diff --git a/backend/app/services/ml/embedder.py b/backend/app/services/ml/embedder.py new file mode 100644 index 0000000..49c40f4 --- /dev/null +++ b/backend/app/services/ml/embedder.py @@ -0,0 +1,62 @@ +"""SigLIP SO400M image-embedding wrapper (PyTorch CPU). + +Direct port of ImageRepo's siglip.py. torch/transformers are imported +lazily inside load() so this module can be imported in the web container +(which never runs inference) without paying the torch import cost. +""" + +import os +from pathlib import Path + +import numpy as np +from PIL import Image, ImageFile + +ImageFile.LOAD_TRUNCATED_IMAGES = True + +MODEL_NAME = os.environ.get( + "SIGLIP_MODEL_NAME", "google/siglip-so400m-patch14-384" +) +MODEL_VERSION = os.environ.get( + "SIGLIP_MODEL_VERSION", "siglip-so400m-patch14-384" +) +EMBED_DIM = 1152 +_LOCAL_DIR = Path(os.environ.get("ML_MODEL_DIR", "/models")) / "siglip" + + +class Embedder: + def __init__(self, model_dir: Path | None = None): + self._model_dir = model_dir or _LOCAL_DIR + self._model = None + self._processor = None + self._torch = None + + def load(self) -> None: + if self._model is not None: + return + import torch + from transformers import AutoModel, AutoProcessor + + self._torch = torch + self._processor = AutoProcessor.from_pretrained(str(self._model_dir)) + self._model = AutoModel.from_pretrained(str(self._model_dir)) + self._model.eval() + + def infer(self, image_path: Path) -> np.ndarray: + """Return a 1152-dim float32 embedding (SigLIP MAP-pooled output).""" + self.load() + img = Image.open(image_path).convert("RGB") + with self._torch.no_grad(): + inputs = self._processor(images=img, return_tensors="pt") + out = self._model.get_image_features(**inputs) + pooled = out.pooler_output if hasattr(out, "pooler_output") else out + return pooled[0].numpy().astype(np.float32) + + +_default_embedder: Embedder | None = None + + +def get_embedder() -> Embedder: + global _default_embedder + if _default_embedder is None: + _default_embedder = Embedder() + return _default_embedder diff --git a/tests/test_ml_embedder.py b/tests/test_ml_embedder.py new file mode 100644 index 0000000..19255cd --- /dev/null +++ b/tests/test_ml_embedder.py @@ -0,0 +1,30 @@ +"""Embedder unit tests. The SigLIP model is a multi-GB download not present +in CI, so these test only the import-safety contract and the singleton. +Real embedding runs in the local integration suite. +""" + +from backend.app.services.ml.embedder import ( + EMBED_DIM, + MODEL_VERSION, + Embedder, + get_embedder, +) + + +def test_embed_dim_matches_schema(): + # image_record.siglip_embedding and tag_reference_embedding.embedding + # are both Vector(1152). This must stay in sync. + assert EMBED_DIM == 1152 + + +def test_model_version_default(): + assert MODEL_VERSION == "siglip-so400m-patch14-384" + + +def test_get_embedder_singleton(): + assert get_embedder() is get_embedder() + + +def test_not_loaded_until_called(): + e = Embedder() + assert e._model is None # not loaded until .load()