Files
2026-07-13 13:39:38 +08:00

100 lines
3.0 KiB
Python

from collections.abc import AsyncIterable
from pathlib import Path
from dotenv import load_dotenv
from llama_index.core import (
SimpleDirectoryReader,
StorageContext,
VectorStoreIndex,
load_index_from_storage,
)
from llama_index.core.chat_engine.types import ChatMode
from llama_index.core.llms import ChatMessage, MessageRole
from livekit.agents import (
Agent,
AgentServer,
AgentSession,
AutoSubscribe,
JobContext,
cli,
inference,
llm,
)
from livekit.agents.voice.agent import ModelSettings
load_dotenv()
# check if storage already exists
THIS_DIR = Path(__file__).parent
PERSIST_DIR = THIS_DIR / "chat-engine-storage"
if not PERSIST_DIR.exists():
# load the documents and create the index
documents = SimpleDirectoryReader(THIS_DIR / "data").load_data()
index = VectorStoreIndex.from_documents(documents)
# store it for later
index.storage_context.persist(persist_dir=PERSIST_DIR)
else:
# load the existing index
storage_context = StorageContext.from_defaults(persist_dir=PERSIST_DIR)
index = load_index_from_storage(storage_context)
class DummyLLM(llm.LLM):
async def chat(self, *args, **kwargs):
raise NotImplementedError("DummyLLM does not support chat")
class ChatEngineAgent(Agent):
def __init__(self, index: VectorStoreIndex):
super().__init__(
instructions=(
"You are a voice assistant created by LiveKit. Your interface "
"with users will be voice. You should use short and concise "
"responses, and avoiding usage of unpronouncable punctuation."
),
stt=inference.STT("deepgram/nova-3"),
llm=DummyLLM(), # use a dummy LLM to enable the pipeline reply
tts=inference.TTS("cartesia/sonic-3"),
)
self.index = index
self.chat_engine = index.as_chat_engine(chat_mode=ChatMode.CONTEXT, llm="default")
async def llm_node(
self,
chat_ctx: llm.ChatContext,
tools: list[llm.FunctionTool],
model_settings: ModelSettings,
) -> AsyncIterable[str]:
user_msg = chat_ctx.items.pop()
assert isinstance(user_msg, llm.ChatMessage) and user_msg.role == "user"
user_query = user_msg.text_content
assert user_query is not None
llama_chat_messages = [
ChatMessage(content=msg.text_content, role=MessageRole(msg.role))
for msg in chat_ctx.messages()
]
stream = await self.chat_engine.astream_chat(user_query, chat_history=llama_chat_messages)
async for delta in stream.async_response_gen():
yield delta
server = AgentServer()
@server.rtc_session()
async def entrypoint(ctx: JobContext):
await ctx.connect(auto_subscribe=AutoSubscribe.AUDIO_ONLY)
agent = ChatEngineAgent(index)
session = AgentSession()
await session.start(agent=agent, room=ctx.room)
await session.say("Hey, how can I help you today?", allow_interruptions=False)
if __name__ == "__main__":
cli.run_app(server)