`ray_lightning` checkpoint dir not saving the checkpoint

[JiahaoYao]

def get_trainer(dir,
                plugins: List[PLUGIN_INPUT],
                max_epochs: int = 1000,
                limit_train_batches: int = 10,
                limit_val_batches: int = 10,
                callbacks: Optional[List[Callback]] = None,
                checkpoint_callback: bool = True,
                **trainer_kwargs) -> Trainer:
    """Returns a Pytorch Lightning Trainer with the provided arguments."""
    callbacks = [] if not callbacks else callbacks
    trainer = pl.Trainer(
        default_root_dir=dir,
        callbacks=callbacks,
        plugins=plugins,
        max_epochs=max_epochs,
        limit_train_batches=limit_train_batches,
        limit_val_batches=limit_val_batches,
        enable_progress_bar=True,
        checkpoint_callback=checkpoint_callback,
        **trainer_kwargs)
    return trainer

if we passed the tmpdir to the get_trainer, the checkpoint will not be saved.

tmpdir = test_ckpt

Traceback (most recent call last):
  File "test_ckpt.py", line 44, in <module>
    ckpt()
  File "test_ckpt.py", line 38, in ckpt
    trained_model = BoringModel.load_from_checkpoint(
  File "/home/ray/anaconda3/lib/python3.8/site-packages/pytorch_lightning/core/saving.py", line 134, in load_from_checkpoint
    checkpoint = pl_load(checkpoint_path, map_location=lambda storage, loc: storage)
  File "/home/ray/anaconda3/lib/python3.8/site-packages/pytorch_lightning/utilities/cloud_io.py", line 37, in load
    with fs.open(path_or_url, "rb") as f:
  File "/home/ray/anaconda3/lib/python3.8/site-packages/fsspec/spec.py", line 976, in open
    f = self._open(
  File "/home/ray/anaconda3/lib/python3.8/site-packages/fsspec/implementations/local.py", line 145, in _open
    return LocalFileOpener(path, mode, fs=self, **kwargs)
  File "/home/ray/anaconda3/lib/python3.8/site-packages/fsspec/implementations/local.py", line 236, in __init__
    self._open()
  File "/home/ray/anaconda3/lib/python3.8/site-packages/fsspec/implementations/local.py", line 241, in _open
    self.f = open(self.path, mode=self.mode)
FileNotFoundError: [Errno 2] No such file or directory: '/home/ray/default/ray_lightning/ray_lightning/tests/test_ckpt/lightning_logs/version_0/checkpoints/epoch=2-step=191.ckpt'

---

tmpdir = None

(RayExecutor pid=31579) Metric val_loss improved. New best score: 1.000
/home/ray/default/ray_lightning/ray_lightning/tests/lightning_logs/version_0/checkpoints/epoch=2-step=191.ckpt