0Pricing
LangChain / RAG / Vector DBs · Aula

Integrando todos os componentes do RAG

Reúna carregadores de documentos, embeddings, armazenamentos vetoriais e LLMs em uma aplicação RAG coesa com LangChain.

Integrando todos os componentes do RAG é uma aula grátis de LangChain / RAG / Vector DBs no CoddyKit. Esta é a aula 1 de 4. Você pode ler a aula completa abaixo gratuitamente — depois pratica ao vivo no navegador com um editor de código integrado e um tutor de IA 24/7. Faz parte do caminho de aprendizado de LangChain / RAG / Vector DBs, e seu progresso é sincronizado entre a web e o app CoddyKit. O curso de LangChain / RAG / Vector DBs inclui 4 aulas no total.

Partes desta aula ainda não foram traduzidas e aparecem em inglês.

Welcome to RAG Integration

Welcome to this lesson on integrating all the components of a Retrieval Augmented Generation (RAG) system using LangChain!

So far, you've learned about individual pieces: document loaders, text splitters, embedding models, vector stores, LLMs, and prompts. Now, it's time to bring them all together.

The RAG Pipeline Flow

A RAG application follows a clear pipeline to answer questions using external knowledge. It generally involves these steps:

  • Load: Ingest data from various sources.
  • Split: Break documents into manageable chunks.
  • Embed: Convert text chunks into numerical vectors.
  • Store: Save these vectors in a searchable database.
  • Retrieve: Find relevant chunks based on a user query.
  • Generate: Use an LLM to answer the query, referencing the retrieved context.

Essential LangChain Imports

To build our RAG application, we'll need several key classes from LangChain. These help us manage documents, create embeddings, interact with vector stores, and connect to LLMs.

We'll use components like Chroma for the vector store, OllamaEmbeddings and ChatOllama for local models, and core LangChain Expression Language (LCEL) tools.

Preparing Documents for RAG

The first step in any RAG system is preparing your knowledge base. This involves loading your data and then splitting it into smaller, manageable chunks.

  • Loading: Fetching content from files, databases, or web pages.
  • Splitting: Breaking large texts into smaller, semantically coherent pieces to fit LLM context windows and improve retrieval accuracy.

For our runnable example, we'll use simple in-memory Document objects for quick setup.

Embedding & Vector Store Setup

Once documents are split, they need to be converted into numerical representations called embeddings. These embeddings capture the semantic meaning of the text.

The embeddings are then stored in a vector store (like Chroma), which is specialized for efficient similarity search. This allows us to quickly find document chunks related to a user's query.

Setting Up the LLM & Retriever

The next crucial steps are setting up our Large Language Model (LLM) and preparing the retriever:

  • LLM: We'll initialize an LLM (e.g., ChatOllama) that will take the retrieved context and user question to generate an answer.
  • Retriever: Our vector store is converted into a retriever. This component's job is to take the user's query, embed it, search the vector store, and return the most relevant document chunks.

Crafting the Prompt Template

A well-designed prompt template is key to guiding the LLM to generate accurate and relevant answers. It instructs the LLM on how to use the provided context.

Our template will clearly define placeholders for the context (retrieved documents) and the user's question, ensuring the LLM focuses on the provided information.

LangChain Expression Language

LangChain Expression Language (LCEL) is a powerful way to compose complex chains from simple components. It uses the | operator to chain runnables together.

  • RunnableParallel: Allows multiple branches to run concurrently, useful for fetching context and passing the question.
  • RunnablePassthrough: Passes its input through, often used to keep the original question available in a parallel branch.

LCEL makes our RAG pipeline flexible and modular.

Assembling the RAG Chain

Now, let's put it all together. The RAG chain conceptually flows like this:

  1. The user's question enters the chain.
  2. RunnableParallel sends the question to two places: to the retriever (to get context) and also passes the original question directly.
  3. The retrieved context and the original question are then fed into the prompt template.
  4. The filled prompt goes to the LLM for generation.
  5. Finally, an StrOutputParser extracts the plain text answer from the LLM's response.

Complete RAG Application Example

Try running this complete LangChain RAG application. Make sure you have Ollama installed and models like nomic-embed-text and llama2 pulled (e.g., ollama pull nomic-embed-text).

from langchain_community.vectorstores import Chroma
from langchain_community.embeddings import OllamaEmbeddings
from langchain_community.chat_models import ChatOllama
from langchain_core.prompts import ChatPromptTemplate
from langchain_core.runnables import RunnablePassthrough, RunnableParallel
from langchain_core.output_parsers import StrOutputParser
from langchain_core.documents import Document

# 1. Prepare Documents (simple in-memory for runnable example)
documents = [
    Document(page_content="LangChain is a framework for developing applications powered by large language models."),
    Document(page_content="It simplifies the process of building complex LLM workflows."),
    Document(page_content="Retrieval Augmented Generation (RAG) combines LLMs with external data retrieval."),
    Document(page_content="Ollama allows running open-source LLMs locally.")
]

# 2. Generate Embeddings and Store in Vector DB
embeddings = OllamaEmbeddings(model="nomic-embed-text")
vectorstore = Chroma.from_documents(documents=documents, embedding=embeddings)
retriever = vectorstore.as_retriever()

# 3. Initialize LLM
llm = ChatOllama(model="llama2")

# 4. Define Prompt Template
prompt = ChatPromptTemplate.from_template("""
Answer the question based ONLY on the following context:
{context}

Question: {question}
""")

# 5. Assemble the RAG Chain
rag_chain = (
    RunnableParallel({"context": retriever, "question": RunnablePassthrough()})
    | prompt
    | llm
    | StrOutputParser()
)

# 6. Invoke the Chain with a question
question = "What is LangChain?"
print(f"Question: {question}")
response = rag_chain.invoke(question)
print(f"Answer: {response}")

question_2 = "What is RAG?"
print(f"\nQuestion: {question_2}")
response_2 = rag_chain.invoke(question_2)
print(f"Answer: {response_2}")

RAG Pipeline Component Check

Which of the following components are typically part of a LangChain RAG pipeline for answering user questions?

RAG Integration Recap

Fantastic work! You've successfully learned how to integrate all the core components into a cohesive LangChain RAG application.

  • We walked through the full RAG pipeline from loading documents to generating answers.
  • You saw how LangChain's modular components and LCEL allow for flexible and powerful chain construction.
  • You now have a runnable example demonstrating a complete RAG system.

Next, we'll explore how to query your RAG system effectively and generate high-quality answers.

Perguntas Frequentes

A aula “Integrando todos os componentes do RAG” é grátis?

Sim — o texto completo de “Integrando todos os componentes do RAG” é grátis para ler aqui na web. Para praticá-la interativamente (um editor de código integrado e um tutor de IA 24/7) e desbloquear o restante do curso de LangChain / RAG / Vector DBs, atualize para CoddyKit PRO. O curso de LangChain / RAG / Vector DBs inclui 4 aulas no total.

O que vou aprender em “Integrando todos os componentes do RAG”?

Reúna carregadores de documentos, embeddings, armazenamentos vetoriais e LLMs em uma aplicação RAG coesa com LangChain. Você pratica LangChain / RAG / Vector DBs com código prático que executa diretamente no navegador, e um tutor de IA 24/7 responde suas dúvidas enquanto trabalha na aula.

Preciso ter experiência prévia para começar LangChain / RAG / Vector DBs?

Nenhuma experiência prévia é necessária. LangChain / RAG / Vector DBs no CoddyKit é estruturado para alunos iniciantes até avançados, então você pode começar aqui ou desde o início e aprender no seu ritmo. Esta é a aula 1 de 4.

Quanto tempo leva a aula “Integrando todos os componentes do RAG”?

A maioria das aulas CoddyKit leva cerca de 5–10 minutos. Cada uma é compacta e interativa, então você faz progresso constante e retoma exatamente de onde parou entre web e app.

Posso escrever e executar código nesta aula de LangChain / RAG / Vector DBs?

Sim. Cada aula de LangChain / RAG / Vector DBs inclui um editor de código integrado, então você escreve e executa código real direto no navegador e recebe feedback de IA instantaneamente — nenhuma configuração local necessária.

Todas as aulas deste curso

  1. Integrando todos os componentes do RAG
  2. Consultando e gerando respostas
  3. Avaliando o desempenho de sistemas RAG
  4. Criando um Conjunto de Testes de Referência para RAG
← Voltar para LangChain / RAG / Vector DBs