Multiple configs from a config group with required fields

[tillwenke]

Imagine the following setting. We want to create a config like this:

server:
  site:
    fb:
      domain: facebook.com
      x: 10
    google:
      domain: google.com
      x: 10
  host: localhost
  port: 443

with .yaml files similar to here https://hydra.cc/docs/patterns/select_multiple_configs_from_config_group/.

How can I tell the configs (fb and google) from the site config group to always have the field x with the default value 10. So it even appears in the config if I do not explicitly mention it in the respective yamls. I should as well be able to set it explicitly in the yaml.

Currently we are setting this kind of required fields in our python script which works but I thought there might be a hydra-way to do it.

Cheers

[odelalleau]

In both fb.yaml and google.yaml, you would have a defaults list that includes a common config that contains x: 10 (before _self_).