Intro

Mill is a build tool like maven or gradle for Scala and Java which focuses on simplicity and performance. In this post I’m going to share what it takes to integrate mill with a typical quarkus web application. I generated my quarkus project using an official template which comes with restful api and database support.

Integrating Mill

The above Quarkus project by default uses gradle (it also supports maven) as the build tool. Let’s see how easy it is to integrate it to an existing Java project.

Installing Mill

CD into your downloaded Quarkus project root and run below commands in powershell. I’m using Windows 😊 but Mac and Linux has comparable commands.

curl -L https://repo1.maven.org/maven2/com/lihaoyi/mill-dist/0.13.0-M0/mill.bat -o mill.bat 
echo 0.12.7 > .mill-version

Running above will download mill into %USERPROFILE%\.mill\download directory. Now we can run mill commands like ./mill --version

package build
import mill._, javalib._

object quarkus extends MavenModule { 

  val quarkusPluginId = "io.quarkus"
  val quarkusPluginVersion = "3.18.1"
  val quarkusPlatformGroupId = "io.quarkus.platform"
  val quarkusPlatformArtifactId = "quarkus-bom"
  val quarkusPlatformVersion = "3.18.1"

  def hello = Task{
    System.out.println("sdfsdfsdf");
  }

  def ivyDeps = Agg(
    // System.out.printasd("hello..")
    ivy"${quarkusPlatformGroupId}:${quarkusPlatformArtifactId}:${quarkusPlatformVersion}",
    ivy"io.quarkus:quarkus-rest:${quarkusPlatformVersion}",
    ivy"io.quarkus:quarkus-rest-jackson:${quarkusPlatformVersion}",
    ivy"io.quarkus:quarkus-hibernate-orm-panache:${quarkusPlatformVersion}",
    ivy"io.quarkus:quarkus-jdbc-postgresql:${quarkusPlatformVersion}",
    ivy"io.quarkus:quarkus-arc:${quarkusPlatformVersion}",
    ivy"io.quarkus:quarkus-hibernate-orm:${quarkusPlatformVersion}"
    
  )

  object test extends JavaTests with TestModule.Junit4 {
    def ivyDeps = super.ivyDeps() ++ Agg(
      ivy"io.quarkus:quarkus-junit5${quarkusPlatformVersion}", 
      ivy"io.rest-assured:rest-assured${quarkusPlatformVersion}"
    )
  }
}

As you can see the mill build file is written in scala so your build file tasks can take advantage of whole scala/java eco system.

We can run ./mill resolve __ to see what tasks can be executed in our build just like gradle tasks. Running this initially will download all the decalred dependencies.