Extract the expected keys from a deserializable struct

[nitnelave]

Hey,

I'm trying to detect typos in env variables used to set the config values in my program. I understand that providers don't know the expected keys (they're just providing a dict), the magic happens in extract, with deserialization. However, I couldn't follow the logic, so:
For a given struct T: Deserialize, how can I get the list of keys? If I have that, I think I can compare it with my Env provider, and flag for any env variable that doesn't match a config key.

One (awkward) idea is to deserialize to json, and then walk the json to generate the (flat) list of keys. Is there a more direct way?

[joshka]

Try

let figment = Figment::from(Serialized::defaults(MyConfig::default()));
dbg!(&figment.data()?[figment.profile()]); // or iterate over the keys here

[nitnelave]

Thanks, that's cleaner than the json version. For posterity, taking the separators and nesting into account, that gives you this: https://github.com/lldap/lldap/pull/973/files

[joshka]

No probs. I saw discussion as I was searching for an answer to a similar problem. I wanted to generically show config settings that come from different sources (defaults, toml file, cli args) in a Web UI.