app.py

from langchain.agents import initialize_agent, Tool
from langchain.embeddings.openai import OpenAIEmbeddings
from langchain.agents import AgentType
from langchain.tools import BaseTool
from langchain.llms import OpenAI
from langchain import SerpAPIWrapper, LLMChain
from langchain.chains import RetrievalQA
from langchain.chat_models import ChatOpenAI
from langchain.agents import ZeroShotAgent, Tool, AgentExecutor
from langchain.memory import ConversationBufferMemory, ReadOnlySharedMemory
from langchain.document_loaders import TextLoader, DirectoryLoader
from langchain.vectorstores import Chroma
import os
import arxiv
import chainlit as cl
from chainlit import user_session

@cl.langchain_factory(use_async=True)
async def init():
    # Set the OpenAI Embeddings model
    embeddings = embeddings = OpenAIEmbeddings()

    # Set the persist directory
    persist_directory = "vector_db"

    # Load the persisted Chroma vector store
    vectordb = Chroma(persist_directory=persist_directory, embedding_function=embeddings)

    # Create a chain that uses the Chroma vector store
    alice_qa = RetrievalQA.from_chain_type(
        ChatOpenAI(
            model_name="gpt-3.5-turbo-16k",
            temperature=0,
        ),
        chain_type="stuff",
        retriever=vectordb.as_retriever(),
    )
    
    search = SerpAPIWrapper()

    memory = ConversationBufferMemory(memory_key="chat_history")
    readonlymemory = ReadOnlySharedMemory(memory=memory)
    
    tools = [
        Tool(
            name = "Alice in Wonderland QA System",
            func=alice_qa.run,
            description="useful for when you need to answer questions about Alice in Wonderland. Input should be a fully formed question."
        )
    ]

    prefix = """Have a conversation with a human, answering the following questions as best you can. You have access to the following tools:"""
    suffix = """Begin!"
    
    {chat_history}
    Question: {input}
    {agent_scratchpad}"""
    
    prompt = ZeroShotAgent.create_prompt(
        tools, 
        prefix=prefix, 
        suffix=suffix, 
        input_variables=["input", "chat_history", "agent_scratchpad"]
    )

    llm_chain = LLMChain(
        llm=ChatOpenAI(
            model_name="gpt-3.5-turbo-16k",
            temperature=0,
        ), 
        prompt=prompt
    )

    agent = ZeroShotAgent(llm_chain=llm_chain, tools=tools, verbose=True)
    agent_chain = AgentExecutor.from_agent_and_tools(agent=agent, tools=tools, verbose=True, memory=memory)

    # Let the user know that the system is ready
    await cl.Message(
        content=f"You can begin by asking any questions about Alice in Wonderland!"
    ).send()

    return agent_chain

@cl.langchain_run
async def run(agent, input_str):
    res = await cl.make_async(agent)(input_str, callbacks=[cl.LangchainCallbackHandler()])
    print(res)
    await cl.Message(content=res["output"]).send()