Lumen RAG Framework

Lumen is a high-performance, modular, and database-agnostic RAG (Retrieval-Augmented Generation) framework written in Rust.

It abstracts the complexity of vector storage and retrieval, allowing you to switch seamlessly between MongoDB, CosmosDB, Qdrant, and SAP HANA Cloud, while providing built-in support for state-of-the-art embeddings (BERT) via candle.

🚀 Features

🔌 Modular Backends: Switch between MongoDB, Qdrant, and SAP HANA Cloud with Feature Flags.
⚡ High Performance: Built on Tokio, Actix-web, and Rayon for async and parallel processing.
🧠 Local Embeddings: Integrated BERT support using Hugging Face's candle (no external API needed for embeddings).
📄 Smart Chunking: Intelligent text segmentation preserving semantic context.
🤖 LLM Agnostic: Compatible with any OpenAI-compatible API (Ollama, vLLM, OpenAI, Mistral, etc.).

📦 Installation

Add lumen-rag to your Cargo.toml. Select the database backend you need:

[dependencies]

# For MongoDB or CosmosDB support

lumen-rag = { version = "0.1.0", features = ["mongodb"] }



# For Qdrant support

lumen-rag = { version = "0.1.0", features = ["qdrant"] }



# For SAP HANA Cloud support

lumen-rag = { version = "0.1.0", features = ["hana"] }

🛠️ Configuration

Lumen uses environment variables for configuration. Create a .env file in your project root:

# --- LLM Settings ---
LLM_URI=https://api.openai.com/v1/chat/completions
MODEL=gpt-3.5-turbo
LLM_API_KEY=sk-your-api-key-here

# --- Database Settings ---
# MongoDB / CosmosDB
COSMOS_URI=mongodb://admin:password@localhost:27017
DATABASE=lumen_db
COLLECTION=knowledge_base

# Qdrant
QDRANT_URI=http://localhost:6334

# SAP HANA Cloud
HANA_URL=hdb://user:password@host:port
HANA_TABLE=LUMEN_RAG_TABLE

🏗️ Architecture

Lumen is built around the VectorStore trait, enabling easy integration of new vector databases.

#[async_trait]
pub trait VectorStore: Send + Sync {
    async fn add_passages(&self, passages: Vec<Passage>) -> Result<Vec<String>>;
    async fn search(&self, query_embedding: &[f32], limit: usize) -> Result<Vec<Passage>>;
}

Supported Stores

Database	Feature Flag	Search Type
MongoDB	`mongodb`	Hybrid (Fetch + In-memory Cosine Similarity)
CosmosDB	`mongodb`	Hybrid (Mongo API Compatible)
Qdrant	`qdrant`	Native HNSW Vector Search
SAP HANA Cloud	`hana`	Native Vector Search (REAL_VECTOR)

[!WARNING] Experimental Feature: SAP HANA Cloud support is currently in beta and has not been fully validated against a live instance.

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Fork the project
Create your feature branch (git checkout -b feature/AmazingFeature)
Commit your changes (git commit -m 'Add some AmazingFeature')
Push to the branch (git push origin feature/AmazingFeature)
Open a Pull Request

📄 License

Distributed under the MIT License. See LICENSE for more information.

lumen-rag 0.2.1