mirror of
https://github.com/hwchase17/langchain
synced 2024-10-31 15:20:26 +00:00
e4b38e2822
Update Neo4j Cypher templates to use function callback to pass context instead of passing it in user prompt. Co-authored-by: Erick Friis <erick@langchain.dev>
119 lines
3.2 KiB
Python
119 lines
3.2 KiB
Python
from typing import List, Union
|
|
|
|
from langchain.chains.graph_qa.cypher_utils import CypherQueryCorrector, Schema
|
|
from langchain_community.graphs import Neo4jGraph
|
|
from langchain_core.messages import (
|
|
AIMessage,
|
|
SystemMessage,
|
|
ToolMessage,
|
|
)
|
|
from langchain_core.output_parsers import StrOutputParser
|
|
from langchain_core.prompts import (
|
|
ChatPromptTemplate,
|
|
HumanMessagePromptTemplate,
|
|
MessagesPlaceholder,
|
|
)
|
|
from langchain_core.pydantic_v1 import BaseModel
|
|
from langchain_core.runnables import RunnablePassthrough
|
|
from langchain_openai import ChatOpenAI
|
|
|
|
# Connection to Neo4j
|
|
graph = Neo4jGraph()
|
|
|
|
# Cypher validation tool for relationship directions
|
|
corrector_schema = [
|
|
Schema(el["start"], el["type"], el["end"])
|
|
for el in graph.structured_schema.get("relationships")
|
|
]
|
|
cypher_validation = CypherQueryCorrector(corrector_schema)
|
|
|
|
# LLMs
|
|
cypher_llm = ChatOpenAI(model="gpt-4", temperature=0.0)
|
|
qa_llm = ChatOpenAI(model="gpt-3.5-turbo", temperature=0.0)
|
|
|
|
# Generate Cypher statement based on natural language input
|
|
cypher_template = """Based on the Neo4j graph schema below, write a Cypher query that would answer the user's question:
|
|
{schema}
|
|
|
|
Question: {question}
|
|
Cypher query:""" # noqa: E501
|
|
|
|
cypher_prompt = ChatPromptTemplate.from_messages(
|
|
[
|
|
(
|
|
"system",
|
|
"Given an input question, convert it to a Cypher query. No pre-amble.",
|
|
),
|
|
("human", cypher_template),
|
|
]
|
|
)
|
|
|
|
cypher_response = (
|
|
RunnablePassthrough.assign(
|
|
schema=lambda _: graph.get_schema,
|
|
)
|
|
| cypher_prompt
|
|
| cypher_llm.bind(stop=["\nCypherResult:"])
|
|
| StrOutputParser()
|
|
)
|
|
|
|
response_system = """You are an assistant that helps to form nice and human
|
|
understandable answers based on the provided information from tools.
|
|
Do not add any other information that wasn't present in the tools, and use
|
|
very concise style in interpreting results!
|
|
"""
|
|
|
|
response_prompt = ChatPromptTemplate.from_messages(
|
|
[
|
|
SystemMessage(content=response_system),
|
|
HumanMessagePromptTemplate.from_template("{question}"),
|
|
MessagesPlaceholder(variable_name="function_response"),
|
|
]
|
|
)
|
|
|
|
|
|
def get_function_response(
|
|
query: str, question: str
|
|
) -> List[Union[AIMessage, ToolMessage]]:
|
|
context = graph.query(cypher_validation(query))
|
|
TOOL_ID = "call_H7fABDuzEau48T10Qn0Lsh0D"
|
|
messages = [
|
|
AIMessage(
|
|
content="",
|
|
additional_kwargs={
|
|
"tool_calls": [
|
|
{
|
|
"id": TOOL_ID,
|
|
"function": {
|
|
"arguments": '{"question":"' + question + '"}',
|
|
"name": "GetInformation",
|
|
},
|
|
"type": "function",
|
|
}
|
|
]
|
|
},
|
|
),
|
|
ToolMessage(content=str(context), tool_call_id=TOOL_ID),
|
|
]
|
|
return messages
|
|
|
|
|
|
chain = (
|
|
RunnablePassthrough.assign(query=cypher_response)
|
|
| RunnablePassthrough.assign(
|
|
function_response=lambda x: get_function_response(x["query"], x["question"])
|
|
)
|
|
| response_prompt
|
|
| qa_llm
|
|
| StrOutputParser()
|
|
)
|
|
|
|
# Add typing for input
|
|
|
|
|
|
class Question(BaseModel):
|
|
question: str
|
|
|
|
|
|
chain = chain.with_types(input_type=Question)
|