query.py

import gradio as gr

from langchain_astradb import AstraDBVectorStore

from langchain_core.prompts import ChatPromptTemplate
from langchain_core.output_parsers import StrOutputParser
from langchain_core.runnables import RunnablePassthrough, RunnableLambda
from langchain_core.messages import SystemMessage, AIMessage, HumanMessage
from langchain_openai import OpenAIEmbeddings, ChatOpenAI

import os

prompt_template = os.environ.get("PROMPT_TEMPLATE")

prompt = ChatPromptTemplate.from_messages([('system', prompt_template)])

AI = False

def ai_setup():
    global llm, prompt_chain
    llm = ChatOpenAI(model = "gpt-4o", temperature=0.8)
    
    if AI:
        embedding = OpenAIEmbeddings()
        vstore = AstraDBVectorStore(
            embedding=embedding,
            collection_name=os.environ.get("ASTRA_DB_COLLECTION"),
            token=os.environ.get("ASTRA_DB_APPLICATION_TOKEN"),
            api_endpoint=os.environ.get("ASTRA_DB_API_ENDPOINT"),
        )

        retriever = vstore.as_retriever(search_kwargs={'k': 10})
    else:
        retriever = RunnableLambda(just_read)

    prompt_chain = (
        {"context": retriever, "question": RunnablePassthrough()}
        | RunnableLambda(format_context) 
        | prompt
        # | llm
        # | StrOutputParser()
    )

def group_and_sort(documents):
    grouped = {}
    for document in documents:
        title = document.metadata["Title"]
        docs = grouped.get(title, [])
        grouped[title] = docs
        
        docs.append((document.page_content, document.metadata["range"]))
    
    for title, values in grouped.items():
        values.sort(key=lambda doc:doc[1][0])

    for title in grouped:
        text = ''
        prev_last = 0
        for fragment, (start, last) in grouped[title]:
            if   start < prev_last:
                text += fragment[prev_last-start:]
            elif start == prev_last:
                text += fragment
            else:
                text += ' [...] '
                text += fragment
            prev_last = last

        grouped[title] = text
                
    return grouped
        
def format_context(pipeline_state):
    """Print the state passed between Runnables in a langchain and pass it on"""

    context = ''
    documents = group_and_sort(pipeline_state["context"])
    for title, text in documents.items():
        context += f"\nTitle: {title}\n"
        context += text
        context += '\n\n---\n'

    pipeline_state["context"] = context
    return pipeline_state

def just_read(pipeline_state):
    fname = "docs.pickle"
    import pickle
    
    return pickle.load(open(fname, "rb"))

def new_state():
    return gr.State({
        "system": None,
    })

def chat(message, history, state):    
    if not history:
        system_prompt = prompt_chain.invoke(message)
        system_prompt = system_prompt.messages[0]
        state["system"] = system_prompt
    else:
        system_prompt = state["system"]
        
    messages = [system_prompt]
    for human, ai in history:
        messages.append(HumanMessage(human))
        messages.append(AIMessage(ai))
    messages.append(HumanMessage(message))
    
    all = ''
    for response in llm.stream(messages):
        all += response.content
        yield all

def gr_main():
    theme = gr.Theme.from_hub("freddyaboulton/[email protected]")
    theme.set(
        color_accent_soft="#818eb6",            # ChatBot.svelte / .message-row.panel.user-row
        background_fill_secondary="#6272a4",    # ChatBot.svelte / .message-row.panel.bot-row
        button_primary_text_color="*button_secondary_text_color",
        button_primary_background_fill="*button_secondary_background_fill")

    with gr.Blocks(
        title="Sherlock Holmes stories",
        fill_height=True,
        theme=theme
        ) as app:
            state = new_state()
            gr.ChatInterface(
                chat,
                chatbot=gr.Chatbot(show_label=False, render=False, scale=1),
                title="Sherlock Holmes stories",
                examples=[
                    ["I arrived late last night and found a dead goose in my bed"],
                    ["Help please sir. I'm about to get married, to the most lovely lady,"
                    "and I just received a letter threatening me to make public some things"
                    "of my past I'd rather keep quiet, unless I don't marry"],
                ],
            additional_inputs=[state])
    app.launch(show_api=False)
if __name__ == "__main__":
    ai_setup()
    gr_main()