Overriding config file with another config before applying CLI overrides?

[stwerner97]

Hi, I want to merge an additional config file into the config that Hydra composes before it applies the CLI overrides.

The intended use case is a package that comes with its own Hydra configs and I want to override some of its parameters through an additional config file.

model: some-model
quantize: true
imgsize: 640

The extra config file is located somewhere else:

quantize: false

I think a possible solution would be to make the extra config the primary config and add a defaults section to it that includes the other config's values. This is, however, not possible for me, as I cannot change the extra config file or make it the primary config.

I would be interested in having an option python app.py --extra-config=<path to extra config> imgsize=320 that gives me the config

{"model": "some-model",  "quantize": False, "imgsize": 320}

I've tried merging the configs in the app, but then the extra config's values take precedence over those of the CLI (which I do not want).

extracfg = OmegaConf.load(<path>)
config = OmegaConf.merge(config, extracfg)

[odelalleau]

I think a possible solution would be to make the extra config the primary config and add a defaults section to it that includes the other config's values. This is, however, not possible for me, as I cannot change the extra config file or make it the primary config.

Yes that would indeed be the "normal" way to achieve this.

Alternatively, you could append your extra config to the default list (e.g. +extra=extra_config), using the #@package _global_ directive to override the root config and this config found under conf/extra/extra_config.yaml (you might need to modify the config search path to find it if you can't put it in the base conf folder).