raise error when running registered config with incompatible recipe

[felipemello1]

Running the code below raises errors about parameters missing, instead of saying that "lora config is not compatible with full finetune recipe"

tune run --nnodes 1 --nproc_per_node 8 full_finetune_distributed --config gemma/2B_lora

[Ankur-singh]

It would be helpful to have a consistent way to validate the config file across all recipes, not just in the example above.

One idea is to define a _validate_config method for each recipe and call it in the setup method. This method could check for required keys and return True if everything is correct, or raise an error with a clear, user-friendly message if any required key is missing.

Sample code:

def validate_config(config, required_fields):
    for field in required_fields:
        # Handle nested keys by splitting them and navigating through the structure
        keys = field.split('.')
        current_config = config

        for key in keys:
            # If the key is a dictionary, check if it exists
            if isinstance(current_config, dict) and key in current_config:
                current_config = current_config[key]
            else:
                raise ValueError(f"Missing required field: '{field}'")

# Example usage with nested config:
required_fields = ['field1', 'nested.field2', 'nested.subnested.field3']
config = OmegaConf.create({
    'field1': 'value1',
    'nested': {
        'field2': 'value2'
        # 'subnested' and 'field3' are missing
    }
})

try:
    validate_config(config, required_fields)
except ValueError as e:
    print(e)

Any thoughts?