app.py

import logging

from langchain import PromptTemplate, LLMChain
from langchain.chains.question_answering import load_qa_chain
from langchain.vectorstores import FAISS
from langchain.embeddings import HuggingFaceEmbeddings
from langchain.chat_models import ChatOpenAI
import gradio as gr
import json

from prompts import PROMPT_EXTRACT_DATE, PROMPT_FED_ANALYST
from filterminutes import search_with_filter

# --------------------------Load the sentence transformer and the vector store--------------------------#
model_name = 'sentence-transformers/all-mpnet-base-v2'
model_kwargs = {'device': 'cpu'}
encode_kwargs = {'normalize_embeddings': False}
embeddings = HuggingFaceEmbeddings(model_name=model_name, model_kwargs=model_kwargs, encode_kwargs=encode_kwargs)
vs = FAISS.load_local("MINUTES_FOMC_HISTORY", embeddings)

# --------------------------Import the prompts------------------#
PROMPT_DATE = PromptTemplate.from_template(PROMPT_EXTRACT_DATE)
PROMPT_ANALYST = PromptTemplate.from_template(PROMPT_FED_ANALYST)


# --------------------------define the qa chain for answering queries--------------------------#
def load_chains(open_ai_key):
    date_extractor = LLMChain(llm=ChatOpenAI(temperature=0, model_name='gpt-3.5-turbo', openai_api_key=open_ai_key),
                              prompt=PROMPT_DATE)
    fed_chain = load_qa_chain(llm=ChatOpenAI(model_name='gpt-3.5-turbo', temperature=0, openai_api_key=open_ai_key),
                              chain_type='stuff', prompt=PROMPT_ANALYST)
    return date_extractor, fed_chain


def get_chain(query, api_key):
    """
    Detects the date, computes similarity, and answers the query using
    only documents corresponding to the date requested.
    The query is first passed to the date extractor to extract the date
    and then to the qa chain to answer the query.
    Parameters
    ----------
    query : str
        Query to be answered.
    api_key : str
        OpenAI API key.

    Returns
        Answer to the query.
    """
    date_extractor, fed_chain = load_chains(api_key)
    logging.info('Extracting the date in numeric format..')
    date_response = date_extractor.run(query)
    if date_response != 'False':
        filter_date = json.loads(date_response)

        logging.info(f'Date parameters retrieved: {filter_date}')
        logging.info('Running the qa with filtered context..')
        filtered_context = search_with_filter(vs, query, init_k=200, step=300, target_k=7, filter_dict=filter_date)

        logging.info(20 * '-' + 'Metadata for the documents to be used' + 20 * '-')
        for doc in filtered_context:
            logging.info(doc.metadata)
    else:
        logging.info('No date elements found. Running the qa without filtering can output incorrect results.')
        filtered_context = vs.similarity_search(query, k=7)
    return fed_chain({'input_documents': filtered_context[:7], 'question': query})['output_text']


if __name__ == '__main__':
    app = gr.Interface(fn=get_chain,
                        inputs=[gr.Textbox(lines=2, placeholder="Enter your query", label='Your query'),
                                gr.Textbox(lines=1, placeholder="Your OpenAI API key here", label='OpenAI Key')],
                        description='Query the public database in FRED from 1936-2023',
                        outputs=gr.Textbox(lines=1,  label='Answer'),
                        title='Chat with the FOMC meeting minutes',
                        examples=[['What was the economic outlook from the staff presented in the meeting '
                                   'of April 2009 with respect to labour market developments and industrial production?'],
                                   ['Who were the voting members present in the meeting on March 2010?'],
                                   ['How important was the pandemic of Covid-19 in the discussions during 2020?'],
                                   ['What was the impact of the oil crisis for the economic outlook during 1973?']],
                        )
    app.launch()