unsloth/studio/backend/core/training/training.py
Leo Borcherding 69d8a57ee9
Studio: lazy-import matplotlib so the server starts when the wheel is blocked (#6596)
* Studio: lazy-import matplotlib so the server starts when the wheel is blocked

matplotlib.pyplot was imported at the top of core/training/training.py, on the
server boot path. When matplotlib's native extension fails to load (e.g. an
unsigned wheel blocked by Windows Smart App Control), that import crashed the
whole Studio server at startup instead of just disabling loss plots.

Move it into a lazy _load_pyplot() helper called from _create_loss_plot, using
the headless Agg backend, and return None when matplotlib is unavailable so
plotting degrades gracefully. The plot return was already Optional, so callers
need no changes. Keep the type-only import under TYPE_CHECKING and quote the
annotations.

Fixes #6588

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

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

* Studio: pin matplotlib==3.11.0

Pin matplotlib to the current latest so a new unsigned release does not
reintroduce the Smart App Control block on Windows. Belt-and-suspenders on
top of the lazy import. Pinned in both studio.txt and extras.txt.

* Pin matplotlib to 3.10.9 so Studio still installs on Python 3.10

matplotlib 3.11.0 requires Python >=3.11, so the pin had no installable wheel on
Python 3.10 (still supported) and pip install failed there. 3.10.9 is the latest
3.10.x (requires-python >=3.10) and covers Python 3.10 through 3.13. Also tighten
the lazy-import docstrings.

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: danielhanchen <danielhanchen@gmail.com>
2026-06-23 06:22:20 -07:00

1260 lines
50 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
"""
Training backend — subprocess orchestrator.
Each job runs in a fresh spawn subprocess (solving transformers version-switching);
the in-process UnslothTrainer singleton is only used inside the worker. This file
orchestrates the subprocess lifecycle, pumps events from the worker's mp.Queue, and
exposes the same API to routes/training.py. Pattern follows data_recipe/jobs/manager.py.
"""
import json as _json
import math
import multiprocessing as mp
import os
import queue
import re
import shutil
import threading
import time
import structlog
from datetime import datetime, timezone
from loggers import get_logger
from dataclasses import dataclass, field
from pathlib import Path
from typing import Optional, Tuple, Any, TYPE_CHECKING
if TYPE_CHECKING:
import matplotlib.pyplot as plt
from utils.hardware import prepare_gpu_selection
from utils.native_path_leases import (
native_path_secret_removed_for_child_start,
run_without_native_path_secret,
)
from utils.paths import outputs_root
logger = get_logger(__name__)
_pyplot = None
_pyplot_failed = False
def _load_pyplot():
"""Lazily import matplotlib.pyplot (headless Agg); return it, or None if
matplotlib is unavailable. Deferred so a blocked native wheel (e.g. Windows
Smart App Control) never breaks server startup, only loss plotting.
"""
global _pyplot, _pyplot_failed
if _pyplot is not None or _pyplot_failed:
return _pyplot
try:
import matplotlib
matplotlib.use("Agg") # headless backend
import matplotlib.pyplot as plt
_pyplot = plt
except Exception as e:
_pyplot_failed = True
logger.warning("matplotlib unavailable; loss plots disabled", error = str(e))
return _pyplot
def _coerce_seed(value, default = 3407) -> int:
"""Normalize None / non-int to `default` (transformers.set_seed(None) raises)."""
if value is None:
return int(default)
try:
return int(value)
except (TypeError, ValueError):
return int(default)
def _coerce_optional_bool(value, default: bool) -> bool:
"""Treat explicit None as `default` instead of `bool(None) == False`."""
if value is None:
return bool(default)
if isinstance(value, str):
normalized = value.strip().lower()
if normalized in ("true", "1", "yes", "on"):
return True
if normalized in ("false", "0", "no", "off", ""):
return False
return bool(value)
def _coerce_optional_nonneg_float(name: str, value):
"""Reject negatives; HTTP `ge=0` doesn't cover raw `**kwargs` callers."""
if value is None:
return None
try:
coerced = float(value)
except (TypeError, ValueError):
raise ValueError(f"Unsloth: {name}={value!r} must be a non-negative float or None.")
if coerced < 0:
raise ValueError(f"Unsloth: {name}={coerced} must be >= 0 (use 0 or None to disable).")
return coerced
_HF_TMP_CHECKPOINT_RE = re.compile(r"^tmp-checkpoint-\d+$")
def _sanitize_db_config(config: dict[str, Any]) -> dict[str, Any]:
# ``subject`` (the run owner's username / API-key id) is worker-only metadata; never
# persist it to config_json, which run-history GET returns to any authenticated user.
db_config = {
k: v
for k, v in config.items()
if k not in {"hf_token", "wandb_token", "s3_config", "subject"}
}
s3_config = config.get("s3_config")
if hasattr(s3_config, "model_dump"):
s3_config = s3_config.model_dump()
if isinstance(s3_config, dict) and s3_config:
db_config["dataset_source"] = "s3"
db_config["s3_dataset"] = {
"bucket": s3_config.get("bucket"),
"region": s3_config.get("region"),
"prefix": s3_config.get("prefix"),
"use_iam_role": bool(s3_config.get("use_iam_role")),
}
return db_config
def _s3_dataset_name(s3_dataset: Any) -> Optional[str]:
if not isinstance(s3_dataset, dict):
return None
bucket = s3_dataset.get("bucket")
if not bucket:
return None
prefix = s3_dataset.get("prefix")
return f"s3://{bucket}/{prefix}" if prefix else f"s3://{bucket}"
def _cleanup_cancelled_checkpoints(output_dir: str | os.PathLike) -> None:
"""Remove only HF Trainer ``tmp-checkpoint-<step>/`` partials after a cancel.
Completed ``checkpoint-<int>/`` dirs survive. Symlinked output_dir / children
are skipped so containment can't be bypassed.
"""
out = Path(output_dir)
if not out.exists() or not out.is_dir() or out.is_symlink():
return
try:
out_real = out.resolve()
out_root_real = Path(outputs_root()).resolve()
except OSError:
return
try:
out_real.relative_to(out_root_real)
except ValueError:
logger.warning(
"Skipping checkpoint cleanup - %s is not under outputs_root %s",
out_real,
out_root_real,
)
return
removed = 0
for entry in out.iterdir():
if not entry.is_dir() or entry.is_symlink():
continue
if not _HF_TMP_CHECKPOINT_RE.match(entry.name):
continue
try:
shutil.rmtree(entry, ignore_errors = False)
removed += 1
except OSError as exc:
logger.warning("Could not remove %s: %s", entry, exc)
logger.info(
"Cancelled-run cleanup removed %d in-flight tmp-checkpoint dir(s) under %s",
removed,
out,
)
_CTX = mp.get_context("spawn")
# Plot styling constants
PLOT_WIDTH = 8
PLOT_HEIGHT = 3.5
@dataclass
class TrainingProgress:
"""Mirror of trainer.TrainingProgress so the parent never imports heavy ML modules."""
epoch: float = 0
step: int = 0
total_steps: int = 0
loss: Optional[float] = None
learning_rate: Optional[float] = None
is_training: bool = False
is_completed: bool = False
error: Optional[str] = None
status_message: str = "Ready to train"
elapsed_seconds: Optional[float] = None
eta_seconds: Optional[float] = None
grad_norm: Optional[float] = None
num_tokens: Optional[int] = None
eval_loss: Optional[float] = None
peak_memory_gb: Optional[float] = None
class TrainingBackend:
"""
Training orchestration backend — subprocess-based.
Launches a fresh subprocess per job, communicates via mp.Queue.
"""
FLUSH_THRESHOLD: int = 10
def __init__(self):
# Subprocess state
self._proc: Optional[mp.Process] = None
self._event_queue: Any = None
self._stop_queue: Any = None
self._pump_thread: Optional[threading.Thread] = None
self._lock = threading.Lock()
# Progress state (updated by pump thread from subprocess events)
self._progress = TrainingProgress()
self._should_stop = False
self._cancel_requested = False # True only for stop(save=False)
# Training metrics (consumed by routes for SSE and /metrics)
self.loss_history: list = []
self.lr_history: list = []
self.step_history: list = []
self.grad_norm_history: list = []
self.grad_norm_step_history: list = []
self.eval_loss_history: list = []
self.eval_step_history: list = []
self.eval_enabled: bool = False
self.current_theme: str = "light"
# Job metadata
self.current_job_id: Optional[str] = None
self._output_dir: Optional[str] = None
# DB persistence
self._metric_buffer: list[dict] = []
self._run_finalized: bool = False
self._db_run_created: bool = False
self._db_total_steps_set: bool = False
self._db_config: Optional[dict] = None
self._db_started_at: Optional[str] = None
# Xet -> HTTP model-load fallback state (config kept for the respawn).
self._last_full_config: Optional[dict] = None
self._in_model_load: bool = False
self._xet_fallback_used: bool = False
self._needs_xet_respawn: bool = False
logger.info("TrainingBackend initialized (subprocess mode)")
# ------------------------------------------------------------------
# Public API (called by routes/training.py)
# ------------------------------------------------------------------
def start_training(
self,
job_id: str,
*,
before_spawn = None,
**kwargs,
) -> bool:
"""Spawn a subprocess to run the full training pipeline.
All kwargs are serialized into a config dict and sent to the worker.
Returns True if the subprocess started successfully.
``before_spawn`` is an optional no-arg callable run after synchronous
validation (start guards, config build, explicit gpu_ids) passes but
before VRAM-dependent auto GPU-selection and the spawn -- used to free
VRAM (e.g. unload chat) without tearing it down on a refused start, while
still letting auto-selection place training against the freed memory.
Hook failures never block the start.
"""
with self._lock:
if self._proc is not None and self._proc.is_alive():
logger.warning("Training subprocess already running")
return False
# Join prior pump thread — refuse to start if it won't die
if self._pump_thread is not None and self._pump_thread.is_alive():
self._pump_thread.join(timeout = 5.0)
if self._pump_thread.is_alive():
logger.warning("Previous pump thread did not exit within 5s — refusing to start")
return False
self._pump_thread = None
# Build config dict for the subprocess
config = {
"model_name": kwargs["model_name"],
"training_type": kwargs.get("training_type", "LoRA/QLoRA"),
"hf_token": kwargs.get("hf_token", ""),
"load_in_4bit": kwargs.get("load_in_4bit", True),
"max_seq_length": kwargs.get("max_seq_length", 2048),
"vision_image_size": kwargs.get("vision_image_size"),
"hf_dataset": kwargs.get("hf_dataset", ""),
"local_datasets": kwargs.get("local_datasets"),
"local_eval_datasets": kwargs.get("local_eval_datasets"),
"format_type": kwargs.get("format_type", ""),
"subset": kwargs.get("subset"),
"train_split": kwargs.get("train_split", "train"),
"eval_split": kwargs.get("eval_split"),
"eval_steps": kwargs.get("eval_steps", 0.00),
"dataset_streaming": kwargs.get("dataset_streaming", False),
"dataset_slice_start": kwargs.get("dataset_slice_start"),
"dataset_slice_end": kwargs.get("dataset_slice_end"),
"custom_format_mapping": kwargs.get("custom_format_mapping"),
"is_dataset_image": kwargs.get("is_dataset_image", False),
"is_dataset_audio": kwargs.get("is_dataset_audio", False),
"is_embedding": kwargs.get("is_embedding", False),
"num_epochs": kwargs.get("num_epochs", 3),
"learning_rate": kwargs.get("learning_rate", "2e-4"),
"embedding_learning_rate": kwargs.get("embedding_learning_rate"),
"batch_size": kwargs.get("batch_size", 2),
"gradient_accumulation_steps": kwargs.get("gradient_accumulation_steps", 4),
"warmup_steps": kwargs.get("warmup_steps"),
"warmup_ratio": kwargs.get("warmup_ratio"),
"max_steps": kwargs.get("max_steps", 0),
"save_steps": kwargs.get("save_steps", 0),
"weight_decay": kwargs.get("weight_decay", 0.001),
"max_grad_norm": kwargs.get("max_grad_norm", 0.0),
"max_grad_value": _coerce_optional_nonneg_float(
"max_grad_value", kwargs.get("max_grad_value")
),
"max_grad_leaf_norm": _coerce_optional_nonneg_float(
"max_grad_leaf_norm", kwargs.get("max_grad_leaf_norm")
),
"cast_norm_output_to_input_dtype": _coerce_optional_bool(
kwargs.get("cast_norm_output_to_input_dtype"), True
),
# MLX/CUDA/embedding workers need an int (transformers.set_seed(None) raises).
"random_seed": _coerce_seed(kwargs.get("random_seed")),
"packing": kwargs.get("packing", False),
"optim": kwargs.get("optim", "adamw_8bit"),
"lr_scheduler_type": kwargs.get("lr_scheduler_type", "linear"),
"use_lora": kwargs.get("use_lora", True),
"lora_r": kwargs.get("lora_r", 16),
"lora_alpha": kwargs.get("lora_alpha", 16),
"lora_dropout": kwargs.get("lora_dropout", 0.0),
"target_modules": kwargs.get("target_modules"),
"gradient_checkpointing": kwargs.get("gradient_checkpointing", "unsloth"),
"use_rslora": kwargs.get("use_rslora", False),
"use_loftq": kwargs.get("use_loftq", False),
"train_on_completions": kwargs.get("train_on_completions", False),
"finetune_vision_layers": kwargs.get("finetune_vision_layers", True),
"finetune_language_layers": kwargs.get("finetune_language_layers", True),
"finetune_attention_modules": kwargs.get("finetune_attention_modules", True),
"finetune_mlp_modules": kwargs.get("finetune_mlp_modules", True),
"enable_wandb": kwargs.get("enable_wandb", False),
"wandb_token": kwargs.get("wandb_token"),
"wandb_project": kwargs.get("wandb_project", "unsloth-training"),
"enable_tensorboard": kwargs.get("enable_tensorboard", False),
"tensorboard_dir": kwargs.get("tensorboard_dir", "runs"),
"resume_from_checkpoint": kwargs.get("resume_from_checkpoint"),
"trust_remote_code": kwargs.get("trust_remote_code", False),
"approved_remote_code_fingerprint": kwargs.get("approved_remote_code_fingerprint"),
"subject": kwargs.get("subject"),
"gpu_ids": kwargs.get("gpu_ids"),
"s3_config": kwargs.get("s3_config"),
# Flipped to True only by the HTTP-fallback respawn after a stall.
"disable_xet": kwargs.get("disable_xet", False),
}
# Full finetuning always runs in 16-bit; LoRA/QLoRA/CPT keep the request.
if config["training_type"] == "Full Finetuning":
config["load_in_4bit"] = False
# Split GPU validation from placement around the VRAM hook:
# * Explicit gpu_ids are validated here (raises -> the route returns 400
# before any teardown) and their placement is VRAM-independent, so it
# stays correct after the hook frees memory.
# * Auto-selection ranks GPUs by *free* VRAM, so it is deferred until
# after the hook frees export/chat -- otherwise it could pin training
# onto a GPU the hook is about to clear (and onto a kept chat model).
from utils.hardware import hardware as _hw
gpu_ids = kwargs.get("gpu_ids")
gpu_selection_kwargs = dict(
model_name = config["model_name"],
hf_token = config["hf_token"] or None,
training_type = config["training_type"],
load_in_4bit = config["load_in_4bit"],
batch_size = config.get("batch_size", 4),
max_seq_length = config.get("max_seq_length", 2048),
lora_rank = config.get("lora_r", 16),
target_modules = config.get("target_modules"),
gradient_checkpointing = config.get("gradient_checkpointing", "unsloth"),
optimizer = config.get("optim", "adamw_8bit"),
)
defer_auto_selection = False
if _hw.DEVICE == _hw.DeviceType.MLX:
config["resolved_gpu_ids"] = None
config["gpu_selection"] = None
elif gpu_ids:
resolved_gpu_ids, gpu_selection = prepare_gpu_selection(gpu_ids, **gpu_selection_kwargs)
config["resolved_gpu_ids"] = resolved_gpu_ids
config["gpu_selection"] = gpu_selection
else:
defer_auto_selection = True
# Synchronous validation passed -> free VRAM (export + chat) now, before
# auto-selection and the spawn, so placement sees the freed memory.
if before_spawn is not None:
try:
before_spawn()
except Exception:
logger.warning("before_spawn hook failed; continuing", exc_info = True)
if defer_auto_selection:
resolved_gpu_ids, gpu_selection = prepare_gpu_selection(None, **gpu_selection_kwargs)
config["resolved_gpu_ids"] = resolved_gpu_ids
config["gpu_selection"] = gpu_selection
from .worker import run_training_process
try:
with native_path_secret_removed_for_child_start():
event_queue = _CTX.Queue()
stop_queue = _CTX.Queue()
proc = _CTX.Process(
target = run_without_native_path_secret,
args = (run_training_process,),
kwargs = {
"event_queue": event_queue,
"stop_queue": stop_queue,
"config": config,
},
daemon = True,
)
proc.start()
from utils.process_lifetime import adopt_pid
adopt_pid(proc.pid) # bind to parent lifetime (Windows job / sweep)
except Exception:
logger.error("Failed to start training subprocess", exc_info = True)
return False
logger.info("Training subprocess started (pid=%s)", proc.pid)
# Reset state (old pump thread dead, proc.start() succeeded).
self.current_job_id = job_id
self._should_stop = False
self._cancel_requested = False
self._progress = TrainingProgress(
is_training = True, status_message = "Initializing training..."
)
self.loss_history.clear()
self.lr_history.clear()
self.step_history.clear()
self.grad_norm_history.clear()
self.grad_norm_step_history.clear()
self.eval_loss_history.clear()
self.eval_step_history.clear()
self.eval_enabled = False
self._output_dir = None
self._metric_buffer.clear()
self._run_finalized = False
self._db_run_created = False
self._db_total_steps_set = False
self._db_config = _sanitize_db_config(config)
self._db_started_at = datetime.now(timezone.utc).isoformat()
# Start each job Xet-first; keep config so a stall can respawn over HTTP.
self._last_full_config = config
self._in_model_load = False
self._xet_fallback_used = False
self._needs_xet_respawn = False
# Assign subprocess handles after state reset.
self._event_queue = event_queue
self._stop_queue = stop_queue
self._proc = proc
# Eagerly create DB run row so it appears in history during model loading.
self._ensure_db_run_created()
self._pump_thread = threading.Thread(target = self._pump_loop, daemon = True)
self._pump_thread.start()
return True
def stop_training(self, save: bool = True) -> bool:
"""Send stop signal to the training subprocess."""
self._should_stop = True
if not save:
self._cancel_requested = True
with self._lock:
if self._stop_queue is not None:
try:
self._stop_queue.put({"type": "stop", "save": save})
except (OSError, ValueError):
pass
# Update progress immediately for responsive UI.
self._progress.status_message = (
"Stopping training and saving checkpoint..." if save else "Cancelling training..."
)
return True
def force_terminate(self) -> None:
"""Force-kill the training subprocess so state can be reset immediately."""
with self._lock:
if self._proc is not None and self._proc.is_alive():
logger.info("Force-terminating training subprocess (pid=%s)", self._proc.pid)
self._proc.terminate()
proc = self._proc
cancelled = self._cancel_requested
output_dir = self._output_dir
if proc is not None:
proc.join(timeout = 5.0)
if proc.is_alive():
proc.kill()
proc.join(timeout = 2.0)
# Wait for pump thread to finish DB finalization (8s covers SQLite's 5s lock timeout).
if self._pump_thread is not None and self._pump_thread.is_alive():
self._pump_thread.join(timeout = 8.0)
if cancelled and output_dir:
try:
_cleanup_cancelled_checkpoints(output_dir)
except Exception:
logger.exception(
"Failed to clean up cancelled-run checkpoints under %s",
output_dir,
)
def _handle_stall_event(self, event: dict) -> None:
"""A worker reported a no-progress download stall.
On the first model-load, terminate the worker so the pump loop respawns it
over HTTP. A later stall (already on HTTP, or outside model-load) surfaces
as an error instead.
"""
msg = event.get("message", "Download stalled")
with self._lock:
recover = self._in_model_load and not self._xet_fallback_used
proc = self._proc
if recover:
self._xet_fallback_used = True
self._needs_xet_respawn = True
self._progress.status_message = (
"Model download stalled on Xet; retrying over HTTP..."
)
else:
self._progress.error = self._progress.error or (
"Model download stalled even over HTTP -- check your network connection"
)
if recover:
logger.warning("Training model-load stalled on Xet; respawning over HTTP: %s", msg)
else:
logger.error("Training download stalled with no further fallback: %s", msg)
# Terminate either way so the pump loop proceeds (respawn or finalize).
if proc is not None and proc.is_alive():
proc.terminate()
def _respawn_worker_disable_xet(self) -> None:
"""Respawn the worker once with HF_HUB_DISABLE_XET=1 after a model-load
stall. Runs on the exiting pump thread, reaps the terminated worker, and
starts a fresh worker + pump. DB/progress run-state is preserved so the
history row is not duplicated; the new worker re-formats and loads over HTTP.
"""
config = self._last_full_config
if config is None:
logger.error("Cannot respawn training worker: no stored config")
return
with self._lock:
old_proc = self._proc
if old_proc is not None:
old_proc.join(timeout = 5.0)
if old_proc.is_alive():
old_proc.kill()
old_proc.join(timeout = 2.0)
config = {**config, "disable_xet": True}
self._last_full_config = config
logger.warning("Respawning training worker with HF_HUB_DISABLE_XET=1 after Xet stall")
from .worker import run_training_process
try:
with native_path_secret_removed_for_child_start():
event_queue = _CTX.Queue()
stop_queue = _CTX.Queue()
new_proc = _CTX.Process(
target = run_without_native_path_secret,
args = (run_training_process,),
kwargs = {
"event_queue": event_queue,
"stop_queue": stop_queue,
"config": config,
},
daemon = True,
)
new_proc.start()
from utils.process_lifetime import adopt_pid
adopt_pid(new_proc.pid) # bind to parent lifetime (Windows job / sweep)
except Exception:
logger.error("Failed to respawn training subprocess", exc_info = True)
with self._lock:
self._progress.is_training = False
self._progress.error = "Failed to recover stalled model download"
self._ensure_db_run_created()
self._finalize_run_in_db(
status = "error",
error_message = "Failed to recover stalled model download",
)
return
logger.info("Training subprocess respawned with Xet disabled (pid=%s)", new_proc.pid)
new_pump = threading.Thread(target = self._pump_loop, daemon = True)
with self._lock:
self._in_model_load = False
self._event_queue = event_queue
self._stop_queue = stop_queue
self._proc = new_proc
self._pump_thread = new_pump
new_pump.start()
def is_training_active(self) -> bool:
"""Check if training is currently active."""
with self._lock:
if self._proc is not None and self._proc.is_alive():
return True
if self._should_stop:
return False
p = self._progress
if p.is_training:
return True
if p.is_completed or p.error:
return False
# Infer activity from the status message.
status_lower = (p.status_message or "").lower()
if any(
k in status_lower
for k in [
"cancelled",
"canceled",
"stopped",
"completed",
"ready to train",
]
):
return False
if any(
k in status_lower
for k in [
"loading",
"preparing",
"training",
"configuring",
"tokenizing",
"starting",
"importing",
]
):
return True
return False
def get_training_status(self, theme: str = "light") -> Tuple:
"""Get current training status and loss plot."""
with self._lock:
progress = self._progress
if not (progress.is_training or progress.is_completed or progress.error):
return (None, progress)
plot = self._create_loss_plot(progress, theme)
return (plot, progress)
def refresh_plot_for_theme(self, theme: str) -> "Optional[plt.Figure]":
"""Refresh plot with new theme."""
if theme and isinstance(theme, str) and theme in ["light", "dark"]:
self.current_theme = theme
if self.loss_history:
with self._lock:
progress = self._progress
return self._create_loss_plot(progress, self.current_theme)
return None
# ------------------------------------------------------------------
# Compatibility shims — routes/training.py accesses these
# ------------------------------------------------------------------
class _TrainerShim:
"""Minimal shim so routes that access backend.trainer.* still work."""
def __init__(self, backend: "TrainingBackend"):
self._backend = backend
self.should_stop = False
@property
def training_progress(self):
return self._backend._progress
@training_progress.setter
def training_progress(self, value):
self._backend._progress = value
def get_training_progress(self):
return self._backend._progress
def _update_progress(self, **kwargs):
with self._backend._lock:
for key, value in kwargs.items():
if hasattr(self._backend._progress, key):
setattr(self._backend._progress, key, value)
@property
def trainer(self):
"""Compatibility shim for routes that access backend.trainer.*"""
return self._TrainerShim(self)
# ------------------------------------------------------------------
# Event pump (background thread)
# ------------------------------------------------------------------
def _pump_loop(self) -> None:
"""Background thread: consume events from subprocess → update state."""
while True:
if self._proc is None or self._event_queue is None:
return
event = self._read_queue(self._event_queue, timeout_sec = 0.25)
if event is not None:
self._handle_event(event)
continue
if self._proc.is_alive():
continue
# Process exited — drain remaining events.
for e in self._drain_queue(self._event_queue):
self._handle_event(e)
# Model-load stall: respawn over HTTP instead of finalizing as failure.
# Runs on THIS exiting pump thread and starts a fresh pump (never joins
# the current thread); DB run-state is preserved.
if self._needs_xet_respawn:
self._needs_xet_respawn = False
self._respawn_worker_disable_xet()
return
# Mark done if no explicit complete/error was received.
with self._lock:
if self._progress.is_training:
if self._should_stop:
self._progress.is_training = False
self._progress.status_message = "Training stopped."
else:
self._progress.is_training = False
self._progress.error = (
self._progress.error or "Training process exited unexpectedly"
)
self._ensure_db_run_created()
self._finalize_run_in_db(
status = "stopped" if self._should_stop else "error",
error_message = None
if self._should_stop
else "Training process terminated unexpectedly",
)
return
def _handle_event(self, event: dict) -> None:
"""Apply a subprocess event to local state.
State updates happen inside self._lock; DB I/O happens after releasing
it so status-polling endpoints aren't blocked by slow SQLite writes.
"""
etype = event.get("type")
db_action: Optional[str] = None
db_action_kwargs: dict = {}
# Model-load lifecycle + stall recovery (no DB metrics); handled first.
if etype == "model_load_started":
with self._lock:
self._in_model_load = True
return
if etype == "model_load_completed":
with self._lock:
self._in_model_load = False
return
if etype == "stall":
self._handle_stall_event(event)
return
with self._lock:
if etype == "progress":
self._progress.step = event.get("step", self._progress.step)
self._progress.epoch = event.get("epoch", self._progress.epoch)
# loss/lr sanitized below.
_raw_loss = event.get("loss")
_raw_lr = event.get("learning_rate")
try:
_safe_loss = float(_raw_loss) if _raw_loss is not None else None
except (TypeError, ValueError):
logger.debug("Could not convert loss to float: %s", _raw_loss)
_safe_loss = None
_loss_is_nonfinite = _safe_loss is not None and not math.isfinite(_safe_loss)
if _loss_is_nonfinite:
# Drop the value rather than laundering it back to the last
# finite loss; clients see loss=None at this step so the NaN
# is not hidden behind a stale value. Training continues.
_safe_loss = None
if not getattr(self._progress, "_nonfinite_loss_warned", False):
self._progress._nonfinite_loss_warned = True
logger.warning(
"Training produced non-finite loss at step %s; "
"loss field will report null until it recovers.",
event.get("step", "?"),
)
try:
_safe_lr = float(_raw_lr) if _raw_lr is not None else None
except (TypeError, ValueError):
logger.debug("Could not convert learning_rate to float: %s", _raw_lr)
_safe_lr = None
if _safe_lr is not None and not math.isfinite(_safe_lr):
_safe_lr = None
if _safe_loss is not None:
self._progress.loss = _safe_loss
elif _loss_is_nonfinite:
# Clear stale finite loss so the API doesn't keep
# reporting the last good value while NaN is happening.
self._progress.loss = None
if _safe_lr is not None:
self._progress.learning_rate = _safe_lr
self._progress.total_steps = event.get("total_steps", self._progress.total_steps)
self._progress.elapsed_seconds = event.get("elapsed_seconds")
self._progress.eta_seconds = event.get("eta_seconds")
self._progress.grad_norm = event.get("grad_norm")
self._progress.num_tokens = event.get("num_tokens")
self._progress.eval_loss = event.get("eval_loss")
_peak = event.get("peak_memory_gb")
if _peak is not None:
try:
self._progress.peak_memory_gb = float(_peak)
except (TypeError, ValueError):
pass
self._progress.is_training = True
status = event.get("status_message", "")
if status:
self._progress.status_message = status
# Update metric histories using sanitized values.
step = event.get("step", 0)
loss = _safe_loss
lr = _safe_lr
if step > 0 and loss is not None:
self.loss_history.append(loss)
self.lr_history.append(lr if lr is not None else 0.0)
self.step_history.append(step)
grad_norm = event.get("grad_norm")
gn = None
if grad_norm is not None:
try:
gn = float(grad_norm)
except (TypeError, ValueError):
gn = None
if step > 0 and gn is not None and math.isfinite(gn):
self.grad_norm_history.append(gn)
self.grad_norm_step_history.append(step)
else:
gn = None
eval_loss = event.get("eval_loss")
if eval_loss is not None:
try:
eval_loss = float(eval_loss)
except (TypeError, ValueError):
logger.debug("Could not convert eval_loss to float: %s", eval_loss)
eval_loss = None
if step > 0 and eval_loss is not None and math.isfinite(eval_loss):
self.eval_loss_history.append(eval_loss)
self.eval_step_history.append(step)
self.eval_enabled = True
else:
eval_loss = None
# Buffer metric for DB flush.
self._metric_buffer.append(
{
"step": step,
"loss": loss,
"learning_rate": lr,
"grad_norm": gn,
"eval_loss": eval_loss,
"epoch": event.get("epoch"),
"num_tokens": event.get("num_tokens"),
"elapsed_seconds": event.get("elapsed_seconds"),
}
)
# Pick the DB action to run after releasing the lock.
if not self._db_run_created and self.current_job_id and self._db_config:
db_action = "create_run"
db_action_kwargs = {
"job_id": self.current_job_id,
"model_name": self._db_config["model_name"],
"dataset_name": self._db_config.get("hf_dataset")
or next(iter(self._db_config.get("local_datasets") or []), "unknown"),
"config_json": _json.dumps(self._db_config),
"started_at": self._db_started_at or datetime.now(timezone.utc).isoformat(),
"total_steps": event.get("total_steps"),
}
elif (
event.get("total_steps")
and self._db_run_created
and not self._db_total_steps_set
):
db_action = "update_total_steps"
db_action_kwargs = {
"job_id": self.current_job_id,
"total_steps": event["total_steps"],
}
elif len(self._metric_buffer) >= self.FLUSH_THRESHOLD:
db_action = "flush"
elif etype == "eval_configured":
self.eval_enabled = True
elif etype == "status":
self._progress.status_message = event.get("message", "")
self._progress.is_training = True
elif etype == "complete":
self._progress.is_training = False
self._progress.is_completed = True
self._output_dir = event.get("output_dir")
msg = event.get("status_message", "Training completed")
self._progress.status_message = msg
if not self._db_run_created and self.current_job_id and self._db_config:
db_action = "create_and_finalize"
else:
db_action = "finalize"
db_action_kwargs = {
"status": "stopped" if self._should_stop else "completed",
"output_dir": self._output_dir,
}
elif etype == "error":
self._progress.is_training = False
self._progress.error = event.get("error", "Unknown error")
logger.error("Training error: %s", event.get("error"))
stack = event.get("stack", "")
if stack:
logger.error("Stack trace:\n%s", stack)
if not self._db_run_created and self.current_job_id and self._db_config:
db_action = "create_and_finalize"
else:
db_action = "finalize"
db_action_kwargs = {
"status": "stopped" if self._should_stop else "error",
"error_message": event.get("error", "Unknown error"),
}
# --- DB I/O outside the lock ---
if db_action == "create_run":
try:
from storage.studio_db import create_run
create_run(
id = db_action_kwargs["job_id"],
model_name = db_action_kwargs["model_name"],
dataset_name = db_action_kwargs["dataset_name"],
config_json = db_action_kwargs["config_json"],
started_at = db_action_kwargs["started_at"],
total_steps = db_action_kwargs["total_steps"],
)
self._db_run_created = True
if db_action_kwargs["total_steps"]:
self._db_total_steps_set = True
except Exception:
logger.warning("Failed to create DB run record", exc_info = True)
elif db_action == "create_and_finalize":
self._ensure_db_run_created()
self._finalize_run_in_db(**db_action_kwargs)
elif db_action == "update_total_steps":
try:
from storage.studio_db import update_run_total_steps
update_run_total_steps(db_action_kwargs["job_id"], db_action_kwargs["total_steps"])
self._db_total_steps_set = True
except Exception:
logger.warning("Failed to update total_steps in DB", exc_info = True)
elif db_action == "flush":
self._flush_metrics_to_db()
elif db_action == "finalize":
self._finalize_run_in_db(**db_action_kwargs)
def _ensure_db_run_created(self) -> None:
"""Create the DB row if it doesn't exist yet. Called outside the lock."""
if self._db_run_created or not self.current_job_id or not self._db_config:
return
try:
from storage.studio_db import create_run
dataset_name = (
self._db_config.get("hf_dataset")
or next(iter(self._db_config.get("local_datasets") or []), None)
or _s3_dataset_name(self._db_config.get("s3_dataset"))
or "unknown"
)
create_run(
id = self.current_job_id,
model_name = self._db_config["model_name"],
dataset_name = dataset_name,
config_json = _json.dumps(self._db_config),
started_at = self._db_started_at or datetime.now(timezone.utc).isoformat(),
total_steps = self._progress.total_steps or None,
)
self._db_run_created = True
except Exception:
logger.warning("Failed to create DB run record for early failure", exc_info = True)
def _finalize_run_in_db(
self,
status: str,
error_message: Optional[str] = None,
output_dir: Optional[str] = None,
) -> None:
"""Flush remaining metrics and mark a run as finished in the DB."""
if not self.current_job_id or not self._db_run_created or self._run_finalized:
return
self._flush_metrics_to_db()
try:
from storage.studio_db import finish_run
from utils.downsample import downsample
sparkline = downsample(self.loss_history, 50)
finish_run(
id = self.current_job_id,
status = status,
ended_at = datetime.now(timezone.utc).isoformat(),
final_step = self._progress.step,
final_loss = self._progress.loss
if (self._progress.loss is not None and math.isfinite(self._progress.loss))
else None,
duration_seconds = self._progress.elapsed_seconds,
loss_sparkline = _json.dumps(sparkline),
output_dir = output_dir,
error_message = error_message,
)
self._run_finalized = True
except Exception:
logger.warning("Failed to finalize run in DB (status=%s)", status, exc_info = True)
def _flush_metrics_to_db(self) -> None:
"""Flush buffered metrics to the database and update live progress."""
if not self._metric_buffer or not self.current_job_id or not self._db_run_created:
return
# Cap buffer to bound memory growth.
if len(self._metric_buffer) > 500:
logger.warning(
"Metric buffer exceeded 500 entries (%d) — trimming oldest",
len(self._metric_buffer),
)
self._metric_buffer = self._metric_buffer[-500:]
# Snapshot before insert so metrics arriving during the write survive.
batch = list(self._metric_buffer)
try:
from storage.studio_db import insert_metrics_batch, update_run_progress
insert_metrics_batch(self.current_job_id, batch)
del self._metric_buffer[: len(batch)]
update_run_progress(
id = self.current_job_id,
step = self._progress.step,
loss = self._progress.loss
if (self._progress.loss is not None and math.isfinite(self._progress.loss))
else None,
duration_seconds = self._progress.elapsed_seconds,
)
except Exception:
# Leave buffer intact for retry on next flush
logger.warning("Failed to flush metrics to DB", exc_info = True)
@staticmethod
def _read_queue(q: Any, timeout_sec: float) -> Optional[dict]:
try:
return q.get(timeout = timeout_sec)
except queue.Empty:
return None
except (EOFError, OSError, ValueError):
return None
@staticmethod
def _drain_queue(q: Any) -> list:
events = []
while True:
try:
events.append(q.get_nowait())
except queue.Empty:
return events
except (EOFError, OSError, ValueError):
return events
# ------------------------------------------------------------------
# Plot generation
# ------------------------------------------------------------------
def _create_loss_plot(
self,
progress: TrainingProgress,
theme: str = "light",
) -> "Optional[plt.Figure]":
"""Create training loss plot with theme-aware styling.
matplotlib is loaded lazily; returns None if it is unavailable.
"""
plt = _load_pyplot()
if plt is None:
return None
plt.close("all")
LIGHT_STYLE = {
"facecolor": "#ffffff",
"grid_color": "#d1d5db",
"line": "#16b88a",
"text": "#1f2937",
"empty_text": "#6b7280",
}
DARK_STYLE = {
"facecolor": "#292929",
"grid_color": "#404040",
"line": "#4ade80",
"text": "#e5e7eb",
"empty_text": "#9ca3af",
}
style = LIGHT_STYLE if theme == "light" else DARK_STYLE
fig, ax = plt.subplots(figsize = (PLOT_WIDTH, PLOT_HEIGHT))
fig.patch.set_facecolor(style["facecolor"])
ax.set_facecolor(style["facecolor"])
if self.loss_history:
steps = self.step_history
losses = self.loss_history
scatter_color = "#60a5fa"
ax.scatter(
steps,
losses,
s = 16,
alpha = 0.6,
color = scatter_color,
linewidths = 0,
label = "Training Loss (raw)",
)
MA_WINDOW = 20
window = min(MA_WINDOW, len(losses))
if window >= 2:
cumsum = [0.0]
for v in losses:
cumsum.append(cumsum[-1] + float(v))
ma = []
for i in range(len(losses)):
start = max(0, i - window + 1)
denom = i - start + 1
ma.append((cumsum[i + 1] - cumsum[start]) / denom)
ax.plot(
steps,
ma,
color = style["line"],
linewidth = 2.5,
alpha = 0.95,
label = f"Moving Avg ({ma[-1]:.4f})",
)
leg = ax.legend(frameon = False, fontsize = 9)
for t in leg.get_texts():
t.set_color(style["text"])
ax.set_xlabel("Steps", fontsize = 10, color = style["text"])
ax.set_ylabel("Loss", fontsize = 10, color = style["text"])
if progress.error:
title = f"Error: {progress.error}"
elif progress.is_completed:
loss_str = f"{progress.loss:.4f}" if progress.loss is not None else "--"
title = f"Training completed! Final loss: {loss_str}"
elif progress.status_message:
title = progress.status_message
elif progress.step > 0:
loss_str = f"{progress.loss:.4f}" if progress.loss is not None else "--"
title = f"Epoch: {progress.epoch} | Step: {progress.step}/{progress.total_steps} | Loss: {loss_str}"
else:
title = "Training Loss"
ax.set_title(title, fontsize = 11, fontweight = "bold", pad = 10, color = style["text"])
ax.grid(True, alpha = 0.4, linestyle = "--", color = style["grid_color"])
ax.tick_params(colors = style["text"], which = "both")
ax.spines["top"].set_visible(False)
ax.spines["right"].set_visible(False)
ax.spines["bottom"].set_color(style["text"])
ax.spines["left"].set_color(style["text"])
else:
display_msg = (
progress.status_message
if progress.status_message
else "Waiting for training data..."
)
ax.text(
0.5,
0.5,
display_msg,
ha = "center",
va = "center",
fontsize = 16,
color = style["empty_text"],
transform = ax.transAxes,
)
ax.set_xticks([])
ax.set_yticks([])
for spine in ax.spines.values():
spine.set_visible(False)
fig.tight_layout()
return fig
def _transfer_to_inference_backend(self) -> bool:
"""Transfer model to inference backend.
No-op: with subprocess training the model is freed on exit, so inference
must load from the saved checkpoint on disk.
"""
logger.info(
"_transfer_to_inference_backend: subprocess training — "
"model must be loaded from disk (output_dir=%s)",
self._output_dir,
)
return False
# ========== GLOBAL INSTANCE ==========
_training_backend = None
def get_training_backend() -> TrainingBackend:
"""Get global training backend instance"""
global _training_backend
if _training_backend is None:
_training_backend = TrainingBackend()
return _training_backend