SBT PLUGINS Alexey Novakov, Ultra Tendency 

ABOUT ME ➤ Solution Architect at Ultra Tendency, Germany ➤ Experience: ➤ Scala - 5yrs. ➤ Java - 10 yrs. ➤ Big Data, Kubernetes ➤ My interests: ➤ 8 string guitars ➤ Astronomy ➤ FP ➤ Rust 

Scala Build Tool Download: https://www.scala-sbt.org/download.html Alexey Novakov, Ultra Tendency, 2020 

SBT Tasks (commands) sbt clean - deletes previously built files sbt compile - compiles source code sbt test - run tests, if any exists sbt run - runs detected “Main” class sbt package - makes jar file … user can define new tasks in *.sbt files Alexey Novakov, Ultra Tendency, 2020 

Scala IDEs IntelliJ + Scala Plugin VSCode + Metals (Scala LSP) Alexey Novakov, Ultra Tendency, 2020 

Build Definition build.sbt: Alexey Novakov, Ultra Tendency, 2020 import Dependencies._ ThisBuild / scalaVersion := "2.13.1" ThisBuild / version := "0.1.0-SNAPSHOT" ThisBuild / organization := "com.example" ThisBuild / organizationName := "example" lazy val root = (project in file(".")) .settings( name := "akka-http-api", libraryDependencies += scalaTest % Test ) Scope: build level, default for all sub-projects 

Managed Dependencies import Dependencies._ lazy val root = (project in file(".")) .settings( libraryDependencies += scalaTest % Test ) import sbt._ object Dependencies { lazy val scalaTest = "org.scalatest" %% "scalatest" % “3.0.8" } Alexey Novakov, Ultra Tendency, 2020 build.sbt project/ Dependencies.scala 

libraryDependencies += “org.scalatest" %% "scalatest" % "3.0.8" % Test groupID % artifactID % revision % configuration "org.scalatest" % “scalatest_2.13” % "3.0.8" % Test %% - matches current build Scala version Alexey Novakov, Ultra Tendency, 2020 

- SBT is using Coursier to download Ivy or Maven dependencies Coursier - Pure Scala Artifact Fetching Alexey Novakov, Ultra Tendency, 2020 

SBT Plugins 

1. Giter8 

Giter8 allows to create your own project template and host on GitHub: sbt new novakov-alexey/scalaboot.g8 —> https://github.com/novakov-alexey/scalaboot.g8 Alexey Novakov, Ultra Tendency, 2020 

Project Template 

ThisBuild / organization := "com.example" ThisBuild / scalaVersion := "$scalaVersion$" ThisBuild / description := "$desc$" lazy val root = (project in file(".")). settings( name := "$name;format="lower,hyphen"$", libraryDependencies ++= Seq( akkaHttp, akkaStreams, scalaLogging, logback, … parameters 

name=Project Name desc=Describe your project a bit scalaVersion=2.13.1 src/main/g8/default.properties [info] Loading settings for project global-plugins from idea.sbt,gpg.sbt ... [info] Loading global plugins from /Users/alexey/.sbt/1.0/plugins [info] Set current project to git (in build file:/Users/alexey/dev/git/) name [Project Name]: app-1 desc [Describe your project a bit]: order registration scalaVersion [2.13.1]: 2.13.2 Template applied in /Users/alexey/dev/git/./app-1 

2. sbt-revolver - restarts running application automatically, if source files are modified addSbtPlugin("io.spray" % "sbt-revolver" % “x.y.z") sbt “~reStart” - enables a super-fast development turnaround for your Scala applications Alexey Novakov, Ultra Tendency, 2020 

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Forked JVM Alexey Novakov, Ultra Tendency, 2020 

configuration javaOptions in reStart += "-Xmx2g" mainClass in reStart := Some("com.example.Main") Revolver.enableDebugging(port = 5050, suspend = true) envVars in reStart := Map(“K8S_NAMESPACE" -> “test") Alexey Novakov, Ultra Tendency, 2020 

First start New start Alexey Novakov, Ultra Tendency, 2020 

• sbt-revolver -> SBT Triggered Execution > ~ testQuick > ~ testOnly org.alexeyn.SomeTest > ~ test > ~ clean; test ~tilde Alexey Novakov, Ultra Tendency, 2020 

3. sbt-tpolecat addSbtPlugin( “io.github.davidgregory084" % "sbt-tpolecat" % “0.1.10" ) - enables scalac options according to Rob Noris (doobie) recommendations - P.S. the same options can be enabled manually, but why bother Alexey Novakov, Ultra Tendency, 2020 

scalacOptions ++= Seq( "-deprecation", "-encoding", "utf-8", "-explaintypes", "-language:higherKinds", "-language:implicitConversions", "-unchecked", "-Xfatal-warnings", "-Xlint:infer-any", "-Ywarn-dead-code", "-Ywarn-extra-implicit", "-Ywarn-inaccessible", "-Ywarn-infer-any", "-Ywarn-numeric-widen", "-Ywarn-unused:implicits", "-Ywarn-unused:imports", "-Ywarn-unused:locals", "-Ywarn-unused:params", "-Ywarn-unused:patvars", "-Ywarn-unused:privates", "-Ywarn-value-discard" … ) ~54 Scala Compiler Options Enabled Automatically Alexey Novakov, Ultra Tendency, 2020 

4. sbt-native-packager lets you build application packages in native formats: •universal zip, tar.gz, xz archives •deb and rpm packages •dmg •msi •docker images •graalvm native images addSbtPlugin("com.typesafe.sbt" %% "sbt-native-packager" % “x.y.z") Alexey Novakov, Ultra Tendency, 2020 

usage lazy val root = (project in file(".")). settings( name := "exchange", …. dockerBaseImage := “openjdk:8-jre-alpine”, dockerExposedPorts ++= Seq(8080), dockerRepository := Some(“alexeyn") ).enablePlugins(AshScriptPlugin) // DockerPlugin, JavaAppPackaging 

sbt universal:packageBin Linux and Windows shell scripts universal zip archive Alexey Novakov, Ultra Tendency, 2020 

docker image sbt docker:stage sbt docker:publish preview docker build / push 

[info] * Cmd(FROM,WrappedArray(openjdk:8, as, stage0)) [info] * Cmd(LABEL,WrappedArray(snp-multi-stage="intermediate")) [info] * Cmd(LABEL,WrappedArray(snp-multi-stage-id="b8437d6f-af0a-459c-ae51-cd3b9c5b7404")) [info] * Cmd(WORKDIR,WrappedArray(/opt/docker)) [info] * Cmd(COPY,WrappedArray(opt /opt)) [info] * Cmd(USER,WrappedArray(root)) [info] * ExecCmd(RUN,List(chmod, -R, u=rX,g=rX, /opt/docker)) [info] * ExecCmd(RUN,List(chmod, u+x,g+x, /opt/docker/bin/exchange)) dockerCommands := Seq( Cmd("FROM", "openjdk:8"), Cmd("LABEL", s"""MAINTAINER="${maintainer.value}""""), ExecCmd("CMD", "echo", "Hello, World from Docker") ) 

5. sbt-release addSbtPlugin( "com.github.gseitz" % "sbt-release" % “1.0.12" ) provides customisable release process … Alexey Novakov, Ultra Tendency, 2020 

Git artifacts tag increment version publish run tests build release 

releaseProcess := Seq[ReleaseStep]( checkSnapshotDependencies, inquireVersions, runTest, setReleaseVersion, commitReleaseVersion, tagRelease, publishArtifacts, inquireVersions, setNextVersion, commitNextVersion, pushChanges ) Default list of steps: sbt 'release with-defaults' includes 

releaseProcess := Seq[ReleaseStep]( checkSnapshotDependencies, inquireVersions, runTest, setReleaseVersion, commitReleaseVersion, tagRelease, publishArtifacts, inquireVersions, setNextVersion, commitNextVersion, pushChanges ) Alexey Novakov, Ultra Tendency, 2020 $PROJECT_ROOT/version.sbt version in ThisBuild := "0.1.1-SNAPSHOT" version in ThisBuild := “0.1.1" version in ThisBuild := “0.1.2-SNAPSHOT" build.sbt: sbt 'release with-defaults' 1 2 3 

commit 99b1094dce14bf99b6f38a8ff9870edaf7c728d3 (HEAD -> master, origin/master) Date: Fri Feb 7 09:20:03 2020 +0100 Setting version to 0.1.2-SNAPSHOT commit cb9ec293a11a5f6d989c936b18922d3f3ec40bcd (tag: v0.2.2) Date: Fri Feb 7 09:16:59 2020 +0100 Setting version to 0.1.1 commit 63abea7141901419ad732d354dc703f884e53010 Merge: b180810 a1c0c14 Date: Fri Feb 7 08:57:00 2020 +0100 Merge pull request #35 from novakov-alexey/add-cookier-attributes add string property attributes to put user defined parameters into th… setNextVersion setReleaseVersion time 

other useful plugins sbt-updates sbt-scalafmt sbt-mdoc sbt-scoverage 

Thank you! Questions? Alexey Novakov email: - alexey.novakov at ultratendency.com - novakov.alex at gmail.com Blog: https://novakov-alexey.github.io/ https://medium.com/se-notes-by-alexey-novakov Code: https://github.com/novakov-alexey Twitter: @alexey_novakov