Add support for loading flattened meta_tags.csv

[S-aiueo32]

🚀 Feature

Motivation

PL+TensorBoard can log hierarchical dict after #1152, however, meta_tags.csv has been disabled by the change.

Pitch

• Make meta_tags.csv back to a hierarchical dict based on their delimiter.

Alternatives

62de794

Additional context

1. We can consider the deprecation of meta_tags.csv, then adopt config.yaml.
2. We can interpret primitive-type parameters through the files, so it is needed to rethink parameter sanitization or update docs.

[williamFalcon]

can you elaborate on what the .yaml would look like? i kind of like the idea.
@luiscape

[S-aiueo32]

@williamFalcon thank you for replying.

Roughly, I plan to make the following change for tags_csv replacement with yaml:

1. Replace here with yaml.dump().

   import yaml
   
   with open("config.yaml", "w") as wf:
       yaml.dump(self.tags, wf)

2. Create load_hparams_from_yaml like here

   import yaml
   
   def load_hparams_from_yaml(config_yaml: str) -> Dict[str, Any]:
       if not os.path.isfile(config_yaml):
           log.warning(f'Missing Tags: {config_yaml}.')
           return {}
   
       with open(config_yaml) as f:
          tags = yaml.load(f, Loader=yaml.SafeLoader)
   
       return tags

[Borda]

I very much support replacing CSV by YAML it is much easier to read and handle (also comment)