unsloth/studio/backend/core/inference/worker.py
Roland Tannous cc5e4fbf17
fix: auto-retry stalled HF downloads with HF_HUB_DISABLE_XET=1 (#4712)
* fix: auto-retry stalled HF downloads with HF_HUB_DISABLE_XET=1

The heartbeat thread now monitors the HF Hub cache directory for
file-size growth. If no bytes are written for 3 minutes, it sends a
"stall" message to the orchestrator, which kills the subprocess and
retries with HF_HUB_DISABLE_XET=1 (falling back from Xet to standard
HTTPS). If the retry also stalls, it errors out with a clear message.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* fix: include transport type (xet/https) in heartbeat and stall log messages

Makes it clear in backend logs whether the download is using xet or
https transport, and which transport stalled — helpful for debugging.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* fix: monitor HF Hub .tmp dir to avoid false stall detections

huggingface_hub downloads into .tmp/ before atomically moving to
blobs/. Without monitoring .tmp, a large shard actively downloading
for several minutes would show zero blob growth and trigger a false
stall.

* fix: scope HF cache size check to specific model being loaded

Instead of scanning every models--*/blobs directory (O(N) with cached
models), only check the specific model's blobs dir plus the global
.tmp dir. Much faster on systems with many cached models.

* Fix false stall detection on cached/local models and cleanup issues

- Only fire stall if download activity was observed (cache size changed
  at least once). Previously, any model load taking >180s would trigger
  a false stall, even for already-cached or local models where no
  download is happening.
- Return -1 from _get_hf_cache_size on exception to distinguish
  "unable to measure" from "genuinely zero bytes". Skip stall logic
  when measurement fails.
- Add _shutdown_subprocess before raising on terminal stall path to
  prevent leaking a stuck subprocess.
- Detect pre-existing HF_HUB_DISABLE_XET=1 in the parent environment
  to avoid a redundant retry cycle when Xet is already disabled.
- Remove global .tmp directory scanning (not used by modern
  huggingface_hub; in-progress downloads use .incomplete files in
  blobs/ which are already captured by iterdir).
- Add f.is_file() guard in cache size calculation.
- Replace em dashes with ASCII dashes for Windows terminal compat.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Harden stall detection edge cases

- Guard -1 to valid value transition: when initial _get_hf_cache_size
  returns -1 (error) and later recovers to a real value, do not count
  that as download activity. Only set saw_download_activity when the
  previous measurement was also valid (>= 0).
- Move os import to top-level in orchestrator.py instead of inline
  import os as _os.
- Fix misleading comment about post-download protection.

* Use .incomplete files to detect active downloads for stall detection

Replace the saw_download_activity heuristic with direct .incomplete file
detection. huggingface_hub creates *.incomplete files in blobs/ during
active downloads and removes them on completion. This gives a reliable
signal for whether a download is actually in progress.

Benefits:
- Cached models: no .incomplete files -> no stall fired even after 180s
- Post-download init (quantization, GPU loading): .incomplete files gone
  so stall timer resets, long init phases are not killed
- Pre-download hangs (XET handshake stall): .incomplete files are
  created at download start, so zero-byte stalls are now detected
- No more false positives from -1 to valid measurement transitions

The _get_hf_download_state function now returns (total_bytes,
has_incomplete) tuple or None on error, replacing _get_hf_cache_size.

* Add debug logging to download state exception handler

Log the exception at debug level when _get_hf_download_state fails,
instead of silently returning None. Helps with troubleshooting cache
measurement issues.

* Watch both adapter and base model repos for LoRA stall detection

When loading a LoRA adapter, the actual download bottleneck is often
the base model, not the adapter itself. Update the heartbeat to watch
both mc.identifier and mc.base_model cache directories so stall
detection works for LoRA loads where the base model stalls on Xet.

Also update _get_hf_download_state to accept multiple model names and
skip names without "/" (local paths) since those do not have HF cache
directories.

* Fix model name filtering for official HF models without org prefix

Models like gpt2 and bert-base-uncased do not contain a slash but are
still valid HF Hub models with cache directories. Replace the "/" check
with a proper local-path detection that checks for path separators and
path-like prefixes instead.

Also fix the base_model watch list to not require "/" in the base model
name, so official models used as LoRA bases are also monitored.

* Fix local path detection that broke all org/model names on Linux

The os.path.sep check matched "/" in HF model IDs like "org/model" on
Linux, causing the stall detector to skip ALL standard HF models.

Replace with a check that only skips names starting with "/" (absolute
paths), "." (relative paths), "~" (home-relative), or containing "\"
(Windows paths). HF model IDs like "org/model" or "gpt2" pass through
correctly on all platforms.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Daniel Han <danielhanchen@gmail.com>
2026-03-31 03:00:46 -07:00

889 lines
30 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
"""
Inference subprocess entry point.
Each inference session runs in a persistent subprocess (mp.get_context("spawn")).
This gives us a clean Python interpreter with no stale module state —
solving the transformers version-switching problem completely.
The subprocess stays alive while a model is loaded, accepting commands
(generate, load, unload) via mp.Queue. It exits on shutdown or unload.
Pattern follows core/training/worker.py.
"""
from __future__ import annotations
import base64
import structlog
from loggers import get_logger
import os
import queue as _queue
import sys
import threading
import time
import traceback
from io import BytesIO
from pathlib import Path
from typing import Any
logger = get_logger(__name__)
from utils.hardware import apply_gpu_ids
def _activate_transformers_version(model_name: str) -> None:
"""Activate the correct transformers version BEFORE any ML imports.
If the model needs transformers 5.x, prepend the pre-installed .venv_t5/
directory to sys.path. Otherwise do nothing (default 4.57.x in .venv/).
"""
# Ensure backend is on path for utils imports
backend_path = str(Path(__file__).resolve().parent.parent.parent)
if backend_path not in sys.path:
sys.path.insert(0, backend_path)
from utils.transformers_version import (
needs_transformers_5,
_resolve_base_model,
_ensure_venv_t5_exists,
_VENV_T5_DIR,
)
resolved = _resolve_base_model(model_name)
if needs_transformers_5(resolved):
if not _ensure_venv_t5_exists():
raise RuntimeError(
f"Cannot activate transformers 5.x: .venv_t5 missing at {_VENV_T5_DIR}"
)
if _VENV_T5_DIR not in sys.path:
sys.path.insert(0, _VENV_T5_DIR)
logger.info("Activated transformers 5.x from %s", _VENV_T5_DIR)
# Propagate to child subprocesses (e.g. GGUF converter)
_pp = os.environ.get("PYTHONPATH", "")
os.environ["PYTHONPATH"] = _VENV_T5_DIR + (os.pathsep + _pp if _pp else "")
else:
logger.info("Using default transformers (4.57.x) for %s", model_name)
def _decode_image(image_base64: str):
"""Decode base64 string to PIL.Image."""
from PIL import Image
image_data = base64.b64decode(image_base64)
return Image.open(BytesIO(image_data))
def _resize_image(img, max_size: int = 800):
"""Resize image while maintaining aspect ratio."""
if img is None:
return None
if img.size[0] > max_size or img.size[1] > max_size:
from PIL import Image
ratio = min(max_size / img.size[0], max_size / img.size[1])
new_size = (int(img.size[0] * ratio), int(img.size[1] * ratio))
return img.resize(new_size, Image.Resampling.LANCZOS)
return img
def _send_response(resp_queue: Any, response: dict) -> None:
"""Send a response to the parent process."""
try:
resp_queue.put(response)
except (OSError, ValueError) as exc:
logger.error("Failed to send response: %s", exc)
def _build_model_config(config: dict):
"""Build a ModelConfig from the config dict."""
from utils.models import ModelConfig
model_name = config["model_name"]
hf_token = config.get("hf_token")
hf_token = hf_token if hf_token and hf_token.strip() else None
gguf_variant = config.get("gguf_variant")
mc = ModelConfig.from_identifier(
model_id = model_name,
hf_token = hf_token,
gguf_variant = gguf_variant,
)
if not mc:
raise ValueError(f"Invalid model identifier: {model_name}")
return mc
def _get_hf_download_state(
model_names: list[str] | None = None,
) -> tuple[int, bool] | None:
"""Return (total_bytes, has_incomplete) for the HF Hub cache, or None on error.
When *model_names* is provided, only those models' ``blobs/``
directories are checked instead of scanning every cached model --
much faster on systems with many models. Accepts multiple names so
that LoRA loads can watch both the adapter repo and the base model
repo simultaneously.
*has_incomplete* is True when any ``*.incomplete`` files exist in the
watched blobs directories, indicating that ``huggingface_hub`` is
actively downloading.
Returns None if the state cannot be determined (import error,
permission error, etc.) so callers can skip stall logic.
"""
try:
from huggingface_hub.constants import HF_HUB_CACHE
cache = Path(HF_HUB_CACHE)
if not cache.exists():
return (0, False)
total = 0
has_incomplete = False
blobs_dirs: list[Path] = []
if model_names:
for name in model_names:
if not name:
continue
# Skip local filesystem paths -- HF model IDs use forward
# slashes (org/model) but never start with / . ~ or contain
# backslashes. This distinguishes them from absolute paths,
# relative paths, and Windows paths.
if name.startswith(("/", ".", "~")) or "\\" in name:
continue
# HF cache dir format: models--org--name (slashes -> --)
cache_dir_name = "models--" + name.replace("/", "--")
blobs_dir = cache / cache_dir_name / "blobs"
if blobs_dir.exists():
blobs_dirs.append(blobs_dir)
else:
blobs_dirs = list(cache.glob("models--*/blobs"))
for bdir in blobs_dirs:
for f in bdir.iterdir():
try:
if f.is_file():
total += f.stat().st_size
if f.name.endswith(".incomplete"):
has_incomplete = True
except OSError:
pass
return (total, has_incomplete)
except Exception as e:
logger.debug("Failed to determine HF download state: %s", e)
return None
def _start_heartbeat(
resp_queue: Any,
interval: float = 30.0,
stall_timeout: float = 180.0,
xet_disabled: bool = False,
model_names: list[str] | None = None,
) -> threading.Event:
"""Start a daemon thread that sends periodic status heartbeats.
Monitors the HF Hub cache directory for download activity. A stall
is only reported when ``*.incomplete`` files are present (indicating
``huggingface_hub`` is actively downloading) **and** the total cache
size has not changed for *stall_timeout* seconds.
Once the download finishes (no more ``.incomplete`` files), the stall
timer resets, so post-download initialization (quantization, GPU
weight loading) is never misclassified as a stalled download.
Returns a stop event -- set it to terminate the heartbeat thread.
"""
stop = threading.Event()
transport = "https" if xet_disabled else "xet"
def _beat():
state = _get_hf_download_state(model_names)
last_size = state[0] if state is not None else 0
last_change = time.monotonic()
while not stop.wait(interval):
state = _get_hf_download_state(model_names)
now = time.monotonic()
# Skip stall logic if we cannot measure the cache
if state is None:
_send_response(
resp_queue,
{
"type": "status",
"message": f"Loading model ({transport} transport)...",
"ts": time.time(),
},
)
continue
current_size, has_incomplete = state
if current_size != last_size:
last_size = current_size
last_change = now
# Only fire stall when .incomplete files are present,
# confirming a download is actively in progress.
# Once downloads finish (no .incomplete), reset the timer
# so model init time is not counted as a stall.
if not has_incomplete:
last_change = now
elif now - last_change >= stall_timeout:
_send_response(
resp_queue,
{
"type": "stall",
"message": (
f"Download appears stalled ({transport} transport) "
f"-- no progress for {int(now - last_change)}s"
),
"ts": time.time(),
},
)
# Only fire once -- the orchestrator will kill us
return
_send_response(
resp_queue,
{
"type": "status",
"message": f"Loading model ({transport} transport)...",
"ts": time.time(),
},
)
t = threading.Thread(target = _beat, daemon = True)
t.start()
return stop
def _handle_load(backend, config: dict, resp_queue: Any) -> None:
"""Handle a load command: load a model into the backend."""
try:
mc = _build_model_config(config)
hf_token = config.get("hf_token")
hf_token = hf_token if hf_token and hf_token.strip() else None
# Auto-detect quantization for LoRA adapters
load_in_4bit = config.get("load_in_4bit", True)
if mc.is_lora and mc.path:
import json
from pathlib import Path
adapter_cfg_path = Path(mc.path) / "adapter_config.json"
if adapter_cfg_path.exists():
try:
with open(adapter_cfg_path) as f:
adapter_cfg = json.load(f)
training_method = adapter_cfg.get("unsloth_training_method")
if training_method == "lora" and load_in_4bit:
logger.info(
"adapter_config.json says lora — setting load_in_4bit=False"
)
load_in_4bit = False
elif training_method == "qlora" and not load_in_4bit:
logger.info(
"adapter_config.json says qlora — setting load_in_4bit=True"
)
load_in_4bit = True
elif not training_method:
if (
mc.base_model
and "-bnb-4bit" not in mc.base_model.lower()
and load_in_4bit
):
logger.info(
"No training method, base model has no -bnb-4bit — setting load_in_4bit=False"
)
load_in_4bit = False
except Exception as e:
logger.warning("Could not read adapter_config.json: %s", e)
# Auto-enable trust_remote_code for unsloth/* transformers 5.x models
# (matches the training worker logic in core/training/worker.py)
trust_remote_code = config.get("trust_remote_code", False)
if not trust_remote_code:
from utils.transformers_version import needs_transformers_5
model_name = config["model_name"]
if needs_transformers_5(model_name) and model_name.lower().startswith(
"unsloth/"
):
trust_remote_code = True
logger.info(
"Auto-enabled trust_remote_code for unsloth/* transformers 5.x model: %s",
model_name,
)
# Send heartbeats every 30s so the orchestrator knows we're still alive
# (download / weight loading can take a long time on slow connections)
xet_disabled = os.environ.get("HF_HUB_DISABLE_XET") == "1"
# Watch both the model repo and base model repo (for LoRA loads
# where the base model download is the actual bottleneck)
watch_repos = [mc.identifier]
base = getattr(mc, "base_model", None)
if base and str(base) != mc.identifier:
watch_repos.append(str(base))
heartbeat_stop = _start_heartbeat(
resp_queue,
interval = 30.0,
xet_disabled = xet_disabled,
model_names = watch_repos,
)
try:
success = backend.load_model(
config = mc,
max_seq_length = config.get("max_seq_length", 2048),
load_in_4bit = load_in_4bit,
hf_token = hf_token,
trust_remote_code = trust_remote_code,
gpu_ids = config.get("resolved_gpu_ids"),
)
finally:
heartbeat_stop.set()
if success:
# Build model_info for the parent to mirror
model_info = {
"identifier": mc.identifier,
"display_name": mc.display_name,
"is_vision": mc.is_vision,
"is_lora": mc.is_lora,
"is_gguf": False,
"is_audio": getattr(mc, "is_audio", False),
"audio_type": getattr(mc, "audio_type", None),
"has_audio_input": getattr(mc, "has_audio_input", False),
}
_send_response(
resp_queue,
{
"type": "loaded",
"success": True,
"model_info": model_info,
"ts": time.time(),
},
)
else:
_send_response(
resp_queue,
{
"type": "loaded",
"success": False,
"error": "Failed to load model",
"ts": time.time(),
},
)
except Exception as exc:
_send_response(
resp_queue,
{
"type": "loaded",
"success": False,
"error": str(exc),
"stack": traceback.format_exc(limit = 20),
"ts": time.time(),
},
)
def _handle_generate(
backend,
cmd: dict,
resp_queue: Any,
cancel_event,
) -> None:
"""Handle a generate command: stream tokens back via resp_queue.
cancel_event is an mp.Event shared with the parent process.
The parent can set it at any time (e.g. user stops generation,
or user loads a new model while generating) and generation
stops within 1-2 tokens.
"""
request_id = cmd.get("request_id", "")
try:
# Decode image if provided
image = None
image_b64 = cmd.get("image_base64")
if image_b64:
image = _decode_image(image_b64)
image = _resize_image(image)
# Build generation kwargs
gen_kwargs = {
"messages": cmd["messages"],
"system_prompt": cmd.get("system_prompt", ""),
"image": image,
"temperature": cmd.get("temperature", 0.7),
"top_p": cmd.get("top_p", 0.9),
"top_k": cmd.get("top_k", 40),
"min_p": cmd.get("min_p", 0.0),
"max_new_tokens": cmd.get("max_new_tokens", 256),
"repetition_penalty": cmd.get("repetition_penalty", 1.0),
"cancel_event": cancel_event,
}
# Choose generation path
use_adapter = cmd.get("use_adapter")
if use_adapter is not None:
generator = backend.generate_with_adapter_control(
use_adapter = use_adapter,
**gen_kwargs,
)
else:
generator = backend.generate_chat_response(**gen_kwargs)
logger.info("Starting text generation for request_id=%s", request_id)
for cumulative_text in generator:
# cancel_event is an mp.Event — checked instantly, no queue polling
if cancel_event.is_set():
logger.info("Generation cancelled for request %s", request_id)
break
_send_response(
resp_queue,
{
"type": "token",
"request_id": request_id,
"text": cumulative_text,
"ts": time.time(),
},
)
_send_response(
resp_queue,
{
"type": "gen_done",
"request_id": request_id,
"ts": time.time(),
},
)
logger.info("Finished text generation for request_id=%s", request_id)
except Exception as exc:
logger.error("Generation error: %s", exc, exc_info = True)
_send_response(
resp_queue,
{
"type": "gen_error",
"request_id": request_id,
"error": str(exc),
"stack": traceback.format_exc(limit = 20),
"ts": time.time(),
},
)
def _handle_generate_audio(
backend,
cmd: dict,
resp_queue: Any,
) -> None:
"""Handle TTS audio generation — returns WAV bytes + sample_rate."""
request_id = cmd.get("request_id", "")
try:
logger.info("Starting audio generation for request_id=%s", request_id)
wav_bytes, sample_rate = backend.generate_audio_response(
text = cmd["text"],
temperature = cmd.get("temperature", 0.6),
top_p = cmd.get("top_p", 0.95),
top_k = cmd.get("top_k", 50),
min_p = cmd.get("min_p", 0.0),
max_new_tokens = cmd.get("max_new_tokens", 2048),
repetition_penalty = cmd.get("repetition_penalty", 1.0),
use_adapter = cmd.get("use_adapter"),
)
# Send WAV bytes as base64 (bytes can't go through mp.Queue directly)
_send_response(
resp_queue,
{
"type": "audio_done",
"request_id": request_id,
"wav_base64": base64.b64encode(wav_bytes).decode("ascii"),
"sample_rate": sample_rate,
"ts": time.time(),
},
)
logger.info("Finished audio generation for request_id=%s", request_id)
except Exception as exc:
logger.error("Audio generation error: %s", exc, exc_info = True)
_send_response(
resp_queue,
{
"type": "audio_error",
"request_id": request_id,
"error": str(exc),
"stack": traceback.format_exc(limit = 20),
"ts": time.time(),
},
)
def _handle_generate_audio_input(
backend,
cmd: dict,
resp_queue: Any,
cancel_event,
) -> None:
"""Handle audio input generation (ASR/Whisper) — streams text tokens back."""
request_id = cmd.get("request_id", "")
try:
import numpy as np
# Decode audio array from list (numpy arrays can't go through mp.Queue)
audio_array = np.array(cmd["audio_data"], dtype = np.float32)
audio_type = cmd.get("audio_type")
if audio_type == "whisper":
generator = backend.generate_whisper_response(
audio_array = audio_array,
cancel_event = cancel_event,
)
else:
generator = backend.generate_audio_input_response(
messages = cmd.get("messages", []),
system_prompt = cmd.get("system_prompt", ""),
audio_array = audio_array,
temperature = cmd.get("temperature", 0.7),
top_p = cmd.get("top_p", 0.9),
top_k = cmd.get("top_k", 40),
min_p = cmd.get("min_p", 0.0),
max_new_tokens = cmd.get("max_new_tokens", 512),
repetition_penalty = cmd.get("repetition_penalty", 1.0),
cancel_event = cancel_event,
)
logger.info("Starting audio input generation for request_id=%s", request_id)
for text_chunk in generator:
if cancel_event.is_set():
logger.info(
"Audio input generation cancelled for request %s", request_id
)
break
_send_response(
resp_queue,
{
"type": "token",
"request_id": request_id,
"text": text_chunk,
"ts": time.time(),
},
)
_send_response(
resp_queue,
{
"type": "gen_done",
"request_id": request_id,
"ts": time.time(),
},
)
logger.info("Finished audio input generation for request_id=%s", request_id)
except Exception as exc:
logger.error("Audio input generation error: %s", exc, exc_info = True)
_send_response(
resp_queue,
{
"type": "gen_error",
"request_id": request_id,
"error": str(exc),
"stack": traceback.format_exc(limit = 20),
"ts": time.time(),
},
)
def _handle_unload(backend, cmd: dict, resp_queue: Any) -> None:
"""Handle an unload command."""
model_name = cmd.get("model_name", "")
try:
if model_name and model_name in backend.models:
backend.unload_model(model_name)
elif backend.active_model_name:
backend.unload_model(backend.active_model_name)
_send_response(
resp_queue,
{
"type": "unloaded",
"model_name": model_name,
"ts": time.time(),
},
)
except Exception as exc:
logger.error("Unload error: %s", exc)
_send_response(
resp_queue,
{
"type": "unloaded",
"model_name": model_name,
"error": str(exc),
"ts": time.time(),
},
)
def run_inference_process(
*,
cmd_queue: Any,
resp_queue: Any,
cancel_event,
config: dict,
) -> None:
"""Subprocess entrypoint. Persistent — runs command loop until shutdown.
Args:
cmd_queue: mp.Queue for receiving commands from parent.
resp_queue: mp.Queue for sending responses to parent.
cancel_event: mp.Event shared with parent — set by parent to cancel generation.
config: Initial configuration dict with model info.
"""
os.environ["TOKENIZERS_PARALLELISM"] = "false"
os.environ["PYTHONWARNINGS"] = (
"ignore" # Suppress warnings at C-level before imports
)
if config.get("disable_xet"):
os.environ["HF_HUB_DISABLE_XET"] = "1"
logger.info("Xet transport disabled (HF_HUB_DISABLE_XET=1)")
import warnings
from loggers.config import LogConfig
if os.getenv("ENVIRONMENT_TYPE", "production") == "production":
warnings.filterwarnings("ignore")
LogConfig.setup_logging(
service_name = "unsloth-studio-inference-worker",
env = os.getenv("ENVIRONMENT_TYPE", "production"),
)
apply_gpu_ids(config.get("resolved_gpu_ids"))
model_name = config["model_name"]
# ── 1. Activate correct transformers version BEFORE any ML imports ──
try:
_activate_transformers_version(model_name)
except Exception as exc:
_send_response(
resp_queue,
{
"type": "error",
"error": f"Failed to activate transformers version: {exc}",
"stack": traceback.format_exc(limit = 20),
"ts": time.time(),
},
)
return
# ── 1b. On Windows, check Triton availability (must be before import torch) ──
if sys.platform == "win32":
try:
import triton # noqa: F401
logger.info("Triton available — torch.compile enabled")
except ImportError:
os.environ["TORCHDYNAMO_DISABLE"] = "1"
logger.warning(
"Triton not found on Windows — torch.compile disabled. "
'Install for better performance: pip install "triton-windows<3.7"'
)
# ── 2. Import ML libraries (fresh in this clean process) ──
try:
_send_response(
resp_queue,
{
"type": "status",
"message": "Importing Unsloth...",
"ts": time.time(),
},
)
backend_path = str(Path(__file__).resolve().parent.parent.parent)
if backend_path not in sys.path:
sys.path.insert(0, backend_path)
from core.inference.inference import InferenceBackend
import transformers
logger.info("Subprocess loaded transformers %s", transformers.__version__)
except Exception as exc:
_send_response(
resp_queue,
{
"type": "error",
"error": f"Failed to import ML libraries: {exc}",
"stack": traceback.format_exc(limit = 20),
"ts": time.time(),
},
)
return
# ── 3. Create inference backend and load initial model ──
try:
backend = InferenceBackend()
_send_response(
resp_queue,
{
"type": "status",
"message": "Loading model...",
"ts": time.time(),
},
)
_handle_load(backend, config, resp_queue)
except Exception as exc:
_send_response(
resp_queue,
{
"type": "error",
"error": f"Failed to initialize inference backend: {exc}",
"stack": traceback.format_exc(limit = 20),
"ts": time.time(),
},
)
return
# ── 4. Command loop — process commands until shutdown ──
# cancel_event is an mp.Event shared with parent — parent can set it
# at any time to cancel generation instantly (no queue polling needed).
logger.info("Inference subprocess ready, entering command loop")
while True:
try:
cmd = cmd_queue.get(timeout = 1.0)
except _queue.Empty:
continue
except (EOFError, OSError):
logger.info("Command queue closed, shutting down")
return
if cmd is None:
continue
cmd_type = cmd.get("type", "")
logger.info("Received command: %s", cmd_type)
try:
if cmd_type == "generate":
cancel_event.clear()
_handle_generate(backend, cmd, resp_queue, cancel_event)
elif cmd_type == "load":
# Load a new model (reusing this subprocess)
# First unload current model
if backend.active_model_name:
backend.unload_model(backend.active_model_name)
_handle_load(backend, cmd, resp_queue)
elif cmd_type == "generate_audio":
cancel_event.clear()
_handle_generate_audio(backend, cmd, resp_queue)
elif cmd_type == "generate_audio_input":
cancel_event.clear()
_handle_generate_audio_input(backend, cmd, resp_queue, cancel_event)
elif cmd_type == "unload":
_handle_unload(backend, cmd, resp_queue)
elif cmd_type == "cancel":
# Redundant with mp.Event but handle gracefully
cancel_event.set()
logger.info("Cancel command received")
elif cmd_type == "reset":
cancel_event.set()
backend.reset_generation_state()
_send_response(
resp_queue,
{
"type": "reset_ack",
"ts": time.time(),
},
)
elif cmd_type == "status":
# Return current status
_send_response(
resp_queue,
{
"type": "status_response",
"active_model": backend.active_model_name,
"models": {
name: {
"is_vision": info.get("is_vision", False),
"is_lora": info.get("is_lora", False),
}
for name, info in backend.models.items()
},
"loading": list(backend.loading_models),
"ts": time.time(),
},
)
elif cmd_type == "shutdown":
logger.info("Shutdown command received, exiting")
# Unload all models
for model_name in list(backend.models.keys()):
try:
backend.unload_model(model_name)
except Exception:
pass
_send_response(
resp_queue,
{
"type": "shutdown_ack",
"ts": time.time(),
},
)
return
else:
logger.warning("Unknown command type: %s", cmd_type)
_send_response(
resp_queue,
{
"type": "error",
"error": f"Unknown command type: {cmd_type}",
"ts": time.time(),
},
)
except Exception as exc:
logger.error(
"Error handling command '%s': %s", cmd_type, exc, exc_info = True
)
_send_response(
resp_queue,
{
"type": "error",
"error": f"Command '{cmd_type}' failed: {exc}",
"stack": traceback.format_exc(limit = 20),
"ts": time.time(),
},
)