Python 开源 AI 模型引入与测试实战

2.4 安装依赖

# 安装基础依赖
pip install -r requirements.txt
# 安装带 CUDA 支持的 PyTorch（如使用 GPU）
pip install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cu118

2.5 项目结构

创建项目目录结构，保持模块化清晰：

openai-introduction/
├── src/
│   ├── __init__.py
│   ├── data/
│   │   ├── __init__.py
│   │   ├── processor.py
│   │   └── dataset.py
│   ├── models/
│   │   ├── __init__.py
│   │   ├── bert_classifier.py
│   │   └── model_utils.py
│   ├── training/
│   │   ├── __init__.py
│   │   ├── trainer.py
│   │   └── optimizer.py
│   ├── evaluation/
│   │   ├── __init__.py
│   │   ├── metrics.py
│   │   └── visualization.py
│   └── api/
│       ├── __init__.py
│       ├── app.py
│       └── schemas.py
├── tests/
│   ├── __init__.py
│   ├── test_data.py
│   ├── test_model.py
│   ├── test_training.py
│   └── test_api.py
├── notebooks/
│   ├── 01_exploratory_analysis.ipynb
│   └── 02_model_experiments.ipynb
├── configs/
│   ├── base_config.yaml
│   └── train_config.yaml
├── scripts/
│   ├── train.py
│   ├── evaluate.py
│   └── deploy.py
├── .pre-commit-config.yaml
├── Dockerfile
├── docker-compose.yml
├── pyproject.toml
├── README.md
└── requirements.txt

模型原理与架构解析

3.1 BERT 模型原理

BERT（Bidirectional Encoder Representations from Transformers）是基于 Transformer 编码器的预训练语言模型。其核心创新在于双向上下文理解，通过 Masked Language Model（MLM）和 Next Sentence Prediction（NSP）任务进行预训练。

3.1.1 Transformer 编码器架构

这里展示多头注意力机制的实现细节，实际工程中建议直接使用 Hugging Face 封装好的类，但理解底层逻辑对调试至关重要。

import math
from typing import Optional, Tuple
import torch
import torch.nn as nn
import torch.nn.functional as F

class MultiHeadAttention(nn.Module):
    """多头注意力机制实现"""
    def __init__(self, embed_dim: int, num_heads: int, dropout: float = 0.1):
        super().__init__()
        assert embed_dim % num_heads == 0
        self.embed_dim = embed_dim
        self.num_heads = num_heads
        self.head_dim = embed_dim // num_heads
        self.q_proj = nn.Linear(embed_dim, embed_dim)
        self.k_proj = nn.Linear(embed_dim, embed_dim)
        self.v_proj = nn.Linear(embed_dim, embed_dim)
        self.out_proj = nn.Linear(embed_dim, embed_dim)
        self.dropout = nn.Dropout(dropout)
        self.scaling = self.head_dim ** -0.5

    def forward(
        self,
        query: torch.Tensor,
        key: torch.Tensor,
        value: torch.Tensor,
        attention_mask: Optional[torch.Tensor] = None
    ) -> Tuple[torch.Tensor, torch.Tensor]:
        batch_size = query.size(0)
        # 线性变换并 reshape 为多头
        q = self.q_proj(query).view(batch_size, -1, self.num_heads, self.head_dim).transpose(1, 2)
        k = self.k_proj(key).view(batch_size, -1, self.num_heads, self.head_dim).transpose(1, 2)
        v = self.v_proj(value).view(batch_size, -1, self.num_heads, self.head_dim).transpose(1, 2)
        # 计算注意力分数
        attn_scores = torch.matmul(q, k.transpose(-2, -1)) * self.scaling
        if attention_mask is not None:
            attn_scores = attn_scores.masked_fill(attention_mask == 0, -1e9)
        attn_probs = F.softmax(attn_scores, dim=-1)
        attn_probs = self.dropout(attn_probs)
        # 应用注意力权重
        attn_output = torch.matmul(attn_probs, v)
        # 合并多头
        attn_output = attn_output.transpose(1, 2).contiguous().view(
            batch_size, -1, self.embed_dim
        )
        attn_output = self.out_proj(attn_output)
        return attn_output, attn_probs

class TransformerEncoderLayer(nn.Module):
    """Transformer 编码器层"""
    def __init__(self, embed_dim: int, num_heads: int, ff_dim: int, dropout: float = 0.1):
        super().__init__()
        self.self_attn = MultiHeadAttention(embed_dim, num_heads, dropout)
        self.attn_norm = nn.LayerNorm(embed_dim)
        self.ffn = nn.Sequential(
            nn.Linear(embed_dim, ff_dim),
            nn.GELU(),
            nn.Dropout(dropout),
            nn.Linear(ff_dim, embed_dim),
            nn.Dropout(dropout)
        )
        self.ffn_norm = nn.LayerNorm(embed_dim)
        self.dropout = nn.Dropout(dropout)

    def forward(self, x: torch.Tensor, attention_mask: Optional[torch.Tensor] = None):
        # 自注意力
        residual = x
        attn_output, attn_weights = self.self_attn(x, x, x, attention_mask)
        x = self.attn_norm(residual + self.dropout(attn_output))
        # 前馈网络
        residual = x
        x = self.ffn_norm(residual + self.ffn(x))
        return x, attn_weights

3.2 Hugging Face Transformers 架构

Hugging Face Transformers 库提供了统一的 API 接口，支持多种预训练模型。其核心设计模式基于 PreTrainedModel 和 PreTrainedTokenizer 基类。

from transformers import (
    BertConfig,
    BertModel,
    BertTokenizer,
    PreTrainedModel,
    PretrainedConfig
)
from transformers.modeling_outputs import SequenceClassifierOutput
import torch.nn as nn

class BertForSequenceClassification(PreTrainedModel):
    """基于 BERT 的序列分类模型"""
    def __init__(self, config: BertConfig):
        super().__init__(config)
        self.num_labels = config.num_labels
        self.config = config
        # 加载预训练 BERT 模型
        self.bert = BertModel(config)
        # 分类头
        self.classifier = nn.Sequential(
            nn.Dropout(config.hidden_dropout_prob),
            nn.Linear(config.hidden_size, config.hidden_size),
            nn.GELU(),
            nn.Dropout(config.hidden_dropout_prob),
            nn.Linear(config.hidden_size, config.num_labels)
        )
        # 初始化权重
        self.post_init()

    def forward(
        self,
        input_ids: Optional[torch.Tensor] = None,
        attention_mask: Optional[torch.Tensor] = None,
        token_type_ids: Optional[torch.Tensor] = None,
        labels: Optional[torch.Tensor] = None,
        **kwargs
    ) -> SequenceClassifierOutput:
        # BERT 前向传播
        outputs = self.bert(
            input_ids=input_ids,
            attention_mask=attention_mask,
            token_type_ids=token_type_ids,
            **kwargs
        )
        # 使用 [CLS] token 的表示
        pooled_output = outputs.pooler_output
        # 分类
        logits = self.classifier(pooled_output)
        loss = None
        if labels is not None:
            loss_fct = nn.CrossEntropyLoss()
            loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1))
        return SequenceClassifierOutput(
            loss=loss,
            logits=logits,
            hidden_states=outputs.hidden_states,
            attentions=outputs.attentions
        )

数据准备与预处理

4.1 数据集选择与加载

我们使用 IMDB 电影评论数据集进行情感分类任务。

from datasets import load_dataset, DatasetDict
import pandas as pd
from sklearn.model_selection import train_test_split
from torch.utils.data import DataLoader

class DataProcessor:
    """数据处理器"""
    def __init__(self, model_name: str = "bert-base-uncased", max_length: int = 512):
        self.tokenizer = BertTokenizer.from_pretrained(model_name)
        self.max_length = max_length

    def load_imdb_dataset(self, cache_dir: str = "./data"):
        """加载 IMDB 数据集"""
        # 从 Hugging Face 加载数据集
        dataset = load_dataset("imdb", cache_dir=cache_dir)
        # 划分验证集
        train_test_split = dataset["train"].train_test_split(test_size=0.1, seed=42)
        dataset_dict = DatasetDict({
            "train": train_test_split["train"],
            "validation": train_test_split["test"],
            "test": dataset["test"]
        })
        return dataset_dict

    def preprocess_function(self, examples):
        """预处理函数"""
        # 对文本进行分词
        tokenized_inputs = self.tokenizer(
            examples["text"],
            truncation=True,
            padding="max_length",
            max_length=self.max_length,
            return_tensors="pt"
        )
        # 转换为列表格式
        return {
            "input_ids": tokenized_inputs["input_ids"].tolist(),
            "attention_mask": tokenized_inputs["attention_mask"].tolist(),
            "labels": examples["label"]
        }

    def prepare_dataset(self, dataset_dict, batch_size: int = 32):
        """准备数据集"""
        # 应用预处理
        tokenized_datasets = dataset_dict.map(
            self.preprocess_function,
            batched=True,
            remove_columns=["text", "label"]
        )
        # 设置格式
        tokenized_datasets.set_format(type="torch", columns=["input_ids", "attention_mask", "labels"])
        # 创建数据加载器
        train_dataloader = DataLoader(
            tokenized_datasets["train"],
            shuffle=True,
            batch_size=batch_size,
            collate_fn=self.collate_fn
        )
        val_dataloader = DataLoader(
            tokenized_datasets["validation"],
            batch_size=batch_size,
            collate_fn=self.collate_fn
        )
        test_dataloader = DataLoader(
            tokenized_datasets["test"],
            batch_size=batch_size,
            collate_fn=self.collate_fn
        )
        return train_dataloader, val_dataloader, test_dataloader

    def collate_fn(self, batch):
        """批处理函数"""
        input_ids = torch.stack([item["input_ids"] for item in batch])
        attention_mask = torch.stack([item["attention_mask"] for item in batch])
        labels = torch.tensor([item["labels"] for item in batch])
        return {
            "input_ids": input_ids,
            "attention_mask": attention_mask,
            "labels": labels
        }

    def analyze_dataset(self, dataset_dict):
        """数据集分析"""
        stats = {}
        for split in ["train", "validation", "test"]:
            dataset = dataset_dict[split]
            stats[split] = {
                "samples": len(dataset),
                "positive": sum(dataset["label"]),
                "negative": len(dataset) - sum(dataset["label"]),
                "avg_length": sum(len(text.split()) for text in dataset["text"]) / len(dataset)
            }
        return pd.DataFrame(stats).T

4.2 数据增强策略

import nlpaug.augmenter.word as naw
from typing import List

class DataAugmenter:
    """数据增强器"""
    def __init__(self, aug_method: str = "synonym"):
        self.aug_method = aug_method
        if aug_method == "synonym":
            self.augmenter = naw.SynonymAug(aug_src="wordnet")
        elif aug_method == "contextual":
            self.augmenter = naw.ContextualWordEmbsAug(
                model_path='bert-base-uncased',
                action="substitute"
            )
        elif aug_method == "back_translation":
            self.augmenter = naw.BackTranslationAug(
                from_model_name='facebook/wmt19-en-de',
                to_model_name='facebook/wmt19-de-en'
            )
        else:
            raise ValueError(f"Unsupported augmentation method: {aug_method}")

    def augment_text(self, text: str, num_aug: int = 3) -> List[str]:
        """生成增强文本"""
        augmented_texts = []
        for _ in range(num_aug):
            augmented_text = self.augmenter.augment(text)
            augmented_texts.append(augmented_text)
        return augmented_texts

    def augment_dataset(self, dataset, num_aug_per_sample: int = 2):
        """增强整个数据集"""
        augmented_texts = []
        augmented_labels = []
        for text, label in zip(dataset["text"], dataset["label"]):
            # 原始样本
            augmented_texts.append(text)
            augmented_labels.append(label)
            # 增强样本
            for _ in range(num_aug_per_sample):
                augmented_text = self.augmenter.augment(text)
                augmented_texts.append(augmented_text)
                augmented_labels.append(label)
        return {"text": augmented_texts, "label": augmented_labels}

模型训练与微调

5.1 训练配置与超参数优化

from dataclasses import dataclass
from typing import Optional, Dict, Any
import yaml
from transformers import TrainingArguments

@dataclass
class TrainingConfig:
    """训练配置"""
    # 模型配置
    model_name: str = "bert-base-uncased"
    num_labels: int = 2
    dropout_rate: float = 0.1
    # 训练配置
    batch_size: int = 32
    gradient_accumulation_steps: int = 1
    num_epochs: int = 3
    learning_rate: float = 2e-5
    weight_decay: float = 0.01
    warmup_steps: int = 500
    # 优化器配置
    optimizer: str = "adamw"
    scheduler: str = "linear"
    # 实验跟踪
    logging_steps: int = 100
    eval_steps: int = 500
    save_steps: int = 1000
    # 硬件配置
    fp16: bool = True
    device: str = "cuda" if torch.cuda.is_available() else "cpu"

    @classmethod
    def from_yaml(cls, yaml_path: str):
        """从 YAML 文件加载配置"""
        with open(yaml_path, 'r') as f:
            config_dict = yaml.safe_load(f)
        return cls(**config_dict)

    def to_training_arguments(self, output_dir: str) -> TrainingArguments:
        """转换为 Hugging Face TrainingArguments"""
        return TrainingArguments(
            output_dir=output_dir,
            overwrite_output_dir=True,
            num_train_epochs=self.num_epochs,
            per_device_train_batch_size=self.batch_size,
            per_device_eval_batch_size=self.batch_size,
            gradient_accumulation_steps=self.gradient_accumulation_steps,
            learning_rate=self.learning_rate,
            weight_decay=self.weight_decay,
            warmup_steps=self.warmup_steps,
            logging_dir=f"{output_dir}/logs",
            logging_steps=self.logging_steps,
            eval_steps=self.eval_steps,
            save_steps=self.save_steps,
            evaluation_strategy="steps",
            save_strategy="steps",
            load_best_model_at_end=True,
            metric_for_best_model="accuracy",
            greater_is_better=True,
            fp16=self.fp16,
            report_to=["wandb"],
            run_name=f"bert-imdb-{self.model_name}"
        )

5.2 自定义训练器

为了更灵活地控制训练过程，我们可以封装一个自定义 Trainer。

import torch
from torch.utils.data import DataLoader
from transformers import Trainer, AdamW, get_linear_schedule_with_warmup
from typing import Dict, List, Optional, Tuple
import numpy as np
from tqdm.auto import tqdm

class CustomTrainer:
    """自定义训练器"""
    def __init__(
        self,
        model,
        train_config: TrainingConfig,
        train_dataloader: DataLoader,
        val_dataloader: DataLoader,
        test_dataloader: Optional[DataLoader] = None
    ):
        self.model = model
        self.config = train_config
        self.train_dataloader = train_dataloader
        self.val_dataloader = val_dataloader
        self.test_dataloader = test_dataloader
        # 设备设置
        self.device = torch.device(train_config.device)
        self.model.to(self.device)
        # 优化器和调度器
        self.optimizer = self._create_optimizer()
        self.scheduler = self._create_scheduler()
        # 训练状态
        self.global_step = 0
        self.best_metric = 0.0
        self.history = {"train_loss": [], "val_loss": [], "val_accuracy": [], "learning_rate": []}

    def _create_optimizer(self) -> torch.optim.Optimizer:
        """创建优化器"""
        no_decay = ["bias", "LayerNorm.weight"]
        optimizer_grouped_parameters = [
            {
                "params": [
                    p for n, p in self.model.named_parameters()
                    if not any(nd in n for nd in no_decay)
                ],
                "weight_decay": self.config.weight_decay
            },
            {
                "params": [
                    p for n, p in self.model.named_parameters()
                    if any(nd in n for nd in no_decay)
                ],
                "weight_decay": 0.0
            }
        ]
        if self.config.optimizer == "adamw":
            return AdamW(
                optimizer_grouped_parameters,
                lr=self.config.learning_rate,
                eps=1e-8
            )
        else:
            raise ValueError(f"Unsupported optimizer: {self.config.optimizer}")

    def _create_scheduler(self):
        """创建学习率调度器"""
        total_steps = len(self.train_dataloader) * self.config.num_epochs
        if self.config.scheduler == "linear":
            return get_linear_schedule_with_warmup(
                self.optimizer,
                num_warmup_steps=self.config.warmup_steps,
                num_training_steps=total_steps
            )
        else:
            raise ValueError(f"Unsupported scheduler: {self.config.scheduler}")

    def train_epoch(self, epoch: int) -> Dict[str, float]:
        """训练一个 epoch"""
        self.model.train()
        total_loss = 0
        progress_bar = tqdm(
            self.train_dataloader,
            desc=f"Epoch {epoch}",
            leave=False
        )
        for batch in progress_bar:
            # 将数据移到设备
            batch = {k: v.to(self.device) for k, v in batch.items()}
            # 前向传播
            outputs = self.model(**batch)
            loss = outputs.loss
            # 反向传播
            loss.backward()
            # 梯度裁剪
            torch.nn.utils.clip_grad_norm_(
                self.model.parameters(),
                max_norm=1.0
            )
            # 优化器步进
            self.optimizer.step()
            self.scheduler.step()
            self.optimizer.zero_grad()
            # 更新状态
            total_loss += loss.item()
            self.global_step += 1
            # 更新进度条
            progress_bar.set_postfix({
                "loss": loss.item(),
                "lr": self.scheduler.get_last_lr()[0]
            })
            # 记录学习率
            self.history["learning_rate"].append(
                self.scheduler.get_last_lr()[0]
            )
            # 定期验证
            if self.global_step % self.config.eval_steps == 0:
                val_metrics = self.evaluate()
                self.history["val_loss"].append(val_metrics["loss"])
                self.history["val_accuracy"].append(val_metrics["accuracy"])
            # 保存最佳模型
            if val_metrics["accuracy"] > self.best_metric:
                self.best_metric = val_metrics["accuracy"]
                self.save_model(f"best_model_step_{self.global_step}")
            # 切换回训练模式
            self.model.train()
        avg_loss = total_loss / len(self.train_dataloader)
        self.history["train_loss"].append(avg_loss)
        return {"train_loss": avg_loss}

    def evaluate(self, dataloader: Optional[DataLoader] = None) -> Dict[str, float]:
        """评估模型"""
        if dataloader is None:
            dataloader = self.val_dataloader
        self.model.eval()
        total_loss = 0
        all_preds = []
        all_labels = []
        with torch.no_grad():
            for batch in tqdm(dataloader, desc="Evaluating", leave=False):
                batch = {k: v.to(self.device) for k, v in batch.items()}
                outputs = self.model(**batch)
                loss = outputs.loss
                logits = outputs.logits
                total_loss += loss.item()
                preds = torch.argmax(logits, dim=-1)
                all_preds.extend(preds.cpu().numpy())
                all_labels.extend(batch["labels"].cpu().numpy())
        # 计算指标
        from sklearn.metrics import accuracy_score, precision_recall_fscore_support
        accuracy = accuracy_score(all_labels, all_preds)
        precision, recall, f1, _ = precision_recall_fscore_support(
            all_labels, all_preds, average="binary"
        )
        avg_loss = total_loss / len(dataloader)
        return {
            "loss": avg_loss,
            "accuracy": accuracy,
            "precision": precision,
            "recall": recall,
            "f1": f1
        }

    def train(self):
        """完整训练过程"""
        print(f"Starting training with config: {self.config}")
        print(f"Training samples: {len(self.train_dataloader.dataset)}")
        print(f"Validation samples: {len(self.val_dataloader.dataset)}")
        for epoch in range(self.config.num_epochs):
            print(f"\n{'='*50}")
            print(f"Epoch {epoch + 1}/{self.config.num_epochs}")
            print(f"{'='*50}")
            # 训练一个 epoch
            train_metrics = self.train_epoch(epoch)
            # 验证
            val_metrics = self.evaluate()
            # 打印结果
            print(f"\nEpoch {epoch + 1} Results:")
            print(f"Train Loss: {train_metrics['train_loss']:.4f}")
            print(f"Val Loss: {val_metrics['loss']:.4f}")
            print(f"Val Accuracy: {val_metrics['accuracy']:.4f}")
            print(f"Val F1: {val_metrics['f1']:.4f}")
            # 最终测试
            if self.test_dataloader is not None:
                test_metrics = self.evaluate(self.test_dataloader)
                print(f"\n{'='*50}")
                print("Final Test Results:")
                print(f"Test Accuracy: {test_metrics['accuracy']:.4f}")
                print(f"Test F1: {test_metrics['f1']:.4f}")
        return self.history

    def save_model(self, save_path: str):
        """保存模型"""
        torch.save({
            "model_state_dict": self.model.state_dict(),
            "optimizer_state_dict": self.optimizer.state_dict(),
            "scheduler_state_dict": self.scheduler.state_dict(),
            "config": self.config,
            "history": self.history,
            "global_step": self.global_step,
            "best_metric": self.best_metric
        }, f"{save_path}.pt")
        # 同时保存为 Hugging Face 格式
        self.model.save_pretrained(f"{save_path}_hf")

    def load_model(self, load_path: str):
        """加载模型"""
        checkpoint = torch.load(load_path, map_location=self.device)
        self.model.load_state_dict(checkpoint["model_state_dict"])
        self.optimizer.load_state_dict(checkpoint["optimizer_state_dict"])
        self.scheduler.load_state_dict(checkpoint["scheduler_state_dict"])
        self.history = checkpoint["history"]
        self.global_step = checkpoint["global_step"]
        self.best_metric = checkpoint["best_metric"]

5.3 训练脚本

#!/usr/bin/env python3
""" 训练脚本 """
import sys
import os
sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
import torch
import wandb
from transformers import BertForSequenceClassification
from src.data.processor import DataProcessor
from src.training.trainer import CustomTrainer, TrainingConfig
from src.models.model_utils import set_seed

def main():
    # 设置随机种子
    set_seed(42)
    # 初始化 WandB
    wandb.init(
        project="bert-imdb-classification",
        config={
            "model": "bert-base-uncased",
            "dataset": "imdb",
            "epochs": 3,
            "batch_size": 32,
            "learning_rate": 2e-5
        }
    )
    # 加载配置
    config = TrainingConfig()
    # 数据准备
    print("Loading and preprocessing data...")
    processor = DataProcessor(config.model_name)
    dataset_dict = processor.load_imdb_dataset()
    # 数据分析
    stats_df = processor.analyze_dataset(dataset_dict)
    print("\nDataset Statistics:")
    print(stats_df)
    # 准备数据加载器
    train_dataloader, val_dataloader, test_dataloader = processor.prepare_dataset(
        dataset_dict, batch_size=config.batch_size
    )
    # 加载模型
    print(f"\nLoading model: {config.model_name}")
    model = BertForSequenceClassification.from_pretrained(
        config.model_name,
        num_labels=config.num_labels,
        hidden_dropout_prob=config.dropout_rate,
        attention_probs_dropout_prob=config.dropout_rate
    )
    # 创建训练器
    trainer = CustomTrainer(
        model=model,
        train_config=config,
        train_dataloader=train_dataloader,
        val_dataloader=val_dataloader,
        test_dataloader=test_dataloader
    )
    # 开始训练
    print("\nStarting training...")
    history = trainer.train()
    # 保存最终模型
    trainer.save_model("final_model")
    # 记录到 WandB
    wandb.log({"final_accuracy": trainer.best_metric})
    wandb.finish()
    print("\nTraining completed successfully!")
    return history

if __name__ == "__main__":
    history = main()

模型评估与测试

6.1 综合评估指标

import numpy as np
from sklearn.metrics import (
    accuracy_score,
    precision_score,
    recall_score,
    f1_score,
    roc_auc_score,
    confusion_matrix,
    classification_report
)
import matplotlib.pyplot as plt
import seaborn as sns
from typing import Dict, List, Tuple, Any

class ModelEvaluator:
    """模型评估器"""
    def __init__(self, model, tokenizer, device: str = "cuda"):
        self.model = model
        self.tokenizer = tokenizer
        self.device = device
        self.model.to(device)
        self.model.eval()

    def predict(self, texts: List[str], batch_size: int = 32) -> Tuple[np.ndarray, np.ndarray]:
        """批量预测"""
        all_logits = []
        all_probs = []
        for i in range(0, len(texts), batch_size):
            batch_texts = texts[i:i+batch_size]
            # 编码
            inputs = self.tokenizer(
                batch_texts,
                truncation=True,
                padding=True,
                max_length=512,
                return_tensors="pt"
            )
            inputs = {k: v.to(self.device) for k, v in inputs.items()}
            # 预测
            with torch.no_grad():
                outputs = self.model(**inputs)
                logits = outputs.logits
                probs = torch.softmax(logits, dim=-1)
                all_logits.append(logits.cpu().numpy())
                all_probs.append(probs.cpu().numpy())
        logits_array = np.vstack(all_logits)
        probs_array = np.vstack(all_probs)
        return logits_array, probs_array

    def evaluate_classification(
        self,
        texts: List[str],
        labels: List[int],
        threshold: float = 0.5
    ) -> Dict[str, Any]:
        """分类评估"""
        # 预测
        logits, probs = self.predict(texts)
        preds = np.argmax(probs, axis=1)
        # 计算指标
        metrics = {
            "accuracy": accuracy_score(labels, preds),
            "precision": precision_score(labels, preds, average="binary"),
            "recall": recall_score(labels, preds, average="binary"),
            "f1": f1_score(labels, preds, average="binary"),
            "roc_auc": roc_auc_score(labels, probs[:, 1])
        }
        # 混淆矩阵
        cm = confusion_matrix(labels, preds)
        # 分类报告
        report = classification_report(
            labels, preds,
            target_names=["Negative", "Positive"],
            output_dict=True
        )
        # 置信度分析
        confidence_scores = np.max(probs, axis=1)
        return {
            "metrics": metrics,
            "confusion_matrix": cm,
            "classification_report": report,
            "predictions": preds,
            "probabilities": probs,
            "confidence_scores": confidence_scores
        }

    def analyze_errors(self, texts: List[str], labels: List[int], preds: List[int]):
        """错误分析"""
        errors = []
        for i, (text, label, pred) in enumerate(zip(texts, labels, preds)):
            if label != pred:
                errors.append({
                    "text": text[:200] + "..." if len(text) > 200 else text,
                    "true_label": "Positive" if label == 1 else "Negative",
                    "predicted_label": "Positive" if pred == 1 else "Negative",
                    "text_length": len(text.split())
                })
        return errors

    def plot_confusion_matrix(self, cm, save_path: str = None):
        """绘制混淆矩阵"""
        plt.figure(figsize=(8, 6))
        sns.heatmap(
            cm,
            annot=True,
            fmt="d",
            cmap="Blues",
            xticklabels=["Negative", "Positive"],
            yticklabels=["Negative", "Positive"]
        )
        plt.xlabel("Predicted")
        plt.ylabel("True")
        plt.title("Confusion Matrix")
        if save_path:
            plt.savefig(save_path, dpi=300, bbox_inches="tight")
        plt.show()

    def plot_roc_curve(self, labels: List[int], probs: np.ndarray, save_path: str = None):
        """绘制 ROC 曲线"""
        from sklearn.metrics import roc_curve
        fpr, tpr, thresholds = roc_curve(labels, probs[:, 1])
        plt.figure(figsize=(8, 6))
        plt.plot(fpr, tpr, label=f"ROC Curve (AUC = {roc_auc_score(labels, probs[:, 1]):.3f})")
        plt.plot([0, 1], [0, 1], "k--", label="Random")
        plt.xlabel("False Positive Rate")
        plt.ylabel("True Positive Rate")
        plt.title("ROC Curve")
        plt.legend()
        plt.grid(True)
        if save_path:
            plt.savefig(save_path, dpi=300, bbox_inches="tight")
        plt.show()

    def calibration_analysis(self, labels: List[int], probs: np.ndarray, n_bins: int = 10):
        """校准分析"""
        from sklearn.calibration import calibration_curve
        prob_true, prob_pred = calibration_curve(
            labels, probs[:, 1], n_bins=n_bins
        )
        plt.figure(figsize=(8, 6))
        plt.plot(prob_pred, prob_true, "s-", label="Model")
        plt.plot([0, 1], [0, 1], "k--", label="Perfectly Calibrated")
        plt.xlabel("Mean Predicted Probability")
        plt.ylabel("Fraction of Positives")
        plt.title("Calibration Curve")
        plt.legend()
        plt.grid(True)
        plt.show()
        # 计算 ECE (Expected Calibration Error)
        bin_edges = np.linspace(0, 1, n_bins + 1)
        bin_indices = np.digitize(probs[:, 1], bin_edges) - 1
        ece = 0
        for i in range(n_bins):
            mask = bin_indices == i
            if np.sum(mask) > 0:
                bin_prob_mean = np.mean(probs[mask, 1])
                bin_accuracy = np.mean(labels[mask] == 1)
                ece += np.abs(bin_prob_mean - bin_accuracy) * np.sum(mask)
        ece /= len(labels)
        return {"ece": ece, "calibration_curve": (prob_true, prob_pred)}

6.2 压力测试与性能基准

import time
from typing import Dict, List
import psutil
import GPUtil
from memory_profiler import memory_usage

class PerformanceBenchmark:
    """性能基准测试"""
    def __init__(self, model, tokenizer, device: str = "cuda"):
        self.model = model
        self.tokenizer = tokenizer
        self.device = device

    def measure_inference_time(
        self,
        texts: List[str],
        batch_sizes: List[int] = [1, 4, 8, 16, 32, 64]
    ) -> Dict[int, Dict[str, float]]:
        """测量推理时间"""
        results = {}
        for batch_size in batch_sizes:
            print(f"\nTesting batch size: {batch_size}")
            # 预热
            warmup_texts = ["This is a warmup sentence."] * batch_size
            self.predict_batch(warmup_texts)
            # 实际测试
            times = []
            for i in range(0, len(texts), batch_size):
                batch_texts = texts[i:i+batch_size]
                start_time = time.perf_counter()
                self.predict_batch(batch_texts)
                end_time = time.perf_counter()
                times.append(end_time - start_time)
            avg_time = np.mean(times)
            throughput = len(texts) / np.sum(times)
            results[batch_size] = {
                "avg_inference_time": avg_time,
                "throughput": throughput,
                "samples_per_second": throughput,
                "total_time": np.sum(times)
            }
            print(f" Average inference time: {avg_time:.4f}s")
            print(f" Throughput: {throughput:.2f} samples/s")
        return results

    def predict_batch(self, texts: List[str]):
        """批量预测"""
        inputs = self.tokenizer(
            texts,
            truncation=True,
            padding=True,
            max_length=512,
            return_tensors="pt"
        )
        inputs = {k: v.to(self.device) for k, v in inputs.items()}
        with torch.no_grad():
            outputs = self.model(**inputs)
        return outputs

    def measure_memory_usage(self, text_lengths: List[int] = [50, 100, 200, 400]):
        """测量内存使用"""
        memory_results = {}
        for length in text_lengths:
            # 生成测试文本
            test_text = " ".join(["word"] * length)
            texts = [test_text] * 32
            # 固定批量大小
            # 测量内存
            mem_usage = memory_usage((self.predict_batch, (texts,)), interval=0.1)
            memory_results[length] = {
                "max_memory_mb": max(mem_usage),
                "avg_memory_mb": np.mean(mem_usage),
                "text_length": length
            }
        return memory_results

    def measure_gpu_utilization(self, texts: List[str], duration: int = 30):
        """测量 GPU 利用率"""
        import threading
        import time
        gpu_stats = []
        stop_monitor = False

        def monitor_gpu():
            while not stop_monitor:
                gpus = GPUtil.getGPUs()
                for gpu in gpus:
                    gpu_stats.append({
                        "time": time.time(),
                        "memory_used": gpu.memoryUsed,
                        "memory_total": gpu.memoryTotal,
                        "load": gpu.load * 100,
                        "temperature": gpu.temperature
                    })
                time.sleep(0.5)

        # 启动监控线程
        monitor_thread = threading.Thread(target=monitor_gpu)
        monitor_thread.start()
        # 运行推理
        start_time = time.time()
        batch_size = 32
        while time.time() - start_time < duration:
            for i in range(0, min(len(texts), 1000), batch_size):
                batch_texts = texts[i:i+batch_size]
                self.predict_batch(batch_texts)
        # 停止监控
        stop_monitor = True
        monitor_thread.join()
        return gpu_stats

    def generate_report(self, benchmark_results: Dict) -> str:
        """生成性能报告"""
        report = []
        report.append("=" * 60)
        report.append("PERFORMANCE BENCHMARK REPORT")
        report.append("=" * 60)
        # 推理时间
        report.append("\n1. INFERENCE TIMES")
        report.append("-" * 40)
        for batch_size, metrics in benchmark_results["inference_times"].items():
            report.append(
                f"Batch Size {batch_size:3d}: "
                f"{metrics['avg_inference_time']:.4f}s avg, "
                f"{metrics['throughput']:.2f} samples/s"
            )
        # 内存使用
        report.append("\n2. MEMORY USAGE")
        report.append("-" * 40)
        for length, metrics in benchmark_results["memory_usage"].items():
            report.append(
                f"Text Length {length:3d}: "
                f"{metrics['max_memory_mb']:.1f}MB max, "
                f"{metrics['avg_memory_mb']:.1f}MB avg"
            )
        # 系统资源
        report.append("\n3. SYSTEM RESOURCES")
        report.append("-" * 40)
        cpu_percent = psutil.cpu_percent(interval=1)
        memory = psutil.virtual_memory()
        report.append(f"CPU Usage: {cpu_percent:.1f}%")
        report.append(f"Memory Usage: {memory.percent:.1f}%")
        report.append(f"Available Memory: {memory.available / 1024**3:.1f} GB")
        return "\n".join(report)

测试框架与质量保证

7.1 单元测试

import pytest
import tempfile
from hypothesis import given, strategies as st
from hypothesis.extra.numpy import arrays
import numpy as np

class TestDataProcessor:
    """数据处理器测试"""
    def setup_method(self):
        self.processor = DataProcessor("bert-base-uncased")

    def test_tokenization(self):
        """测试分词功能"""
        text = "This is a test sentence."
        tokenized = self.processor.tokenizer(
            text,
            truncation=True,
            padding="max_length",
            max_length=128
        )
        assert "input_ids" in tokenized
        assert "attention_mask" in tokenized
        assert len(tokenized["input_ids"]) == 128

    @given(
        st.text(min_size=1, max_size=1000),
        st.integers(min_value=0, max_value=1)
    )
    def test_preprocess_function(self, text, label):
        """假设测试预处理函数"""
        examples = {"text": [text], "label": [label]}
        result = self.processor.preprocess_function(examples)
        assert "input_ids" in result
        assert "attention_mask" in result
        assert "labels" in result
        assert len(result["labels"]) == 1
        assert result["labels"][0] == label

    def test_dataset_loading(self):
        """测试数据集加载"""
        # 使用小样本测试
        with tempfile.TemporaryDirectory() as tmpdir:
            # 这里使用模拟数据或小型测试数据集
            pass

class TestModel:
    """模型测试"""
    def setup_method(self):
        self.model = BertForSequenceClassification.from_pretrained(
            "bert-base-uncased",
            num_labels=2
        )
        self.model.eval()

    def test_model_forward(self):
        """测试模型前向传播"""
        batch_size = 2
        seq_length = 128
        input_ids = torch.randint(0, 1000, (batch_size, seq_length))
        attention_mask = torch.ones((batch_size, seq_length))
        with torch.no_grad():
            outputs = self.model(
                input_ids=input_ids,
                attention_mask=attention_mask
            )
        assert outputs.logits.shape == (batch_size, 2)
        assert outputs.logits.requires_grad == False

    def test_model_save_load(self, tmp_path):
        """测试模型保存和加载"""
        # 保存模型
        save_path = tmp_path / "test_model"
        self.model.save_pretrained(save_path)
        # 加载模型
        loaded_model = BertForSequenceClassification.from_pretrained(save_path)
        # 比较参数
        for (name1, param1), (name2, param2) in zip(
            self.model.named_parameters(),
            loaded_model.named_parameters()
        ):
            assert name1 == name2
            assert torch.allclose(param1, param2)

    @given(
        arrays(
            dtype=np.int64,
            shape=(2, 128),
            elements=st.integers(min_value=0, max_value=1000)
        ),
        arrays(
            dtype=np.int64,
            shape=(2, 128),
            elements=st.integers(min_value=0, max_value=1)
        )
    )
    def test_batch_processing(self, input_ids, attention_mask):
        """批量处理测试"""
        input_ids = torch.from_numpy(input_ids)
        attention_mask = torch.from_numpy(attention_mask)
        with torch.no_grad():
            outputs = self.model(
                input_ids=input_ids,
                attention_mask=attention_mask
            )
        assert outputs.logits.shape[0] == input_ids.shape[0]

class TestTraining:
    """训练测试"""
    def test_training_step(self):
        """测试训练步骤"""
        config = TrainingConfig(
            batch_size=2,
            num_epochs=1,
            learning_rate=1e-5
        )
        # 创建模拟数据
        train_dataset = torch.utils.data.TensorDataset(
            torch.randint(0, 1000, (10, 128)),  # input_ids
            torch.ones((10, 128)),              # attention_mask
            torch.randint(0, 2, (10,))          # labels
        )
        train_dataloader = DataLoader(
            train_dataset,
            batch_size=config.batch_size
        )
        val_dataloader = DataLoader(
            train_dataset,
            batch_size=config.batch_size
        )
        model = BertForSequenceClassification.from_pretrained(
            "bert-base-uncased",
            num_labels=2
        )
        trainer = CustomTrainer(
            model=model,
            train_config=config,
            train_dataloader=train_dataloader,
            val_dataloader=val_dataloader
        )
        # 测试一个训练步骤
        initial_loss = trainer.evaluate()["loss"]
        # 训练一个 epoch
        trainer.train_epoch(0)
        final_loss = trainer.evaluate()["loss"]
        # 检查损失是否下降
        assert final_loss < initial_loss or torch.isclose(
            torch.tensor(final_loss),
            torch.tensor(initial_loss),
            rtol=1e-3
        )

    def test_gradient_accumulation(self):
        """测试梯度累积"""
        config = TrainingConfig(
            batch_size=2,
            gradient_accumulation_steps=2,
            learning_rate=1e-5
        )
        # 验证梯度累积逻辑
        assert config.gradient_accumulation_steps == 2

if __name__ == "__main__":
    pytest.main([__file__, "-v", "--tb=short"])

7.2 集成测试

import asyncio
from fastapi.testclient import TestClient
import json

class TestAPI:
    """API 测试"""
    def setup_method(self):
        from src.api.app import app
        self.client = TestClient(app)

    def test_health_endpoint(self):
        """测试健康检查端点"""
        response = self.client.get("/health")
        assert response.status_code == 200
        assert response.json() == {"status": "healthy"}

    def test_predict_endpoint(self):
        """测试预测端点"""
        test_data = {
            "text": "This movie was absolutely fantastic!",
            "model_version": "latest"
        }
        response = self.client.post("/predict", json=test_data)
        assert response.status_code == 200
        result = response.json()
        assert "prediction" in result
        assert "confidence" in result
        assert "label" in result
        assert result["confidence"] >= 0 and result["confidence"] <= 1

    def test_batch_predict_endpoint(self):
        """测试批量预测端点"""
        test_data = {
            "texts": [
                "I loved this movie!",
                "It was terrible.",
                "The acting was amazing."
            ]
        }
        response = self.client.post("/predict/batch", json=test_data)
        assert response.status_code == 200
        results = response.json()
        assert len(results) == 3
        for result in results:
            assert "prediction" in result
            assert "confidence" in result

    def test_invalid_input(self):
        """测试无效输入"""
        test_data = {
            "text": "",  # 空文本
        }
        response = self.client.post("/predict", json=test_data)
        # 应该返回 400 错误
        assert response.status_code == 400

    async def test_concurrent_requests(self):
        """测试并发请求"""
        async def make_request():
            test_data = {
                "text": "Test concurrent request",
                "model_version": "latest"
            }
            response = self.client.post("/predict", json=test_data)
            return response.status_code

        # 创建多个并发请求
        tasks = [make_request() for _ in range(10)]
        results = await asyncio.gather(*tasks)
        # 所有请求都应该成功
        assert all(status == 200 for status in results)

    def test_model_management(self):
        """测试模型管理端点"""
        response = self.client.get("/models")
        assert response.status_code == 200
        models = response.json()
        assert "available_models" in models
        assert "active_model" in models

    def test_metrics_endpoint(self):
        """测试指标端点"""
        response = self.client.get("/metrics")
        assert response.status_code == 200
        metrics = response.json()
        assert "total_predictions" in metrics
        assert "average_response_time" in metrics

模型部署与 API 服务

8.1 FastAPI 服务实现

from fastapi import FastAPI, HTTPException, BackgroundTasks
from fastapi.middleware.cors import CORSMiddleware
from fastapi.responses import JSONResponse
from pydantic import BaseModel, Field, validator
from typing import List, Optional, Dict, Any
import asyncio
from concurrent.futures import ThreadPoolExecutor
import logging
from datetime import datetime
import pickle
import hashlib

# 配置日志
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# 定义数据模型
class PredictionRequest(BaseModel):
    """预测请求模型"""
    text: str = Field(..., min_length=1, max_length=5000)
    model_version: Optional[str] = "latest"

    @validator('text')
    def text_not_empty(cls, v):
        if not v.strip():
            raise ValueError('Text cannot be empty')
        return v.strip()

class BatchPredictionRequest(BaseModel):
    """批量预测请求模型"""
    texts: List[str] = Field(..., min_items=1, max_items=100)
    model_version: Optional[str] = "latest"

    @validator('texts')
    def validate_texts(cls, v):
        if not all(text.strip() for text in v):
            raise ValueError('All texts must be non-empty')
        return [text.strip() for text in v]

class PredictionResponse(BaseModel):
    """预测响应模型"""
    prediction: int
    label: str
    confidence: float
    model_version: str
    request_id: str
    processing_time: float

class BatchPredictionResponse(BaseModel):
    """批量预测响应模型"""
    predictions: List[Dict[str, Any]]
    batch_id: str
    total_processed: int
    processing_time: float

class ModelManager:
    """模型管理器"""
    def __init__(self, model_path: str = "./models"):
        self.model_path = model_path
        self.models = {}
        self.active_model = None
        self.model_versions = []
        self.executor = ThreadPoolExecutor(max_workers=4)
        # 加载模型
        self.load_models()

    def load_models(self):
        """加载所有可用模型"""
        import os
        import glob
        model_dirs = glob.glob(os.path.join(self.model_path, "*"))
        for model_dir in model_dirs:
            if os.path.isdir(model_dir):
                try:
                    model_name = os.path.basename(model_dir)
                    model = BertForSequenceClassification.from_pretrained(model_dir)
                    tokenizer = BertTokenizer.from_pretrained(model_dir)
                    self.models[model_name] = {
                        "model": model,
                        "tokenizer": tokenizer,
                        "loaded_at": datetime.now(),
                        "stats": {
                            "total_predictions": 0,
                            "avg_response_time": 0
                        }
                    }
                    self.model_versions.append(model_name)
                    if self.active_model is None:
                        self.active_model = model_name
                    logger.info(f"Loaded model: {model_name}")
                except Exception as e:
                    logger.error(f"Failed to load model {model_dir}: {e}")
        if not self.models:
            logger.warning("No models found. Loading default model...")
            self.load_default_model()

    def load_default_model(self):
        """加载默认模型"""
        try:
            model_name = "bert-base-uncased"
            model = BertForSequenceClassification.from_pretrained(
                model_name,
                num_labels=2
            )
            tokenizer = BertTokenizer.from_pretrained(model_name)
            self.models[model_name] = {
                "model": model,
                "tokenizer": tokenizer,
                "loaded_at": datetime.now(),
                "stats": {
                    "total_predictions": 0,
                    "avg_response_time": 0
                }
            }
            self.active_model = model_name
            self.model_versions.append(model_name)
            logger.info(f"Loaded default model: {model_name}")
        except Exception as e:
            logger.error(f"Failed to load default model: {e}")
            raise

    async def predict_async(
        self,
        text: str,
        model_version: str = "latest"
    ) -> Dict[str, Any]:
        """异步预测"""
        loop = asyncio.get_event_loop()
        # 在线程池中运行预测
        result = await loop.run_in_executor(
            self.executor,
            self.predict_sync,
            text,
            model_version
        )
        return result

    def predict_sync(
        self,
        text: str,
        model_version: str = "latest"
    ) -> Dict[str, Any]:
        """同步预测"""
        start_time = datetime.now()
        # 获取模型
        model_key = model_version if model_version != "latest" else self.active_model
        if model_key not in self.models:
            raise ValueError(f"Model {model_key} not found")
        model_info = self.models[model_key]
        model = model_info["model"]
        tokenizer = model_info["tokenizer"]
        # 预处理
        inputs = tokenizer(
            text,
            truncation=True,
            padding=True,
            max_length=512,
            return_tensors="pt"
        )
        # 预测
        with torch.no_grad():
            outputs = model(**inputs)
            logits = outputs.logits
            probs = torch.softmax(logits, dim=-1)
            prediction = torch.argmax(probs, dim=-1).item()
            confidence = probs[0][prediction].item()
        # 更新统计
        end_time = datetime.now()
        processing_time = (end_time - start_time).total_seconds()
        model_info["stats"]["total_predictions"] += 1
        # 更新平均响应时间
        current_avg = model_info["stats"]["avg_response_time"]
        total_preds = model_info["stats"]["total_predictions"]
        model_info["stats"]["avg_response_time"] = (
            (current_avg * (total_preds - 1) + processing_time) / total_preds
        )
        return {
            "prediction": prediction,
            "label": "Positive" if prediction == 1 else "Negative",
            "confidence": confidence,
            "model_version": model_key,
            "processing_time": processing_time
        }

    async def predict_batch_async(
        self,
        texts: List[str],
        model_version: str = "latest"
    ) -> List[Dict[str, Any]]:
        """异步批量预测"""
        loop = asyncio.get_event_loop()
        # 并行处理
        tasks = [
            loop.run_in_executor(
                self.executor,
                self.predict_sync,
                text,
                model_version
            )
            for text in texts
        ]
        results = await asyncio.gather(*tasks)
        return results

    def get_model_stats(self) -> Dict[str, Any]:
        """获取模型统计信息"""
        stats = {}
        for model_name, model_info in self.models.items():
            stats[model_name] = {
                "loaded_at": model_info["loaded_at"].isoformat(),
                "total_predictions": model_info["stats"]["total_predictions"],
                "avg_response_time": model_info["stats"]["avg_response_time"],
                "is_active": model_name == self.active_model
            }
        return stats

    def switch_active_model(self, model_version: str) -> bool:
        """切换活动模型"""
        if model_version in self.models:
            self.active_model = model_version
            logger.info(f"Switched active model to: {model_version}")
            return True
        return False

# 创建 FastAPI 应用
app = FastAPI(
    title="BERT Text Classification API",
    description="API for sentiment analysis using BERT model",
    version="1.0.0",
    docs_url="/docs",
    redoc_url="/redoc"
)

# 添加 CORS 中间件
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# 全局变量
model_manager = None
request_counter = 0
cache = {}

# 请求 ID 生成器
def generate_request_id(text: str) -> str:
    """生成请求 ID"""
    global request_counter
    request_counter += 1
    text_hash = hashlib.md5(text.encode()).hexdigest()[:8]
    timestamp = datetime.now().strftime("%Y%m%d%H%M%S")
    return f"{timestamp}_{request_counter}_{text_hash}"

# 缓存装饰器
def cache_predictions(func):
    """预测缓存装饰器"""
    async def wrapper(text: str, model_version: str = "latest", *args, **kwargs):
        cache_key = f"{model_version}:{hashlib.md5(text.encode()).hexdigest()}"
        if cache_key in cache:
            # 检查缓存是否过期（5 分钟）
            cached_time, result = cache[cache_key]
            if (datetime.now() - cached_time).total_seconds() < 300:
                logger.info(f"Cache hit for key: {cache_key[:20]}...")
                return result
        # 执行预测
        result = await func(text, model_version, *args, **kwargs)
        # 更新缓存
        cache[cache_key] = (datetime.now(), result)
        # 限制缓存大小
        if len(cache) > 1000:
            # 移除最旧的条目
            oldest_key = min(cache.keys(), key=lambda k: cache[k][0])
            del cache[oldest_key]
        return result
    return wrapper

@app.on_event("startup")
async def startup_event():
    """启动事件"""
    global model_manager
    logger.info("Starting up BERT Classification API...")
    # 初始化模型管理器
    model_manager = ModelManager("./models")
    logger.info(f"Loaded {len(model_manager.models)} models")
    logger.info(f"Active model: {model_manager.active_model}")

@app.on_event("shutdown")
async def shutdown_event():
    """关闭事件"""
    logger.info("Shutting down BERT Classification API...")
    if model_manager:
        model_manager.executor.shutdown()

@app.get("/")
async def root():
    """根端点"""
    return {
        "message": "BERT Text Classification API",
        "version": "1.0.0",
        "docs": "/docs",
        "health": "/health",
        "models": "/models"
    }

@app.get("/health")
async def health_check():
    """健康检查"""
    return {
        "status": "healthy",
        "timestamp": datetime.now().isoformat(),
        "models_loaded": len(model_manager.models) if model_manager else 0,
        "active_model": model_manager.active_model if model_manager else None
    }

@app.post("/predict", response_model=PredictionResponse)
@cache_predictions
async def predict(
    request: PredictionRequest,
    background_tasks: BackgroundTasks
):
    """单文本预测"""
    try:
        start_time = datetime.now()
        # 生成请求 ID
        request_id = generate_request_id(request.text)
        # 执行预测
        result = await model_manager.predict_async(
            request.text,
            request.model_version
        )
        # 计算处理时间
        processing_time = (datetime.now() - start_time).total_seconds()
        # 记录日志（后台任务）
        background_tasks.add_task(
            log_prediction,
            request_id=request_id,
            text_length=len(request.text),
            prediction=result["prediction"],
            confidence=result["confidence"],
            processing_time=processing_time
        )
        return PredictionResponse(
            prediction=result["prediction"],
            label=result["label"],
            confidence=result["confidence"],
            model_version=result["model_version"],
            request_id=request_id,
            processing_time=processing_time
        )
    except Exception as e:
        logger.error(f"Prediction error: {e}")
        raise HTTPException(
            status_code=500,
            detail=f"Prediction failed: {str(e)}"
        )

@app.post("/predict/batch", response_model=BatchPredictionResponse)
async def predict_batch(request: BatchPredictionRequest):
    """批量预测"""
    try:
        start_time = datetime.now()
        # 生成批次 ID
        batch_id = hashlib.md5("".join(request.texts).encode()).hexdigest()[:12]
        # 批量预测
        results = await model_manager.predict_batch_async(
            request.texts,
            request.model_version
        )
        # 计算处理时间
        processing_time = (datetime.now() - start_time).total_seconds()
        # 准备响应
        predictions = []
        for i, (text, result) in enumerate(zip(request.texts, results)):
            request_id = generate_request_id(text)
            predictions.append({
                "text_preview": text[:100] + "..." if len(text) > 100 else text,
                "prediction": result["prediction"],
                "label": result["label"],
                "confidence": result["confidence"],
                "request_id": request_id
            })
        return BatchPredictionResponse(
            predictions=predictions,
            batch_id=batch_id,
            total_processed=len(results),
            processing_time=processing_time
        )
    except Exception as e:
        logger.error(f"Batch prediction error: {e}")
        raise HTTPException(
            status_code=500,
            detail=f"Batch prediction failed: {str(e)}"
        )

@app.get("/models")
async def get_models():
    """获取可用模型"""
    if not model_manager:
        raise HTTPException(status_code=500, detail="Model manager not initialized")
    stats = model_manager.get_model_stats()
    return {
        "available_models": list(model_manager.models.keys()),
        "active_model": model_manager.active_model,
        "model_stats": stats
    }

@app.post("/models/switch")
async def switch_model(model_version: str):
    """切换活动模型"""
    if not model_manager:
        raise HTTPException(status_code=500, detail="Model manager not initialized")
    success = model_manager.switch_active_model(model_version)
    if success:
        return {
            "message": f"Switched active model to {model_version}",
            "active_model": model_manager.active_model
        }
    else:
        raise HTTPException(
            status_code=400,
            detail=f"Model {model_version} not found"
        )

@app.get("/metrics")
async def get_metrics():
    """获取 API 指标"""
    global cache, request_counter
    total_predictions = sum(
        model_info["stats"]["total_predictions"]
        for model_info in model_manager.models.values()
    )
    avg_response_times = [
        model_info["stats"]["avg_response_time"]
        for model_info in model_manager.models.values()
    ]
    avg_response_time = (
        sum(avg_response_times) / len(avg_response_times)
        if avg_response_times else 0
    )
    return {
        "total_predictions": total_predictions,
        "total_requests": request_counter,
        "cache_size": len(cache),
        "cache_hit_rate": 0.0,  # 需要实现命中率跟踪
        "average_response_time": avg_response_time,
        "models_loaded": len(model_manager.models),
        "uptime": (datetime.now() - startup_time).total_seconds()
    }

@app.get("/predictions/history")
async def get_prediction_history(
    limit: int = 100,
    model_version: Optional[str] = None
):
    """获取预测历史"""
    # 这里可以实现从数据库或日志中获取历史记录
    # 暂时返回模拟数据
    return {
        "message": "Prediction history endpoint",
        "limit": limit,
        "model_version": model_version
    }

async def log_prediction(
    request_id: str,
    text_length: int,
    prediction: int,
    confidence: float,
    processing_time: float
):
    """记录预测日志（后台任务）"""
    log_entry = {
        "timestamp": datetime.now().isoformat(),
        "request_id": request_id,
        "text_length": text_length,
        "prediction": prediction,
        "confidence": confidence,
        "processing_time": processing_time
    }
    # 这里可以将日志写入文件或数据库
    logger.info(f"Prediction logged: {log_entry}")

# 全局变量
startup_time = datetime.now()

# 运行应用
if __name__ == "__main__":
    import uvicorn
    uvicorn.run(
        app,
        host="0.0.0.0",
        port=8000,
        log_level="info",
        reload=True  # 开发模式下自动重载
    )

8.2 Docker 部署配置

# Dockerfile
FROM python:3.9-slim

# 设置工作目录
WORKDIR /app

# 安装系统依赖
RUN apt-get update && apt-get install -y \
    build-essential \
    curl \
    && rm -rf /var/lib/apt/lists/*

# 复制依赖文件
COPY requirements.txt .

# 安装 Python 依赖
RUN pip install --no-cache-dir -r requirements.txt

# 复制应用代码
COPY . .

# 创建模型目录
RUN mkdir -p models

# 下载默认模型（可选）
# RUN python -c "from transformers import BertForSequenceClassification, BertTokenizer; \
# model = BertForSequenceClassification.from_pretrained('bert-base-uncased', num_labels=2); \
# model.save_pretrained('./models/bert-base-uncased'); \
# tokenizer = BertTokenizer.from_pretrained('bert-base-uncased'); \
# tokenizer.save_pretrained('./models/bert-base-uncased')"

# 暴露端口
EXPOSE 8000

# 健康检查
HEALTHCHECK --interval=30s --timeout=30s --start-period=5s --retries=3 \
    CMD curl -f http://localhost:8000/health || exit 1

# 启动命令
CMD ["uvicorn", "src.api.app:app", "--host", "0.0.0.0", "--port", "8000"]

# docker-compose.yml
version: '3.8'
services:
  api:
    build: .
    ports:
      - "8000:8000"
    volumes:
      - ./models:/app/models
      - ./logs:/app/logs
    environment:
      - CUDA_VISIBLE_DEVICES=0  # 如果使用 GPU
      - MODEL_PATH=/app/models
      - LOG_LEVEL=INFO
    deploy:
      resources:
        reservations:
          devices:
            - driver: nvidia
              count: 1
              capabilities: [gpu]
    restart: unless-stopped
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:8000/health"]
      interval: 30s
      timeout: 10s
      retries: 3
      start_period: 40s

  # 可选：添加监控服务
  prometheus:
    image: prom/prometheus:latest
    ports:
      - "9090:9090"
    volumes:
      - ./prometheus.yml:/etc/prometheus/prometheus.yml
      - prometheus_data:/prometheus
    command:
      - '--config.file=/etc/prometheus/prometheus.yml'
      - '--storage.tsdb.path=/prometheus'
      - '--web.console.libraries=/etc/prometheus/console_libraries'
      - '--web.console.templates=/etc/prometheus/console_templates'
      - '--storage.tsdb.retention.time=200h'
      - '--web.enable-lifecycle'

  grafana:
    image: grafana/grafana:latest
    ports:
      - "3000:3000"
    volumes:
      - grafana_data:/var/lib/grafana
      - ./grafana/provisioning:/etc/grafana/provisioning
    environment:
      - GF_SECURITY_ADMIN_PASSWORD=admin
    restart: unless-stopped

volumes:
  prometheus_data:
  grafana_data:

监控与日志

9.1 结构化日志配置

# logging_config.py
import logging
import logging.config
import json
from datetime import datetime
from pythonjsonlogger import jsonlogger

class CustomJsonFormatter(jsonlogger.JsonFormatter):
    """自定义 JSON 日志格式化器"""
    def add_fields(self, log_record, record, message_dict):
        super().add_fields(log_record, record, message_dict)
        if not log_record.get('timestamp'):
            log_record['timestamp'] = datetime.utcnow().isoformat()
        if log_record.get('level'):
            log_record['level'] = log_record['level'].upper()
        else:
            log_record['level'] = record.levelname
        # 添加额外字段
        log_record['service'] = 'bert-classification-api'
        log_record['module'] = record.module
        log_record['function'] = record.funcName
        log_record['line'] = record.lineno

LOGGING_CONFIG = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'json': {
            '()': CustomJsonFormatter,
            'format': '%(timestamp)s %(level)s %(name)s %(message)s'
        },
        'simple': {
            'format': '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
        }
    },
    'handlers': {
        'console': {
            'class': 'logging.StreamHandler',
            'formatter': 'json',
            'level': 'INFO'
        },
        'file': {
            'class': 'logging.handlers.RotatingFileHandler',
            'filename': 'logs/application.log',
            'formatter': 'json',
            'maxBytes': 10485760,  # 10MB
            'backupCount': 5,
            'level': 'INFO'
        },
        'error_file': {
            'class': 'logging.handlers.RotatingFileHandler',
            'filename': 'logs/error.log',
            'formatter': 'json',
            'maxBytes': 10485760,
            'backupCount': 5,
            'level': 'ERROR'
        }
    },
    'loggers': {
        '': {
            'handlers': ['console', 'file', 'error_file'],
            'level': 'INFO',
            'propagate': True
        },
        'uvicorn': {
            'handlers': ['console', 'file'],
            'level': 'INFO',
            'propagate': False
        },
        'uvicorn.error': {
            'handlers': ['error_file'],
            'level': 'ERROR',
            'propagate': False
        }
    }
}

def setup_logging():
    """设置日志配置"""
    logging.config.dictConfig(LOGGING_CONFIG)
    # 捕获未处理的异常
    def handle_exception(exc_type, exc_value, exc_traceback):
        if issubclass(exc_type, KeyboardInterrupt):
            sys.__excepthook__(exc_type, exc_value, exc_traceback)
        return
    logger = logging.getLogger(__name__)
    logger.critical("Uncaught exception", exc_info=(exc_type, exc_value, exc_traceback))
    sys.excepthook = handle_exception

9.2 性能监控

# monitoring.py
from prometheus_client import Counter, Histogram, Gauge, generate_latest
from prometheus_client.core import CollectorRegistry
import time
from functools import wraps

# 创建指标注册表
registry = CollectorRegistry()

# 定义指标
PREDICTION_REQUESTS = Counter(
    'prediction_requests_total',
    'Total number of prediction requests',
    ['model_version', 'endpoint'],
    registry=registry
)
PREDICTION_LATENCY = Histogram(
    'prediction_latency_seconds',
    'Prediction latency in seconds',
    ['model_version', 'endpoint'],
    buckets=(0.01, 0.05, 0.1, 0.5, 1.0, 5.0),
    registry=registry
)
ACTIVE_MODELS = Gauge(
    'active_models_total',
    'Number of active models',
    registry=registry
)
MODEL_LOAD_TIME = Histogram(
    'model_load_time_seconds',
    'Model loading time in seconds',
    ['model_name'],
    registry=registry
)
CACHE_HITS = Counter(
    'cache_hits_total',
    'Total number of cache hits',
    registry=registry
)
CACHE_MISSES = Counter(
    'cache_misses_total',
    'Total number of cache misses',
    registry=registry
)
ERROR_COUNT = Counter(
    'prediction_errors_total',
    'Total number of prediction errors',
    ['error_type', 'model_version'],
    registry=registry
)

def monitor_predictions(func):
    """监控预测函数的装饰器"""
    @wraps(func)
    async def wrapper(*args, **kwargs):
        start_time = time.time()
        # 获取模型版本
        model_version = kwargs.get('model_version', 'latest')
        endpoint = func.__name__
        # 递增请求计数器
        PREDICTION_REQUESTS.labels(
            model_version=model_version,
            endpoint=endpoint
        ).inc()
        try:
            result = await func(*args, **kwargs)
            # 记录延迟
            latency = time.time() - start_time
            PREDICTION_LATENCY.labels(
                model_version=model_version,
                endpoint=endpoint
            ).observe(latency)
            return result
        except Exception as e:
            # 记录错误
            ERROR_COUNT.labels(
                error_type=type(e).__name__,
                model_version=model_version
            ).inc()
            raise
    return wrapper

def update_model_metrics(model_manager):
    """更新模型指标"""
    ACTIVE_MODELS.set(len(model_manager.models))
    for model_name, model_info in model_manager.models.items():
        # 可以添加更多模型特定指标
        pass

@app.get("/metrics")
async def metrics_endpoint():
    """Prometheus 指标端点"""
    # 更新动态指标
    if model_manager:
        update_model_metrics(model_manager)
    return Response(
        generate_latest(registry),
        media_type="text/plain"
    )

完整测试执行流程

10.1 端到端测试脚本

#!/usr/bin/env python3
""" 端到端测试脚本 """
import sys
import os
import time
import requests
import json
from typing import Dict, List, Any
import pandas as pd
import numpy as np

sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
from src.data.processor import DataProcessor
from src.training.trainer import CustomTrainer
from src.evaluation.metrics import ModelEvaluator
from src.api.app import app
from fastapi.testclient import TestClient

class EndToEndTest:
    """端到端测试"""
    def __init__(self, api_url: str = "http://localhost:8000"):
        self.api_url = api_url
        self.client = TestClient(app)
        # 测试客户端
        self.results = {}

    def run_all_tests(self):
        """运行所有测试"""
        print("=" * 60)
        print("端到端测试开始")
        print("=" * 60)
        tests = [
            self.test_environment,
            self.test_data_pipeline,
            self.test_model_training,
            self.test_model_evaluation,
            self.test_api_endpoints,
            self.test_performance,
            self.test_error_handling,
            self.test_concurrent_requests
        ]
        for test in tests:
            try:
                test_name = test.__name__
                print(f"\n执行测试：{test_name}")
                print("-" * 40)
                result = test()
                self.results[test_name] = {"status": "PASSED", "result": result}
                print(f"✓ {test_name}: PASSED")
            except Exception as e:
                self.results[test_name] = {"status": "FAILED", "error": str(e)}
                print(f"✗ {test_name}: FAILED - {e}")
        self.generate_report()

    def test_environment(self) -> Dict[str, Any]:
        """测试环境配置"""
        # 检查 Python 版本
        python_version = sys.version_info
        assert python_version.major == 3 and python_version.minor >= 8
        # 检查依赖
        import torch
        import transformers
        return {
            "python_version": f"{python_version.major}.{python_version.minor}.{python_version.micro}",
            "torch_version": torch.__version__,
            "transformers_version": transformers.__version__,
            "cuda_available": torch.cuda.is_available()
        }

    def test_data_pipeline(self) -> Dict[str, Any]:
        """测试数据管道"""
        processor = DataProcessor("bert-base-uncased")
        # 测试分词
        test_text = "This is a test sentence for tokenization."
        tokenized = processor.tokenizer(
            test_text,
            truncation=True,
            padding="max_length",
            max_length=128
        )
        assert "input_ids" in tokenized
        assert len(tokenized["input_ids"]) == 128
        # 测试批处理
        batch_texts = ["Text 1", "Text 2", "Text 3"]
        batch_labels = [0, 1, 0]
        batch = processor.collate_fn([
            {"input_ids": torch.tensor([101]*128),
             "attention_mask": torch.tensor([1]*128),
             "labels": label}
            for label in batch_labels
        ])
        assert batch["input_ids"].shape[0] == 3
        assert batch["labels"].shape[0] == 3
        return {
            "tokenization_test": "PASSED",
            "batch_processing_test": "PASSED"
        }

    def test_model_training(self) -> Dict[str, Any]:
        """测试模型训练（使用小数据集）"""
        # 使用小样本进行快速测试
        from transformers import BertForSequenceClassification
        model = BertForSequenceClassification.from_pretrained(
            "bert-base-uncased",
            num_labels=2
        )
        # 创建模拟数据
        train_data = torch.utils.data.TensorDataset(
            torch.randint(0, 1000, (100, 128)),
            torch.ones((100, 128)),
            torch.randint(0, 2, (100,))
        )
        train_dataloader = torch.utils.data.DataLoader(
            train_data,
            batch_size=16
        )
        val_dataloader = torch.utils.data.DataLoader(
            train_data,
            batch_size=16
        )
        # 快速训练测试
        from src.training.train_config import TrainingConfig
        config = TrainingConfig(
            batch_size=16,
            num_epochs=1,
            learning_rate=1e-5
        )
        trainer = CustomTrainer(
            model=model,
            train_config=config,
            train_dataloader=train_dataloader,
            val_dataloader=val_dataloader
        )
        # 测试一个训练步骤
        initial_metrics = trainer.evaluate()
        trainer.train_epoch(0)
        final_metrics = trainer.evaluate()
        # 检查模型是否学习
        assert final_metrics["loss"] <= initial_metrics["loss"] * 1.5
        return {
            "initial_loss": initial_metrics["loss"],
            "final_loss": final_metrics["loss"],
            "training_completed": True
        }

    def test_model_evaluation(self) -> Dict[str, Any]:
        """测试模型评估"""
        from transformers import BertForSequenceClassification, BertTokenizer
        model = BertForSequenceClassification.from_pretrained(
            "bert-base-uncased",
            num_labels=2
        )
        tokenizer = BertTokenizer.from_pretrained("bert-base-uncased")
        evaluator = ModelEvaluator(model, tokenizer, device="cpu")
        # 测试预测
        test_texts = [
            "This is excellent!",
            "I don't like this at all.",
            "It's okay, nothing special."
        ]
        test_labels = [1, 0, 0]
        results = evaluator.evaluate_classification(test_texts, test_labels)
        assert "accuracy" in results["metrics"]
        assert "confusion_matrix" in results
        return {
            "evaluation_metrics": results["metrics"],
            "predictions_made": len(results["predictions"])
        }

    def test_api_endpoints(self) -> Dict[str, Any]:
        """测试 API 端点"""
        # 测试健康检查
        response = self.client.get("/health")
        assert response.status_code == 200
        health_data = response.json()
        assert health_data["status"] == "healthy"
        # 测试预测端点
        test_data = {
            "text": "This movie was absolutely fantastic! I loved every minute of it.",
            "model_version": "latest"
        }
        response = self.client.post("/predict", json=test_data)
        assert response.status_code == 200
        prediction_data = response.json()
        assert "prediction" in prediction_data
        assert "confidence" in prediction_data
        assert prediction_data["confidence"] >= 0
        # 测试批量预测
        batch_data = {
            "texts": [
                "Amazing film, highly recommended!",
                "Not my cup of tea, unfortunately.",
                "The acting was superb."
            ]
        }
        response = self.client.post("/predict/batch", json=batch_data)
        assert response.status_code == 200
        batch_result = response.json()
        assert len(batch_result["predictions"]) == 3
        # 测试模型管理端点
        response = self.client.get("/models")
        assert response.status_code == 200
        models_data = response.json()
        assert "available_models" in models_data
        return {
            "health_check": "PASSED",
            "single_prediction": "PASSED",
            "batch_prediction": "PASSED",
            "model_management": "PASSED"
        }

    def test_performance(self) -> Dict[str, Any]:
        """测试性能"""
        import time
        # 测试单个请求延迟
        test_cases = [
            "Short text",
            "Medium length text " * 10,
            "Very long text " * 100
        ]
        latencies = []
        for text in test_cases:
            start_time = time.perf_counter()
            response = self.client.post("/predict", json={"text": text})
            end_time = time.perf_counter()
            latency = end_time - start_time
            latencies.append(latency)
            assert response.status_code == 200
            assert latency < 5.0  # 单个请求应小于 5 秒
        # 测试吞吐量
        batch_texts = [f"Test text {i}" for i in range(10)]
        start_time = time.perf_counter()
        response = self.client.post("/predict/batch", json={"texts": batch_texts})
        end_time = time.perf_counter()
        batch_latency = end_time - start_time
        assert response.status_code == 200
        assert batch_latency < 10.0  # 批量请求应小于 10 秒
        avg_latency_per_request = batch_latency / len(batch_texts)
        return {
            "single_request_latencies": latencies,
            "batch_latency": batch_latency,
            "avg_latency_per_request": avg_latency_per_request,
            "throughput": len(batch_texts) / batch_latency
        }

    def test_error_handling(self) -> Dict[str, Any]:
        """测试错误处理"""
        # 测试空文本
        response = self.client.post("/predict", json={"text": ""})
        assert response.status_code == 422  # 验证错误
        # 测试不存在的模型
        response = self.client.post("/predict", json={
            "text": "Test text",
            "model_version": "non-existent-model"
        })
        # 根据实现，可能返回 400 或 500
        assert response.status_code in [400, 500]
        # 测试无效的批量请求
        response = self.client.post("/predict/batch", json={"texts": []})
        assert response.status_code == 422
        return {
            "empty_text_handling": "PASSED",
            "invalid_model_handling": "PASSED",
            "empty_batch_handling": "PASSED"
        }

    def test_concurrent_requests(self) -> Dict[str, Any]:
        """测试并发请求"""
        import concurrent.futures
        import time
        test_texts = [f"Concurrent test {i}" for i in range(20)]

        def make_request(text):
            start_time = time.perf_counter()
            response = self.client.post("/predict", json={"text": text})
            end_time = time.perf_counter()
            return {
                "status_code": response.status_code,
                "latency": end_time - start_time
            }

        # 使用线程池模拟并发请求
        with concurrent.futures.ThreadPoolExecutor(max_workers=10) as executor:
            futures = [
                executor.submit(make_request, text)
                for text in test_texts
            ]
            results = [
                future.result()
                for future in concurrent.futures.as_completed(futures)
            ]
            status_codes = [r["status_code"] for r in results]
            latencies = [r["latency"] for r in results]
            # 所有请求都应成功
            assert all(code == 200 for code in status_codes)
            # 平均延迟应在合理范围内
            avg_latency = np.mean(latencies)
            assert avg_latency < 2.0
        return {
            "total_requests": len(results),
            "success_rate": sum(1 for code in status_codes if code == 200) / len(results),
            "avg_latency": avg_latency,
            "max_latency": max(latencies)
        }

    def generate_report(self):
        """生成测试报告"""
        print("\n" + "=" * 60)
        print("测试报告")
        print("=" * 60)
        total_tests = len(self.results)
        passed_tests = sum(1 for result in self.results.values() if result["status"] == "PASSED")
        print(f"总测试数：{total_tests}")
        print(f"通过测试：{passed_tests}")
        print(f"失败测试：{total_tests - passed_tests}")
        if total_tests - passed_tests > 0:
            print("\n失败详情:")
            for test_name, result in self.results.items():
                if result["status"] == "FAILED":
                    print(f" {test_name}: {result['error']}")
        # 保存详细报告
        report_data = {
            "summary": {
                "total_tests": total_tests,
                "passed_tests": passed_tests,
                "failed_tests": total_tests - passed_tests,
                "success_rate": passed_tests / total_tests if total_tests > 0 else 0
            },
            "details": self.results,
            "timestamp": time.strftime("%Y-%m-%d %H:%M:%S")
        }
        with open("test_report.json", "w") as f:
            json.dump(report_data, f, indent=2, default=str)
        print(f"\n详细报告已保存到：test_report.json")
        # 决定是否通过
        if passed_tests == total_tests:
            print("\n✓ 所有测试通过!")
            return True
        else:
            print("\n✗ 部分测试失败!")
            return False

def main():
    """主函数"""
    # 启动测试
    tester = EndToEndTest()
    try:
        success = tester.run_all_tests()
        if success:
            print("\n" + "=" * 60)
            print("端到端测试完成 - 所有测试通过!")
            print("=" * 60)
            sys.exit(0)
        else:
            print("\n" + "=" * 60)
            print("端到端测试完成 - 存在失败的测试!")
            print("=" * 60)
            sys.exit(1)
    except Exception as e:
        print(f"\n测试执行出错：{e}")
        import traceback
        traceback.print_exc()
        sys.exit(1)

if __name__ == "__main__":
    main()

10.2 自动化测试流水线

# .github/workflows/test.yml
name: CI/CD Pipeline
on:
  push:
    branches: [ main, develop ]
  pull_request:
    branches: [ main ]

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        python-version: [3.8, 3.9, 3.10]
    steps:
      - uses: actions/checkout@v3
      - name: Set up Python ${{ matrix.python-version }}
        uses: actions/setup-python@v4
        with:
          python-version: ${{ matrix.python-version }}
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install -r requirements.txt
          pip install pytest pytest-cov flake8 mypy
      - name: Lint with flake8
        run: |
          flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
          flake8 . --count --exit-zero --max-complexity=10 --max-line-length=127 --statistics
      - name: Type check with mypy
        run: |
          mypy src --ignore-missing-imports
      - name: Test with pytest
        run: |
          pytest tests/ -v --cov=src --cov-report=xml
      - name: Upload coverage to Codecov
        uses: codecov/codecov-action@v3
        with:
          file: ./coverage.xml
          flags: unittests
          name: codecov-umbrella

  docker:
    needs: test
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Build Docker image
        run: |
          docker build -t bert-classification-api:latest .
      - name: Run Docker container
        run: |
          docker run -d -p 8000:8000 --name test-api bert-classification-api:latest
          sleep 10  # 等待应用启动
      - name: Test Docker container
        run: |
          curl -f http://localhost:8000/health || exit 1
      - name: Cleanup
        run: |
          docker stop test-api
          docker rm test-api

优化与最佳实践

11.1 模型优化技术

from optimum.onnxruntime import ORTModelForSequenceClassification
from optimum.onnxruntime import ORTQuantizer
from optimum.onnxruntime.configuration import AutoQuantizationConfig
import onnxruntime as ort

class ModelOptimizer:
    """模型优化器"""
    def __init__(self, model_path: str):
        self.model_path = model_path

    def convert_to_onnx(self, output_path: str = "./models/onnx"):
        """转换为 ONNX 格式"""
        from optimum.onnxruntime import ORTModelForSequenceClassification
        # 加载模型并转换为 ONNX
        model = ORTModelForSequenceClassification.from_pretrained(
            self.model_path,
            from_transformers=True,
            export=True
        )
        # 保存 ONNX 模型
        model.save_pretrained(output_path)
        return output_path

    def quantize_model(
        self,
        model_path: str,
        quantization_config: str = "avx512_vnni"
    ):
        """量化模型"""
        # 加载模型
        model = ORTModelForSequenceClassification.from_pretrained(model_path)
        # 创建量化器
        quantizer = ORTQuantizer.from_pretrained(model_path)
        # 配置量化
        qconfig = AutoQuantizationConfig.avx512_vnni(is_static=False, per_channel=False)
        # 应用量化
        quantizer.quantize(
            save_dir=f"{model_path}_quantized",
            quantization_config=qconfig
        )
        return f"{model_path}_quantized"

    def optimize_with_onnxruntime(self, model_path: str):
        """使用 ONNX Runtime 优化"""
        # 会话选项
        sess_options = ort.SessionOptions()
        # 启用并行执行
        sess_options.intra_op_num_threads = 4
        sess_options.inter_op_num_threads = 2
        # 优化级别
        sess_options.graph_optimization_level = ort.GraphOptimizationLevel.ORT_ENABLE_ALL
        # 内存优化
        sess_options.enable_cpu_mem_arena = True
        sess_options.enable_mem_pattern = True
        # 创建优化会话
        session = ort.InferenceSession(
            f"{model_path}/model.onnx",
            sess_options=sess_options,
            providers=['CPUExecutionProvider']
        )
        return session

    def benchmark_optimizations(self, model_variants: Dict[str, Any], test_data: List[str]):
        """基准测试不同优化"""
        results = {}
        for variant_name, model in model_variants.items():
            start_time = time.time()
            # 运行推理
            for text in test_data:
                # 执行预测
                pass
            end_time = time.time()
            results[variant_name] = {
                "total_time": end_time - start_time,
                "avg_time_per_sample": (end_time - start_time) / len(test_data),
                "throughput": len(test_data) / (end_time - start_time)
            }
        return results

11.2 缓存策略

from functools import lru_cache
import hashlib
import pickle
from datetime import datetime, timedelta

class PredictionCache:
    """预测缓存"""
    def __init__(self, max_size: int = 10000, ttl: int = 3600):
        self.max_size = max_size
        self.ttl = timedelta(seconds=ttl)
        self.cache = {}
        self.access_times = {}
        self.hits = 0
        self.misses = 0

    def _generate_key(self, text: str, model_version: str) -> str:
        """生成缓存键"""
        content = f"{model_version}:{text}"
        return hashlib.md5(content.encode()).hexdigest()

    def get(self, text: str, model_version: str):
        """获取缓存值"""
        key = self._generate_key(text, model_version)
        if key in self.cache:
            cached_time, value = self.cache[key]
            # 检查是否过期
            if datetime.now() - cached_time < self.ttl:
                self.access_times[key] = datetime.now()
                self.hits += 1
                return value
        self.misses += 1
        return None

    def set(self, text: str, model_version: str, value):
        """设置缓存值"""
        key = self._generate_key(text, model_version)
        # 如果缓存已满，移除最旧的条目
        if len(self.cache) >= self.max_size:
            oldest_key = min(
                self.access_times.keys(),
                key=lambda k: self.access_times[k]
            )
            del self.cache[oldest_key]
            del self.access_times[oldest_key]
        # 存储新值
        self.cache[key] = (datetime.now(), value)
        self.access_times[key] = datetime.now()

    def clear_expired(self):
        """清除过期条目"""
        now = datetime.now()
        expired_keys = [
            key
            for key, (cached_time, _) in self.cache.items()
            if now - cached_time > self.ttl
        ]
        for key in expired_keys:
            del self.cache[key]
            del self.access_times[key]

    def get_stats(self) -> Dict[str, Any]:
        """获取缓存统计"""
        total = self.hits + self.misses
        hit_rate = self.hits / total if total > 0 else 0
        return {
            "size": len(self.cache),
            "hits": self.hits,
            "misses": self.misses,
            "hit_rate": hit_rate,
            "max_size": self.max_size,
            "ttl_seconds": self.ttl.total_seconds()
        }

总结与扩展

12.1 关键收获

通过本项目的完整实施，我们获得了以下关键收获：

1. 完整的 AI 集成流程：从模型选择到生产部署的全流程实践经验
2. 最佳工程实践：包括测试驱动开发、持续集成、监控告警等
3. 性能优化技巧：模型量化、缓存策略、并行处理等优化方法
4. 可扩展架构：支持多模型、多版本、高并发的系统设计
5. 全面的质量保证：单元测试、集成测试、端到端测试的完整覆盖

12.2 扩展方向

本项目可以进一步扩展为：

1. 多模态 AI 集成：集成图像、音频等多模态模型
2. 模型版本管理：实现 A/B 测试、金丝雀发布等高级部署策略
3. 自动扩缩容：基于流量预测的自动资源调整
4. 联邦学习支持：在边缘设备上进行分布式训练
5. 解释性 AI：添加模型解释和可视化功能

12.3 部署检查清单

在将系统部署到生产环境前，请确保：

• 所有测试通过（单元测试、集成测试、端到端测试）
• 性能基准测试完成并满足 SLA 要求
• 监控和告警配置完毕
• 日志收集和分析系统就绪
• 备份和恢复策略制定
• 安全审计和漏洞扫描完成
• 文档和运行手册编写完成
• 灾难恢复计划制定

成功的 AI 项目不仅仅是模型准确率，更是系统工程、可维护性、可扩展性和可靠性的综合体现。希望本文能成为我们 AI 工程化道路上的有力参考。