Files
hermes-agent/tools/transcription_local.py
ethernet b4a294fff9 Merge origin/main; keep PM as plugin dependency owner
Reconcile plugin declarations and validation through PM's atomic generation publication; preserve external runtimes, target markers, and conflict refusal. Keep one source-update completion owner and port upstream lifecycle changes to the PM desktop/runtime paths.
2026-09-17 13:52:05 -04:00

305 lines
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Python

"""Local STT backends.
faster-whisper loading (CUDA->CPU fallback, Apple Silicon pinning), the
anti-hallucination transcribe kwargs and segment gate, and the local whisper CLI
(``local_command``) provider. The cached-model singleton and idle-unload watcher
stay in ``transcription_tools`` (module state) and are read from it lazily.
"""
from __future__ import annotations
import logging
import os
import platform
import shlex
import subprocess
import tempfile
import importlib.util as _ilu
from pathlib import Path
from typing import Any, Dict, Optional
from tools.transcription_audio import _find_whisper_binary, _prepare_local_audio, _run_quiet
from tools.transcription_common import (
DEFAULT_LOCAL_MODEL, DEFAULT_LOCAL_STT_LANGUAGE, GROQ_MODELS, LOCAL_STT_COMMAND_ENV,
OPENAI_MODELS, _config_number, _error_result, _log_prompt_unsupported, _ok_result,
_process_error_detail)
# Log-record parity with the origin module.
logger = logging.getLogger("tools.transcription_tools")
def _get_local_command_template() -> Optional[str]:
configured = os.getenv(LOCAL_STT_COMMAND_ENV, "").strip()
if configured:
return configured
whisper_binary = _find_whisper_binary()
return (f"{shlex.quote(whisper_binary)} {{input_path}} --model {{model}} --output_format txt "
"--output_dir {output_dir} --language {language}") if whisper_binary else None
def _has_local_command() -> bool:
return _get_local_command_template() is not None
def _normalize_local_model(model_name: Optional[str]) -> str:
"""Return a valid faster-whisper size; cloud-only names (``whisper-1`` …) fall back to the default with a warning."""
if not model_name:
return DEFAULT_LOCAL_MODEL
if model_name in OPENAI_MODELS | GROQ_MODELS:
logger.warning(
"STT model '%s' is a cloud-only name and cannot be used with the local "
"provider. Falling back to '%s'. Set stt.local.model to a valid "
"faster-whisper size (tiny, base, small, medium, large-v3).",
model_name, DEFAULT_LOCAL_MODEL)
return DEFAULT_LOCAL_MODEL
return model_name
def _try_lazy_install_stt() -> bool:
"""Install faster-whisper and re-check dynamically so it's usable without a restart.
ACTION paths only (``_transcribe_local``). Nothing that merely *resolves* or *reports* a
provider may call this: the install takes the per-install lock for as long as a full extra-set
rebuild, and a status probe must never start one."""
try:
# pm installs are gated by security.allow_lazy_installs; never a blocking
# prompt mid-session. See #40490.
import pm
pm.ensure_import("stt-whisper")
if _ilu.find_spec("faster_whisper"):
return True
logger.warning("faster-whisper was installed but importlib still cannot find it (may require Python restart)")
except Exception as exc:
logger.warning(
"Lazy install of faster-whisper failed: %s. "
"When the message names a restart, this process selected its dependency generation at "
"boot and a new one cannot take effect in-flight; otherwise the Hermes process user "
"may not be able to write to the dependency environment. Run `hermes tools` as the "
"Hermes installation owner and select Local Whisper under Speech-to-Text.",
exc)
return False
# Substrings identifying a missing/unloadable CUDA runtime library: the "auto" device
# picker has already committed to CUDA, so we fall back to CPU and reload. Deliberately
# narrow (library names + dlopen phrasing) so legitimate runtime failures like "CUDA
# out of memory" surface to the user instead of silently running on CPU.
_CUDA_LIB_ERROR_MARKERS = (
"libcublas", "libcudnn", "libcudart", "cannot be loaded", "cannot open shared object",
"no kernel image is available", "CUBLAS_STATUS_NOT_SUPPORTED", "no CUDA-capable device",
"CUDA driver version is insufficient")
def _looks_like_cuda_lib_error(exc: BaseException) -> bool:
"""Heuristic: is this a missing/broken CUDA runtime library (not a legitimate runtime failure)?"""
return any(marker in str(exc) for marker in _CUDA_LIB_ERROR_MARKERS)
def _sysctl_value(name: str) -> str:
"""Return a sysctl value, or an empty string when unavailable."""
try:
return subprocess.check_output(["/usr/sbin/sysctl", "-n", name], stderr=subprocess.DEVNULL,
stdin=subprocess.DEVNULL, text=True, encoding="utf-8", errors="replace",
timeout=2).strip()
except Exception:
return ""
def _should_force_faster_whisper_cpu() -> bool:
"""Force CPU on Apple Silicon (incl. x86_64 under Rosetta), where ctranslate2's
``device="auto"`` can abort inside native code before Python can catch it."""
if platform.system() != "Darwin":
return False
if platform.machine().lower() in {"arm64", "aarch64"}:
return True
# Under Rosetta platform.machine() reports x86_64; sysctl.proc_translated
# flags translation and hw.optional.arm64 distinguishes Apple Silicon hosts.
return _sysctl_value("sysctl.proc_translated") == "1" or _sysctl_value("hw.optional.arm64") == "1"
def _get_idle_unload_seconds(local_cfg: Dict[str, Any]) -> int:
"""Resolve the idle unload timeout from config; 0 = never (default), negatives clamp to 0."""
return max(_config_number(local_cfg, "unload_after_idle_seconds", 0, int), 0)
def _hub_cache_miss_error() -> type:
"""Exception faster-whisper raises for a model missing from the local Hub cache.
``huggingface_hub`` is an optional dependency (it arrives with faster-whisper); when it is
absent, its ``LocalEntryNotFoundError`` base class ``OSError`` is the closest match.
"""
try:
from huggingface_hub.errors import LocalEntryNotFoundError
except ImportError:
return OSError
return LocalEntryNotFoundError
def _create_whisper_model(model_name: str, *, device: str, compute_type: str):
"""Use a cached model without contacting the Hub, downloading only on a cache miss."""
from faster_whisper import WhisperModel
kwargs = {"device": device, "compute_type": compute_type}
try:
return WhisperModel(model_name, local_files_only=True, **kwargs)
except (_hub_cache_miss_error(), RuntimeError) as exc:
# An interrupted first download leaves a snapshot folder without the weights;
# snapshot_download still returns it and ctranslate2 raises "Unable to open file".
if isinstance(exc, RuntimeError) and "Unable to open file" not in str(exc):
raise
logger.info("faster-whisper model '%s' is not cached; downloading it from the Hugging Face Hub", model_name)
# huggingface_hub surfaces every Hub/network failure as an OSError subclass
# (LocalEntryNotFoundError wrapping the ConnectTimeout, HfHubHTTPError). Anything else
# (CUDA runtime, invalid model size) is not a download problem and propagates untouched.
try:
return WhisperModel(model_name, local_files_only=False, **kwargs)
except OSError as exc:
raise RuntimeError(
f"Unable to download faster-whisper model '{model_name}': {exc}. "
"If huggingface.co is unreachable, set HF_ENDPOINT to an accessible mirror; "
"when using a mirror with hf-xet installed, also set HF_HUB_DISABLE_XET=1."
) from exc
def _load_local_whisper_model(model_name: str, device: str = "auto", compute_type: str = "auto"):
"""Load faster-whisper with graceful CUDA → CPU fallback. ``device="auto"`` picks CUDA
whenever the ctranslate2 wheel ships CUDA libs, even on hosts without the NVIDIA runtime (WSL2,
headless servers): try the requested config first; on a CUDA library load failure fall back to
CPU + int8. Pass ``stt.local.device`` / ``compute_type`` to pin.
``device`` / ``compute_type`` default to ``"auto"`` so the historical behaviour is unchanged; pass
explicit values from ``stt.local.device`` / ``stt.local.compute_type`` to pin a configuration (#9088).
"""
force_cpu = _should_force_faster_whisper_cpu()
if force_cpu:
# Importing ctranslate2 can itself abort on Apple Silicon/Rosetta when
# multiple Intel OpenMP runtimes are loaded — set before the import.
os.environ.setdefault("KMP_DUPLICATE_LIB_OK", "TRUE")
if force_cpu:
logger.info("Apple Silicon/Rosetta detected — loading faster-whisper on CPU "
"(int8) to avoid native device autodetection crashes")
return _create_whisper_model(model_name, device="cpu", compute_type="int8")
try:
return _create_whisper_model(model_name, device=device, compute_type=compute_type)
except Exception as exc:
if not _looks_like_cuda_lib_error(exc):
raise
logger.warning("faster-whisper CUDA load failed (%s) — falling back to CPU (int8). "
"Install the NVIDIA CUDA runtime (libcublas/libcudnn) to use GPU.", exc)
return _create_whisper_model(model_name, device="cpu", compute_type="int8")
# Silence-hallucination hardening for local faster-whisper (whisper decodes junk like
# "You"/"Thank you." from pure silence). Three layers, all tunable under ``stt.local``:
# Silero VAD so silence never reaches the model (``vad: false`` restores raw behaviour
# for music/ambient audio); condition_on_previous_text=False so one hallucinated token
# can't seed a run; and the segment confidence gate in _is_hallucinated_segment.
_VAD_MIN_SILENCE_MS_DEFAULT = 500
_NO_SPEECH_PROB_THRESHOLD_DEFAULT = 0.6
_LOGPROB_THRESHOLD_DEFAULT = -1.0
def build_local_transcribe_kwargs(stt_config: Optional[Dict[str, Any]] = None) -> Dict[str, Any]:
"""Kwargs for EVERY local faster-whisper ``model.transcribe`` call — single owner of the anti-hallucination hardening."""
from tools.transcription_tools import _load_stt_config, _resolve_stt_language
stt_config = stt_config if isinstance(stt_config, dict) else _load_stt_config()
local_cfg = stt_config.get("local") or {}
# ``vad: null`` in YAML means "default on".
vad_enabled = local_cfg.get("vad", True)
kwargs: Dict[str, Any] = {
"beam_size": 5,
"condition_on_previous_text": False,
"vad_filter": vad_enabled is None or bool(vad_enabled)}
if kwargs["vad_filter"]:
kwargs["vad_parameters"] = {
"min_silence_duration_ms": _config_number(local_cfg, "vad_min_silence_ms", _VAD_MIN_SILENCE_MS_DEFAULT, int)
}
# Push the confidence gate into faster-whisper itself: its internal defaults drop
# low-confidence segments BEFORE our post-filter sees them, so the ``stt.local``
# threshold knobs were dead for that first gate (non-English speech decodes at
# lower avg_logprob and was silently discarded). Same values feed both gates.
kwargs["no_speech_threshold"], kwargs["log_prob_threshold"] = _confidence_thresholds(local_cfg)
forced_lang = _resolve_stt_language("local", stt_config)
if forced_lang:
kwargs["language"] = forced_lang
initial_prompt = local_cfg.get("initial_prompt")
if isinstance(initial_prompt, str) and initial_prompt.strip():
kwargs["initial_prompt"] = initial_prompt
return kwargs
def _confidence_thresholds(local_cfg: Dict[str, Any]) -> tuple[float, float]:
"""Resolve (no_speech_prob, avg_logprob) gate thresholds from config."""
return (_config_number(local_cfg, "no_speech_prob_threshold", _NO_SPEECH_PROB_THRESHOLD_DEFAULT),
_config_number(local_cfg, "logprob_threshold", _LOGPROB_THRESHOLD_DEFAULT))
def _is_hallucinated_segment(segment: Any, no_speech_threshold: float, logprob_threshold: float) -> bool:
"""True when a segment is very likely a silence hallucination. Conservative AND gate
(openai-whisper's own heuristic): non-speech AND low decode confidence, so quiet-but-real speech
survives. Unknown segment shapes are never dropped."""
try:
return (float(segment.no_speech_prob) > no_speech_threshold
and float(segment.avg_logprob) < logprob_threshold)
except (AttributeError, TypeError, ValueError):
return False
def _join_confident_segments(segments: Any, local_cfg: Dict[str, Any]) -> str:
"""Join segment texts, dropping probable silence hallucinations."""
no_speech_threshold, logprob_threshold = _confidence_thresholds(local_cfg)
kept: list[str] = []
for segment in segments:
if _is_hallucinated_segment(segment, no_speech_threshold, logprob_threshold):
logger.debug("Dropping probable hallucinated segment %r (no_speech_prob=%.3f, avg_logprob=%.3f)",
getattr(segment, "text", ""), getattr(segment, "no_speech_prob", float("nan")),
getattr(segment, "avg_logprob", float("nan")))
continue
kept.append(segment.text.strip())
return " ".join(kept).strip()
def _transcribe_local_command(
file_path: str, model_name: str, *, language: Optional[str] = None, prompt: Optional[str] = None
) -> Dict[str, Any]:
"""Run the configured local STT command template and read back a .txt transcript."""
from tools.transcription_tools import _resolve_stt_language
if prompt:
_log_prompt_unsupported("STT provider 'local_command'")
command_template = _get_local_command_template()
if not command_template:
return _error_result(f"{LOCAL_STT_COMMAND_ENV} not configured and no local whisper binary was found")
# Language: hook override > stt.local.language > stt.language > env > "en".
language = language or _resolve_stt_language("local") or DEFAULT_LOCAL_STT_LANGUAGE
normalized_model = _normalize_local_model(model_name)
try:
with tempfile.TemporaryDirectory(prefix="hermes-local-stt-") as output_dir:
prepared_input, prep_error = _prepare_local_audio(file_path, output_dir)
if prep_error:
return _error_result(prep_error)
command = command_template.format(
input_path=shlex.quote(prepared_input), output_dir=shlex.quote(output_dir),
language=shlex.quote(language), model=shlex.quote(normalized_model))
# Scrub Hermes secrets from the child env (same policy as _run_command_stt).
# Scrub Hermes secrets from the child env (sibling path to #56332 / _run_command_stt — this
# local-whisper path previously inherited the full process environment).
from tools.environments.local import hermes_subprocess_env
_run_quiet(shlex.split(command), timeout=300, env=hermes_subprocess_env(inherit_credentials=False))
txt_files = sorted(Path(output_dir).glob("*.txt"))
if not txt_files:
return _error_result("Local STT command completed but did not produce a .txt transcript")
transcript_text = txt_files[0].read_text(encoding="utf-8-sig").strip()
logger.info("Transcribed %s via local STT command (%s, %d chars)",
Path(file_path).name, normalized_model, len(transcript_text))
return _ok_result(transcript_text, "local_command")
except KeyError as e:
return _error_result(f"Invalid {LOCAL_STT_COMMAND_ENV} template, missing placeholder: {e}")
except subprocess.CalledProcessError as e:
details = _process_error_detail(e)
logger.error("Local STT command failed for %s: %s", file_path, details)
return _error_result(f"Local STT failed: {details}")
except Exception as e:
logger.error("Unexpected error during local command transcription: %s", e, exc_info=True)
return _error_result(f"Local transcription failed: {e}")