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

from pathlib import Path
from typing import Any

from app.config import get_settings
from app.core.logging import logger

settings = get_settings()


async def test_model(model_id: str, prompt: str, max_new_tokens: int = 128, temperature: float = 0.8, top_p: float = 0.95) -> dict[str, Any]:
    """加载已缓存模型并生成测试响应。"""
    if settings.use_remote_compute:
        return _test_model_remote(model_id, prompt, max_new_tokens, temperature, top_p)
    return _test_model_local(model_id, prompt, max_new_tokens, temperature, top_p)


def _test_model_remote(model_id: str, prompt: str, max_new_tokens: int, temperature: float, top_p: float) -> dict[str, Any]:
    """通过 SSH 在算力节点执行模型测试。"""
    import json
    from app.core.remote_executor import ssh_exec

    safe_prompt = prompt.replace('"', '\\"').replace("'", "\\'").replace("\n", "\\n")
    container = settings.compute_node_docker_container
    python = settings.compute_node_python

    remote_cmd = (
        f"docker exec {container} "
        f"{python} -c \""
        "import json, asyncio; "
        "from app.services.model_service import resolve_model_path; "
        "model_path = asyncio.run(resolve_model_path('" + model_id + "')); "
        "import torch; "
        "from transformers import AutoTokenizer, AutoModelForCausalLM, AutoModel; "
        "t = AutoTokenizer.from_pretrained(model_path, trust_remote_code=True); "
        "t.pad_token = t.pad_token or t.eos_token; "
        "m = None; "
        "for cls, kw in [(AutoModelForCausalLM, {'trust_remote_code': True}), (AutoModel, {'trust_remote_code': True})]: "
        "    try: m = cls.from_pretrained(model_path, torch_dtype=torch.float16, device_map='auto', **kw); break; "
        "    except: pass; "
        "m.eval(); "
        "inp = t('" + safe_prompt + "', return_tensors='pt').to(m.device); "
        "out = m.generate(**inp, max_new_tokens=" + str(max_new_tokens) + ", temperature=" + str(temperature) + ", top_p=" + str(top_p) + ", do_sample=" + str(temperature > 0).lower() + ", pad_token_id=t.eos_token_id); "
        "gen = t.decode(out[0][inp['input_ids'].shape[1]:], skip_special_tokens=True); "
        "print(json.dumps({'generated_text': gen}))\" 2>&1"
    )

    code, stdout, stderr = ssh_exec(remote_cmd, timeout=600)

    if code != 0:
        logger.error(f"Remote model test failed: {stderr}")
        return {"error": stderr.strip() or "Remote test failed"}

    # 提取最后一行 JSON
    for line in reversed(stdout.strip().split("\n")):
        line = line.strip()
        if line.startswith("{"):
            try:
                result = json.loads(line)
                result["model_id"] = model_id
                result["prompt"] = prompt
                return result
            except json.JSONDecodeError:
                continue

    return {"error": f"Invalid response: {stdout[:500]}"}


async def _test_model_local(model_id: str, prompt: str, max_new_tokens: int, temperature: float, top_p: float) -> dict[str, Any]:
    """本地执行模型测试（仅用于开发环境）。"""
    import torch
    from transformers import AutoModel, AutoModelForCausalLM, AutoTokenizer, AutoConfig

    from app.services.model_service import resolve_model_path
    model_path = await resolve_model_path(model_id)
    if not model_path:
        return {"error": f"Model not found in cache: {model_id}"}

    model_dir = Path(model_path)
    if not (model_dir / "config.json").exists():
        return {"error": f"Model directory not found: {model_dir}"}

    tokenizer = AutoTokenizer.from_pretrained(model_dir, trust_remote_code=True)
    if tokenizer.pad_token is None:
        tokenizer.pad_token = tokenizer.eos_token

    # 通用加载策略：尝试多种加载方式，自动兼容各种新架构
    model = None
    for loader_cls, kwargs in [
        (AutoModelForCausalLM, {"trust_remote_code": True}),
        (AutoModel, {"trust_remote_code": True}),
    ]:
        try:
            model = loader_cls.from_pretrained(
                model_dir,
                torch_dtype=torch.float16,
                device_map="auto",
                **kwargs,
            )
            break
        except Exception:
            continue

    if model is None:
        return {"error": f"Unable to load model with any available loader. Model type may not be supported yet."}
    model.eval()

    inputs = tokenizer(prompt, return_tensors="pt").to(model.device)

    with torch.no_grad():
        outputs = model.generate(
            **inputs,
            max_new_tokens=max_new_tokens,
            temperature=temperature,
            top_p=top_p,
            do_sample=temperature > 0,
            pad_token_id=tokenizer.eos_token_id,
        )

    generated_text = tokenizer.decode(outputs[0][inputs["input_ids"].shape[1]:], skip_special_tokens=True)

    return {
        "model_id": model_id,
        "prompt": prompt,
        "generated_text": generated_text,
    }