* Replace standalone Studio wording with Unsloth Replace the single word Studio with Unsloth wherever it is used as shorthand for Unsloth Studio in docs, CLI output, UI strings, i18n locales, workflow display names, comments and docstrings. Kept unchanged: the full name Unsloth Studio, third party product names (LM Studio, Visual Studio, Mac Studio), feature names (Recipe Studio, Fine-tuning Studio and its translations), and all identifiers such as env vars, commands, paths and filenames. * Address review feedback on the Studio wording rename Use "an" before Unsloth where the rename left the article as "a". Restore the split brand where Unsloth and Studio render as two halves of the full product name: the onboarding sidebar subtitle and the IPv6 localhost warning. Scope two messages to the full name Unsloth Studio where plain Unsloth was misleading: the AMD README bullet and the CLI studio setup error.
431 lines
16 KiB
Python
431 lines
16 KiB
Python
# SPDX-License-Identifier: AGPL-3.0-only
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# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
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"""Dense embedder facade dispatching to a process-wide backend from
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``config.EMBED_BACKEND`` (``auto`` picks by hardware): ``sentence-transformers``
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(torch) or ``llama-server`` (GGUF, no torch).
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Backends produce different vectors, so switching requires rebuilding the index. We
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degrade to llama.cpp rather than crash when ST breaks on a machine: an init-time
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probe falls back before any vector is produced (so spaces can't mix), and a
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runtime ``encode`` failure swaps the process to llama-server for the rest of its
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life (KBs already embedded with ST should then be reindexed).
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"""
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from __future__ import annotations
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import logging
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import os
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import threading
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from functools import lru_cache
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from typing import Callable
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from utils.hardware.hardware import DeviceType, get_device
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from utils.transformers_dtype import dtype_kwargs
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from . import config
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logger = logging.getLogger(__name__)
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# "false" silences the fast tokenizer's fork warning; encode() flips it to "true"
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# only during a batch tokenize (rayon speedup), then restores it.
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os.environ.setdefault("TOKENIZERS_PARALLELISM", "false")
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_lock = threading.Lock()
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# Serializes encode/tokenize (HF fast tokenizer isn't thread-safe). Separate from
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# _lock so a long encode never blocks a reload.
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_compute_lock = threading.Lock()
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_model = None
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_name: str | None = None
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# Unsloth device -> torch device string. Apple has no torch device -> CPU.
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_TORCH_DEVICE = {DeviceType.CUDA: "cuda", DeviceType.XPU: "xpu"}
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def _device() -> str:
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return _TORCH_DEVICE.get(get_device(), "cpu")
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_torchao_stub_done = False
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def _install_torchao_stub_once() -> None:
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"""Neutralize torchao before importing sentence-transformers. On Windows ROCm,
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torchao (pulled in by transformers.quantizers) imports an absent c10d backend
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and aborts, dropping the embedder to llama-server. Workers stub it too; the
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embedder runs in the main process. No-op elsewhere; runs once under ``_lock``."""
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global _torchao_stub_done
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if _torchao_stub_done:
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return
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_torchao_stub_done = True
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from core._torchao_stub import install_torchao_windows_rocm_stub
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install_torchao_windows_rocm_stub()
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class UnsafeEmbeddingModelError(RuntimeError):
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"""Raised when the embedding model repo is flagged unsafe. A distinct type so the
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llama-server fallback paths re-raise it instead of masking a security block as a
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routine ST failure."""
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def _ambient_hf_token() -> str | None:
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"""The HF token the loader itself would use (HF_TOKEN env or the cached login), so
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the scan can reach a gated/private repo instead of failing open. None if unavailable."""
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try:
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from huggingface_hub import get_token
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return get_token()
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except Exception:
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return None
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def _st_module_subdirs(name: str, token: str | None) -> tuple[str, ...]:
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"""The module directories a SentenceTransformer load reads weights from, taken from
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the repo's ``modules.json`` (each module's non-empty ``path``, e.g. ``0_Transformer``).
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ST deserializes ``pytorch_model.bin`` from these dirs, so they are load roots for the
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security scan: a flagged pickle directly under one must block. Returns () on any
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failure (no modules.json, offline, malformed) so the guard never bricks the embedder.
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"""
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try:
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import json
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from utils.paths import is_local_path
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if is_local_path(name):
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from pathlib import Path
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from utils.paths import normalize_path
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path = Path(normalize_path(name)).expanduser() / "modules.json"
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if not path.is_file():
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return ()
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data = json.loads(path.read_text())
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else:
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from huggingface_hub import hf_hub_download
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from huggingface_hub.utils import EntryNotFoundError
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try:
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local = hf_hub_download(name, "modules.json", token = token or None)
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except EntryNotFoundError:
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return ()
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data = json.loads(open(local).read())
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subdirs = []
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for module in data or ():
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sub = str((module or {}).get("path", "")).strip().strip("/")
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if sub:
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subdirs.append(sub)
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return tuple(dict.fromkeys(subdirs))
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except Exception:
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return ()
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def _guard_model_security(name: str) -> None:
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"""Refuse to load a repo HF flagged as unsafe: a poisoned pickle deserializes inside
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SentenceTransformer regardless of trust_remote_code. Defense in depth behind the
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/settings gate (a name can also arrive via env/default); local paths and unreachable
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scans fail open inside evaluate_file_security. Never bricks the embedder on a gate error.
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"""
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try:
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from utils.security import evaluate_file_security, security_load_subdirs
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token = _ambient_hf_token()
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# Union the audio-model load roots with the ST module dirs so a flagged pickle
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# directly under a Transformer module dir (0_Transformer/) blocks instead of
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# passing as an unreferenced nested shard.
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load_subdirs = tuple(
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dict.fromkeys((*security_load_subdirs(name, token), *_st_module_subdirs(name, token)))
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)
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blocked = evaluate_file_security(name, hf_token = token, load_subdirs = load_subdirs).blocked
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except Exception:
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return
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if blocked:
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raise UnsafeEmbeddingModelError(
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f"Embedding model {name!r} is flagged as unsafe by Hugging Face's security "
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"scan; refusing to load. Set a different RAG embedding model."
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)
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def _get(model_name: str | None = None):
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"""Cached SentenceTransformer, (re)loading on a name change. Loaded in fp16
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for a ~1.5x speedup at negligible accuracy loss."""
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global _model, _name
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name = model_name or config.effective_embedding_model()
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with _lock:
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if _model is None or _name != name:
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_install_torchao_stub_once()
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from sentence_transformers import SentenceTransformer
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device = _device()
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logger.info("loading embedding model %s on %s", name, device)
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_guard_model_security(name)
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_model = SentenceTransformer(name, device = device, model_kwargs = dtype_kwargs("float16"))
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_name = name
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return _model
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@lru_cache(maxsize = 1)
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def _inference_ctx_factory():
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"""``torch.inference_mode`` if torch imports, else ``nullcontext``. Returns the
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factory so each call gets a fresh single-use guard."""
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try:
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import torch
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return torch.inference_mode
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except Exception: # noqa: BLE001 - torch may be missing or broken
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from contextlib import nullcontext
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return nullcontext
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def _inference_ctx():
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return _inference_ctx_factory()()
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def _st_encode(
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texts: list[str],
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*,
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model_name: str | None = None,
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normalize: bool = True,
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):
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"""ST encode -> (N, dim) float32. Serialized (fast-tokenizer borrow check),
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under inference_mode when torch is present, with rayon enabled for the call."""
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model = _get(model_name)
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with _compute_lock:
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os.environ["TOKENIZERS_PARALLELISM"] = "true"
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try:
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with _inference_ctx():
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out = model.encode(
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texts,
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normalize_embeddings = normalize,
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convert_to_numpy = True,
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show_progress_bar = False,
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)
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finally:
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os.environ["TOKENIZERS_PARALLELISM"] = "false"
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# fp16 weights yield fp16 output; store float32 for sqlite-vec + stable cosine.
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if hasattr(out, "astype"):
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out = out.astype("float32", copy = False)
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return out
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def _st_dim(model_name: str | None = None) -> int:
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return _get(model_name).get_sentence_embedding_dimension()
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def _st_token_counter(model_name: str | None = None) -> Callable[[str], int]:
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"""Token counter using the model's tokenizer, under the compute lock (the same
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fast tokenizer backs encode and isn't thread-safe), with rayon enabled for the
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call. Mirrors ``_st_encode``."""
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tok = _get(model_name).tokenizer
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def _count(t: str) -> int:
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with _compute_lock:
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os.environ["TOKENIZERS_PARALLELISM"] = "true"
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try:
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return len(tok.encode(t, add_special_tokens = False))
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finally:
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os.environ["TOKENIZERS_PARALLELISM"] = "false"
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return _count
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class _SentenceTransformersBackend:
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"""Default backend; delegates to the module-level ST helpers so the ``_get``
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monkeypatch in tests keeps working."""
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def encode(
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self,
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texts,
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*,
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model_name = None,
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normalize = True,
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):
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try:
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return _st_encode(texts, model_name = model_name, normalize = normalize)
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except UnsafeEmbeddingModelError:
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raise # a security block must hard-fail, not fall back to llama-server
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except Exception as st_err: # noqa: BLE001 - runtime ST/CUDA encode failure
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# ST loaded but this encode blew up; swap the process to the llama-server
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# embedder (so later encodes stay in one space) and retry.
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fallback = _switch_to_llama_fallback(st_err)
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if fallback is None:
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raise
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return fallback.encode(texts, model_name = model_name, normalize = normalize)
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def token_counter(self, *, model_name = None):
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return _st_token_counter(model_name)
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def dim(self, *, model_name = None):
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return _st_dim(model_name)
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def warm(self, *, model_name = None):
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_get(model_name)
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_backend_lock = threading.Lock()
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_backend = None
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_backend_key: str | None = None
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_ST_ALIASES = frozenset({"sentence-transformers", "sentence_transformers", "st"})
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_LLAMA_ALIASES = frozenset(
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{"llama-server", "llama_server", "llama", "llama.cpp", "llamacpp", "gguf"}
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)
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_AUTO_ALIASES = frozenset({"auto", ""})
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def _resolve_auto() -> str:
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"""Pick a backend for ``auto``: sentence-transformers when a CUDA/ROCm GPU is
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present (torch fp16 wins bulk indexing), else the torch-free GGUF llama-server
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-- or ST if its binary is missing. GPU check is torch-free (nvidia-smi)."""
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from core.inference.llama_cpp import LlamaCppBackend
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if LlamaCppBackend._get_gpu_free_memory():
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return "sentence-transformers"
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if LlamaCppBackend._find_llama_server_binary():
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return "llama-server"
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return "sentence-transformers"
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def _try_make_llama_backend():
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"""A llama-server GGUF embedding backend if its binary is present, else None.
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Construction is lazy -- no server starts until warm."""
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from core.inference.llama_cpp import LlamaCppBackend
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if not LlamaCppBackend._find_llama_server_binary():
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return None
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from .embed_llama_server import LlamaServerBackend
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return LlamaServerBackend()
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def _build_st_backend_or_fallback():
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"""Build the ST backend, probing it by loading the model now. If the probe
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raises (no torch, CUDA mismatch, bad wheel) and the GGUF llama-server embedder
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is available, fall back to it. The probe runs before any vector is produced, so
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this never mixes spaces. Re-raises if no embedder can start."""
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backend = _SentenceTransformersBackend()
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try:
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backend.warm(model_name = None)
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return backend
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except UnsafeEmbeddingModelError:
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raise # a security block must hard-fail, not fall back to llama-server
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except Exception as st_err: # noqa: BLE001 - any ST/torch import or load failure
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fallback = _try_make_llama_backend()
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if fallback is None:
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raise
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logger.warning(
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"sentence-transformers embedder unavailable (%s); falling back to the "
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"llama-server GGUF embedder",
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st_err,
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)
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return fallback
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def _switch_to_llama_fallback(err):
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"""An ST encode failed at runtime even though the model had loaded. Swap the
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process embedder to llama-server so every later encode stays in one space, and
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return it (None if no binary). Vectors written before the swap were ST, so any
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KB already embedded with ST should be reindexed."""
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global _backend, _backend_key
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with _backend_lock:
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if not isinstance(_backend, _SentenceTransformersBackend):
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return _backend # another thread already swapped (or was never ST)
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fallback = _try_make_llama_backend()
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if fallback is None:
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return None
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logger.warning(
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"sentence-transformers encode failed (%s); switching to the llama-server "
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"embedder for the rest of this process. Reindex any knowledge base that "
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"was already embedded with sentence-transformers.",
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err,
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)
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_backend = fallback
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_backend_key = (config.EMBED_BACKEND or "auto").strip().lower()
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return fallback
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def _get_backend():
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"""The process-wide embedding backend for ``config.EMBED_BACKEND``, built once.
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Cached by the raw config value, so ``auto`` detection runs only on a miss and a
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config change rebuilds it."""
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global _backend, _backend_key
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raw = (config.EMBED_BACKEND or "auto").strip().lower()
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with _backend_lock:
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if _backend is not None and _backend_key == raw:
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return _backend
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key = _resolve_auto() if raw in _AUTO_ALIASES else raw
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if key in _ST_ALIASES:
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_backend = _build_st_backend_or_fallback()
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elif key in _LLAMA_ALIASES:
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# Imported lazily so the ST path never imports llama plumbing.
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from .embed_llama_server import LlamaServerBackend
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_backend = LlamaServerBackend()
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else:
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raise ValueError(
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f"Unknown RAG_EMBED_BACKEND={config.EMBED_BACKEND!r}; expected "
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"'auto', 'sentence-transformers' or 'llama-server'"
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)
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_backend_key = raw
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return _backend
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def _reset_backend() -> None:
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"""Drop the cached backend (test teardown / re-init)."""
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global _backend, _backend_key
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with _backend_lock:
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_backend = None
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_backend_key = None
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def active_backend_is_llama() -> bool:
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"""True when this process actually embeds via the llama-server (GGUF) backend.
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Reflects the ACTUAL built backend once one exists: an ``auto`` install that
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resolves to sentence-transformers but then falls back to llama-server at
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runtime (``_build_st_backend_or_fallback`` on a torch/CUDA load failure, or
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``_switch_to_llama_fallback`` on an encode failure) loads only inert GGUF, so
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callers gating on the ST pickle must see llama here. Before any backend is
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built, defers to the resolver (``auto`` -> ``_resolve_auto()``, else the raw
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key) exactly as a fresh process would. Never raises: a backend probe must not
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block saving a model."""
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try:
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with _backend_lock:
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backend = _backend
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if backend is not None:
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# A backend exists: report what it ACTUALLY is. A concrete
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# sentence-transformers backend must return False even if the
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# resolver would now pick llama, so its pickle stays gated. If the
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# llama import fails we cannot be llama, so fall to the safe False.
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try:
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from .embed_llama_server import LlamaServerBackend
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except Exception: # noqa: BLE001 - llama plumbing import must never block
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return False
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return isinstance(backend, LlamaServerBackend)
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raw = (config.EMBED_BACKEND or "auto").strip().lower()
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key = _resolve_auto() if raw in _AUTO_ALIASES else raw
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return key in _LLAMA_ALIASES
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except Exception: # noqa: BLE001 - a backend probe must never block saving
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return False
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def warm(model_name: str | None = None) -> None:
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"""Eagerly load the embedder so the first real request isn't slow."""
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_get_backend().warm(model_name = model_name)
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def encode(
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texts: list[str],
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*,
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model_name: str | None = None,
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normalize: bool = True,
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):
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"""Embed texts into an (N, dim) float32 numpy array."""
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return _get_backend().encode(texts, model_name = model_name, normalize = normalize)
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def dim(model_name: str | None = None) -> int:
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"""Embedding dimension for the (loaded) model."""
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return _get_backend().dim(model_name = model_name)
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def token_counter(model_name: str | None = None) -> Callable[[str], int]:
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"""Callable counting tokens with the embedder's own tokenizer."""
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return _get_backend().token_counter(model_name = model_name)
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