Build RAG Chatbot with LangChain, Zilliz Cloud, Cohere Command R+, and voyage-3-lite

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.
Zilliz Cloud: a fully managed vector database-as-a-service platform built on top of the open-source Milvus, designed to handle high-performance vector data processing at scale. It enables organizations to efficiently store, search, and analyze large volumes of unstructured data, such as text, images, or audio, by leveraging advanced vector search technology. It offers a free tier supporting up to 1 million vectors.
Cohere Command R+: This model specializes in rapid retrieval and dense text understanding, prioritizing performance in search and information extraction tasks. With enhanced contextual awareness, it delivers accurate results, making it ideal for applications in customer support, content recommendation, and enterprise search solutions that demand high efficiency and relevance in responses.
Voyage-3-Lite: This model is designed for resource-constrained environments, offering a lightweight and efficient solution for various NLP tasks. It excels in applications such as chatbots, content generation, and real-time text analysis, providing quick responses while maintaining a balance between performance and computational efficiency. Ideal for developers needing high throughput with limited resources.

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 Cohere Command R+

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.chat_models import init_chat_model

llm = init_chat_model("command-r-plus", model_provider="cohere")

Step 3: Install and Set Up voyage-3-lite

pip install -qU langchain-voyageai

import getpass
import os

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

from langchain-voyageai import VoyageAIEmbeddings

embeddings = VoyageAIEmbeddings(model="voyage-3-lite")

Step 4: Install and Set Up Zilliz Cloud

pip install -qU langchain-milvus

from langchain_milvus import Zilliz

vector_store = Zilliz(
    embedding_function=embeddings,
    connection_args={
        "uri": ZILLIZ_CLOUD_URI,
        "token": ZILLIZ_CLOUD_TOKEN,
    },
)

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.

Zilliz Cloud optimization tips

Optimizing Zilliz Cloud for a RAG system involves efficient index selection, query tuning, and resource management. Use Hierarchical Navigable Small World (HNSW) indexing for high-speed, approximate nearest neighbor search while balancing recall and efficiency. Fine-tune ef_construction and M parameters based on your dataset size and query workload to optimize search accuracy and latency. Enable dynamic scaling to handle fluctuating workloads efficiently, ensuring smooth performance under varying query loads. Implement data partitioning to improve retrieval speed by grouping related data, reducing unnecessary comparisons. Regularly update and optimize embeddings to keep results relevant, particularly when dealing with evolving datasets. Use hybrid search techniques, such as combining vector and keyword search, to improve response quality. Monitor system metrics in Zilliz Cloud’s dashboard and adjust configurations accordingly to maintain low-latency, high-throughput performance.

Cohere Command R+ optimization tips

Cohere Command R+ is an advanced model optimized for retrieval-heavy workloads, making it essential to refine context selection and ranking mechanisms. Use Cohere’s reranking models to sort retrieved passages based on semantic relevance, ensuring only the most pertinent information is processed. Optimize token economy by segmenting documents into meaningful chunks and limiting unnecessary context, preventing prompt overloading. Adjust retrieval depth dynamically based on query complexity—broader searches for complex queries and narrower ones for straightforward prompts. Fine-tune temperature and sampling parameters based on use cases, with lower values ensuring more reliable, factual outputs. For high-throughput applications, implement asynchronous processing and parallel query execution to improve efficiency. Caching and pre-generating responses for frequently accessed topics can significantly reduce inference costs and improve response time. Regularly test and refine retrieval configurations based on user feedback and performance analytics to maintain high-quality outputs in RAG workflows.

voyage-3-lite optimization tips

voyage-3-lite is optimized for speed and efficiency, making it a strong choice for low-latency RAG applications. Improve retrieval by minimizing the number of retrieved documents while maintaining relevance using adaptive filtering techniques. Keep prompts concise and to the point, avoiding redundant context to reduce processing overhead. Set temperature between 0.1 and 0.2 to prioritize factual accuracy and prevent unnecessary response variation. Use caching to reduce repeated API calls for common queries. Implement response streaming to improve user experience in real-time applications. Optimize resource usage by running voyage-3-lite in high-throughput scenarios where speed is prioritized over deep reasoning, reserving larger models for more complex analysis.

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 have you learned? Wow, what an exciting journey we’ve taken through the world of Retrieval-Augmented Generation (RAG) systems! Throughout this tutorial, we’ve seamlessly connected an array of powerful components: the versatile LangChain framework, the lightning-fast Zilliz Cloud vector database, the intelligent Cohere Command R+ Language Model, and the rich embedding capabilities of voyage-3-lite. Each piece of this puzzle plays a pivotal role - the LangChain framework acts like the conductor of an orchestra, harmonizing everything to create a cohesive and efficient system.

With Zilliz Cloud, you've harnessed the capability to perform rapid searches against vast datasets, streamlining the retrieval process and supercharging response times. The Cohere Command R+ LLM has provided us with a sophisticated layer of conversational intelligence, enabling nuanced, human-like interactions. And let's not forget how the embedding model generates profound semantic representations that enrich your data, empowering your RAG system with deeper understanding and context.

Wasn't it fantastic to explore optimization tips and even utilize a free cost calculator? These tools are designed to make your development journey smoother and more informed. Now, it's your turn! Grab this knowledge and start building your own innovative RAG applications. Optimize, customize, and think outside the box! The possibilities are endless when creativity meets technology. Get started today, and let your ideas come to life!

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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