No Callbacks for Validation Batch Step - How To Get Progress of Validation?

🚀 Feature

The Callbacks has two functions on_batch_start and on_batch_end. The documentation and code execution shows that these are only called for training batches, not validaton (or test). I am building a Callback for my own logging/dashboarding via Streamlit and I have a requirement to track the progress of both the train batch steps and validation batch steps during training. I see that there is a validation progress bar in the console during training - how is this implemented (if not via a Callback)?

Current Code

class MyCallback(pl.Callback):
    def on_train_start(self, trainer, pl_module):
        self.train_batch_count = 0
        self.train_batch_total = len(trainer.train_dataloader)

    def on_batch_end(self, train, pl_module):
        self.train_batch_count += 1
        percent_complete = self.train_batch_count / self.train_batch_total
        # display on screen

    def on_epoch_end(self, train, pl_module):
        self.train_batch_count = 0

[awaelchli]

In case this is still relevant to you, we now also have callbacks for validatation and test batches! See https://pytorch-lightning.readthedocs.io/en/latest/callbacks.html#callback-base

[SouthMemory]

https://pytorch-lightning.readthedocs.io/en/latest/callbacks.html#callback-base

good work!