Shorthand way to grab a tracker

[muellerzr]

Shorthand way to grab a tracker

What does this add?

This PR introduces a method to the Accelerator that lets you grab a tracker's internal run if some custom code with it is wanted to be ran

Who is it for?

Closes #592

Why is it needed?

There are needs when using wandb for example to access and toy with the run, such as stated in #592. Currently you need to index into the trackers, hope you find the right one, and then in the case of wandb call run.run which is a bit convoluted.

What parts of the API does this impact?

User-facing:

Adds a new Accelerator.get_tracker method. To get a tracker you should pass in the corresponding string to the .name attribute

Internal structure:

Trackers now have a new abstract property of tracker which should be used to return the internal tracking mechanism normal users would expect to interact with.

Basic Usage Example(s):

accelerator = Accelerator(log_with="wandb")

accelerator.init_trackers("my_project_name")

if accelerator.is_main_process:
    wandb_run = accelerator.get_tracker('wandb')
    wandb_run.log_artifact(test_data_at_xyz)

When would I use it, and when wouldn't I?

When custom interactions with a tracker is wanted.

[sgugger]

Thanks for adding this!

[HuggingFaceDocBuilderDev]

The documentation is not available anymore as the PR was closed or merged.