LangGraph +
RAG総合演習

from typing import TypedDict class SimpleState(TypedDict): question: str # ユーザーの質問 answer: str # AIの回答

def log_node(state: SimpleState) -> dict: print(f"受け取った質問: {state['question']}") return {} def answer_node(state: SimpleState) -> dict: response = model.invoke(state["question"]) return {"answer": response.content}

from langgraph.graph import StateGraph, END graph = StateGraph(SimpleState) graph.add_node("log", log_node) graph.add_node("answer", answer_node) graph.set_entry_point("log") graph.add_edge("log", "answer") graph.add_edge("answer", END) app = graph.compile()

result = app.invoke({ "question": "LangGraphとは何ですか？", "answer": "" }) print(f"回答: {result['answer']}")

# --- 準備 --- model = ChatOpenAI(model="gpt-4o-mini", temperature=0) embeddings = OpenAIEmbeddings(model="text-embedding-3-small") loader = PyPDFLoader("data/sample.pdf") pages = loader.load() splitter = RecursiveCharacterTextSplitter(chunk_size=500, chunk_overlap=50) chunks = splitter.split_documents(pages) vectorstore = FAISS.from_documents(chunks, embeddings) retriever = vectorstore.as_retriever(search_kwargs={"k": 3}) # --- State --- class RAGState(TypedDict): question: str documents: List[str] answer: str # --- Node --- def retrieve_node(state): docs = retriever.invoke(state["question"]) return {"documents": [doc.page_content for doc in docs]} def generate_node(state): context = "\n\n".join(state["documents"]) prompt = ChatPromptTemplate.from_messages([ ("system", "以下の文書を参考に質問に回答してください。\n\n{context}"), ("human", "{question}") ]) chain = prompt | model | StrOutputParser() return {"answer": chain.invoke({"context": context, "question": state["question"]})} # --- Graph --- graph = StateGraph(RAGState) graph.add_node("retrieve", retrieve_node) graph.add_node("generate", generate_node) graph.set_entry_point("retrieve") graph.add_edge("retrieve", "generate") graph.add_edge("generate", END) app = graph.compile()

# 期待される出力 質問: PCが起動しない場合の対処手順を教えてください 回答: PCが起動しない場合の対処手順は以下の通りです。 1. 電源ケーブルが正しく接続されているか確認する。 2. 電源ボタンを10秒間長押しして強制シャットダウン...