Calling module.log(...) within a callback fails

[ananthsub]

🐛 Bug

Calling pl_module.log(...) within a Callback fails, even though this is recommended by the documentation here: https://pytorch-lightning.readthedocs.io/en/latest/loggers.html#logging-from-a-callback

Error

  File "my_callback_file.py", line XX, in on_validation_epoch_end
    pl_module.log_dict(my_metrics_dict)
  File "/home/local/USHERBROOKE/pain5474/opt/miniconda3/envs/cav/lib/python3.8/site-packages/pytorch_lightning/core/lightning.py", line 287, in log_dict
    self.log(
  File "/home/local/USHERBROOKE/pain5474/opt/miniconda3/envs/cav/lib/python3.8/site-packages/pytorch_lightning/core/lightning.py", line 233, in log
    self._results.log(
  File "/home/local/USHERBROOKE/pain5474/opt/miniconda3/envs/cav/lib/python3.8/site-packages/pytorch_lightning/core/step_result.py", line 171, in log
    self.__set_meta(
  File "/home/local/USHERBROOKE/pain5474/opt/miniconda3/envs/cav/lib/python3.8/site-packages/pytorch_lightning/core/step_result.py", line 217, in __set_meta
    _internal = self['meta']['_internal']
KeyError: '_internal'
python-BaseException

cc @nathanpainchaud

This is happening on master

Expected behavior

We can log from callbacks using the lightning module

Environment

Happening on PyTorch Lightning master

[SkafteNicki]

@ananthsub I just tried on master and cannot reproduce (I think it was solved yesterday, as I could reproduce 2 days ago).

[nathanpainchaud]

@SkafteNicki The issue was created by @ananthsub based on a question/issue I initially raised in the slack. I'll try to see if the bug is now resolved on master for me (it was still present as of yesterday afternoon) and I'll update you here as soon as I can.

Edit: @SkafteNicki The issue persists on my end, after having just pulled the master. I'll try to write a test today that can reliably reproduce this behavior, and I'll open a draft PR and link it here once I do.

[tchaton]

Hey @nathanpainchaud,

Did you manage to reliably reproduce this behaviour? And if yes, could share the draft PR associated with this issue ?
I will try to try it out too.

Best regards,
Thomas Chaton.

[nathanpainchaud]

Hey @tchaton,

Thanks for the follow up! I opened the draft PR where I added a test that reproduces the behavior I'm getting.

If I can help in any other way to get this sorted, just let me know!

[nathanpainchaud]

@tchaton Any updates on whether this is a feature that's planned to be supported, or on the contrary it's been abandoned? I'm only asking this question because the issue has been labelled priority for a while, but every PR referring to it have been closed without getting merged 😆

[williamFalcon]

Yes! thats been worked on these weeks. Starting to be merged now (#4439)

[ghost]

I still have problems logging my validation metrics using pl_module.log() in the on_validation_end() hook. Any thoughts?