Installation

Smithy4s generates Scala code from a Smithy model. The generated code includes traits for any services you might define, as well as case classes for models used in these services. It has no dependencies on external libraries or any specific protocol like HTTP or JSON. It does, however, depend on a "core" library that contains a number of interfaces implemented by the generated code.

SBT

For mill support, see Mill below.

smithy4s-sbt-codegen is a code generating sbt plugin that creates .scala files corresponding to the provided .smithy specs.

In project/plugins.sbt:

addSbtPlugin("com.disneystreaming.smithy4s"  % "smithy4s-sbt-codegen" % "0.18.25")

and enable the plugin in the desired sbt module:

import smithy4s.codegen.Smithy4sCodegenPlugin

val myModule = project
  .in(file("modules/my-module"))
  .enablePlugins(Smithy4sCodegenPlugin)
  // version for smithy4s-core is sourced from Smithy4sCodegenPlugin
  .settings(libraryDependencies += "com.disneystreaming.smithy4s" %% "smithy4s-core" % smithy4sVersion.value)

This will enable the plugin on myModule. We also need to add smithy4s-core here since it is needed for compiling the generated code.

By default, the plugin will look in the $MY_MODULE/src/main/smithy directory and will write scala code in $MY_MODULE/target/scala-<version>/src_managed/ when invoking compile. The paths are configurable via the smithy4sInputDirs and smithy4sOutputDir settings keys.

For example, in order for the plugin to source .smithy specs from ./smithy_input (inside the folder where our build.sbt is) and output the generated files into ./smithy_output.

val myModule = project
  .in(file("modules/my-module"))
  .enablePlugins(Smithy4sCodegenPlugin)
  .settings(
    scalaVersion := "2.13.13",
    Compile / smithy4sInputDirs := Seq((ThisBuild / baseDirectory).value / "smithy_input"),
    Compile / smithy4sOutputDir := (ThisBuild / baseDirectory).value / "smithy_output",
    libraryDependencies += "com.disneystreaming.smithy4s" %% "smithy4s-core" % smithy4sVersion.value
  )

Mill

smithy4s-mill-codegen-plugin is a plugin to enable Smithy4s code generation on a mill module.

For example, here, we enabled it on the example module:

import $ivy.`com.disneystreaming.smithy4s::smithy4s-mill-codegen-plugin::0.18.25`
import smithy4s.codegen.mill._

import mill._, mill.scalalib._
object example extends ScalaModule with Smithy4sModule {
  def scalaVersion = "2.13.8"
  override def ivyDeps = Agg(
    ivy"com.disneystreaming.smithy4s::smithy4s-core:${smithy4sVersion()}"
  )
}

By default, the mill plugin will look for Smithy files under the $MY_MODULE/smithy directory. The generated code ends up in out/$MY_MODULE/smithy4sOutputDir.dest/scala/, again, by default. Code generation happens automatically when you before you compile the module. The paths are configurable via the smithy4sInputDirs and smithy4sOutputDir tasks.

For example, here we'll read Smithy files from smithy_input and write to smithy_output.

import $ivy.`com.disneystreaming.smithy4s::smithy4s-mill-codegen-plugin::0.18.25`
import smithy4s.codegen.mill._

import mill._, mill.scalalib._
object example extends ScalaModule with Smithy4sModule {
  def scalaVersion = "2.13.8"
  override def ivyDeps = Agg(
    ivy"com.disneystreaming.smithy4s::smithy4s-core:${smithy4sVersion()}"
  )

  override def smithy4sInputDirs = T.sources {
    Seq(PathRef(T.ctx().workspace / "smithy_input"))
  }
  override def smithy4sOutputDir = T {
    PathRef(T.ctx().workspace / "smithy_output")
  }
}

SBT​

Mill​

SBT

Mill