This is an example .sbt build definition that demonstrates using configurations to group dependencies.
utils module provides utilities for other modules. It uses
configurations to group dependencies so that a dependent project doesn’t
have to pull in all dependencies if it only uses a subset of
functionality. This can be an alternative to having multiple utilities
modules (and consequently, multiple utilities jars).
In this example, consider a
utils project that provides utilities
related to both Scalate and Saxon. It therefore needs both Scalate and
Saxon on the compilation classpath and a project that uses all of the
functionality of ‘utils’ will need these dependencies as well. However,
a only needs the utilities related to Scalate, so it doesn’t
need Saxon. By depending only on the
scalate configuration of
it only gets the Scalate-related dependencies.
/********* Configurations *******/ // Custom configurations lazy val Common = config("common") describedAs("Dependencies required in all configurations.") lazy val Scalate = config("scalate") extend(Common) describedAs("Dependencies for using Scalate utilities.") lazy val Saxon = config("saxon") extend(Common) describedAs("Dependencies for using Saxon utilities.") // Define a customized compile configuration that includes // dependencies defined in our other custom configurations lazy val CustomCompile = config("compile") extend(Saxon, Common, Scalate) /********** Projects ************/ // factor out common settings ThisBuild / organization := "com.example" ThisBuild / scalaVersion := "2.12.8" ThisBuild / version := "0.1.0-SNAPSHOT" // An example project that only uses the Scalate utilities. lazy val a = (project in file("a")) .dependsOn(utils % "compile->scalate") // An example project that uses the Scalate and Saxon utilities. // For the configurations defined here, this is equivalent to doing dependsOn(utils), // but if there were more configurations, it would select only the Scalate and Saxon // dependencies. lazy val b = (project in file("b")) .dependsOn(utils % "compile->scalate,saxon") // Defines the utilities project lazy val utils = (project in file("utils")) .settings( inConfig(Common)(Defaults.configSettings), // Add the src/common/scala/ compilation configuration. addArtifact(artifact in (Common, packageBin), packageBin in Common), // Publish the common artifact // We want our Common sources to have access to all of the dependencies on the classpaths // for compile and test, but when depended on, it should only require dependencies in 'common' classpathConfiguration in Common := CustomCompile, // Modify the default Ivy configurations. // 'overrideConfigs' ensures that Compile is replaced by CustomCompile ivyConfigurations := overrideConfigs(Scalate, Saxon, Common, CustomCompile)(ivyConfigurations.value), // Put all dependencies without an explicit configuration into Common (optional) defaultConfiguration := Some(Common), // Declare dependencies in the appropriate configurations libraryDependencies ++= Seq( "org.fusesource.scalate" % "scalate-core" % "1.5.0" % Scalate, "org.squeryl" %% "squeryl" % "0.9.5-6" % Scalate, "net.sf.saxon" % "saxon" % "8.7" % Saxon ) )