125 lines
4.4 KiB
Python
125 lines
4.4 KiB
Python
import asyncio
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from typing import List, Iterable, AsyncGenerator, Optional
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from transformers import AutoTokenizer, AutoModel
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import torch
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import torch.nn.functional as F
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from torch import Tensor
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class JEmbeddingService:
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def __init__(self, model_path: str = "Qwen/Qwen3-Embedding-0.6B", max_length: int = 8192):
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self.model_path = model_path
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self.max_length = max_length
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self.tokenizer = None
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self.model = None
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self._load_model()
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def _load_model(self) -> None:
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"""加载模型和分词器"""
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self.tokenizer = AutoTokenizer.from_pretrained(
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self.model_path,
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trust_remote_code=True,
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padding_side='left' # 左填充，适合指令模型
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)
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self.model = AutoModel.from_pretrained(
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self.model_path,
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trust_remote_code=True
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)
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self.model.eval()
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def _last_token_pool(self, last_hidden_states: Tensor, attention_mask: Tensor) -> Tensor:
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"""
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提取最后一个有效token的隐藏状态
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这是Qwen3-Embedding模型推荐的池化方式
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"""
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left_padding = (attention_mask[:, -1].sum() == attention_mask.shape[0])
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if left_padding:
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return last_hidden_states[:, -1]
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else:
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sequence_lengths = attention_mask.sum(dim=1) - 1
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batch_size = last_hidden_states.shape[0]
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return last_hidden_states[torch.arange(batch_size, device=last_hidden_states.device), sequence_lengths]
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async def embed(self, texts: List[str], normalize: bool = True) -> List[List[float]]:
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"""
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将文本列表转换为向量表示
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Args:
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texts: 文本列表
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normalize: 是否进行L2归一化，默认True
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Returns:
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向量列表，每个向量对应一个输入文本
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"""
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if not isinstance(texts, list) or any(not isinstance(t, str) for t in texts):
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raise ValueError("texts必须是字符串列表")
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def encode_texts():
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# 批量分词
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batch_dict = self.tokenizer(
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texts,
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padding=True,
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truncation=True,
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max_length=self.max_length,
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return_tensors="pt"
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)
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# 移动到模型设备
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batch_dict = {k: v.to(self.model.device) for k, v in batch_dict.items()}
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# 获取嵌入
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with torch.no_grad():
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outputs = self.model(**batch_dict)
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# 使用last_token_pool提取最后一个有效token的嵌入
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embeddings = self._last_token_pool(outputs.last_hidden_state, batch_dict['attention_mask'])
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# L2归一化（推荐用于相似度计算）
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if normalize:
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embeddings = F.normalize(embeddings, p=2, dim=1)
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return embeddings.tolist()
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loop = asyncio.get_running_loop()
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return await loop.run_in_executor(None, encode_texts)
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async def process_batch(self, items: Iterable[str], normalize: bool = True) -> AsyncGenerator[dict, None]:
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"""
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批量处理文本，生成向量表示
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Args:
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items: 文本迭代器
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normalize: 是否进行L2归一化
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Yields:
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处理结果字典，包含index、status、embedding或message
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"""
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texts: List[str] = []
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indices: List[int] = []
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# 收集有效文本
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for idx, text in enumerate(items):
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try:
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if not isinstance(text, str):
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raise ValueError("每个元素必须是字符串")
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texts.append(text)
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indices.append(idx)
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except Exception as e:
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yield {"index": idx, "status": "error", "message": str(e)}
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await asyncio.sleep(0) # 让出控制权
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if not texts:
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return
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try:
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# 批量处理所有文本
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vectors = await self.embed(texts, normalize=normalize)
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for i, vec in zip(indices, vectors):
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yield {"index": i, "status": "success", "embedding": vec}
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except Exception as e:
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# 如果批量处理失败，为每个文本返回错误
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for i in indices:
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yield {"index": i, "status": "error", "message": str(e)}
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