Confused how to set up a multi-project sbt project

playframework, sbt, scala

Solution

There are a few issues I found in your build definition, but since you bought up Josh's Effective sbt talk, I think we should go whole hog on the style.

Effective sbt

Here are the files.

project/build.properties

sbt.version=0.13.2

project/play.sbt

val playVersion = "2.2.2"

resolvers += Resolver.typesafeRepo("releases")

addSbtPlugin("com.typesafe.play" % "sbt-plugin" % playVersion) 

project/commons.scala

import sbt._
import Keys._

object Commons {
  val appVersion = "1.0"

  val settings: Seq[Def.Setting[_]] = Seq(
    version := appVersion,
    resolvers += Opts.resolver.mavenLocalFile
  )
}

project/dependencies.scala

import sbt._
import Keys._

object Dependencies {
  val slickVersion = "2.0.1"
  val slick = "com.typesafe.slick" %% "slick" % slickVersion
  val slf4jVersion = "1.6.4"
  val slf4jNop = "org.slf4j" % "slf4j-nop" % slf4jVersion
  val mysqlConnectorVersion = "5.1.30"
  val mysqlConnector = "mysql" % "mysql-connector-java" % mysqlConnectorVersion

  val commonDependencies: Seq[ModuleID] = Seq(
    slick,
    slf4jNop
  )
  val modelDependencies: Seq[ModuleID] = Seq()
  val serviceDependencies: Seq[ModuleID] = Seq()
  val webDependencies: Seq[ModuleID] = Seq(
    mysqlConnector
  )
}

build.sbt

import play.Project._
import Dependencies._

lazy val appCommon = (project in file("app-common")).
  settings(Commons.settings: _*).
  settings(
    libraryDependencies ++= commonDependencies
  )

lazy val appModels = (project in file("app-models")).
  settings(Commons.settings: _*).
  settings(
    libraryDependencies ++= modelDependencies
  ).
  dependsOn(appCommon)

lazy val appServices = (project in file("app-services")).
  settings(Commons.settings: _*).
  settings(
    libraryDependencies ++= serviceDependencies
  ).
  dependsOn(appModels, appCommon)

lazy val appWeb = (project in file("app-web")).
  settings(Commons.settings: _*).
  settings(playScalaSettings: _*).
  dependsOn(appServices)

notes

settings parameter vs settings method

For `models` and `services`, you're passing in settings sequence into `Project(...)` constructor, so the default settings are likely not loaded. You can pass in the default settings manually, or use `settings(...)` method on `Project`, which I would recommend.

lazy val appModels = (project in file("app-models")).
  settings(
    libraryDependencies ++= modelDependencies
  ).
  dependsOn(appCommon)

Josh uses postfix notation using parenthesis, but I prefer using dot notation for this, so that's a slight deviation from the talk.

libraryDependencies ++=

As the above example, you have to pass `modelDependencies` to `libraryDependencies`. You had it calling directly into `settings`.

resolvers

The `resolvers` setting is not passed into anything, which likely is not correct.

Problem

Original source