Provide command to delete experiments, so that user can save storage space.

[squirrelsc]

There is user feedback that the local /tmp folder and remote OpenPAI storage is full. So, it needs to support deleting OpenPAI files to save disk space or remove meaningless experiment.

Scenarios

1. Delete an experiment. User likes to remove a incorrect experiment.
2. Delete all experiments. User meets low disk storage, and want to remove all experiments result.
3. Clean NNI experiment files on a target platform. User meets low disk storage on a remote platform, which may be shared among users.

What to delete

1. If to delete an experiment, it should remove all files of this experiment, including cached/duplicated files, experiment configs, logs, and so on. The deleted experiment shouldn't be listed, once it's deleted. If deleted files don't exist, no error should be raised.
2. If to clean on a target platform, all files of experiments should be deleted. And it won't impact NNI runtime on the target platform.

Command line design

1. Delete experiment(s). In this scenario, experiment information can be get from local, so that no target platform needed. User can use nnictl experiment list to get all experiments. A confirmation is needed before removed, but it can be suppressed if needed.

   If this experiment is running or not exists, there should be an error.

   • Usage

   nnictl experiment delete [Options]

   • Options

   Name, shorthand	Required	Default	Description
   id	True		ID of the experiment you want to set. * means delete all experiments.
   --force	False		If specified, there is no confirmation

2. Clean a target platform. In this scenario, the command needs to provide a NNI config file, so that it knows which target platform need to be cleaned. A confirmation is needed before removed, and it should mention this operation may remove NNI data of others.

   • Usage

   nnictl platform clean [OPTIONS]

   • Options

   Name, shorthand	Required	Default	Description
   --config, -c	True		YAML configure file of an experiment, and it should be used to load target platform information, it may be local, remote, pai or others.