app.py

import streamlit as st
from langchain_groq import ChatGroq
from langchain_community.utilities import ArxivAPIWrapper, WikipediaAPIWrapper
from langchain_community.tools import ArxivQueryRun, WikipediaQueryRun, DuckDuckGoSearchRun
from langchain.agents import initialize_agent, AgentType
from langchain.callbacks import StreamlitCallbackHandler
import os
from dotenv import load_dotenv

# Load environment variables
load_dotenv()

## Arxiv and Wikipedia Tools
arxiv_wrapper = ArxivAPIWrapper(top_k_results=1, doc_content_chars_max=200)
arxiv = ArxivQueryRun(api_wrapper=arxiv_wrapper)

wiki_wrapper = WikipediaAPIWrapper(top_k_results=1, doc_content_chars_max=200)
wiki = WikipediaQueryRun(api_wrapper=wiki_wrapper)

search = DuckDuckGoSearchRun(name="Search")

# Streamlit UI
st.title("🔎 LangChain - Chat with search")
st.markdown("""
In this example, we're using `StreamlitCallbackHandler` to display the thoughts and actions of an agent in an interactive Streamlit app.
Try more LangChain 🤝 Streamlit Agent examples at [github.com/langchain-ai/streamlit-agent](https://github.com/langchain-ai/streamlit-agent).
""")

# Sidebar for settings
st.sidebar.title("Settings")
api_key = st.sidebar.text_input("Enter your Groq API Key:", type="password")

# Initialize session state for messages if not already
if "messages" not in st.session_state:
    st.session_state["messages"] = [
        {"role": "assistant", "content": "Hi, I'm a chatbot who can search the web. How can I help you?"}
    ]

# Display previous chat messages
for msg in st.session_state.messages:
    st.chat_message(msg["role"]).write(msg["content"])

# Capture user input from chat
if prompt := st.chat_input(placeholder="What is machine learning?"):
    st.session_state.messages.append({"role": "user", "content": prompt})
    st.chat_message("user").write(prompt)

    # Initialize the language model
    if api_key:  # Ensure API key is entered
        llm = ChatGroq(groq_api_key=api_key, model_name="Llama3-8b-8192", streaming=True)
        tools = [search, arxiv, wiki]

        # Initialize the search agent with tools and the language model
        search_agent = initialize_agent(
            tools,
            llm,
            agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION,
            handle_parsing_errors=True  # Enable error handling for parsing issues
        )

        with st.chat_message("assistant"):
            st_cb = StreamlitCallbackHandler(st.container(), expand_new_thoughts=False)
            
            try:
                # Try running the agent
                response = search_agent.run(st.session_state.messages, callbacks=[st_cb])
                st.session_state.messages.append({'role': 'assistant', "content": response})
                st.write(response)
            
            except ValueError as e:
                # Catch and display output parsing errors
                st.error(f"An error occurred while parsing the LLM's output: {str(e)}")
                st.session_state.messages.append({'role': 'assistant', "content": "Sorry, I encountered an error processing your request."})
                st.write("Sorry, I encountered an error processing your request.")
    else:
        st.error("Please enter your Groq API Key in the settings.")