164 lines
5.9 KiB
Python
164 lines
5.9 KiB
Python
import asyncio
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from typing import List, Optional, Union
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from langchain_core.output_parsers import StrOutputParser
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from langchain_core.prompts import ChatPromptTemplate
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from llama_index.core import Document, VectorStoreIndex
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from llama_index.core.vector_stores import MetadataFilters, MetadataFilter, FilterOperator
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from llama_index.vector_stores.milvus import MilvusVectorStore
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from pydantic import BaseModel, Field
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from app.config.env import env
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from app.utils.llm_utils import create_embeddings, create_llm
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from app.utils.nltk_utils import load_nltk
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class KnowledgeQueryParam(BaseModel):
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question: str = Field(..., description="问题文本")
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kb_code: Union[str, List[str]] = Field(..., description="知识库编码")
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top_k: int = Field(default=5, description="返回结果数量")
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class MilvusSearchNode(BaseModel):
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id: str = Field(..., description="文档id")
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text: str = Field(..., description="文档内容")
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metadata: dict = Field(..., description="文档元信息")
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score: float = Field(..., description="相似度分数")
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class MilvusSearchResponse(BaseModel):
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answer: str = Field(..., description="根据用户问题从检索结果中提取的内容")
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nodes: List[MilvusSearchNode] = Field(..., description="搜索结果")
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class MilvusService:
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def __init__(self):
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milvus_vector_store: Optional[MilvusVectorStore] = None
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self._milvus_vector_store = milvus_vector_store
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self.embeddings = create_embeddings()
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# 获取一个MilvusVectorStore实例，如果不存在就异步创建
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async def get_vector_store(self):
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if not self._milvus_vector_store:
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print("create new_vector_store...")
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self._milvus_vector_store = MilvusVectorStore(
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uri=env.milvus_uri,
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user=env.milvus_username,
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password=env.milvus_password,
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db_name=env.llama_index_database,
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collection_name=env.llama_index_collection,
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dim=env.llama_index_dimension,
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embedding_field="embedding",
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# text_field="text", # 添加文本字段支持混合检索
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id_field="id",
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similarity_metric="COSINE",
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consistency_level="Strong",
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overwrite=False,
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# enable_hybrid=True, # 启用混合检索
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)
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return self._milvus_vector_store
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# 检查Milvus连接是否正常
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async def check_milvus_connection(self):
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await asyncio.sleep(0.1)
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await self.async_search(KnowledgeQueryParam(question="hello", kb_code=""))
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print("✅ Milvus connection successful：", f"Milvus://{env.milvus_username}:{env.milvus_password}@{env.milvus_uri}/{env.llama_index_database}/{env.llama_index_collection}")
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async def async_create_index_from_documents(self, documents: List[Document]) -> VectorStoreIndex:
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vector_store = await self.get_vector_store()
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"""异步创建向量索引并插入文档"""
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vector_index: VectorStoreIndex = VectorStoreIndex.from_vector_store(
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vector_store=vector_store,
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embed_model=self.embeddings,
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)
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from llama_index.core.node_parser import SimpleNodeParser
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# parser = HierarchicalNodeParser.from_defaults(chunk_sizes=[2048, 512, 128])
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parser = SimpleNodeParser()
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# nodes = await parser.aget_nodes_from_documents(documents)
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# 使用同步方法并包装在 asyncio.to_thread 中
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nodes = await asyncio.to_thread(parser.get_nodes_from_documents, documents)
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await vector_index.ainsert_nodes(nodes)
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return vector_index
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# 检索milvus文档
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async def async_search(self, param: KnowledgeQueryParam) -> MilvusSearchResponse:
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"""异步向量搜索"""
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# 创建查询引擎，设置top_k参数
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vector_index = VectorStoreIndex.from_vector_store(
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vector_store=await self.get_vector_store(),
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embed_model=self.embeddings,
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)
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filters = MetadataFilters(filters=[MetadataFilter(key="parent_code", value=param.kb_code, operator=FilterOperator.IN if isinstance(param.kb_code, list) else FilterOperator.EQ)])
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retriever = vector_index.as_retriever(
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retriever_mode="hybrid", # 启用混合模式
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filters=filters,
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similarity_top_k=param.top_k
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)
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result_nodes = await retriever.aretrieve(param.question)
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[print(node.node.metadata.get('name', None), node.score) for node in result_nodes]
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result_nodes = [node for node in result_nodes if node.score >= 0.3]
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chain = ChatPromptTemplate.from_template("""
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请从context标签中的内容提取与用户有关的内容来回答用户问题，如果不存在与用户问题相关的内容，请回答"在提供的资料中未找到相关信息"；
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<context>
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{context}
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</context>
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处理要求：
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- 不要添加检索结果之外的额外知识
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- 回答时优先使用检索结果中的原文表述
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用户的问题是：{question}
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""") | create_llm(disable_streaming=True) | StrOutputParser()
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rag_context = "\n-----------------分隔符------------------\n".join([
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f"""
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文件名：{node.node.metadata.get('name', "未命名文件.txt")}
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文件内容:
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{node.node.text}
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""" for node in result_nodes
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])
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chain_input = {"context": rag_context, "question": param.question}
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print("chain_input", chain_input)
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relative_content = await chain.ainvoke(chain_input)
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# print("milvus search answer", relative_content)
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# print("milvus search nodes", [node.node.text for node in result_nodes])
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return MilvusSearchResponse(
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answer=relative_content,
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nodes=[
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MilvusSearchNode(
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id=node.node.node_id,
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text=node.node.text,
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metadata=node.node.metadata,
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score=node.score
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)
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for node in result_nodes
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]
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)
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async def async_delete(self, doc_id: str):
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vector_index = VectorStoreIndex.from_vector_store(
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vector_store=await self.get_vector_store(),
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embed_model=self.embeddings,
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)
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await vector_index.adelete_ref_doc(doc_id)
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return None
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# 全局实例
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milvus_service = MilvusService()
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