Automatically reading from alternative sources

[absolutejam]

Hey!

I'm using v3 and I'm curious if there's a way to automatically register Sources for all flags? Perhaps in the Before func?

I tried the following:

for _, flag := range cmd.Flags {
   // TODO: Handle all flag types
    if flag, ok := flag.(*cli.StringFlag); ok {
	flag.Sources.Chain = append(flag.Sources.Chain, koanfsource.Koanf(a.Config(), flag.Name))
    }
}

But the flag doesn't seem to be reflected either in the help, or when I get the value. I also tried skipping the Sources and just iterating over the commands' flags in the Before function, and updating the flag Value - but that doesn't seem to have had any effect.

for _, flag := range cmd.Flags {
    if flag, ok := flag.(*cli.StringFlag); ok {
        // TODO: Hacky an example
	value := a.Config().Get(flag.Name)
	if !flag.IsSet() {
            if valStr, ok := value.(string); ok {
                flag.Value = valStr
	    }
	}
    }
}

I basically want to read from Koanf using the Command's Name, as a way of centralising all of the config from the Koanf (which leverages env & file providers), and I also write back to it in the Before hook. This way I have base config from file & env, then flags can override/extend this config, and I have a unified interface for fetching config.

I've created a custom source based on the file & env ones, and that works if I define it manually under Sources. Also Ive noticed it adds [$app.key] to the end of the flag's help (The flag is --app.key) - Can this be defined/overridden anywhere?

Cheers!

[absolutejam]

Ah, it looks like #2032 (comment) is related.