localGPT_UI.py

import torch
import subprocess
import streamlit as st
from run_localGPT import load_model
from langchain.vectorstores import Chroma
from constants import CHROMA_SETTINGS, EMBEDDING_MODEL_NAME, PERSIST_DIRECTORY, MODEL_ID, MODEL_BASENAME
from langchain.embeddings import HuggingFaceInstructEmbeddings
from langchain.chains import RetrievalQA
from streamlit_extras.add_vertical_space import add_vertical_space
from langchain.prompts import PromptTemplate
from langchain.memory import ConversationBufferMemory



def model_memory():
    # Adding history to the model.
    template = """Use the following pieces of context to answer the question at the end. If you don't know the answer,\
    just say that you don't know, don't try to make up an answer.

    {context}

    {history}
    Question: {question}
    Helpful Answer:"""

    prompt = PromptTemplate(input_variables=["history", "context", "question"], template=template)
    memory = ConversationBufferMemory(input_key="question", memory_key="history")

    return prompt, memory

# Sidebar contents
with st.sidebar:
    st.title('🤗💬 Converse with your Data')
    st.markdown('''
    ## About
    This app is an LLM-powered chatbot built using:
    - [Streamlit](https://streamlit.io/)
    - [LangChain](https://python.langchain.com/)
    - [LocalGPT](https://github.com/PromtEngineer/localGPT) 
 
    ''')
    add_vertical_space(5)
    st.write('Made with ❤️ by [Prompt Engineer](https://youtube.com/@engineerprompt)')


DEVICE_TYPE = "cuda" if torch.cuda.is_available() else "cpu"



if "result" not in st.session_state:
    # Run the document ingestion process. 
    run_langest_commands = ["python", "ingest.py"]
    run_langest_commands.append("--device_type")
    run_langest_commands.append(DEVICE_TYPE)

    result = subprocess.run(run_langest_commands, capture_output=True)
    st.session_state.result = result

# Define the retreiver
# load the vectorstore
if "EMBEDDINGS" not in st.session_state:
    EMBEDDINGS = HuggingFaceInstructEmbeddings(model_name=EMBEDDING_MODEL_NAME, model_kwargs={"device": DEVICE_TYPE})
    st.session_state.EMBEDDINGS = EMBEDDINGS

if "DB" not in st.session_state:
    DB = Chroma(
        persist_directory=PERSIST_DIRECTORY,
        embedding_function=st.session_state.EMBEDDINGS,
        client_settings=CHROMA_SETTINGS,
    )
    st.session_state.DB = DB

if "RETRIEVER" not in st.session_state:
    RETRIEVER = DB.as_retriever()
    st.session_state.RETRIEVER = RETRIEVER

if "LLM" not in st.session_state:
    LLM = load_model(device_type=DEVICE_TYPE, model_id=MODEL_ID, model_basename=MODEL_BASENAME)
    st.session_state["LLM"] = LLM




if "QA" not in st.session_state:

    prompt, memory = model_memory()

    QA = RetrievalQA.from_chain_type(
        llm=LLM, 
        chain_type="stuff", 
        retriever=RETRIEVER, 
        return_source_documents=True,
        chain_type_kwargs={"prompt": prompt, "memory": memory},
    )
    st.session_state["QA"] = QA

st.title('LocalGPT App 💬')
    # Create a text input box for the user
prompt = st.text_input('Input your prompt here')
# while True:

    # If the user hits enter
if prompt:
    # Then pass the prompt to the LLM
    response = st.session_state["QA"](prompt)
    answer, docs = response["result"], response["source_documents"]
    # ...and write it out to the screen
    st.write(answer)

    # With a streamlit expander  
    with st.expander('Document Similarity Search'):
        # Find the relevant pages
        search = st.session_state.DB.similarity_search_with_score(prompt) 
        # Write out the first
        for i, doc in enumerate(search): 
            # print(doc)
            st.write(f"Source Document # {i+1} : {doc[0].metadata['source'].split('/')[-1]}")
            st.write(doc[0].page_content) 
            st.write("--------------------------------")