app.py

'''
   gradio_langchain.py:
   Assignment#8 - Lancgchain and gradio example
'''

import os
from typing import Optional, Tuple

import gradio as gr
from langchain.chains import ConversationChain
from langchain.llms import OpenAI
from threading import Lock

import openai

"""Logic for loading the chain you want to use should go here."""
def load_chain():
    llm = OpenAI(temperature=0)
    chain = ConversationChain(llm=llm)
    return chain

def set_openai_api_key(api_key: str):
    """Set the api key and return chain. If no api_key, then None is returned."""

    if api_key:
        os.environ["OPENAI_API_KEY"] = api_key
        chain = load_chain()
        os.environ["OPENAI_API_KEY"] = ""
        return chain

class ChatWrapper:
    """ main class to start chain, create / append history. it also acquires lock mechanism """

    def __init__(self):
        self.lock = Lock()
    def __call__(
        self, api_key: str, inp: str, history: Optional[Tuple[str, str]], chain: Optional[ConversationChain]
    ):
        """Execute the chat functionality."""
        self.lock.acquire()
        try:
            history = history or []
            # If chain is None, that is because no API key was provided.
            if chain is None:
                history.append((inp, "Please paste your OpenAI key to use"))
                return history, history
            # Set OpenAI key
            
            openai.api_key = api_key
            # Run chain and append input.
            output = chain.run(input=inp)
            history.append((inp, output))
        except Exception as e:
            raise e
        finally:
            self.lock.release()
        return history, history

chat = ChatWrapper()

block = gr.Blocks(css=".gradio-container {background-color: lightgray}")

with block:
    with gr.Row():
        gr.Markdown("<h3><center>LangChain / Gradio example </center></h3>")

        openai_api_key_textbox = gr.Textbox(
            placeholder="Paste your OpenAI API key (sk-...)",
            show_label=False,
            lines=1,
            type="password",
        )

    chatbot = gr.Chatbot()

    with gr.Row():
        message = gr.Textbox(
            label="What's your question?",
            placeholder="Please enter your question here",
            lines=1,
        )
        submit = gr.Button(value="Send", variant="secondary").style(full_width=False)

    state = gr.State()
    agent_state = gr.State()

    submit.click(chat, inputs=[openai_api_key_textbox, message, state, agent_state], outputs=[chatbot, state])
    message.submit(chat, inputs=[openai_api_key_textbox, message, state, agent_state], outputs=[chatbot, state])

    openai_api_key_textbox.change(
        set_openai_api_key,
        inputs=[openai_api_key_textbox],
        outputs=[agent_state],
    )

block.launch(debug=True)