Files
AstrAI/astrai/trainer/train_context.py
T
ViperEkura 754624acf0 feat: add online rollout framework for RL strategies
- RolloutRunner: generate + score responses with cached re-rollout trigger
- BaseStrategy.__call__ switches online/offline via runner injection
- GRPO/DPO implement prepare_from_rollout; aliases online_grpo/online_dpo
- TrainConfig + train.py add rollout params and CLI flags
- Tests cover generate_responses, RolloutRunner cache, shared __call__
2026-07-20 03:49:56 +08:00

267 lines
9.3 KiB
Python

from dataclasses import dataclass, field
from pathlib import Path
from typing import Any, Dict, Optional, Self
import torch
import torch.nn as nn
from torch.utils.data import DataLoader, random_split
from astrai.config.train_config import TrainConfig
from astrai.dataset import RDSampler
from astrai.inference.sample import (
SamplingPipeline,
TemperatureStrategy,
TopKStrategy,
TopPStrategy,
)
from astrai.model.components.lora import inject_lora
from astrai.parallel.executor import BaseExecutor, ExecutorFactory
from astrai.parallel.setup import get_current_device, get_rank, get_world_size
from astrai.protocols import OptimizerProtocol, SchedulerProtocol
from astrai.serialization import Checkpoint, load_json
from astrai.tokenize import AutoTokenizer
from astrai.trainer.rollout import RolloutRunner
from astrai.trainer.strategy import BaseStrategy, StrategyFactory, create_ref_model
@dataclass
class TrainContext:
model: nn.Module = field(default=None)
strategy: BaseStrategy = field(default=None)
dataloader: DataLoader = field(default=None)
optimizer: OptimizerProtocol = field(default=None)
scheduler: SchedulerProtocol = field(default=None)
checkpoint: Checkpoint = field(default=None)
config: TrainConfig = field(default=None)
model_config: dict = field(default_factory=dict)
executor: BaseExecutor = field(default=None)
epoch: int = field(default=0)
consumed_samples: int = field(default=0)
loss: float = field(default=0.0)
grad_norm: Optional[float] = field(default=None)
val_dataloader: Optional[DataLoader] = field(default=None)
val_loss: Optional[float] = field(default=None)
world_size: int = field(default=1)
rank: int = field(default=0)
kwargs: Dict[str, Any] = field(default_factory=dict)
@property
def optimizer_step(self) -> int:
return self.consumed_samples // (
self.config.batch_per_device
* self.world_size
* self.config.grad_accum_steps
)
class TrainContextBuilder:
def __init__(
self,
config: TrainConfig,
):
self.config = config
self._param_path: Optional[str] = None
self._resume: bool = False
def with_param_path(self, param_path: Optional[str], resume: bool = False) -> Self:
self._param_path = param_path
self._resume = resume
return self
def build(self) -> TrainContext:
cfg = self.config
device = get_current_device()
executor = ExecutorFactory.create(
cfg.parallel_mode,
grad_accum_steps=cfg.grad_accum_steps,
**cfg.executor_kwargs,
)
model_config = {}
if self._param_path:
config_path = Path(self._param_path) / "config.json"
if config_path.exists():
model_config = load_json(config_path)
preloaded_state_dict = None
preloaded_epoch = cfg.start_epoch
preloaded_consumed = cfg.start_samples * get_world_size()
preloaded_checkpoint = None
if self._param_path:
checkpoint = Checkpoint.load_any(self._param_path)
if checkpoint is not None:
preloaded_state_dict = checkpoint.state_dict
if checkpoint.config:
model_config = checkpoint.config
if self._resume:
preloaded_epoch = checkpoint.epoch or cfg.start_epoch
if checkpoint.consumed_samples > 0:
per_step = (
cfg.batch_per_device
* get_world_size()
* cfg.grad_accum_steps
)
preloaded_consumed = (
checkpoint.consumed_samples // per_step
) * per_step
else:
preloaded_consumed = cfg.start_samples * get_world_size()
preloaded_checkpoint = checkpoint
if not model_config and hasattr(cfg.model_fn(), "config"):
model_config = cfg.model_fn().config.to_dict()
def _before_wrap(m):
m = m.to(device=device)
if preloaded_state_dict is not None:
m.load_state_dict(preloaded_state_dict, strict=False)
if cfg.lora is not None:
inject_lora(
m,
r=cfg.lora.r,
alpha=cfg.lora.alpha,
target_modules=set(cfg.lora.target_modules),
)
return m
context = TrainContext(
world_size=get_world_size(),
rank=get_rank(),
config=cfg,
model_config=model_config,
executor=executor,
epoch=preloaded_epoch,
consumed_samples=preloaded_consumed,
checkpoint=preloaded_checkpoint,
)
context.model, context.optimizer, context.scheduler = executor.prepare(
cfg.model_fn,
cfg.optimizer_fn,
cfg.scheduler_fn,
before_wrap=_before_wrap,
)
train_dataset = cfg.dataset
val_dataset = cfg.val_dataset
if val_dataset is None and cfg.val_split is not None:
n_total = len(cfg.dataset)
n_val = max(1, int(n_total * cfg.val_split))
n_train = n_total - n_val
generator = torch.Generator().manual_seed(cfg.random_seed)
train_dataset, val_dataset = random_split(
cfg.dataset, [n_train, n_val], generator=generator
)
sampler_offset = context.consumed_samples // context.world_size
sampler = RDSampler(
data_source=train_dataset,
start_epoch=context.epoch,
start_iter=sampler_offset,
seed=cfg.random_seed,
)
context.dataloader = DataLoader(
train_dataset,
batch_size=cfg.batch_per_device,
sampler=sampler,
num_workers=cfg.num_workers,
pin_memory=cfg.pin_memory,
prefetch_factor=cfg.prefetch_factor,
collate_fn=cfg.collate_fn,
)
if val_dataset is not None:
val_sampler = RDSampler(
data_source=val_dataset,
start_epoch=0,
start_iter=0,
seed=cfg.random_seed,
shuffle=False,
)
context.val_dataloader = DataLoader(
val_dataset,
batch_size=cfg.batch_per_device,
sampler=val_sampler,
num_workers=cfg.num_workers,
pin_memory=cfg.pin_memory,
prefetch_factor=cfg.prefetch_factor,
collate_fn=cfg.collate_fn,
)
if context.checkpoint and context.checkpoint.extra:
extra = context.checkpoint.extra
for name in ("optimizer", "scheduler"):
if name in extra:
obj = getattr(context, name, None)
if obj is not None:
obj.load_state_dict(extra[name])
strategy_kwargs = dict(cfg.extra_kwargs)
needs_ref = cfg.strategy in (
"dpo",
"grpo",
"online_grpo",
"online_dpo",
)
needs_old = cfg.strategy in ("grpo", "online_grpo")
if needs_ref:
ref_model = create_ref_model(
cfg.model_fn, executor.unwrap_model(context.model)
).to(device=device)
strategy_kwargs["ref_model"] = ref_model
old_model = None
if needs_old:
old_model = create_ref_model(
cfg.model_fn, executor.unwrap_model(context.model)
).to(device=device)
strategy_kwargs["old_model"] = old_model
context.strategy = StrategyFactory.create(
cfg.strategy,
model=context.model,
device=device,
executor=executor,
**strategy_kwargs,
)
# Enable online rollout when the train_type is an ``online_*`` variant.
is_online = cfg.strategy.startswith("online_")
if is_online:
if not context.strategy.supports_online():
raise ValueError(
f"Strategy '{cfg.strategy}' does not support online rollout"
)
if cfg.reward_model_fn is None:
raise ValueError("reward_model_fn is required for online RL strategies")
tokenizer = AutoTokenizer.from_pretrained(self._param_path)
reward_model = cfg.reward_model_fn()
pipeline = SamplingPipeline(
[
TemperatureStrategy(cfg.rollout_temperature),
TopKStrategy(cfg.rollout_top_k),
TopPStrategy(cfg.rollout_top_p),
]
)
runner = RolloutRunner(
policy_model=context.model,
old_model=old_model,
tokenizer=tokenizer,
reward_model=reward_model,
sampling_pipeline=pipeline,
max_tokens=cfg.rollout_max_tokens,
group_size=strategy_kwargs.get("group_size", 8),
rollout_interval=cfg.rollout_interval,
)
context.strategy.set_rollout_runner(runner)
return context