LightRAG/lightrag/llm

1. LlamaIndex (llm/llama_index.py):
   • Provides integration with OpenAI and other providers through LlamaIndex
   • Supports both direct API access and proxy services like LiteLLM
   • Handles embeddings and completions with consistent interfaces
   • See example implementations:
     • Direct OpenAI Usage
     • LiteLLM Proxy Usage

Using LlamaIndex

LightRAG supports LlamaIndex for embeddings and completions in two ways: direct OpenAI usage or through LiteLLM proxy.

Setup

First, install the required dependencies:

pip install llama-index-llms-litellm llama-index-embeddings-litellm

Standard OpenAI Usage

from lightrag import LightRAG
from lightrag.llm.llama_index_impl import llama_index_complete_if_cache, llama_index_embed
from llama_index.embeddings.openai import OpenAIEmbedding
from llama_index.llms.openai import OpenAI
from lightrag.utils import EmbeddingFunc

# Initialize with direct OpenAI access
async def llm_model_func(prompt, system_prompt=None, history_messages=[], **kwargs):
    try:
        # Initialize OpenAI if not in kwargs
        if 'llm_instance' not in kwargs:
            llm_instance = OpenAI(
                model="gpt-4",
                api_key="your-openai-key",
            )
            kwargs['llm_instance'] = llm_instance

        response = await llama_index_complete_if_cache(
            kwargs['llm_instance'],
            prompt,
            system_prompt=system_prompt,
            history_messages=history_messages,
            **kwargs,
        )
        return response
    except Exception as e:
        logger.error(f"LLM request failed: {str(e)}")
        raise

# Initialize LightRAG with OpenAI
rag = LightRAG(
    working_dir="your/path",
    llm_model_func=llm_model_func,
    embedding_func=EmbeddingFunc(
        embedding_dim=1536,
        func=lambda texts: llama_index_embed(
            texts,
            embed_model=OpenAIEmbedding(
                model="text-embedding-3-large",
                api_key="your-openai-key"
            )
        ),
    ),
)

Using LiteLLM Proxy

1. Use any LLM provider through LiteLLM
2. Leverage LlamaIndex's embedding and completion capabilities
3. Maintain consistent configuration across services

from lightrag import LightRAG
from lightrag.llm.llama_index_impl import llama_index_complete_if_cache, llama_index_embed
from llama_index.llms.litellm import LiteLLM
from llama_index.embeddings.litellm import LiteLLMEmbedding
from lightrag.utils import EmbeddingFunc

# Initialize with LiteLLM proxy
async def llm_model_func(prompt, system_prompt=None, history_messages=[], **kwargs):
    try:
        # Initialize LiteLLM if not in kwargs
        if 'llm_instance' not in kwargs:
            llm_instance = LiteLLM(
                model=f"openai/{settings.LLM_MODEL}",  # Format: "provider/model_name"
                api_base=settings.LITELLM_URL,
                api_key=settings.LITELLM_KEY,
            )
            kwargs['llm_instance'] = llm_instance

        response = await llama_index_complete_if_cache(
            kwargs['llm_instance'],
            prompt,
            system_prompt=system_prompt,
            history_messages=history_messages,
            **kwargs,
        )
        return response
    except Exception as e:
        logger.error(f"LLM request failed: {str(e)}")
        raise

# Initialize LightRAG with LiteLLM
rag = LightRAG(
    working_dir="your/path",
    llm_model_func=llm_model_func,
    embedding_func=EmbeddingFunc(
        embedding_dim=1536,
        func=lambda texts: llama_index_embed(
            texts,
            embed_model=LiteLLMEmbedding(
                model_name=f"openai/{settings.EMBEDDING_MODEL}",
                api_base=settings.LITELLM_URL,
                api_key=settings.LITELLM_KEY,
            )
        ),
    ),
)

Environment Variables

For OpenAI direct usage:

OPENAI_API_KEY=your-openai-key

For LiteLLM proxy:

# LiteLLM Configuration
LITELLM_URL=http://litellm:4000
LITELLM_KEY=your-litellm-key

# Model Configuration
LLM_MODEL=gpt-4
EMBEDDING_MODEL=text-embedding-3-large

Key Differences

1. Direct OpenAI:

   • Simpler setup
   • Direct API access
   • Requires OpenAI API key

2. LiteLLM Proxy:

   • Model provider agnostic
   • Centralized API key management
   • Support for multiple providers
   • Better cost control and monitoring