LangChain integration

Learn how to integrate Rememberizer as a LangChain retriever to provide your LangChain application with access to powerful vector database search.

Rememberizer integrates with LangChain through the RememberizerRetriever class, allowing you to easily incorporate Rememberizer's semantic search capabilities into your LangChain-powered applications. This guide explains how to set up and use this integration to build advanced LLM applications with access to your knowledge base.

Introduction

LangChain is a popular framework for building applications with large language models (LLMs). By integrating Rememberizer with LangChain, you can:

• Use your Rememberizer knowledge base in RAG (Retrieval Augmented Generation) applications

• Create chatbots with access to your documents and data

• Build question-answering systems that leverage your knowledge

• Develop agents that can search and reason over your information

The integration is available in the langchain_community.retrievers module.

Rememberizer - Docs by LangChainDocs by LangChain

Getting Started

Prerequisites

Before you begin, you need:

1. A Rememberizer account with Common Knowledge created

2. An API key for accessing your Common Knowledge

3. Python environment with LangChain installed

For detailed instructions on creating Common Knowledge and generating an API key, see Registering and Using API Keys.

Installation

Install the required packages:

pip install langchain langchain_community

If you plan to use OpenAI models (as shown in examples below):

pip install langchain_openai

Authentication Setup

There are two ways to authenticate the RememberizerRetriever:

1. Environment Variable: Set the REMEMBERIZER_API_KEY environment variable

   import os
   os.environ["REMEMBERIZER_API_KEY"] = "rem_ck_your_api_key"

2. Direct Parameter: Pass the API key directly when initializing the retriever

   retriever = RememberizerRetriever(rememberizer_api_key="rem_ck_your_api_key")

Configuration Options

The RememberizerRetriever class accepts these parameters:

Parameter	Type	Default	Description
top_k_results	int	10	Number of documents to return from search
rememberizer_api_key	str	None	API key for authentication (optional if set as environment variable)

Behind the scenes, the retriever makes API calls to Rememberizer's search endpoint with additional configurable parameters:

Advanced Parameter	Description
prev_chunks	Number of chunks before the matched chunk to include (default: 2)
next_chunks	Number of chunks after the matched chunk to include (default: 2)
return_full_content	Whether to return full document content (default: true)

Basic Usage

Here's a simple example of retrieving documents from Rememberizer using LangChain:

import os
from langchain_community.retrievers import RememberizerRetriever

# Set your API key
os.environ["REMEMBERIZER_API_KEY"] = "rem_ck_your_api_key"

# Initialize the retriever
retriever = RememberizerRetriever(top_k_results=5)

# Get relevant documents for a query
docs = retriever.get_relevant_documents(query="How do vector embeddings work?")

# Display the first document
if docs:
    print(f"Document: {docs[0].metadata['name']}")
    print(f"Content: {docs[0].page_content[:200]}...")

Understanding Document Structure

Each document returned by the retriever has:

• page_content: The text content of the matched document chunk

• metadata: Additional information about the document

Example of metadata structure:

{
  'id': 13646493,
  'document_id': '17s3LlMbpkTk0ikvGwV0iLMCj-MNubIaP',
  'name': 'What is a large language model (LLM)_ _ Cloudflare.pdf',
  'type': 'application/pdf',
  'path': '/langchain/What is a large language model (LLM)_ _ Cloudflare.pdf',
  'url': 'https://drive.google.com/file/d/17s3LlMbpkTk0ikvGwV0iLMCj-MNubIaP/view',
  'size': 337089,
  'created_time': '',
  'modified_time': '',
  'indexed_on': '2024-04-04T03:36:28.886170Z',
  'integration': {'id': 347, 'integration_type': 'google_drive'}
}

Advanced Examples

Building a RAG Question-Answering System

This example creates a question-answering system that retrieves information from Rememberizer and uses GPT-3.5 to formulate answers:

import os
from langchain_community.retrievers import RememberizerRetriever
from langchain.chains import RetrievalQA
from langchain_openai import ChatOpenAI

# Set up API keys
os.environ["REMEMBERIZER_API_KEY"] = "rem_ck_your_api_key"
os.environ["OPENAI_API_KEY"] = "your_openai_api_key"

# Initialize the retriever and language model
retriever = RememberizerRetriever(top_k_results=5)
llm = ChatOpenAI(model_name="gpt-3.5-turbo", temperature=0)

# Create a retrieval QA chain
qa_chain = RetrievalQA.from_chain_type(
    llm=llm,
    chain_type="stuff",  # Simplest method - just stuff all documents into the prompt
    retriever=retriever,
    return_source_documents=True
)

# Ask a question
response = qa_chain.invoke({"query": "What is RAG in the context of AI?"})

# Print the answer
print(f"Answer: {response['result']}")
print("\nSources:")
for idx, doc in enumerate(response['source_documents']):
    print(f"{idx+1}. {doc.metadata['name']}")

Building a Conversational Agent with Memory

This example creates a conversational agent that can maintain conversation history:

import os
from langchain_community.retrievers import RememberizerRetriever
from langchain.chains import ConversationalRetrievalChain
from langchain.memory import ConversationBufferMemory
from langchain_openai import ChatOpenAI

# Set up API keys
os.environ["REMEMBERIZER_API_KEY"] = "rem_ck_your_api_key"
os.environ["OPENAI_API_KEY"] = "your_openai_api_key"

# Initialize components
retriever = RememberizerRetriever(top_k_results=5)
llm = ChatOpenAI(model_name="gpt-3.5-turbo")
memory = ConversationBufferMemory(
    memory_key="chat_history",
    return_messages=True
)

# Create the conversational chain
conversation = ConversationalRetrievalChain.from_llm(
    llm=llm,
    retriever=retriever,
    memory=memory
)

# Example conversation
questions = [
    "What is RAG?",
    "How do large language models use it?",
    "What are the limitations of this approach?",
]

for question in questions:
    response = conversation.invoke({"question": question})
    print(f"Question: {question}")
    print(f"Answer: {response['answer']}\n")

Best Practices

Optimizing Retrieval Performance

1. Be specific with queries: More specific queries usually yield better results

2. Adjust top_k_results: Start with 3-5 results and adjust based on application needs

3. Use context windows: The retriever automatically includes context around matched chunks

Security Considerations

1. Protect your API key: Store it securely using environment variables or secret management tools

2. Create dedicated keys: Create separate API keys for different applications

3. Rotate keys regularly: Periodically generate new keys and phase out old ones

Integration Patterns

1. Pre-retrieval processing: Consider preprocessing user queries to improve search relevance

2. Post-retrieval filtering: Filter or rank retrieved documents before passing to the LLM

3. Hybrid search: Combine Rememberizer with other retrievers using EnsembleRetriever

from langchain.retrievers import EnsembleRetriever
from langchain_community.retrievers import RememberizerRetriever, WebResearchRetriever

# Create retrievers
rememberizer_retriever = RememberizerRetriever(top_k_results=3)
web_retriever = WebResearchRetriever(...)  # Configure another retriever

# Create an ensemble with weighted score
ensemble_retriever = EnsembleRetriever(
    retrievers=[rememberizer_retriever, web_retriever],
    weights=[0.7, 0.3]  # Rememberizer results have higher weight
)

Troubleshooting

Common Issues

1. Authentication errors: Verify your API key is correct and properly configured

2. No results returned: Ensure your Common Knowledge contains relevant information

3. Rate limiting: Be mindful of API rate limits for high-volume applications

Debug Tips

• Set the LangChain debug mode to see detailed API calls:

  import langchain
  langchain.debug = True

• Examine raw search results before passing to LLM to identify retrieval issues

Related Resources

• LangChain Retriever conceptual guide

• LangChain Retriever how-to guides

• Rememberizer API Documentation

• Vector Stores in Rememberizer

• Creating a Rememberizer GPT - An alternative approach for AI integration