Fine-tuning/backend/app/services/training_service.py

import asyncio
import json
import uuid
from datetime import datetime
from typing import Any

from app.config import get_settings
from app.core.db import async_session, TrainingJobModel
from app.core.job_queue import JobStatus, TrainingJob, job_queue
from app.core.logging import logger
from sqlalchemy import select

settings = get_settings()


async def create_training_job(config: dict[str, Any]) -> dict[str, Any]:
    """校验配置、创建任务记录、加入队列。"""
    job_id = str(uuid.uuid4())
    model_id = config.get("model_id", "")
    model_type = config.get("model_type", "text")
    dataset_id = config.get("dataset_id", "")
    peft_method = config.get("peft_method", "lora")
    task_type = config.get("task_type", "sft")
    dataset_template = config.get("dataset_template", "auto")

    # 写入数据库
    record = TrainingJobModel(
        id=job_id,
        model_id=model_id,
        model_type=model_type,
        dataset_id=dataset_id,
        peft_method=peft_method,
        task_type=task_type,
        dataset_template=dataset_template,
        status="pending",
        epochs=config.get("epochs", 3),
        batch_size=config.get("batch_size", 4),
        gradient_accumulation=config.get("gradient_accumulation", 4),
        learning_rate=config.get("learning_rate", 2e-4),
        max_seq_length=config.get("max_seq_length", 2048),
        warmup_ratio=config.get("warmup_ratio", 0.05),
        save_strategy=config.get("save_strategy", "epoch"),
        eval_strategy=config.get("eval_strategy", "epoch"),
        eval_steps=config.get("eval_steps", 100),
        lora_r=config.get("lora_r", 16),
        lora_alpha=config.get("lora_alpha", 32),
        lora_dropout=config.get("lora_dropout", 0.05),
        lora_target_modules=config.get("lora_target_modules", "all-linear"),
        qlora_bits=config.get("qlora_bits", 4),
        # PPO fields
        ppo_epochs=config.get("ppo_epochs", 4),
        vf_coef=config.get("vf_coef", 0.1),
        kl_coef=config.get("kl_coef", 0.2),
        response_length=config.get("response_length", 512),
        reward_model_path=config.get("reward_model_path"),
        reward_type=config.get("reward_type", "heuristic"),
        created_at=datetime.utcnow(),
    )
    async with async_session() as session:
        session.add(record)
        await session.commit()

    # 加入 JobQueue
    # DeepSpeed 需要多 GPU，单卡模式已禁用
    if config.get("deepspeed", False):
        config["deepspeed"] = False
        logger.warning("DeepSpeed requires multiple GPUs, but only GPU 3 is available. DeepSpeed disabled.")

    job = TrainingJob(
        id=job_id,
        model_id=model_id,
        model_type=model_type,
        peft_method=peft_method,
        dataset_id=dataset_id,
        config=config,
        status=JobStatus.PENDING,
    )
    await job_queue.enqueue(job_id, job)

    logger.info(f"Training job created: {job_id}")
    return {
        "id": job_id,
        "model_id": model_id,
        "model_type": model_type,
        "peft_method": peft_method,
        "status": "pending",
        "created_at": record.created_at.isoformat(),
    }


async def list_training_jobs() -> list[dict[str, Any]]:
    """列出所有训练任务。"""
    async with async_session() as session:
        result = await session.execute(select(TrainingJobModel).order_by(TrainingJobModel.created_at.desc()))
        records = result.scalars().all()

    return [_job_to_dict(r) for r in records]


async def get_training_job(job_id: str) -> dict[str, Any] | None:
    """获取指定任务详情。"""
    async with async_session() as session:
        result = await session.execute(select(TrainingJobModel).where(TrainingJobModel.id == job_id))
        record = result.scalar_one_or_none()
        if record:
            return _job_to_dict(record)
    return None


async def cancel_training_job(job_id: str) -> dict[str, Any]:
    """向运行中的任务发送取消信号。"""
    await job_queue.cancel(job_id)

    async with async_session() as session:
        result = await session.execute(select(TrainingJobModel).where(TrainingJobModel.id == job_id))
        record = result.scalar_one_or_none()
        if record:
            record.status = "cancelled"
            record.finished_at = datetime.utcnow()
            await session.commit()

    logger.info(f"Job cancelled: {job_id}")
    return {"status": "cancelled"}


async def update_job_in_db(job):
    """JobQueue 回调：同步 job 状态到数据库。"""
    try:
        async with async_session() as session:
            result = await session.execute(select(TrainingJobModel).where(TrainingJobModel.id == job.id))
            record = result.scalar_one_or_none()
            if record:
                record.status = job.status.value if hasattr(job.status, "value") else str(job.status)
                record.progress = job.progress
                record.current_epoch = job.current_epoch
                record.current_step = job.current_step
                record.total_steps = job.total_steps
                record.loss = job.loss
                record.adapter_path = job.adapter_path
                record.error_message = job.error_message
                if job.status == JobStatus.TRAINING and not record.started_at:
                    record.started_at = datetime.utcnow()
                if job.status.is_terminal:
                    record.finished_at = datetime.utcnow()
                await session.commit()
    except Exception as e:
        logger.error(f"Failed to update job {job.id} in DB: {e}")


def _job_to_dict(r) -> dict[str, Any]:
    return {
        "id": r.id,
        "model_id": r.model_id,
        "model_type": r.model_type,
        "peft_method": r.peft_method,
        "status": r.status,
        "progress": r.progress or 0.0,
        "current_epoch": r.current_epoch or 0,
        "current_step": r.current_step or 0,
        "total_steps": r.total_steps or 0,
        "loss": r.loss,
        "created_at": r.created_at.isoformat() if r.created_at else "",
        "started_at": r.started_at.isoformat() if r.started_at else None,
        "finished_at": r.finished_at.isoformat() if r.finished_at else None,
        "error_message": r.error_message,
        "adapter_path": r.adapter_path,
    }


def _generate_deepspeed_config(stage: int = 2) -> str:
    """生成 DeepSpeed 配置文件，返回文件路径。"""
    import json
    from app.config import get_settings
    settings = get_settings()

    ds_config = {
        "fp16": {"enabled": True},
        "zero_optimization": {
            "stage": stage,
            "offload_optimizer": {"device": "cpu", "pin_memory": True},
            "offload_param": {"device": "cpu", "pin_memory": True},
            "overlap_comm": True,
            "contiguous_gradients": True,
            "reduce_bucket_size": "auto",
            "stage3_prefetch_bucket_size": "auto",
            "stage3_param_persistence_threshold": "auto",
        } if stage == 3 else {
            "stage": stage,
            "offload_optimizer": {"device": "cpu", "pin_memory": True},
            "allgather_partitions": True,
            "allgather_bucket_size": 2e8,
            "overlap_comm": True,
            "reduce_scatter": True,
            "reduce_bucket_size": 2e8,
            "contiguous_gradients": True,
        },
        "gradient_accumulation_steps": "auto",
        "gradient_clipping": "auto",
        "steps_per_print": 10,
        "train_batch_size": "auto",
        "train_micro_batch_size_per_gpu": "auto",
        "wall_clock_breakdown": False,
    }

    config_path = settings.data_dir / "deepspeed_config.json"
    with open(config_path, "w") as f:
        json.dump(ds_config, f, indent=2)

    logger.info(f"DeepSpeed config generated: {config_path}")
    return str(config_path)