private-gpt/private_gpt/server/chat/chat_service.py

117 lines
4.4 KiB
Python

from collections.abc import Sequence
from typing import TYPE_CHECKING, Any
from injector import inject, singleton
from llama_index import ServiceContext, StorageContext, VectorStoreIndex
from llama_index.chat_engine import ContextChatEngine
from llama_index.indices.postprocessor import MetadataReplacementPostProcessor
from llama_index.llm_predictor.utils import stream_chat_response_to_tokens
from llama_index.llms import ChatMessage
from llama_index.types import TokenGen
from private_gpt.components.embedding.embedding_component import EmbeddingComponent
from private_gpt.components.llm.llm_component import LLMComponent
from private_gpt.components.node_store.node_store_component import NodeStoreComponent
from private_gpt.components.vector_store.vector_store_component import (
VectorStoreComponent,
)
from private_gpt.open_ai.extensions.context_filter import ContextFilter
if TYPE_CHECKING:
from llama_index.chat_engine.types import (
AgentChatResponse,
StreamingAgentChatResponse,
)
@singleton
class ChatService:
@inject
def __init__(
self,
llm_component: LLMComponent,
vector_store_component: VectorStoreComponent,
embedding_component: EmbeddingComponent,
node_store_component: NodeStoreComponent,
) -> None:
self.llm_service = llm_component
self.vector_store_component = vector_store_component
self.storage_context = StorageContext.from_defaults(
vector_store=vector_store_component.vector_store,
docstore=node_store_component.doc_store,
index_store=node_store_component.index_store,
)
self.service_context = ServiceContext.from_defaults(
llm=llm_component.llm, embed_model=embedding_component.embedding_model
)
self.index = VectorStoreIndex.from_vector_store(
vector_store_component.vector_store,
storage_context=self.storage_context,
service_context=self.service_context,
show_progress=True,
)
def _chat_with_contex(
self,
message: str,
context_filter: ContextFilter | None = None,
chat_history: Sequence[ChatMessage] | None = None,
streaming: bool = False,
) -> Any:
vector_index_retriever = self.vector_store_component.get_retriever(
index=self.index, context_filter=context_filter
)
chat_engine = ContextChatEngine.from_defaults(
retriever=vector_index_retriever,
service_context=self.service_context,
node_postprocessors=[
MetadataReplacementPostProcessor(target_metadata_key="window"),
],
)
if streaming:
result = chat_engine.stream_chat(message, chat_history)
else:
result = chat_engine.chat(message, chat_history)
return result
def stream_chat(
self,
messages: list[ChatMessage],
use_context: bool = False,
context_filter: ContextFilter | None = None,
) -> TokenGen:
if use_context:
last_message = messages[-1].content
response: StreamingAgentChatResponse = self._chat_with_contex(
message=last_message if last_message is not None else "",
chat_history=messages[:-1],
context_filter=context_filter,
streaming=True,
)
response_gen = response.response_gen
else:
stream = self.llm_service.llm.stream_chat(messages)
response_gen = stream_chat_response_to_tokens(stream)
return response_gen
def chat(
self,
messages: list[ChatMessage],
use_context: bool = False,
context_filter: ContextFilter | None = None,
) -> str:
if use_context:
last_message = messages[-1].content
wrapped_response: AgentChatResponse = self._chat_with_contex(
message=last_message if last_message is not None else "",
chat_history=messages[:-1],
context_filter=context_filter,
streaming=False,
)
response = wrapped_response.response
else:
chat_response = self.llm_service.llm.chat(messages)
response_content = chat_response.message.content
response = response_content if response_content is not None else ""
return response