toxic-api / app /models /model_loader.py
handrix
Initial deployment - Toxic Detection API
ae4e2a6
"""
Model Loader
============
Responsible for loading and initializing models (Single Responsibility)
"""
import torch
from transformers import AutoModel, AutoTokenizer
from typing import Tuple
import logging
from app.models.phobert_model import PhoBERTFineTuned
from app.core.config import settings
from app.core.exceptions import ModelNotLoadedException
logger = logging.getLogger(__name__)
class ModelLoader:
"""
Model loader service
Responsibilities:
- Load tokenizer
- Load base model
- Load fine-tuned weights
- Initialize model on correct device
"""
def __init__(self):
self._model: PhoBERTFineTuned | None = None
self._tokenizer: AutoTokenizer | None = None
self._device: torch.device | None = None
def load(self) -> Tuple[PhoBERTFineTuned, AutoTokenizer, torch.device]:
"""
Load model, tokenizer, and set device
Returns:
model: Loaded model
tokenizer: Loaded tokenizer
device: Device (CPU/CUDA)
Raises:
ModelNotLoadedException: If loading fails
"""
try:
# Set device
self._device = torch.device(settings.DEVICE)
logger.info(f"Using device: {self._device}")
# Load tokenizer
logger.info(f"Loading tokenizer: {settings.MODEL_NAME}")
self._tokenizer = AutoTokenizer.from_pretrained(settings.MODEL_NAME)
# Load base model
logger.info(f"Loading base model: {settings.MODEL_NAME}")
phobert = AutoModel.from_pretrained(settings.MODEL_NAME)
# Initialize fine-tuned model
logger.info("Initializing fine-tuned model")
self._model = PhoBERTFineTuned(
embedding_model=phobert,
hidden_dim=768,
dropout=0.3,
num_classes=2,
num_layers_to_finetune=4,
pooling='mean'
)
# Load weights
logger.info(f"Loading weights from: {settings.MODEL_PATH}")
state_dict = torch.load(
settings.MODEL_PATH,
map_location=self._device
)
self._model.load_state_dict(state_dict)
# Move to device and set eval mode
self._model = self._model.to(self._device)
self._model.eval()
logger.info("Model loaded successfully")
return self._model, self._tokenizer, self._device
except Exception as e:
logger.error(f"Failed to load model: {str(e)}")
raise ModelNotLoadedException()
@property
def model(self) -> PhoBERTFineTuned:
"""Get loaded model"""
if self._model is None:
raise ModelNotLoadedException()
return self._model
@property
def tokenizer(self) -> AutoTokenizer:
"""Get loaded tokenizer"""
if self._tokenizer is None:
raise ModelNotLoadedException()
return self._tokenizer
@property
def device(self) -> torch.device:
"""Get device"""
if self._device is None:
raise ModelNotLoadedException()
return self._device
def is_loaded(self) -> bool:
"""Check if model is loaded"""
return all([
self._model is not None,
self._tokenizer is not None,
self._device is not None
])
# Singleton instance
model_loader = ModelLoader()