Langgraph使用MemorySaver建立有记忆的图

学习链接：https://langgraph.com.cn/tutorials/get-started/3-add-memory/index.html

完整实例代码：

from dotenv import load_dotenv
load_dotenv()

from typing import Annotated
from typing_extensions import TypedDict
from langchain_openai import ChatOpenAI
from langgraph.graph import StateGraph, START
from langgraph.graph.message import add_messages
from langgraph.checkpoint.memory import MemorySaver

model = ChatOpenAI(
    model="**",
    temperature=0,
    timeout=60,
    max_retries=3,
)


class State(TypedDict):
    messages: Annotated[list, add_messages]


graph_builder = StateGraph(State)


def chatbot(state: State):
    return {"messages": [model.invoke(state["messages"])]}


graph_builder.add_node("chatbot", chatbot)
graph_builder.add_edge(START, "chatbot")
memory = MemorySaver()
graph = graph_builder.compile(checkpointer=memory)

config = {"configurable": {"thread_id": "1"}}
user_input = "Hi there! My name is Will."


def stream_graph_updates(user_input: str):
    events = graph.stream(
        {"messages": [{"role": "user", "content": user_input}]},
        config,
        stream_mode="values",
    )
    for event in events:
        event["messages"][-1].pretty_print()


stream_graph_updates(user_input)


while True:
    try:
        user_input = input("User: ")
        if user_input.lower() in ["quit", "exit", "q"]:
            print("Goodbye!")
            break
        stream_graph_updates(user_input)
    except Exception:
        user_input = "What do you know about LangGraph?"
        print("User: " + user_input)
        stream_graph_updates(user_input)
        break