[Feature] add HFCheckpointHook to auto save hf model after the whole …

…training phase (#621)

* add HFCheckpointHook to auto save hf model after the whole training phase

* refinie HFCheckpointHook

* fix lint

* delete useless codes

* fix bugs

* support non-dist training

xtuner/engine/hooks/__init__.py

@@ -1,10 +1,11 @@
 # Copyright (c) OpenMMLab. All rights reserved.
 from .dataset_info_hook import DatasetInfoHook
 from .evaluate_chat_hook import EvaluateChatHook
+from .hf_checkpoint_hook import HFCheckpointHook
 from .throughput_hook import ThroughputHook
 from .varlen_attn_args_to_messagehub_hook import VarlenAttnArgsToMessageHubHook
 
 __all__ = [
     'EvaluateChatHook', 'DatasetInfoHook', 'ThroughputHook',
-    'VarlenAttnArgsToMessageHubHook'
+    'VarlenAttnArgsToMessageHubHook', 'HFCheckpointHook'
 ]

xtuner/engine/hooks/hf_checkpoint_hook.py

@@ -0,0 +1,53 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+import os.path as osp
+from pathlib import Path
+from typing import Optional, Union
+
+import torch.distributed as dist
+from mmengine._strategy import DeepSpeedStrategy
+from mmengine.hooks import Hook
+from mmengine.model import is_model_wrapper
+from mmengine.runner import FlexibleRunner
+
+DATA_BATCH = Optional[Union[dict, tuple, list]]
+
+
+class HFCheckpointHook(Hook):
+
+    priority = 95  # lower than CheckpointHook in MMEngine
+
+    def __init__(self, out_dir: Optional[Union[str, Path]] = None) -> None:
+        self.out_dir = out_dir
+
+    def after_run(self, runner) -> None:
+        assert isinstance(runner,
+                          FlexibleRunner), 'Runner should be `FlexibleRunner`'
+        assert isinstance(
+            runner.strategy,
+            DeepSpeedStrategy), 'Strategy should be `DeepSpeedStrategy`'
+
+        if self.out_dir is None:
+            self.out_dir = osp.join(runner.work_dir, 'hf_model')
+
+        wrapped_model = runner.strategy.model
+        if wrapped_model.zero_optimization_partition_weights():
+            assert wrapped_model.zero_gather_16bit_weights_on_model_save(), \
+                ('Please set `gather_16bit_weights_on_model_save=True` '
+                 'in your DeepSpeed config.')
+            state_dict = wrapped_model._zero3_consolidated_16bit_state_dict()
+        else:
+            state_dict = wrapped_model.module_state_dict(
+                exclude_frozen_parameters=runner.strategy.
+                exclude_frozen_parameters)
+
+        model = runner.model
+        if is_model_wrapper(model):
+            model = model.module
+        llm = model.llm
+        if (not dist.is_initialized()) or dist.get_rank() == 0:
+            # keys in state_dict are prefixed with 'llm.'
+            keys = list(state_dict.keys())
+            for k in keys:
+                val = state_dict.pop(k)
+                state_dict[k[4:]] = val
+            llm.save_pretrained(self.out_dir, state_dict=state_dict)