app.py

import os
import streamlit as st
from langchain.chat_models import ChatOpenAI
from langchain.schema import HumanMessage
from langchain.agents import AgentType, initialize_agent, load_tools
from langchain.callbacks import StreamlitCallbackHandler
from langchain.memory import ConversationBufferMemory
from langchain.prompts import MessagesPlaceholder

st.title("Chatbot")

api_model = os.getenv("OPENAI_API_MODEL")
temperature = os.getenv("OPENAI_API_TEMPERATURE")

origin_text = st.sidebar.text_area("システムプロンプト入力")
system_prompt = origin_text if origin_text else os.getenv("system_prompt")
print(system_prompt)

def create_agent_chain():
    chat = ChatOpenAI(
            model_name = api_model,
            temperature = temperature,
            streaming = True,
    )
    
    agent_kwargs = {
        "extra_prompt_messages": [MessagesPlaceholder(variable_name = "memory")],
    }
    
    memory = ConversationBufferMemory(memory_key = "memory", return_messages = True)
    
    tools = load_tools(["ddg-search"])
    return initialize_agent(
        tools, 
        chat, 
        agent = AgentType.OPENAI_FUNCTIONS,
        agent_kwargs = agent_kwargs, 
        memory = memory, 
    )

if "messages" not in st.session_state:
    st.session_state.messages = []

if "agent_chain" not in st.session_state:
    st.session_state.agent_chain = create_agent_chain()


for message in st.session_state.messages:
    with st.chat_message(message["role"]):
        st.markdown(message["content"])

prompt = st.chat_input("What is up?")

if prompt:
    st.session_state.messages.append({"role": "user", "content": prompt})
    
    with st.chat_message("user"):
        st.markdown(prompt)
    
    with st.chat_message("assistant"):
        callback = StreamlitCallbackHandler(st.container())
        response = st.session_state.agent_chain.run(system_prompt + prompt, callbacks = [callback])
        st.markdown(response)
        
    st.session_state.messages.append({"role": "assistant", "content": response})