Build RAG Chatbot with LangChain, Milvus, Mistral AI Ministral 8B, and Cohere embed-multilingual-light-v3.0

Introduction to RAG

Retrieval-Augmented Generation (RAG) is a game-changer for GenAI applications, especially in conversational AI. It combines the power of pre-trained large language models (LLMs) like OpenAI’s GPT with external knowledge sources stored in vector databases such as Milvus and Zilliz Cloud, allowing for more accurate, contextually relevant, and up-to-date response generation. A RAG pipeline usually consists of four basic components: a vector database, an embedding model, an LLM, and a framework.

Key Components We'll Use for This RAG Chatbot

This tutorial shows you how to build a simple RAG chatbot in Python using the following components:

LangChain: An open-source framework that helps you orchestrate the interaction between LLMs, vector stores, embedding models, etc, making it easier to integrate a RAG pipeline.
Milvus: An open-source vector database optimized to store, index, and search large-scale vector embeddings efficiently, perfect for use cases like RAG, semantic search, and recommender systems. If you hate to manage your own infrastructure, we recommend using Zilliz Cloud, which is a fully managed vector database service built on Milvus and offers a free tier supporting up to 1 million vectors.
Mistral AI Ministral 8B: This model is designed for high-performance generative tasks with 8 billion parameters, offering a balance of efficiency and capability. It excels in document generation, conversational AI, and creative content production. Ideal for developers seeking a powerful yet manageable model for sophisticated language applications without the resource demands of larger architectures.
Cohere embed-multilingual-light-v3.0: This model is designed for efficient multilingual text embedding, enabling robust semantic search and similarity tasks across various languages. It excels in scenarios requiring rapid comprehension and matching of diverse linguistic datasets, making it ideal for global applications in content recommendation, categorization, and cross-language information retrieval.

By the end of this tutorial, you’ll have a functional chatbot capable of answering questions based on a custom knowledge base.

Note: Since we may use proprietary models in our tutorials, make sure you have the required API key beforehand.

Step 1: Install and Set Up LangChain

%pip install --quiet --upgrade langchain-text-splitters langchain-community langgraph

Step 2: Install and Set Up Mistral AI Ministral 8B

pip install -qU "langchain[mistralai]"

import getpass
import os

if not os.environ.get("MISTRAL_API_KEY"):
  os.environ["MISTRAL_API_KEY"] = getpass.getpass("Enter API key for Mistral AI: ")

from langchain.chat_models import init_chat_model

llm = init_chat_model("ministral-8b-latest", model_provider="mistralai")

Step 3: Install and Set Up Cohere embed-multilingual-light-v3.0

pip install -qU langchain-cohere

import getpass
import os

if not os.environ.get("COHERE_API_KEY"):
  os.environ["COHERE_API_KEY"] = getpass.getpass("Enter API key for Cohere: ")

from langchain_cohere import CohereEmbeddings

embeddings = CohereEmbeddings(model="embed-multilingual-light-v3.0")

Step 4: Install and Set Up Milvus

pip install -qU langchain-milvus

from langchain_milvus import Milvus

vector_store = Milvus(embedding_function=embeddings)

Step 5: Build a RAG Chatbot

Now that you’ve set up all components, let’s start to build a simple chatbot. We’ll use the Milvus introduction doc as a private knowledge base. You can replace it with your own dataset to customize your RAG chatbot.

import bs4
from langchain import hub
from langchain_community.document_loaders import WebBaseLoader
from langchain_core.documents import Document
from langchain_text_splitters import RecursiveCharacterTextSplitter
from langgraph.graph import START, StateGraph
from typing_extensions import List, TypedDict

# Load and chunk contents of the blog
loader = WebBaseLoader(
    web_paths=("https://milvus.io/docs/overview.md",),
    bs_kwargs=dict(
        parse_only=bs4.SoupStrainer(
            class_=("doc-style doc-post-content")
        )
    ),
)

docs = loader.load()

text_splitter = RecursiveCharacterTextSplitter(chunk_size=1000, chunk_overlap=200)
all_splits = text_splitter.split_documents(docs)

# Index chunks
_ = vector_store.add_documents(documents=all_splits)

# Define prompt for question-answering
prompt = hub.pull("rlm/rag-prompt")


# Define state for application
class State(TypedDict):
    question: str
    context: List[Document]
    answer: str


# Define application steps
def retrieve(state: State):
    retrieved_docs = vector_store.similarity_search(state["question"])
    return {"context": retrieved_docs}


def generate(state: State):
    docs_content = "\n\n".join(doc.page_content for doc in state["context"])
    messages = prompt.invoke({"question": state["question"], "context": docs_content})
    response = llm.invoke(messages)
    return {"answer": response.content}


# Compile application and test
graph_builder = StateGraph(State).add_sequence([retrieve, generate])
graph_builder.add_edge(START, "retrieve")
graph = graph_builder.compile()

Test the Chatbot

Yeah! You've built your own chatbot. Let's ask the chatbot a question.

response = graph.invoke({"question": "What data types does Milvus support?"})
print(response["answer"])

Example Output

Milvus supports various data types including sparse vectors, binary vectors, JSON, and arrays. Additionally, it handles common numerical and character types, making it versatile for different data modeling needs. This allows users to manage unstructured or multi-modal data efficiently.

Optimization Tips

As you build your RAG system, optimization is key to ensuring peak performance and efficiency. While setting up the components is an essential first step, fine-tuning each one will help you create a solution that works even better and scales seamlessly. In this section, we’ll share some practical tips for optimizing all these components, giving you the edge to build smarter, faster, and more responsive RAG applications.

LangChain optimization tips

To optimize LangChain, focus on minimizing redundant operations in your workflow by structuring your chains and agents efficiently. Use caching to avoid repeated computations, speeding up your system, and experiment with modular design to ensure that components like models or databases can be easily swapped out. This will provide both flexibility and efficiency, allowing you to quickly scale your system without unnecessary delays or complications.

Milvus optimization tips

Milvus serves as a highly efficient vector database, critical for retrieval tasks in a RAG system. To optimize its performance, ensure that indexes are properly built to balance speed and accuracy; consider utilizing HNSW (Hierarchical Navigable Small World) for efficient nearest neighbor search where response time is crucial. Partitioning data based on usage patterns can enhance query performance and reduce load times, enabling better scalability. Regularly monitor and adjust cache settings based on query frequency to avoid latency during data retrieval. Employ batch processing for vector insertions, which can minimize database lock contention and enhance overall throughput. Additionally, fine-tune the model parameters by experimenting with the dimensionality of the vectors; higher dimensions can improve retrieval accuracy but may increase search time, necessitating a balance tailored to your specific use case and hardware infrastructure.

Mistral AI Ministral 8B optimization tips

Ministral 8B provides a balance between efficiency and reasoning power, making it a good mid-range choice for RAG applications. Optimize retrieval by leveraging hybrid search (combining vector and keyword search) to improve accuracy. Use prompt engineering techniques, such as structured input formatting and logical ordering of context, to enhance response quality. Adjust temperature (0.1–0.3) and top-k values to balance factual accuracy with creative flexibility. Implement response caching for commonly accessed queries to improve latency. If deploying at scale, use model parallelism to distribute workloads efficiently across multiple GPUs or nodes. Optimize memory management by using half-precision (FP16) or quantized models to improve throughput. Fine-tune retrieval granularity, ensuring that only the most relevant and concise context is included in each query.

Cohere embed-multilingual-light-v3.0 optimization tips

Cohere embed-multilingual-light-v3.0 is optimized for faster and more efficient multilingual embeddings. Reduce input data size by filtering out non-essential elements and focusing on key phrases or terms that provide the most value in cross-lingual search scenarios. Implement approximate nearest neighbor search methods, such as FAISS, to ensure that retrieval remains fast and accurate even in large datasets. Use vector compression techniques to save on storage space while maintaining retrieval quality. Employ caching strategies to store commonly used embeddings and reduce unnecessary recomputation. Optimize search performance by organizing embeddings into a hierarchical structure based on languages or topics, enabling quicker retrieval from specific language groups.

By implementing these tips across your components, you'll be able to enhance the performance and functionality of your RAG system, ensuring it’s optimized for both speed and accuracy. Keep testing, iterating, and refining your setup to stay ahead in the ever-evolving world of AI development.

RAG Cost Calculator: A Free Tool to Calculate Your Cost in Seconds

Estimating the cost of a Retrieval-Augmented Generation (RAG) pipeline involves analyzing expenses across vector storage, compute resources, and API usage. Key cost drivers include vector database queries, embedding generation, and LLM inference.

RAG Cost Calculator is a free tool that quickly estimates the cost of building a RAG pipeline, including chunking, embedding, vector storage/search, and LLM generation. It also helps you identify cost-saving opportunities and achieve up to 10x cost reduction on vector databases with the serverless option.

Calculate your RAG cost now.

Calculate your RAG cost

What Have You Learned?

What a journey we've been on together! You've now mastered the integration of an incredible framework, a powerful vector database, a cutting-edge language model, and an innovative embedding model to create your very own Retrieval-Augmented Generation (RAG) system. Each component plays a vital role: the framework seamlessly ties everything together, ensuring that all elements communicate harmoniously; the Milvus vector database accelerates your searches, allowing you to retrieve information in the blink of an eye; the Mistral AI Ministral 8B LLM adds layers of conversational intelligence, making interactions feel natural and engaging; and the Cohere embed-multilingual-light-v3.0 embedding model crafts rich semantic representations, enabling nuanced understanding of the data you work with.

In this tutorial, we didn’t just scratch the surface; we also explored optimization tips that can enhance performance and introduced a free cost calculator to help you manage and budget your RAG applications effectively. With this knowledge under your belt, the possibilities are endless!

Now it’s your turn! Dive in, experiment, and let your creativity guide you as you start building, optimizing, and innovating your own RAG applications. Don’t just wait for the future to happen—be the one who creates it! The world is eager to see what you’ll accomplish. Let’s get building together!

Further Resources

🌟 In addition to this RAG tutorial, unleash your full potential with these incredible resources to level up your RAG skills.

How to Build a Multimodal RAG | Documentation
How to Enhance the Performance of Your RAG Pipeline
Graph RAG with Milvus | Documentation
How to Evaluate RAG Applications - Zilliz Learn
Generative AI Resource Hub | Zilliz

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