The Neo4j GenAI Package for Python

Getting started with retrieval and GraphRAG

Introduction

If you’ve explored using Neo4j for GraphRAG, you already know its potential to enhance the output quality of generative models. Traditionally, this required deep knowledge of Neo4j and Cypher. In this post, we introduce the official Neo4j GenAI package for Python (neo4j-genai), designed to simplify the integration of Neo4j into Retrieval-Augmented Generation (RAG) applications for developers.

neo4j-genai

Our Python package equips you with the tools to efficiently manage retrieval and generation processes in a RAG setup. By the end of this post, you will be proficient in executing retrieval tasks using our package. In an upcoming post, you will learn more about the generation capabilities of the package, allowing you to build out a full end-to-end RAG pipeline.

What is GraphRAG?

The neo4j-genai package facilitates graph Retrieval-Augmented Generation (GraphRAG). At Neo4j, we believe that integrating graph databases with vector search represents the next frontier for RAG.

Setup

Start by connecting to a pre-configured Neo4j demo database that simulates a movie recommendations knowledge graph. Access it at https://demo.neo4jlabs.com:7473/browser/ using “recommendations” as both the username and password. This setup provides a realistic scenario where your vector embedding data is already part of a Neo4j database ready to be used.

Visualize the data by entering the Cypher command:

MATCH path=()- ->() RETURN path LIMIT 25;

Observe the plotEmbedding attribute in each node’s details on the right. We’ll use these embeddings to conduct vector searches throughout our demonstrations. You can check that there exists a moviePlotsEmbedding vector index by entering the Cypher command:

SHOW INDEXES YIELD * WHERE type='VECTOR';

In your Python environment, install the neo4j-genai package along with these other packages:

pip install neo4j-genai neo4j openai

Proceed by establishing a connection to your Neo4j database using the Neo4j Python driver:

from neo4j import GraphDatabase
# Demo database credentials
URI = "neo4j+s://demo.neo4jlabs.com"
AUTH = ("recommendations", "recommendations")
# Connect to Neo4j database
driver = GraphDatabase.driver(URI, auth=AUTH)

For this demonstration, ensure that you have an OpenAI API key set:

import os
os.environ["OPENAI_API_KEY"] = "sk-…"

Retrieval

Our package provides a variety of retrievers, tailored for different retrieval strategies (see our documentation for the full list). Selecting the appropriate one depends on your specific needs. Here, we employ the VectorRetriever class:

from neo4j_genai.retrievers import VectorRetriever
from neo4j_genai.embeddings.openai import OpenAIEmbeddings
embedder = OpenAIEmbeddings(model="text-embedding-ada-002")
retriever = VectorRetriever(
    driver,
    index_name="moviePlotsEmbedding",
    embedder=embedder,
    return_properties=["title", "plot"],
)

We use the text-embedding-ada-002 model because the movie plot embeddings in the demo database were originally generated using this model, enabling a more relevant retrieval search. Note that there are ways to customize the returned result. For example, here we specify return_properties to have the node properties title and plot returned.

Use the retriever to search for movie plots closely aligned with your query, which executes an approximate nearest-neighbor search to identify the top three movie plots that best match your query:

query_text = "A movie about the famous sinking of the Titanic"
retriever_result = retriever.search(query_text=query_text, top_k=3)
print(retriever_result)

items=[
RetrieverResultItem(content="""
{'title': 'Titanic', 
 'plot': 'An unhappy married couple deal with their problems on board the ill-fated ship.'}""", 
  metadata={'score': 0.9450652599334717, 'nodeLabels': None, 'id': None}), 
RetrieverResultItem(content="""
{'title': 'Night to Remember, A', 
 'plot': 'An account of the ill-fated maiden voyage of RMS Titanic in 1912.'}""", 
  metadata={'score': 0.9428615570068359, 'nodeLabels': None, 'id': None}), 
RetrieverResultItem(content="""
{'title': 'Titanic', 
 'plot': 'A seventeen-year-old aristocrat falls in love with a kind, but poor artist aboard the luxurious, ill-fated R.M.S. Titanic.'}""", 
  metadata={'score': 0.9422949552536011, 'nodeLabels': None, 'id': None})] 

metadata={'__retriever': 'VectorRetriever'}

We can further parse retriever_result using regular expressions:

import re

for k, item in enumerate(retriever_result.items):
    plot = re.search(r"'plot':\s*'([^']*)'", item.content).group(1)
    title = re.search(r"'title':\s*'([^']*)'", item.content).group(1)
    score = item.metadata["score"]
    print(f"Result {k}: {title} - {score} - {plot}")

Result 0: Titanic - 0.9450652599334717 - An unhappy married couple deal with their problems on board the ill-fated ship.
Result 1: Night to Remember, A - 0.9428615570068359 - An account of the ill-fated maiden voyage of RMS Titanic in 1912.
Result 2: Titanic - 0.9422949552536011 - A seventeen-year-old aristocrat falls in love with a kind, but poor artist aboard the luxurious, ill-fated R.M.S. Titanic.

GraphRAG

Let’s see how the retriever fits into a simple GraphRAG pipeline. To perform a GraphRAG query using the neo4j-genai package, a few components are needed:

1. A Neo4j driver — Used to query your Neo4j database.
2. A retriever — The neo4j-genai package provides some implementations and lets you write your own if none of the provided implementations matches your needs.
3. An LLM — We need to call an LLM to generate the answer. The neo4j-genai package currently only provides an implementation for the OpenAI LLMs, but its interface is compatible with LangChain chat models and lets you write your own interface if needed.

In practice, it’s done with only a few lines of code:

from neo4j_genai.llm import OpenAILLM
from neo4j_genai.generation import GraphRAG

# LLM
# Note: the OPENAI_API_KEY must be in the env vars
llm = OpenAILLM(model_name="gpt-4o", model_params={"temperature": 0})

# Initialize the RAG pipeline
rag = GraphRAG(retriever=retriever, llm=llm)

# Query the graph
query_text = "What movies are sad romances?"
response = rag.search(query_text=query_text, retriever_config={"top_k": 5})
print(response.answer)

We will see in an upcoming post how we can customize different types of retrievers.

Summary

We’ve demonstrated using the VectorRetriever class from the neo4j-genai package to execute a straightforward retrieval query. Future posts will explore other retrieval strategies and how you can use different LLMs in your GraphRAG pipelines using this package. Stay tuned!

We invite you to integrate the neo4j-genai package into your projects and share your insights via comments or on our GraphRAG Discord channel.

The package code is open source, and you can find it on GitHub. Feel free to open issues there.

GitHub - neo4j/neo4j-genai-python: Neo4j GenAI for Python