How to bind environment variables to a yaml list of dictionaries

[yohanleb]

Hello,

I am trying to override this yaml struct with environment variables.

auth:
  providers:
    - google:
        name: Google
        client_id: <CHANGE_ME>
        client_secret: <CHANGE_ME>
        issuer: https://accounts.google.com
    - provider:
        name: Provider
        client_id: <CHANGE_ME>
        client_secret: <CHANGE_ME>
        issuer: <CHANGE_ME>

I made this function to bind each AUTH_PROVIDERS_{NAME}_{KEY} env variable to the corresponding dict in the yaml struct.

keys := []string{"name", "client_id", "client_secret", "issuer"}
providers := strings.Split(v.GetString("AUTH_PROVIDERS"), ",")
for _, provider := range providers {
    providerUpper := strings.ToUpper(provider)
    for _, key := range keys {
	    keyUpper := strings.ToUpper(key)
	    _ = v.BindEnv(
		    fmt.Sprintf("auth.providers.%s.%s", provider, key),
		    fmt.Sprintf("AUTH_PROVIDERS_%s_%s", providerUpper, keyUpper),
	    )
    }
}

This is my environment:

AUTH_PROVIDERS=google
AUTH_PROVIDERS_GOOGLE_NAME=Google
AUTH_PROVIDERS_GOOGLE_CLIENT_ID=custom_client_id
AUTH_PROVIDERS_GOOGLE_CLIENT_SECRET=custom_client_secret
AUTH_PROVIDERS_GOOGLE_ISSUER=https://accounts.google.com

However, the result is not what I expected. Sometimes it works and all the variables are set properly, sometimes only the client_id, sometimes only the client_secret, sometimes none of them, etc...

How can I achieve that ?
I went through stackoverflow and the Viper issues and I couldn't find a similar discussion with a satisfying solution. I'm currently learning Go and coming from a Python background so any feedback is welcome.

Thank you !

[sagikazarmark]

To be honest, I'm not entirely sure what you are trying to achieve: are you trying to be able to configure multiple providers at the same time? If so, can one provider of the same type be instantiated multiple times?

One thing I see right off the bat is that providers in your YAML file is an array, not a map, so you will have to address them as by indices. But that's also known to be buggy, so I'd suggest turning it into a map instead.

[yohanleb]

I want to be able to configure different providers at the same time. This way, I will allow users to login via different providers set in the configuration. The number and name of providers is not defined so it can be 1 or more. A provider can be defined twice but will be replaced if it has the same name.

Example:
AUTH_PROVIDERS would define the name of providers (unique) and then I want to bind AUTH_PROVIDERS_{NAME}_{KEY} to its corresponding configuration.

The .env would look like this:

AUTH_PROVIDERS=google,other

AUTH_PROVIDERS_GOOGLE_NAME=Google
AUTH_PROVIDERS_GOOGLE_CLIENT_ID=custom_client_id
AUTH_PROVIDERS_GOOGLE_CLIENT_SECRET=custom_client_secret
AUTH_PROVIDERS_GOOGLE_ISSUER=https://accounts.google.com

AUTH_PROVIDERS_OTHER_NAME=Other
AUTH_PROVIDERS_OTHER_CLIENT_ID=custom_client_id
AUTH_PROVIDERS_OTHER_CLIENT_SECRET=custom_client_secret
AUTH_PROVIDERS_OTHER_ISSUER=https://issuer.com

I'm going to try with a map, I just want it to be generic enough and not being tied to the providers defined in the yaml. There might be a clever way to do it but I didn't find it yet.
Thanks

[yohanleb]

Using a map and setting the providers empty by default solved the issue.

yaml config

auth:
  providers:

Go structs

type AuthConfiguration struct {
	Providers map[string]ProviderConfiguration `mapstructure:"providers" validate:"dive"`
}

type ProviderConfiguration struct {
	Name         string `mapstructure:"name" validate:"required"`
	ClientId     string `mapstructure:"client_id" validate:"required"`
	ClientSecret string `mapstructure:"client_secret" validate:"required"`
	Issuer       string `mapstructure:"issuer" validate:"required"`
}

Env

AUTH_PROVIDERS=google,authelia

AUTH_PROVIDER_GOOGLE_NAME=Google
AUTH_PROVIDER_GOOGLE_CLIENT_ID=clientid.apps.googleusercontent.com
AUTH_PROVIDER_GOOGLE_CLIENT_SECRET=verySecretKeepItSafeDoNotExpose
AUTH_PROVIDER_GOOGLE_ISSUER=https://accounts.google.com

AUTH_PROVIDER_AUTHELIA_NAME=Authelia
AUTH_PROVIDER_AUTHELIA_CLIENT_ID=client_id
AUTH_PROVIDER_AUTHELIA_CLIENT_SECRET=verySecretKeepItSafeDoNotExpose
AUTH_PROVIDER_AUTHELIA_ISSUER=https://auth.local

Code

keys := []string{"name", "client_id", "client_secret", "issuer"}
providers := strings.Split(v.GetString("AUTH_PROVIDERS"), ",")
for _, provider := range providers {
    providerUpper := strings.ToUpper(provider)
    for _, key := range keys {
	    keyUpper := strings.ToUpper(key)
	    _ = v.BindEnv(
		    fmt.Sprintf("auth.providers.%s.%s", provider, key),
		    fmt.Sprintf("AUTH_PROVIDER_%s_%s", providerUpper, keyUpper),
	    )
    }
}