Enver

Environment Variables Solution for kotlin

Install

The main way of installing this library is using jitpack.io

repositories {
    // ...
    mavenCentral()
    maven { url = uri("https://jitpack.io") }
}

dependencies {
    // Replace TAG with the desired version
    implementation("net.lsafer.enver:enver:TAG")
}

How to directly access variables

The following is an example of accessing the current known value of an environment variable from some enver instance.

fun doSomething() {
    Enver["MY_ENV_VAR"]
}

How to access variables using properties

The following are examples of declaring environment variable properties.

val variableOrNull: String? by Enver.string("MY_ENV_VAR")

val variableOrDefault: String by Enver.string("MY_ENV_VAR") {
    it ?: "22" 
}

val variableOrThrow: String by Enver.string("MY_ENV_VAR") { 
    it ?: error("MY_ENV_VAR not set") 
}

val transformedVariableOrNull: Int? by Enver.string("MY_ENV_VAR") { 
    it?.toInt() 
}

val transformedVariableOrDefault: Int by Enver.string("MY_ENV_VAR") { 
    it?.toInt() ?: 22 
}

val transformedVariableOrThrow: Int by Enver.string("MY_ENV_VAR") { 
    it?.toInt() ?: error("MY_ENV_VAR not set") 
}

How to populate the instance

Every Enver instance is initialized with no data and the population process is left for the user to manually do it.

This way, the Enver can be populated from multiple different sources with different ordering.

The following is an example of using different kinds of built-in sources:

fun main() {
    // populate from System.getenv()
    Enver += enverSystem()
    // populate from parsing File(".env")
    Enver += enverFile(".env")
    // populate from parsing bundled file ".env"
    Enver += enverResource(".env")
    // populate from parsing a dotenv literal
    Enver += enverSource("MY_ENV_VAR=22\nMY_ENV_VAR_2=442")
    // populate from a Map
    Enver += mapOf("MY_ENV_VAR" to "22", "MY_ENV_VAR_2" to "442")
    // resolve expansions 
    Enver += enverExpansions(
        Enver.asMap(),
        enverSource("My_EXP_VAR=SOMETHING+\${MY_ENV_VAR}")
    )
}