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scalasbtsbt-assemblysbt-plugin

Multiple main classes with SBT assembly

I'm looking to create jars for AWS Lambda to run job tasks. Currently my build.sbt file looks something like this:

lazy val commonSettings = Seq(...)

lazy val core = project
    .settings(commonSettings: _*)

lazy val job = project
    .settings(commonSettings: _*)
    .dependsOn(core)

lazy val service = project
    .settings(commonSettings: _*)
    .settings(
        mainClass in assembly := Some("io.example.service.Lambda"),
        assemblyJarName in assembly := "lambda.jar"
    )
    .dependsOn(core)

Running sbt assembly assembles the service module into a jar for my API and that works fine. The module job however will have multiple Main classes (one pr. job) and when I run sbt assembly job the service module is also assembled (even through its not depended on).

How can I configure my setup to only assemble the job module when needed, and specify individual mainClasses as separately assembled jars?

Solution

  • Set mainClass in assembly in job to define which main class to use, and run job/assembly to just assemble the job assembly jar.