3.8 KiB
rag_lantern
This template performs RAG with Lantern.
Lantern is an open-source vector database built on top of PostgreSQL. It enables vector search and embedding generation inside your database.
Environment Setup
Set the OPENAI_API_KEY
environment variable to access the OpenAI models.
To get your OPENAI_API_KEY
, navigate to API keys on your OpenAI account and create a new secret key.
To find your LANTERN_URL
and LANTERN_SERVICE_KEY
, head to your Lantern project's API settings.
LANTERN_URL
corresponds to the Project URLLANTERN_SERVICE_KEY
corresponds to theservice_role
API key
export LANTERN_URL=
export LANTERN_SERVICE_KEY=
export OPENAI_API_KEY=
Setup Lantern Database
Use these steps to setup your Lantern database if you haven't already.
-
Head to https://lantern.dev to create your Lantern database.
-
In your favorite SQL client, jump to the SQL editor and run the following script to setup your database as a vector store:
-- Create a table to store your documents create table documents ( id uuid primary key, content text, -- corresponds to Document.pageContent metadata jsonb, -- corresponds to Document.metadata embedding REAL[1536] -- 1536 works for OpenAI embeddings, change as needed ); -- Create a function to search for documents create function match_documents ( query_embedding REAL[1536], filter jsonb default '{}' ) returns table ( id uuid, content text, metadata jsonb, similarity float ) language plpgsql as $$ #variable_conflict use_column begin return query select id, content, metadata, 1 - (documents.embedding <=> query_embedding) as similarity from documents where metadata @> filter order by documents.embedding <=> query_embedding; end; $$;
Setup Environment Variables
Since we are using Lantern
and OpenAIEmbeddings
, we need to load their API keys.
Usage
First, install the LangChain CLI:
pip install -U langchain-cli
To create a new LangChain project and install this as the only package, you can do:
langchain app new my-app --package rag-lantern
If you want to add this to an existing project, you can just run:
langchain app add rag-lantern
And add the following code to your server.py
file:
from rag_lantern.chain import chain as rag_lantern_chain
add_routes(app, rag_lantern_chain, path="/rag-lantern")
(Optional) Let's now configure LangSmith. LangSmith will help us trace, monitor and debug LangChain applications. You can sign up for LangSmith here. If you don't have access, you can skip this section
export LANGCHAIN_TRACING_V2=true
export LANGCHAIN_API_KEY=<your-api-key>
export LANGCHAIN_PROJECT=<your-project> # if not specified, defaults to "default"
If you are inside this directory, then you can spin up a LangServe instance directly by:
langchain serve
This will start the FastAPI app with a server is running locally at http://localhost:8000
We can see all templates at http://127.0.0.1:8000/docs We can access the playground at http://127.0.0.1:8000/rag-lantern/playground
We can access the template from code with:
from langserve.client import RemoteRunnable
runnable = RemoteRunnable("http://localhost:8000/rag-lantern")