langchain/chains/graph_qa/sparql.py

"""
Question answering over an RDF or OWL graph using SPARQL.
"""
from __future__ import annotations

from typing import Any, Dict, List, Optional

from langchain_core.language_models import BaseLanguageModel
from langchain_core.prompts.base import BasePromptTemplate
from langchain_core.pydantic_v1 import Field

from langchain.callbacks.manager import CallbackManagerForChainRun
from langchain.chains.base import Chain
from langchain.chains.graph_qa.prompts import (
    SPARQL_GENERATION_SELECT_PROMPT,
    SPARQL_GENERATION_UPDATE_PROMPT,
    SPARQL_INTENT_PROMPT,
    SPARQL_QA_PROMPT,
)
from langchain.chains.llm import LLMChain
from langchain.graphs.rdf_graph import RdfGraph


class GraphSparqlQAChain(Chain):
    """Question-answering against an RDF or OWL graph by generating SPARQL statements.

    *Security note*: Make sure that the database connection uses credentials
        that are narrowly-scoped to only include necessary permissions.
        Failure to do so may result in data corruption or loss, since the calling
        code may attempt commands that would result in deletion, mutation
        of data if appropriately prompted or reading sensitive data if such
        data is present in the database.
        The best way to guard against such negative outcomes is to (as appropriate)
        limit the permissions granted to the credentials used with this tool.

        See https://python.langchain.com/docs/security for more information.
    """

    graph: RdfGraph = Field(exclude=True)
    sparql_generation_select_chain: LLMChain
    sparql_generation_update_chain: LLMChain
    sparql_intent_chain: LLMChain
    qa_chain: LLMChain
    input_key: str = "query"  #: :meta private:
    output_key: str = "result"  #: :meta private:

    @property
    def input_keys(self) -> List[str]:
        return [self.input_key]

    @property
    def output_keys(self) -> List[str]:
        _output_keys = [self.output_key]
        return _output_keys

    @classmethod
    def from_llm(
        cls,
        llm: BaseLanguageModel,
        *,
        qa_prompt: BasePromptTemplate = SPARQL_QA_PROMPT,
        sparql_select_prompt: BasePromptTemplate = SPARQL_GENERATION_SELECT_PROMPT,
        sparql_update_prompt: BasePromptTemplate = SPARQL_GENERATION_UPDATE_PROMPT,
        sparql_intent_prompt: BasePromptTemplate = SPARQL_INTENT_PROMPT,
        **kwargs: Any,
    ) -> GraphSparqlQAChain:
        """Initialize from LLM."""
        qa_chain = LLMChain(llm=llm, prompt=qa_prompt)
        sparql_generation_select_chain = LLMChain(llm=llm, prompt=sparql_select_prompt)
        sparql_generation_update_chain = LLMChain(llm=llm, prompt=sparql_update_prompt)
        sparql_intent_chain = LLMChain(llm=llm, prompt=sparql_intent_prompt)

        return cls(
            qa_chain=qa_chain,
            sparql_generation_select_chain=sparql_generation_select_chain,
            sparql_generation_update_chain=sparql_generation_update_chain,
            sparql_intent_chain=sparql_intent_chain,
            **kwargs,
        )

    def _call(
        self,
        inputs: Dict[str, Any],
        run_manager: Optional[CallbackManagerForChainRun] = None,
    ) -> Dict[str, str]:
        """
        Generate SPARQL query, use it to retrieve a response from the gdb and answer
        the question.
        """
        _run_manager = run_manager or CallbackManagerForChainRun.get_noop_manager()
        callbacks = _run_manager.get_child()
        prompt = inputs[self.input_key]

        _intent = self.sparql_intent_chain.run({"prompt": prompt}, callbacks=callbacks)
        intent = _intent.strip()

        if "SELECT" in intent and "UPDATE" not in intent:
            sparql_generation_chain = self.sparql_generation_select_chain
            intent = "SELECT"
        elif "UPDATE" in intent and "SELECT" not in intent:
            sparql_generation_chain = self.sparql_generation_update_chain
            intent = "UPDATE"
        else:
            raise ValueError(
                "I am sorry, but this prompt seems to fit none of the currently "
                "supported SPARQL query types, i.e., SELECT and UPDATE."
            )

        _run_manager.on_text("Identified intent:", end="\n", verbose=self.verbose)
        _run_manager.on_text(intent, color="green", end="\n", verbose=self.verbose)

        generated_sparql = sparql_generation_chain.run(
            {"prompt": prompt, "schema": self.graph.get_schema}, callbacks=callbacks
        )

        _run_manager.on_text("Generated SPARQL:", end="\n", verbose=self.verbose)
        _run_manager.on_text(
            generated_sparql, color="green", end="\n", verbose=self.verbose
        )

        if intent == "SELECT":
            context = self.graph.query(generated_sparql)

            _run_manager.on_text("Full Context:", end="\n", verbose=self.verbose)
            _run_manager.on_text(
                str(context), color="green", end="\n", verbose=self.verbose
            )
            result = self.qa_chain(
                {"prompt": prompt, "context": context},
                callbacks=callbacks,
            )
            res = result[self.qa_chain.output_key]
        elif intent == "UPDATE":
            self.graph.update(generated_sparql)
            res = "Successfully inserted triples into the graph."
        else:
            raise ValueError("Unsupported SPARQL query type.")
        return {self.output_key: res}