CodeGen / src /models /load_model.py
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import os
import logging
import torch
from pathlib import Path
from tqdm import tqdm
from peft import LoraConfig, get_peft_model, PeftModel
from transformers import AutoModelForCausalLM, AutoTokenizer
from torch.utils.data import DataLoader, Dataset
os.environ["PYTORCH_MPS_HIGH_WATERMARK_RATIO"] = "0.0"
logger = logging.getLogger(__name__)
class SpiderDataset(Dataset):
"""Formats Spider JSON data into causal LM training examples (Question -> MongoDB Query)."""
def __init__(self, data, tokenizer, max_length=512):
self.data = data
self.tokenizer = tokenizer
self.max_length = max_length
def __len__(self):
return len(self.data)
def __getitem__(self, idx):
item = self.data[idx]
question = item.get("question", "")
mongodb_query = item.get("generated_mongodb_query", "")
# Handle if stored as a list
if isinstance(mongodb_query, list) and len(mongodb_query) > 0:
mongodb_query = mongodb_query[0]
prompt = f"### Task: Generate MongoDB Query (MQL)\n### Question:\n{question}\n\n### MongoDB Query:\n"
prompt_enc = self.tokenizer(prompt, truncation=True, max_length=self.max_length, return_tensors="pt")
completion_enc = self.tokenizer(mongodb_query, truncation=True, max_length=self.max_length, return_tensors="pt")
input_ids = torch.cat([prompt_enc.input_ids[0], completion_enc.input_ids[0]], dim=0)
attention_mask = torch.cat([prompt_enc.attention_mask[0], completion_enc.attention_mask[0]], dim=0)
prompt_len = prompt_enc.input_ids.shape[1]
labels = torch.cat([torch.full((prompt_len,), -100, dtype=torch.long), completion_enc.input_ids[0]], dim=0)
return {
"input_ids": input_ids,
"attention_mask": attention_mask,
"labels": labels
}
class ModelLoader:
def __init__(self, config, device_override=None):
self.config = config
self.device = device_override or self._detect_device()
if self.device == "cuda":
self.dtype = torch.float16
elif self.device == "mps":
self.dtype = torch.float16
else:
self.dtype = torch.float32
self.tokenizer = None
self.base_model = None
self.lora_model = None
logger.info(f"πŸ–₯️ Initialized ModelLoader | Device: {self.device} | Dtype: {self.dtype}")
def _detect_device(self):
if torch.cuda.is_available():
return "cuda"
if hasattr(torch.backends, "mps") and torch.backends.mps.is_available():
return "mps"
return "cpu"
def load_tokenizer(self):
model_name = getattr(self.config, "model_name", "Qwen/Qwen2.5-Coder-0.5B-Instruct")
logger.info(f"πŸ”„ Loading tokenizer: {model_name}")
self.tokenizer = AutoTokenizer.from_pretrained(model_name, trust_remote_code=True)
if self.tokenizer.pad_token is None:
self.tokenizer.pad_token = self.tokenizer.eos_token
return self.tokenizer
def load_base_model(self):
model_name = getattr(self.config, "model_name", "Qwen/Qwen2.5-Coder-0.5B-Instruct")
logger.info(f"πŸ”„ Loading base model: {model_name}")
if self.device == "cuda":
self.base_model = AutoModelForCausalLM.from_pretrained(
model_name,
torch_dtype=self.dtype,
trust_remote_code=True,
low_cpu_mem_usage=True,
device_map="auto"
)
else:
self.base_model = AutoModelForCausalLM.from_pretrained(
model_name,
torch_dtype=self.dtype,
trust_remote_code=True,
low_cpu_mem_usage=True
)
self.base_model.to(self.device)
self.base_model.eval()
return self.base_model
def setup_lora(self, trainable_fraction=1.0, r=16, alpha=32, dropout=0.05):
if self.base_model is None:
self.load_base_model()
target_modules = ["q_proj", "k_proj", "v_proj", "o_proj", "gate_proj", "up_proj", "down_proj"]
peft_config = LoraConfig(
r=r,
lora_alpha=alpha,
target_modules=target_modules,
lora_dropout=dropout,
bias="none",
task_type="CAUSAL_LM"
)
self.lora_model = get_peft_model(self.base_model, peft_config)
if trainable_fraction < 1.0:
self._apply_trainable_fraction(trainable_fraction)
else:
logger.info("βœ… LoRA configured with 100% trainable parameters.")
self.lora_model.print_trainable_parameters()
return self.lora_model
def _apply_trainable_fraction(self, fraction):
lora_params = [(n, p) for n, p in self.lora_model.named_parameters() if "lora_" in n and p.requires_grad]
total_lora = len(lora_params)
num_to_freeze = int(total_lora * (1.0 - fraction))
if num_to_freeze > 0:
for i, (name, param) in enumerate(lora_params):
if i < num_to_freeze:
param.requires_grad = False
trainable_count = sum(1 for p in self.lora_model.parameters() if p.requires_grad)
logger.info(f"πŸ”’ Froze {num_to_freeze}/{total_lora} LoRA parameters. Remaining trainable: {trainable_count} ({fraction*100}%).")
def autodetect_saved_model(self, output_dir):
output_dir = Path(output_dir)
if output_dir.exists() and (output_dir / "adapter_config.json").exists():
logger.info(f"βœ… Found saved LoRA adapter at {output_dir}. Loading...")
if self.base_model is None:
self.load_base_model()
# NOTE (ZeroGPU compatibility): peft's from_pretrained() infers the load
# device via infer_device(), NOT from the base model's actual .device.
# On HF Spaces ZeroGPU, `spaces` monkey-patches torch.cuda.is_available()
# to report True even before a real GPU is attached to the process, so
# infer_device() always says "cuda" here -- which makes peft try to load
# the adapter's .safetensors weights with a raw, direct CUDA file load.
# That bypasses spaces' safe .to("cuda") staging and crashes with
# "No CUDA GPUs are available". Forcing torch_device="cpu" here loads the
# adapter safely on CPU; the single .to(self.device) call right after is
# a normal nn.Module.to() move, which spaces *does* stage/support.
self.lora_model = PeftModel.from_pretrained(self.base_model, str(output_dir), torch_device="cpu")
self.lora_model.to(self.device)
self.lora_model.eval()
return self.lora_model
logger.info(f"ℹ️ No saved adapter found at {output_dir}.")
return None
def train_lora(self, train_data, output_dir, epochs=3, batch_size=1, grad_accum=4, lr=2e-4, max_length=512):
lr = float(lr) # Ensure lr is a float to prevent PyTorch optimizer TypeError
if self.lora_model is None:
self.setup_lora()
dataset = SpiderDataset(train_data, self.tokenizer, max_length)
def collate_fn(batch):
max_len = max(len(b["input_ids"]) for b in batch)
input_ids, attention_mask, labels = [], [], []
pad_id = self.tokenizer.pad_token_id
for b in batch:
pad_len = max_len - len(b["input_ids"])
input_ids.append(b["input_ids"].tolist() + [pad_id] * pad_len)
attention_mask.append(b["attention_mask"].tolist() + [0] * pad_len)
labels.append(b["labels"].tolist() + [-100] * pad_len)
return {
"input_ids": torch.tensor(input_ids, dtype=torch.long).to(self.device),
"attention_mask": torch.tensor(attention_mask, dtype=torch.long).to(self.device),
"labels": torch.tensor(labels, dtype=torch.long).to(self.device)
}
loader = DataLoader(dataset, batch_size=batch_size, shuffle=True, collate_fn=collate_fn)
optimizer = torch.optim.AdamW(
filter(lambda p: p.requires_grad, self.lora_model.parameters()),
lr=lr
)
self.lora_model.train()
logger.info(f"πŸš€ Starting LoRA training | Device: {self.device} | Epochs: {epochs} | Batch: {batch_size} | Grad Accum: {grad_accum} | LR: {lr}")
for epoch in range(epochs):
epoch_loss = 0.0
progress_bar = tqdm(loader, desc=f"Epoch {epoch+1}/{epochs}", leave=False)
optimizer.zero_grad()
for step, batch in enumerate(progress_bar):
outputs = self.lora_model(**batch)
loss = outputs.loss / grad_accum
loss.backward()
epoch_loss += loss.item() * grad_accum
if (step + 1) % grad_accum == 0:
optimizer.step()
optimizer.zero_grad()
progress_bar.set_postfix({"loss": f"{loss.item() * grad_accum:.4f}"})
# Clear MPS cache periodically to prevent memory leaks on Mac
if self.device == "mps" and (step + 1) % 10 == 0:
torch.mps.empty_cache()
optimizer.step()
optimizer.zero_grad()
avg_loss = epoch_loss / len(loader)
logger.info(f"βœ… Epoch {epoch+1} completed | Avg Loss: {avg_loss:.4f}")
output_dir = Path(output_dir)
output_dir.mkdir(parents=True, exist_ok=True)
self.lora_model.save_pretrained(str(output_dir))
self.tokenizer.save_pretrained(str(output_dir))
logger.info(f"πŸ’Ύ LoRA adapter saved to {output_dir}")
self.lora_model.eval()
return self.lora_model
def load_models(self, lora_path=None):
"""Returns a dictionary of models and the tokenizer."""
if self.tokenizer is None:
self.load_tokenizer()
if self.base_model is None:
self.load_base_model()
models = {"base": self.base_model, "lora": None}
if self.lora_model is not None:
logger.info("Reusing already-loaded LoRA model in memory.")
models["lora"] = self.lora_model
elif lora_path:
lora_path = Path(lora_path)
if lora_path.exists() and (lora_path / "adapter_config.json").exists():
logger.info(f"Loading LoRA model from {lora_path}")
self.lora_model = PeftModel.from_pretrained(self.base_model, str(lora_path))
self.lora_model.to(self.device)
self.lora_model.eval()
models["lora"] = self.lora_model
else:
logger.warning(f"LoRA path {lora_path} does not exist or is invalid. Returning base model as 'lora'.")
models["lora"] = self.base_model
return models, self.tokenizer