No support for having no prefix?

[golx]

Hello,

Say I have the following set of existing environment variables within my infrastructure:

DATABASE=foo.example.com
DATABASE_USER=john
DATABASE_PASS=doe

I want to, without modifying them, be able to resolve these variables from both YAML file and environment variables, with latter having precedence.

It seems that such naming is discouraged by konf.

I tried the following:

object Root : ConfigSpec("") {
    val DATABASE by required<String>()
    val DATABASE_USER by required<String>()
    val DATABASE_PASS by required<String>()
}

Config {
    addSpec(Root)
}
        .from.yaml.resource("server.yml")
        .from.env()
        .from.systemProperties()

With YAML file having similar structure to the above:

DATABASE: foo.example.com
DATABASE_USER: john
DATABASE_PASS: doe

Sadly, the moment DATABASE_PASS or similar variable appears in the env, I get the following exception:

Exception in thread "main" com.uchuhimo.konf.source.LoadException: fail to load DATABASE
	at com.uchuhimo.konf.source.SourceKt.loadItem(Source.kt:519)
	at com.uchuhimo.konf.source.SourceKt$load$1.invoke(Source.kt:532)
	at com.uchuhimo.konf.source.SourceKt$load$1.invoke(Source.kt)
	at com.uchuhimo.konf.BaseConfig.lock(BaseConfig.kt:65)
	at com.uchuhimo.konf.source.SourceKt.load(Source.kt:530)
	at com.uchuhimo.konf.BaseConfig.withSource(BaseConfig.kt:585)
	at com.uchuhimo.konf.source.DefaultLoaders.env(DefaultLoaders.kt:118)
	at example.server.ServerSpecKt.getApplicationConfig(ServerSpec.kt:41)
	at example.StarterAppKt.initializeApplicationContext(StarterApp.kt:43)
	at example.StarterAppKt.main(StarterApp.kt:68)
	at example.StarterAppKt.main(StarterApp.kt)
Caused by: com.uchuhimo.konf.source.ObjectMappingException: unable to map source com.uchuhimo.konf.ContainerNode@33c2bd in [type: system-environment] to value of type String
	at com.uchuhimo.konf.source.SourceKt.toValue(Source.kt:820)
	at com.uchuhimo.konf.source.SourceKt.loadItem(Source.kt:512)
	... 10 more
Caused by: com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize instance of `java.lang.String` out of START_OBJECT token
 at [Source: UNKNOWN; line: -1, column: -1]
	at com.fasterxml.jackson.databind.exc.MismatchedInputException.from(MismatchedInputException.java:63)
	at com.fasterxml.jackson.databind.DeserializationContext.reportInputMismatch(DeserializationContext.java:1343)
	at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1139)
	at com.fasterxml.jackson.databind.DeserializationContext.handleUnexpectedToken(DeserializationContext.java:1093)
	at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:63)
	at com.fasterxml.jackson.databind.deser.std.StringDeserializer.deserialize(StringDeserializer.java:10)
	at com.fasterxml.jackson.databind.ObjectMapper._readValue(ObjectMapper.java:3985)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:2343)
	at com.uchuhimo.konf.source.SourceKt.toValue(Source.kt:815)
	... 11 more

Is there a mode to rely on simple naming without inferred nesting?

[uchuhimo]

@golx There is no mode to disable inferred nesting, you can define a new source as a workaround. Here is an example:

fun envSource(): Source {
    return FlatSource(
        System.getenv().filter { (key, _) ->
            !(key.startsWith('.') || key.endsWith('.'))
        }.toSortedMap(),
        type = "system-environment",
        allowConflict = true
    )
}

Config {
    addSpec(Root)
}
        .from.yaml.resource("server.yml")
        .withSource(envSource())
        .from.systemProperties()

[golx]

@uchuhimo thanks! your workaround worked for me.
Any plans to add such functionality in the future? This could help those like me who would want to introduce konf with minimal impact to their existing infrastructure.

In any case, this ticket can now be closed.

[DanySK]

I hit the same issue as well. In my case, it's a TOML configuration of the kind:

[ arbitraryname1 ]
description = "..."

[ arbitraryname1.configuration ]
...

[ arbitraryname1.expectations ]
...

there are several entries with arbitrary prefixes

[uchuhimo]

@DanySK Would you like to provide a minimal code snippet of your ConfigSpec and Config for me to debug?

[uchuhimo]

@golx I would like to add this feature to the next release. Thank you for your proposal!

[uchuhimo]

@golx I have added this feature in v0.22.0. You can use the following code to achieve the same purpose:

Config {
    addSpec(Root)
}.from.env(nested=false)

[golx]

Thanks! We'll give it a try.