In this tutorial, we’ll demonstrate how to use Gradio to build an interactive Semantic Search and Question Answering app using Hugging Face embeddings, Upstash Vector, and LangChain. Users can enter a question, and the app will retrieve relevant information and provide an answer.

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Important Note on Python Version

Recent Python versions may cause compatibility issues with torch, a dependency for Hugging Face models. Therefore, we recommend using Python 3.9 to avoid any installation issues.

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Installation and Setup

First, we need to set up our environment and install the necessary libraries. Install the dependencies by running the following command: 
pip install gradio langchain sentence_transformers upstash-vector python-dotenv transformers langchain-community langchain-huggingface
Next, create a .env file in your project directory with the following content, replacing your_upstash_url and your_upstash_token with your actual Upstash credentials: 
UPSTASH_VECTOR_REST_URL=your_upstash_url
UPSTASH_VECTOR_REST_TOKEN=your_upstash_token
This configuration file will allow us to load the required environment variables.

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Code

We will load our environment variables, initialize the Hugging Face embeddings model, set up Upstash Vector, and configure a Hugging Face Question Answering model. 
# Import libraries
import gradio as gr
from dotenv import load_dotenv
from langchain_huggingface.embeddings import HuggingFaceEmbeddings
from langchain_community.vectorstores.upstash import UpstashVectorStore
from transformers import pipeline
from langchain.schema import Document

# Load environment variables
load_dotenv()

# Set up embeddings and Upstash Vector store
embeddings = HuggingFaceEmbeddings(model_name="sentence-transformers/all-mpnet-base-v2")
vector_store = UpstashVectorStore(embedding=embeddings)
Next, we will create sample documents, embed them using Hugging Face embeddings, and store them in Upstash Vector. 
# Sample documents to embed and store
documents = [
    Document(page_content="Global warming is causing sea levels to rise."),
    Document(page_content="AI is transforming many industries."),
    Document(page_content="Renewable energy is vital for sustainable development.")
]
vector_store.add_documents(documents=documents, batch_size=100, embedding_chunk_size=200)
When inserting documents, they are first embedded using the Embeddings object. Many embedding models, such as the Hugging Face models, support embedding multiple documents at once. This allows for efficient processing by batching documents and embedding them in parallel.
  • The embedding_chunk_size parameter controls the number of documents processed in parallel when creating embeddings.
Once the embeddings are created, they are stored in Upstash Vector. To reduce the number of HTTP requests, the vectors are also batched when they are sent to Upstash Vector.
  • The batch_size parameter controls the number of vectors included in each HTTP request when sending to Upstash Vector.
In the Upstash Vector free tier, there is a limit of 1000 vectors per batch.
Now, we can set up a Question Answering model and the Gradio interface. 
# Set up a Hugging Face Question Answering model
qa_pipeline = pipeline("question-answering", model="distilbert-base-cased-distilled-squad")

# Gradio interface function
def answer_question(query):
    # Retrieve relevant documents from Upstash Vector
    results = vector_store.similarity_search(query, k=3)
    
    # Use the most relevant document for QA
    if results:
        context = results[0].page_content
        qa_input = {"question": query, "context": context}
        answer = qa_pipeline(qa_input)["answer"]
        return f"Answer: {answer}\n\nContext: {context}"
    else:
        return "No relevant context found."

# Set up Gradio interface
iface = gr.Interface(
    fn=answer_question,
    inputs="text",
    outputs="text",
    title="RAG Application",
    description="Ask a question, and the app will retrieve relevant information and provide an answer."
)

# Launch the Gradio app
iface.launch()

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Running the App

After setting up the code, run your script to start the Gradio app. You will be presented with an interface where you can enter a question. The app will retrieve the most relevant information from the embedded documents and provide an answer based on the content.

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Notes

  • Deployment: To create a public link, set share=True in launch(). This will generate a public URL for your Gradio app. This share link expires in 72 hours. For free permanent hosting and GPU upgrades, run gradio deploy from Terminal to deploy to Hugging Face Spaces
  • Batch Processing: The batch_size and embedding_chunk_size parameters allow you to control the efficiency of document processing and storage in Upstash Vector.
  • Namespaces: Upstash Vector supports namespaces for organizing different types of documents. You can set a namespace while creating the UpstashVectorStore instance.