How to pass non primitive data to a custom hook

[FrancescoSaverioZuppichini]

Hi guys,

I hope you are doing great! So, I have the following custom hook

from logging import log
from pprint import pprint
from mmcv.runner.hooks import HOOKS
from mmcv.runner.hooks import TextLoggerHook
from gust import TrainHandler


@HOOKS.register_module()
class TrainHandlerCallback(TextLoggerHook):
    def __init__(self, train_handler: TrainHandler, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.train_handler = train_handler

    def _dump_log(self, log_dict, runner):
        pprint(log_dict)
        mode = log_dict.get("mode", None)
        if mode == "val":
            self.train_handler.log_metric("train/loss", log_dict["loss"])

And I need to set train_handler but the config system doesn't support non primitive data, I've tried to inject my config using the merge dict option

"log_config.hooks": [
              dict(type="TrainHandlerCallback", train_handler=train_handler)
          ],

But yeah, as expected got a "serialization" error:

  File "/opt/conda/lib/python3.7/ast.py", line 35, in parse
    return compile(source, filename, mode, PyCF_ONLY_AST)
  File "<unknown>", line 267
    train_handler=<gust.train_handler.TrainHandler object at 0x7f4bfbf4dd50>)])

The doc unfortunately is not helping.

Thanks

Francesco

[zhouzaida]

hi @FrancescoSaverioZuppichini , sorry for the late reply. The config can not contain a custom object like train_handler here.

[hhaAndroid]

@FrancescoSaverioZuppichini Can the train_handler object also be constructed through the register mode so that the train_handler can be configured in the configuration？

class TrainHandlerCallback(TextLoggerHook):
   def __init__(self, train_handler: TrainHandler, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.train_handler = build_from_cfg(train_handler)
        ...

[FrancescoSaverioZuppichini]

Hi @hhaAndroid , thank you for your reply. The main problem is that train_handler is created a run time so I am not sure how to inject a hook at run time. Is there a way maybe to reference the hooks list and append a new one?

[hhaAndroid]

@FrancescoSaverioZuppichini Can you describe in detail what train_handler does？

[FrancescoSaverioZuppichini]

@hhaAndroid A class with some methods to call an external API. I use it to store the metrics during training/val in a third party service

[FrancescoSaverioZuppichini]

I'll end up spawing a thread and reading the .json log file (that is not stored as a correct json file btw) to extract the metrics. We can close it since I won't be using it in the future and there is no solution. Thank you very much for all the help

[hhaAndroid]

I'll end up spawing a thread and reading the .json log file (that is not stored as a correct json file btw) to extract the metrics. We can close it since I won't be using it in the future and there is no solution. Thank you very much for all the help

The requirements you provide are very important, and we will seriously consider improving scalability in later versions.