Oct 26

_posts/years/2023/43/2023-10-26-scala-native-dependencies.md

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+---
+layout: post
+title:  "Scala Native Dependencies"
+date:   2023-10-26 21:29:48
+categories: "tools"
+excerpt: "A quick-start list of dependencies for a Scala Native project"
+tags:
+  - scala
+  - scala native
+  - jvm
+  - sbt
+---
+
+I'm working on a side project, building a cli app with Scala Native.  Since the libraries available for Scala Native are a subset of the libraries available for JVM Scala, it can be tricky to find the basic libraries + versions to perform basic tasks when getting started.  So this post will be a way to keep track of a group of libraries that work well together for building a practical Scala Native app.
+
+## Dependencies
+
+A few things that we can accomplish with this list of dependencies:
+
+- working with files and processes (OS-Lib)
+- handling JSON that you might write to disk with OS-Lib (circe)
+- building a subcommand-style cli interface like `kubectl`
+- doing anything you would normally do with the `java.time` APIs (which is not available by default in scala native)
+
+```scala
+import sbt._
+
+object Dependencies {
+  lazy val munit = "org.scalameta" %% "munit" % "0.7.29" % Test
+
+  val circeVersion = "0.14.3"
+  val circe = Seq(
+    "io.circe" % "circe-core_native0.4_2.13" % circeVersion,
+    "io.circe" % "circe-generic_native0.4_2.13" % circeVersion,
+    "io.circe" % "circe-generic-extras_native0.4_2.13" % circeVersion,
+    "io.circe" % "circe-parser_native0.4_2.13" % circeVersion
+  )
+
+  val osLib = "com.lihaoyi" % "os-lib_native0.4_2.13" % "0.9.1"
+
+  val decline = "com.monovore" % "decline_native0.4_2.13" % "2.2.0"
+
+  val javaTime = "io.github.cquiroz" % "scala-java-time_native0.4_2.13" % "2.5.0"
+}
+```
+
+Note that I am being explicit with the Scala version in this example, e.g. including `_native0.4_2.13` in each module name.
+
+A more "sbt" way to define these dependencies is to use the `%%%` dependency builder.  I don't really care, I find sbt unpronounceable operators to be an unnecessary abstraction. 
+
+
+## build file
+
+Here's a full `build.sbt` for reference, that includes all the Scala Native goodies.  
+
+And for reference, `sbt.version=1.9.6`. (defined in `project/build.properties`)
+
+```scala
+import Dependencies._
+
+ThisBuild / scalaVersion := "2.13.11"
+ThisBuild / version := "0.1.0-SNAPSHOT"
+ThisBuild / organization := "com.example"
+ThisBuild / organizationName := "example"
+
+enablePlugins(ScalaNativePlugin)
+
+scalacOptions ++= Seq(
+  "-Xfatal-warnings",
+  "-deprecation"
+)
+
+lazy val root = (project in file("."))
+  .settings(
+    name := "my-cool-project",
+    libraryDependencies ++= Seq(
+      osLib,
+      decline,
+      javaTime
+    ) ++ circe :+ munit
+  )
+
+// set to Debug for compilation details (Info is default)
+logLevel := Level.Info
+
+// import to add Scala Native options
+import scala.scalanative.build._
+
+// defaults set with common options shown
+nativeConfig ~= { c =>
+  c.withLTO(LTO.none) // thin
+    .withMode(Mode.debug) // releaseFast
+    .withGC(GC.immix) // commix
+}
+```
+
+## plugins
+
+And the plugins in use (`./project/plugins.sbt`):
+
+```scala
+addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.4.15")
+addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.4.6")
+```
+
+## next
+If I add more dependencies, I'll try to add them here.  For example, an http client lib.