dotenv per subproject

[seglo]

Hi. In an sbt multi project build I tried defining a envFilename per sub project (each sub project has a main method). Since this setting must be in global scope (ThisBuild) it doesn't matter whether it's defined at the top level or within a subproject in an sbt file, the last value it was set with will be used.

Is there a way to scope dotenv files to projects?

[seglo]

The self-answered SO post here may define what i'm seeing better

https://stackoverflow.com/questions/33417180/how-to-define-build-scoped-settings-in-multi-project-sbt-builds

Keys in larger scopes like ThisBuild or Global seem to be able to be defined in any project, but "later" projects will then take priority. This is probably related to the order the projects are processed. I have expected that the order of evaluation of lazy vals would affect this, and I've tried adding .aggregate(child) to the root project to force the child project to be evaluated first, but it didn't seem to have any effect: globally scoped values from child project still have priority.

[yasha-spare]

Yeah, as far as I can tell, this plugin is simply unusable in sbt multi-project builds :/

What I ended up doing in a sbt multi-project build with multiple Scala Play apps, instead of using this plugin:

• Made a little helper to share between projects, in project/EnvVarFile.scala:

import scala.io.Source
import scala.util.Using

/**
 * Parses an env var file into a Map[String, String], for use in builds.
 *
 * As an example, this file:
 *
 * foo=bar
 * # Some comment
 * foo_bar=baz
 * other_foo_bar="stuff"
 * ANOTHER_FOO_BAR = "things"
 *
 * Would be parsed to:
 *
 * Map(
 *   "foo" -> "bar",
 *   "foo_bar" -> "baz",
 *   "other_foo_bar" -> "stuff",
 *   "ANOTHER_FOO_BAR" -> "things"
 * )
 */
object EnvVarFile {

  def parseFile(path: String): Map[String, String] = Using(Source.fromFile(path)) { source =>
    source.getLines.toList.flatMap { line =>
      // Split on the = character, with optional whitespace before or after
      line.split("[ \\t]*=[ \\t]*").toList match {
        /**
         * Find all lines that are a single key/value pair, where the key has only alphanumeric characters or
         * underscores (e.g. looks like an env var). And strip quotes from the value
         */
        case List(key, value) if key.matches("^[a-zA-Z][a-zA-Z0-9_]*$") => Some(key -> value.replaceAll("^\"|\"$", ""))
        case _ => None
      }
    }.toMap
  }.getOrElse(throw new RuntimeException(s"Failed to read $path"))
}

• Use it like this in my sbt config to set env vars when running tests:

Test / envVars := EnvVarFile.parseFile(s"${baseDirectory.value.getAbsolutePath}/test.env")

• But when running the app in local dev mode, I couldn't make it work from within the build, so I have to do it all from the shell:

export $(grep -v '^#' my-service/.env | xargs) && sbt "myService / run"

It's a little ugly but has been fine in practice.