, **kwargs: Any) -> LLMChain:
    """Load LLM chain from config dict."""
    if "llm" in config:
"""Load LLM chain from config dict."""
    if "llm" in config:
        llm_config = config.pop("llm")
        llm = load_llm_from_config(llm_config)
    elif "llm_path" in config:
        llm = load_llm(config.pop("llm_path"))
    else:
        raise ValueError("One of `llm` or `llm_path` must be present.")
    if "prompt" in config:
        prompt_config = config.pop("prompt")
        prompt = load_prompt_from_config(prompt_config)
    elif "prompt_path" in config:
        prompt = load_prompt(config.pop("prompt_path"))
    else:
        raise ValueError("One of `prompt` or `prompt_path` must be present.")
    return LLMChain(llm=llm, prompt=prompt, **config)
def _load_hyde_chain(config: dict, **kwargs: Any) -> HypotheticalDocumentEmbedder:
    """Load hypothetical document embedder chain from config dict."""
    if "llm_chain" in config:
        llm_chain_config = config.pop("llm_chain")
        llm_chain = load_chain_from_config(llm_chain_config)
    elif "llm_chain_path" in config:
        llm_chain = load_chain(config.pop("llm_chain_path"))
    else:
        raise ValueError("One of `llm_chain` or `llm_chain_path` must be present.")
    if "embeddings" in kwargs:
        embeddings = kwargs.pop("embeddings")
    else:
        raise ValueError("`embeddings` must be present.")
    return HypotheticalDocumentEmbedder(
        llm_chain=llm_chain, base_embeddings=embeddings, **config
    )
llm_chain=llm_chain, base_embeddings=embeddings, **config
    )
def _load_stuff_documents_chain(config: dict, **kwargs: Any) -> StuffDocumentsChain:
    if "llm_chain" in config:
        llm_chain_config = config.pop("llm_chain")
        llm_chain = load_chain_from_config(llm_chain_config)
    elif "llm_chain_path" in config:
        llm_chain = load_chain(config.pop("llm_chain_path"))
    else:
        raise ValueError("One of `llm_chain` or `llm_chain_config` must be present.")
    if not isinstance(llm_chain, LLMChain):
        raise ValueError(f"Expected LLMChain, got {llm_chain}")
    if "document_prompt" in config:
        prompt_config = config.pop("document_prompt")
        document_prompt = load_prompt_from_config(prompt_config)
    elif "document_prompt_path" in config:
        document_prompt = load_prompt(config.pop("document_prompt_path"))
    else:
        raise ValueError(
            "One of `document_prompt` or `document_prompt_path` must be present."
        )
    return StuffDocumentsChain(
        llm_chain=llm_chain, document_prompt=document_prompt, **config
    )
def _load_map_reduce_documents_chain(
    config: dict, **kwargs: Any
) -> MapReduceDocumentsChain:
    if "llm_chain" in config:
        llm_chain_config = config.pop("llm_chain")
        llm_chain = load_chain_from_config(llm_chain_config)
    elif "llm_chain_path" in config:
        llm_chain = load_chain(config.pop("llm_chain_path"))
    else:
llm_chain = load_chain(config.pop("llm_chain_path"))
    else:
        raise ValueError("One of `llm_chain` or `llm_chain_config` must be present.")
    if not isinstance(llm_chain, LLMChain):
        raise ValueError(f"Expected LLMChain, got {llm_chain}")
    if "combine_document_chain" in config:
        combine_document_chain_config = config.pop("combine_document_chain")
        combine_document_chain = load_chain_from_config(combine_document_chain_config)
    elif "combine_document_chain_path" in config:
        combine_document_chain = load_chain(config.pop("combine_document_chain_path"))
    else:
        raise ValueError(
            "One of `combine_document_chain` or "
            "`combine_document_chain_path` must be present."
        )
    if "collapse_document_chain" in config:
        collapse_document_chain_config = config.pop("collapse_document_chain")
        if collapse_document_chain_config is None:
            collapse_document_chain = None
        else:
            collapse_document_chain = load_chain_from_config(
                collapse_document_chain_config
            )
    elif "collapse_document_chain_path" in config:
        collapse_document_chain = load_chain(config.pop("collapse_document_chain_path"))
    return MapReduceDocumentsChain(
        llm_chain=llm_chain,
        combine_document_chain=combine_document_chain,
        collapse_document_chain=collapse_document_chain,
        **config,
    )
def _load_llm_bash_chain(config: dict, **kwargs: Any) -> LLMBashChain:
    if "llm" in config:
        llm_config = config.pop("llm")
        llm = load_llm_from_config(llm_config)
    elif "llm_path" in config:
elif "llm_path" in config:
        llm = load_llm(config.pop("llm_path"))
    else:
        raise ValueError("One of `llm` or `llm_path` must be present.")
    if "prompt" in config:
        prompt_config = config.pop("prompt")
        prompt = load_prompt_from_config(prompt_config)
    elif "prompt_path" in config:
        prompt = load_prompt(config.pop("prompt_path"))
    return LLMBashChain(llm=llm, prompt=prompt, **config)
def _load_llm_checker_chain(config: dict, **kwargs: Any) -> LLMCheckerChain:
    if "llm" in config:
        llm_config = config.pop("llm")
        llm = load_llm_from_config(llm_config)
    elif "llm_path" in config:
        llm = load_llm(config.pop("llm_path"))
    else:
        raise ValueError("One of `llm` or `llm_path` must be present.")
    if "create_draft_answer_prompt" in config:
        create_draft_answer_prompt_config = config.pop("create_draft_answer_prompt")
        create_draft_answer_prompt = load_prompt_from_config(
            create_draft_answer_prompt_config
        )
    elif "create_draft_answer_prompt_path" in config:
        create_draft_answer_prompt = load_prompt(
            config.pop("create_draft_answer_prompt_path")
        )
    if "list_assertions_prompt" in config:
        list_assertions_prompt_config = config.pop("list_assertions_prompt")
        list_assertions_prompt = load_prompt_from_config(list_assertions_prompt_config)
    elif "list_assertions_prompt_path" in config:
        list_assertions_prompt = load_prompt(config.pop("list_assertions_prompt_path"))
list_assertions_prompt = load_prompt(config.pop("list_assertions_prompt_path"))
    if "check_assertions_prompt" in config:
        check_assertions_prompt_config = config.pop("check_assertions_prompt")
        check_assertions_prompt = load_prompt_from_config(
            check_assertions_prompt_config
        )
    elif "check_assertions_prompt_path" in config:
        check_assertions_prompt = load_prompt(
            config.pop("check_assertions_prompt_path")
        )
    if "revised_answer_prompt" in config:
        revised_answer_prompt_config = config.pop("revised_answer_prompt")
        revised_answer_prompt = load_prompt_from_config(revised_answer_prompt_config)
    elif "revised_answer_prompt_path" in config:
        revised_answer_prompt = load_prompt(config.pop("revised_answer_prompt_path"))
    return LLMCheckerChain(
        llm=llm,
        create_draft_answer_prompt=create_draft_answer_prompt,
        list_assertions_prompt=list_assertions_prompt,
        check_assertions_prompt=check_assertions_prompt,
        revised_answer_prompt=revised_answer_prompt,
        **config,
    )
def _load_llm_math_chain(config: dict, **kwargs: Any) -> LLMMathChain:
    if "llm" in config:
        llm_config = config.pop("llm")
        llm = load_llm_from_config(llm_config)
    elif "llm_path" in config:
        llm = load_llm(config.pop("llm_path"))
    else:
        raise ValueError("One of `llm` or `llm_path` must be present.")
    if "prompt" in config:
        prompt_config = config.pop("prompt")
        prompt = load_prompt_from_config(prompt_config)
    elif "prompt_path" in config:
prompt = load_prompt_from_config(prompt_config)
    elif "prompt_path" in config:
        prompt = load_prompt(config.pop("prompt_path"))
    return LLMMathChain(llm=llm, prompt=prompt, **config)
def _load_map_rerank_documents_chain(
    config: dict, **kwargs: Any
) -> MapRerankDocumentsChain:
    if "llm_chain" in config:
        llm_chain_config = config.pop("llm_chain")
        llm_chain = load_chain_from_config(llm_chain_config)
    elif "llm_chain_path" in config:
        llm_chain = load_chain(config.pop("llm_chain_path"))
    else:
        raise ValueError("One of `llm_chain` or `llm_chain_config` must be present.")
    return MapRerankDocumentsChain(llm_chain=llm_chain, **config)
def _load_pal_chain(config: dict, **kwargs: Any) -> PALChain:
    if "llm" in config:
        llm_config = config.pop("llm")
        llm = load_llm_from_config(llm_config)
    elif "llm_path" in config:
        llm = load_llm(config.pop("llm_path"))
    else:
        raise ValueError("One of `llm` or `llm_path` must be present.")
    if "prompt" in config:
        prompt_config = config.pop("prompt")
        prompt = load_prompt_from_config(prompt_config)
    elif "prompt_path" in config:
        prompt = load_prompt(config.pop("prompt_path"))
    else:
        raise ValueError("One of `prompt` or `prompt_path` must be present.")
    return PALChain(llm=llm, prompt=prompt, **config)
return PALChain(llm=llm, prompt=prompt, **config)
def _load_refine_documents_chain(config: dict, **kwargs: Any) -> RefineDocumentsChain:
    if "initial_llm_chain" in config:
        initial_llm_chain_config = config.pop("initial_llm_chain")
        initial_llm_chain = load_chain_from_config(initial_llm_chain_config)
    elif "initial_llm_chain_path" in config:
        initial_llm_chain = load_chain(config.pop("initial_llm_chain_path"))
    else:
        raise ValueError(
            "One of `initial_llm_chain` or `initial_llm_chain_config` must be present."
        )
    if "refine_llm_chain" in config:
        refine_llm_chain_config = config.pop("refine_llm_chain")
        refine_llm_chain = load_chain_from_config(refine_llm_chain_config)
    elif "refine_llm_chain_path" in config:
        refine_llm_chain = load_chain(config.pop("refine_llm_chain_path"))
    else:
        raise ValueError(
            "One of `refine_llm_chain` or `refine_llm_chain_config` must be present."
        )
    if "document_prompt" in config:
        prompt_config = config.pop("document_prompt")
        document_prompt = load_prompt_from_config(prompt_config)
    elif "document_prompt_path" in config:
        document_prompt = load_prompt(config.pop("document_prompt_path"))
    return RefineDocumentsChain(
        initial_llm_chain=initial_llm_chain,
        refine_llm_chain=refine_llm_chain,
        document_prompt=document_prompt,
        **config,
    )
def _load_qa_with_sources_chain(config: dict, **kwargs: Any) -> QAWithSourcesChain:
if "combine_documents_chain" in config:
        combine_documents_chain_config = config.pop("combine_documents_chain")
        combine_documents_chain = load_chain_from_config(combine_documents_chain_config)
    elif "combine_documents_chain_path" in config:
        combine_documents_chain = load_chain(config.pop("combine_documents_chain_path"))
    else:
        raise ValueError(
            "One of `combine_documents_chain` or "
            "`combine_documents_chain_path` must be present."
        )
    return QAWithSourcesChain(combine_documents_chain=combine_documents_chain, **config)
def _load_sql_database_chain(config: dict, **kwargs: Any) -> SQLDatabaseChain:
    if "database" in kwargs:
        database = kwargs.pop("database")
    else:
        raise ValueError("`database` must be present.")
    if "llm" in config:
        llm_config = config.pop("llm")
        llm = load_llm_from_config(llm_config)
    elif "llm_path" in config:
        llm = load_llm(config.pop("llm_path"))
    else:
        raise ValueError("One of `llm` or `llm_path` must be present.")
    if "prompt" in config:
        prompt_config = config.pop("prompt")
        prompt = load_prompt_from_config(prompt_config)
    else:
        prompt = None
    return SQLDatabaseChain.from_llm(llm, database, prompt=prompt, **config)
def _load_vector_db_qa_with_sources_chain(
    config: dict, **kwargs: Any
) -> VectorDBQAWithSourcesChain:
    if "vectorstore" in kwargs:
        vectorstore = kwargs.pop("vectorstore")
    else:
        raise ValueError("`vectorstore` must be present.")
else:
        raise ValueError("`vectorstore` must be present.")
    if "combine_documents_chain" in config:
        combine_documents_chain_config = config.pop("combine_documents_chain")
        combine_documents_chain = load_chain_from_config(combine_documents_chain_config)
    elif "combine_documents_chain_path" in config:
        combine_documents_chain = load_chain(config.pop("combine_documents_chain_path"))
    else:
        raise ValueError(
            "One of `combine_documents_chain` or "
            "`combine_documents_chain_path` must be present."
        )
    return VectorDBQAWithSourcesChain(
        combine_documents_chain=combine_documents_chain,
        vectorstore=vectorstore,
        **config,
    )
def _load_vector_db_qa(config: dict, **kwargs: Any) -> VectorDBQA:
    if "vectorstore" in kwargs:
        vectorstore = kwargs.pop("vectorstore")
    else:
        raise ValueError("`vectorstore` must be present.")
    if "combine_documents_chain" in config:
        combine_documents_chain_config = config.pop("combine_documents_chain")
        combine_documents_chain = load_chain_from_config(combine_documents_chain_config)
    elif "combine_documents_chain_path" in config:
        combine_documents_chain = load_chain(config.pop("combine_documents_chain_path"))
    else:
        raise ValueError(
            "One of `combine_documents_chain` or "
            "`combine_documents_chain_path` must be present."
        )
    return VectorDBQA(
        combine_documents_chain=combine_documents_chain,
        vectorstore=vectorstore,
        **config,
    )
def _load_api_chain(config: dict, **kwargs: Any) -> APIChain:
    if "api_request_chain" in config:
        api_request_chain_config = config.pop("api_request_chain")
api_request_chain_config = config.pop("api_request_chain")
        api_request_chain = load_chain_from_config(api_request_chain_config)
    elif "api_request_chain_path" in config:
        api_request_chain = load_chain(config.pop("api_request_chain_path"))
    else:
        raise ValueError(
            "One of `api_request_chain` or `api_request_chain_path` must be present."
        )
    if "api_answer_chain" in config:
        api_answer_chain_config = config.pop("api_answer_chain")
        api_answer_chain = load_chain_from_config(api_answer_chain_config)
    elif "api_answer_chain_path" in config:
        api_answer_chain = load_chain(config.pop("api_answer_chain_path"))
    else:
        raise ValueError(
            "One of `api_answer_chain` or `api_answer_chain_path` must be present."
        )
    if "requests_wrapper" in kwargs:
        requests_wrapper = kwargs.pop("requests_wrapper")
    else:
        raise ValueError("`requests_wrapper` must be present.")
    return APIChain(
        api_request_chain=api_request_chain,
        api_answer_chain=api_answer_chain,
        requests_wrapper=requests_wrapper,
        **config,
    )
def _load_llm_requests_chain(config: dict, **kwargs: Any) -> LLMRequestsChain:
    if "llm_chain" in config:
        llm_chain_config = config.pop("llm_chain")
        llm_chain = load_chain_from_config(llm_chain_config)
    elif "llm_chain_path" in config:
        llm_chain = load_chain(config.pop("llm_chain_path"))
    else:
        raise ValueError("One of `llm_chain` or `llm_chain_path` must be present.")
    if "requests_wrapper" in kwargs:
if "requests_wrapper" in kwargs:
        requests_wrapper = kwargs.pop("requests_wrapper")
        return LLMRequestsChain(
            llm_chain=llm_chain, requests_wrapper=requests_wrapper, **config
        )
    else:
        return LLMRequestsChain(llm_chain=llm_chain, **config)
type_to_loader_dict = {
    "api_chain": _load_api_chain,
    "hyde_chain": _load_hyde_chain,
    "llm_chain": _load_llm_chain,
    "llm_bash_chain": _load_llm_bash_chain,
    "llm_checker_chain": _load_llm_checker_chain,
    "llm_math_chain": _load_llm_math_chain,
    "llm_requests_chain": _load_llm_requests_chain,
    "pal_chain": _load_pal_chain,
    "qa_with_sources_chain": _load_qa_with_sources_chain,
    "stuff_documents_chain": _load_stuff_documents_chain,
    "map_reduce_documents_chain": _load_map_reduce_documents_chain,
    "map_rerank_documents_chain": _load_map_rerank_documents_chain,
    "refine_documents_chain": _load_refine_documents_chain,
    "sql_database_chain": _load_sql_database_chain,
    "vector_db_qa_with_sources_chain": _load_vector_db_qa_with_sources_chain,
    "vector_db_qa": _load_vector_db_qa,
}
def load_chain_from_config(config: dict, **kwargs: Any) -> Chain:
    """Load chain from Config Dict."""
    if "_type" not in config:
        raise ValueError("Must specify a chain Type in config")
    config_type = config.pop("_type")
    if config_type not in type_to_loader_dict:
if config_type not in type_to_loader_dict:
        raise ValueError(f"Loading {config_type} chain not supported")
    chain_loader = type_to_loader_dict[config_type]
    return chain_loader(config, **kwargs)
[docs]def load_chain(path: Union[str, Path], **kwargs: Any) -> Chain:
    """Unified method for loading a chain from LangChainHub or local fs."""
    if hub_result := try_load_from_hub(
        path, _load_chain_from_file, "chains", {"json", "yaml"}, **kwargs
    ):
        return hub_result
    else:
        return _load_chain_from_file(path, **kwargs)
def _load_chain_from_file(file: Union[str, Path], **kwargs: Any) -> Chain:
    """Load chain from file."""
    # Convert file to Path object.
    if isinstance(file, str):
        file_path = Path(file)
    else:
        file_path = file
    # Load from either json or yaml.
    if file_path.suffix == ".json":
        with open(file_path) as f:
            config = json.load(f)
    elif file_path.suffix == ".yaml":
        with open(file_path, "r") as f:
            config = yaml.safe_load(f)
    else:
        raise ValueError("File type must be json or yaml")
    # Override default 'verbose' and 'memory' for the chain
    if "verbose" in kwargs:
        config["verbose"] = kwargs.pop("verbose")
    if "memory" in kwargs:
        config["memory"] = kwargs.pop("memory")
    # Load the chain from the config now.
    return load_chain_from_config(config, **kwargs)
By Harrison Chase
By Harrison Chase