app.py

from langchain_openai import ChatOpenAI
from langchain_core.prompts import ChatPromptTemplate
from langchain_core.output_parsers import StrOutputParser
from langchain_community.llms import Ollama
import streamlit as st
import os
from dotenv import load_dotenv

# Load environment variables
load_dotenv()

# Set environment variables
os.environ["LANGCHAIN_TRACING_V2"] = "true"
os.environ["LANGCHAIN_API_KEY"] = os.getenv("LANGCHAIN_API_KEY")

# Prompt Template
prompt = ChatPromptTemplate.from_messages(
    [
        ("system", "You are a helpful assistant. Please respond to the user queries"),
        ("user", "Question: {question}")
    ]
)

# Streamlit app
st.title('Langchain Demo With Ollama Llama2 API')
input_text = st.text_input("Search the topic you want")

# Ollama LLama2 LLM with remote or local settings
# Ensure the model points to a valid URL if not running locally
llm = Ollama(
    model="llama2",
    server_url=os.getenv("OLLAMA_SERVER_URL", "http://localhost:11434")  # Add server URL to env
)
output_parser = StrOutputParser()
chain = prompt | llm | output_parser

# Display result when user inputs text
if input_text:
    try:
        response = chain.invoke({"question": input_text})
        st.write(response)
    except Exception as e:
        st.error(f"Error: {e}")