基于 LlamaIndex 构建自己的 RAG 知识库

news2025/10/31 18:34:15

创建虚拟环境用于运行

运行 InternLM 的基础环境，命名为 llamaindex
conda create -n llamaindex python=3.10

查看存在的环境
```
conda env list
```
激活刚刚创建的环境
```
conda activate llamaindex
```
安装基本库pytorch,torchvision ,torchaudio,pytorch-cuda 并指定通道（建议写上对应的版本号）
1. ```
conda install pytorch==2.0.1 torchvision==0.15.2 torchaudio==2.0.2 pytorch-cuda=11.7 -c pytorch -c nvidia
```

安装 Llamaindex

此操作在对应的虚拟环境中安装 Llamaindex和相关的包

pip install llama-index==0.10.38 llama-index-llms-huggingface==0.2.0 "transformers[torch]==4.41.1" "huggingface_hub[inference]==0.23.1" huggingface_hub==0.23.1 sentence-transformers==2.7.0 sentencepiece==0.2.0

下载 Sentence Transformer 模型
1. 为了方面管理建立对应的路径,在根目录下创建2个文件（
```
mkdir llamaindex_demo
mkdir model
```
  ）
2. 然后在llamaindex_demo目录下创建下载脚本（
```
touch llamaindex_demo/download_hf.py
```
  ）
3. 在download_hf.py文件中写入
  1. import os
    
    # 设置环境变量
    os.environ['HF_ENDPOINT'] = 'https://hf-mirror.com'
    
    # 下载模型下载源词向量模型Sentence Transformer
    os.system('huggingface-cli download --resume-download sentence-transformers/paraphrase-multilingual-MiniLM-L12-v2 --local-dir /root/model/sentence-transformer')
4. 执行下载模型脚本
```
python download_hf.py
```
5. 如果上面的步骤不存在nltk此处需要手动下载nltk模型（cd /root
  git clone https://gitee.com/yzy0612/nltk_data.git --branch gh-pages
  cd nltk_data
  mv packages/* ./
  cd tokenizers
  unzip punkt.zip
  cd ../taggers
  unzip averaged_perceptron_tagger.zip）

LlamaIndex HuggingFaceLLM

下载模型internlm2-chat-1_8b (pip install internlm2-chat-1_8b )
如果有对应的模型可以软链接出来ln -s 模型路径要复制到哪里的路径如（
```
cd ~/model
ln -s /root/share/new_models/Shanghai_AI_Laboratory/internlm2-chat-1_8b/ ./
```
）

创建运行模型脚本 touch

touch ~/llamaindex_demo/llamaindex_internlm.py

编辑llamaindex_internlm.py文件（

from llama_index.llms.huggingface import HuggingFaceLLM
from llama_index.core.llms import ChatMessage
llm = HuggingFaceLLM(
    model_name="/root/model/internlm2-chat-1_8b",
    tokenizer_name="/root/model/internlm2-chat-1_8b",
    model_kwargs={"trust_remote_code":True},
    tokenizer_kwargs={"trust_remote_code":True}
)

rsp = llm.chat(messages=[ChatMessage(content="xtuner是什么？")])
print(rsp)

）

运行模型
```
python llamaindex_internlm.py
```

LlamaIndex RAG

安装 LlamaIndex 词嵌入向量依赖（

pip install llama-index-embeddings-huggingface llama-index-embeddings-instructor

）

如果上面步骤报错请根据提示安装对应的插件版本（如 pip install huggingface-hub==0.23.5）
获取知识库（创建data 把xtuner包中文件移动到对应的目录cd ~/llamaindex_demo
mkdir data
cd data
git clone https://github.com/InternLM/xtuner.git
mv xtuner/README_zh-CN.md ./）
创建运行模型代码
```
llamaindex_RAG.py
```

llamaindex_RAG.py文件内容（from llama_index.core import VectorStoreIndex, SimpleDirectoryReader, Settings

from llama_index.embeddings.huggingface import HuggingFaceEmbedding
from llama_index.llms.huggingface import HuggingFaceLLM

embed_model = HuggingFaceEmbedding(
    model_name="/root/model/sentence-transformer"
)

Settings.embed_model = embed_model

llm = HuggingFaceLLM(
    model_name="/root/model/internlm2-chat-1_8b",
    tokenizer_name="/root/model/internlm2-chat-1_8b",
    model_kwargs={"trust_remote_code":True},
    tokenizer_kwargs={"trust_remote_code":True}
)
Settings.llm = llm

documents = SimpleDirectoryReader("/root/llamaindex_demo/data").load_data()
index = VectorStoreIndex.from_documents(documents)
query_engine = index.as_query_engine()
response = query_engine.query("xtuner是什么?")

print(response)）

运行
```
python llamaindex_RAG.py
```

浏览器上运行对话
1. 安装服务依赖
```
pip install streamlit==1.36.0
```
2. 创建运行脚本app.py
  import streamlit as st
  from llama_index.core import VectorStoreIndex, SimpleDirectoryReader, Settings
  from llama_index.embeddings.huggingface import HuggingFaceEmbedding
  from llama_index.llms.huggingface import HuggingFaceLLM
  
  st.set_page_config(page_title="llama_index_demo", page_icon="🦜🔗")
  st.title("llama_index_demo")
  
  # 初始化模型
  @st.cache_resource
  def init_models():
  embed_model = HuggingFaceEmbedding(
  model_name="/root/model/sentence-transformer"
  )
  Settings.embed_model = embed_model
  
  llm = HuggingFaceLLM(
  model_name="/root/model/internlm2-chat-1_8b",
  tokenizer_name="/root/model/internlm2-chat-1_8b",
  model_kwargs={"trust_remote_code": True},
  tokenizer_kwargs={"trust_remote_code": True}
  )
  Settings.llm = llm
  
  documents = SimpleDirectoryReader("/root/llamaindex_demo/data").load_data()
  index = VectorStoreIndex.from_documents(documents)
  query_engine = index.as_query_engine()
  
  return query_engine
  
  # 检查是否需要初始化模型
  if 'query_engine' not in st.session_state:
  st.session_state['query_engine'] = init_models()
  
  def greet2(question):
  response = st.session_state['query_engine'].query(question)
  return response
  
  # Store LLM generated responses
  if "messages" not in st.session_state.keys():
  st.session_state.messages = [{"role": "assistant", "content": "你好，我是你的助手，有什么我可以帮助你的吗？"}]
  
  # Display or clear chat messages
  for message in st.session_state.messages:
  with st.chat_message(message["role"]):
  st.write(message["content"])
  
  def clear_chat_history():
  st.session_state.messages = [{"role": "assistant", "content": "你好，我是你的助手，有什么我可以帮助你的吗？"}]
  
  st.sidebar.button('Clear Chat History', on_click=clear_chat_history)
  
  # Function for generating LLaMA2 response
  def generate_llama_index_response(prompt_input):
  return greet2(prompt_input)
  
  # User-provided prompt
  if prompt := st.chat_input():
  st.session_state.messages.append({"role": "user", "content": prompt})
  with st.chat_message("user"):
  st.write(prompt)
  
  # Gegenerate_llama_index_response last message is not from assistant
  if st.session_state.messages[-1]["role"] != "assistant":
  with st.chat_message("assistant"):
  with st.spinner("Thinking..."):
  response = generate_llama_index_response(prompt)
  placeholder = st.empty()
  placeholder.markdown(response)
  message = {"role": "assistant", "content": response}
  st.session_state.messages.append(message)
3. 运行
```
streamlit run app.py
```
4. 默认端口8503（ http://localhost:8503）
5. 最终效果