I'd like to get a certain value from an environment variable in my Kotlin app, but I can't find anything about reading environment variables in the core libraries documentation.
I'd expect it to be under kotlin.system but there's really not that much there.
It is really easy to get a environment value if it exists or a default value by using the elvis operator in kotlin:
val envVar: String = System.getenv("varname") ?: "default_value"
You could always go down this approach:
val envVar : String? = System.getenv("varname")
Though, to be fair, this doesn't feel particularly idiomatic, as you're leveraging Java's System class, not Kotlin's.
And if you want to handle env var which do exists but is empty:
val myEnv = (System.getenv("MY_ENV") ?: "").ifEmpty { "default_value" }
(see edit history for previous versions)
You can use the kotlin extension Konfig
Konfig - A Type Safe Configuration API for Kotlin
Konfig provides an extensible, type-safe API for configuration properties gathered from multiple sources — built in resources, system properties, property files, environment variables, command-line arguments, etc.
For example: Key("http.port", intType)
