Confused how to set up a multi-project sbt project - scala

Question

I'm using sbt .13 here.
I have this so far:
import sbt._
import Keys._
import play.Project._
object ApplicationBuild extends Build {
val appVersion = "1.0"
resolvers += "local maven" at "/Users/blankman/.m2/repository/"
val commonDependencies = Seq()
val modelDependencies = Seq(
"com.typesafe.slick" %% "slick" % "2.0.1",
"org.slf4j" % "slf4j-nop" % "1.6.4"
)
val serviceDependencies = Seq(
"com.typesafe.slick" %% "slick" % "2.0.1",
"org.slf4j" % "slf4j-nop" % "1.6.4"
)
val webDependencies = Seq(
//"org.apache.tomcat" % "tomcat-jdbc" % "8.0.3",
"mysql" % "mysql-connector-java" % "5.1.30",
"com.typesafe.slick" %% "slick" % "2.0.1"
)
lazy val common = Project(
id = "app-common",
base = file("app-common"),
dependencies = commonDependencies
)
lazy val models = Project(
id = "app-models",
base = file("app-models"),
settings(modelDependencies: _*)
)
).dependsOn(common)
lazy val services = Project(
id = "app-services",
base = file("app-services"),
settings = Seq(
libraryDependencies ++= serviceDependencies
)
).dependsOn(models, common)
lazy val web = play.Project("app-web", appVersion, webDependencies,
path = file("app-web"))
.settings(playScalaSettings: _*)
.dependsOn(services)
}
This doesn't work. For example, if I go into:
project app-models
and try and compile, it says compile isn't valid or something.
I'm really confused how to set up a project. What is the correct way?
Looking at this slide #10 here http://jsuereth.com/scala/2013/06/11/effective-sbt.html it says I can do:
lazy val web = (
Project("app-models", file("app-models"))
settings(
libraryDependencies += modelDependencies
)
)
But when I do this I get an error also.
I basically have a few projects inside of sbt:
common
models
services
web (which is play)
models depends on commons
services depends on commons + models
web depends on services
Can someone help me get this to work?

Answer 1

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.