First draft of the mill plugin for smithy4s

.github/workflows/ci.yml

@@ -61,6 +61,14 @@ jobs:
         with:
           java-version: temurin@17
 
+      - name: Get mill version
+        run: echo "MILL_VERSION=$(cat .mill-version)" >> $GITHUB_ENV
+
+      - name: Setup Mill
+        uses: jodersky/setup-mill@master
+        with:
+          mill-version: ${{ env.MILL_VERSION }}
+
       - name: Run tests
         run: |
           sbt test_$BUILD_KEY \

.mill-version

@@ -0,0 +1 @@
+0.10.7

build.sbt

@@ -27,7 +27,7 @@ Global / licenses := Seq(
 sonatypeCredentialHost := "s01.oss.sonatype.org"
 
 ThisBuild / version := {
-  if (!sys.env.contains("CI")) "dev"
+  if (!sys.env.contains("CI")) "dev-SNAPSHOT"
   else (ThisBuild / version).value
 }
 
@@ -46,6 +46,7 @@ lazy val root = project
 lazy val allModules = Seq(
   core.projectRefs,
   codegen.projectRefs,
+  millCodegenPlugin.projectRefs,
   json.projectRefs,
   example.projectRefs,
   tests.projectRefs,
@@ -383,6 +384,47 @@ lazy val codegenPlugin = (projectMatrix in file("modules/codegen-plugin"))
     scriptedBufferLog := false
   )
 
+/**
+ * Mill plugin to run codegen
+ */
+lazy val millCodegenPlugin = projectMatrix
+  .in(file("modules/mill-codegen-plugin"))
+  .enablePlugins(BuildInfoPlugin)
+  .jvmPlatform(
+    scalaVersions = List(Scala213),
+    simpleJVMLayout
+  )
+  .settings(
+    name := "mill-codegen-plugin",
+    buildInfoKeys := Seq[BuildInfoKey](version),
+    buildInfoPackage := "smithy4s.codegen.mill",
+    libraryDependencies ++= Seq(
+      "com.lihaoyi" %% "mill-scalalib" % millVersion,
+      "com.lihaoyi" %% "mill-main" % millVersion,
+      "com.lihaoyi" %% "mill-main-api" % millVersion,
+      "com.lihaoyi" %% "mill-main-testkit" % millVersion % Test
+    ),
+    publishLocal := {
+      // make sure that core and codegen are published before the
+      // plugin is published
+      // this allows running `scripted` alone
+      val _ = List(
+        // for the code being built
+        (core.jvm(Scala213) / publishLocal).value,
+        (dynamic.jvm(Scala213) / publishLocal).value,
+        (codegen.jvm(Scala213) / publishLocal).value,
+        // dependency of codegen
+        (openapi.jvm(Scala213) / publishLocal).value,
+
+        // for mill
+        (protocol.jvm(autoScalaLibrary = false) / publishLocal).value
+      )
+      publishLocal.value
+    },
+    libraryDependencies ++= munitDeps.value
+  )
+  .dependsOn(codegen)
+
 lazy val decline = (projectMatrix in file("modules/decline"))
   .settings(
     name := "decline",

modules/codegen-plugin/src/smithy4s/codegen/Smithy4sCodegenPlugin.scala

@@ -60,7 +60,7 @@ object Smithy4sCodegenPlugin extends AutoPlugin {
 
     val smithy4sSmithyLibrary =
       settingKey[Boolean](
-        "Sets whether this project should be use as a Smithy library by packaging the Smithy specs in the resulting jar"
+        "Sets whether this project should be used as a Smithy library by packaging the Smithy specs in the resulting jar"
       )
 
     val Smithy4s =

modules/mill-codegen-plugin/src/smithy4s/codegen/mill/Smithy4sModule.scala

@@ -0,0 +1,108 @@
+/*
+ *  Copyright 2021-2022 Disney Streaming
+ *
+ *  Licensed under the Tomorrow Open Source Technology License, Version 1.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *     https://disneystreaming.github.io/TOST-1.0.txt
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+package smithy4s.codegen.mill
+
+import coursier.maven.MavenRepository
+import mill._
+import mill.api.PathRef
+import mill.define.{Source, Sources}
+import mill.scalalib._
+import smithy4s.codegen.{CodegenArgs, Codegen => Smithy4s, FileType}
+import smithy4s.codegen.mill.BuildInfo
+
+trait Smithy4sModule extends ScalaModule {
+
+  /** Input directory for .smithy files */
+  protected def smithy4sInputDir: Source = T.source {
+    PathRef(millSourcePath / "smithy")
+  }
+
+  protected def smithy4sOutputDir: T[PathRef] = T {
+    PathRef(T.ctx().dest / "scala")
+  }
+
+  protected def smithy4sResourceOutputDir: T[PathRef] = T {
+    PathRef(T.ctx().dest / "resources")
+  }
+  protected def generateOpenApiSpecs: T[Boolean] = true
+
+  def smithy4sAllowedNamespaces: T[Option[Set[String]]] = None
+
+  def smithy4sExcludedNamespaces: T[Option[Set[String]]] = None
+
+  def smithy4sCodegenDependencies: T[List[String]] = List.empty[String]
+
+  def smithy4sLocalJars: T[List[os.Path]] = T {
+    T.traverse(moduleDeps)(_.jar)
+      .map(_.toList.map(_.path))
+  }
+
+  def smithy4sModelTransformers: T[List[String]] = List.empty[String]
+
+  def smithy4sRepositories: T[List[String]] = repositoriesTask().toList
+    .collect { case repository: MavenRepository =>
+      repository.root
+    }
+
+  def smithy4sVersion: T[String] = BuildInfo.version
+  def smithy4sSmithyLibrary: T[Boolean] = true
+
+  def smithy4sCodegen: T[(PathRef, PathRef)] = T {
+
+    val specFiles = if (os.exists(smithy4sInputDir().path)) {
+      os.walk(smithy4sInputDir().path, skip = _.ext != "smithy")
+    } else Seq.empty
+
+    val scalaOutput = smithy4sOutputDir().path
+    val resourcesOutput = smithy4sResourceOutputDir().path
+
+    val skipResources: Set[FileType] =
+      if (smithy4sSmithyLibrary()) Set.empty
+      else Set(FileType.Resource)
+
+    val skipOpenApi: Set[FileType] =
+      if (generateOpenApiSpecs()) Set.empty
+      else Set(FileType.Openapi)
+
+    val skipSet = skipResources ++ skipOpenApi
+
+    val args = CodegenArgs(
+      specs = specFiles.toList,
+      output = scalaOutput,
+      resourceOutput = resourcesOutput,
+      skip = skipSet,
+      discoverModels = true,
+      allowedNS = smithy4sAllowedNamespaces(),
+      excludedNS = smithy4sExcludedNamespaces(),
+      repositories = smithy4sRepositories(),
+      dependencies = smithy4sCodegenDependencies(),
+      transformers = smithy4sModelTransformers(),
+      localJars = smithy4sLocalJars()
+    )
+    Smithy4s.processSpecs(args)
+    (PathRef(scalaOutput), PathRef(resourcesOutput))
+  }
+
+  override def generatedSources: T[Seq[PathRef]] = T {
+    val (scalaOutput, _) = smithy4sCodegen()
+    scalaOutput +: super.generatedSources()
+  }
+
+  override def resources: Sources = T.sources {
+    super.resources() :+ smithy4sResourceOutputDir()
+  }
+}

modules/mill-codegen-plugin/test/src/smithy4s/codegen/mill/Smithy4sModuleSpec.scala

@@ -0,0 +1,122 @@
+package smithy4s.codegen.mill
+
+import mill.testkit.MillTestKit
+import mill.scalalib._
+import mill._
+import munit.Location
+import sourcecode.FullName
+
+class Smithy4sModuleSpec extends munit.FunSuite {
+  object testKit extends MillTestKit
+
+  val coreDep =
+    ivy"com.disneystreaming.smithy4s::smithy4s-core:${smithy4s.codegen.BuildInfo.version}"
+
+  object foo extends testKit.BaseModule with Smithy4sModule {
+    override def scalaVersion = "2.13.8"
+    override def ivyDeps = Agg(coreDep)
+  }
+
+  object bar extends testKit.BaseModule with Smithy4sModule {
+    override def moduleDeps = Seq(foo)
+    override def scalaVersion = "2.13.8"
+    override def ivyDeps = Agg(coreDep)
+  }
+
+  test("codegen runs") {
+    val ev = testKit.staticTestEvaluator(foo)(FullName("codegen-runs"))
+    os.write.over(
+      foo.millSourcePath / "smithy" / "foo.smithy",
+      s"""|$$version: "2"
+          |
+          |namespace basic
+          |
+          |string MyNewString""".stripMargin,
+      createFolders = true
+    )
+
+    compileWorks(foo, ev)
+    checkFileExist(
+      ev.outPath / "smithy4sOutputDir.dest" / "scala" / "basic" / "MyNewString.scala",
+      shouldExist = true
+    )
+  }
+
+  test("multi-module codegen works") {
+    val fooEv = testKit.staticTestEvaluator(foo)(FullName("multi-module-foo"))
+    val barEv = testKit.staticTestEvaluator(foo)(FullName("multi-module-bar"))
+    os.write.over(
+      foo.millSourcePath / "smithy" / "foo.smithy",
+      s"""|$$version: "2.0"
+          |
+          |namespace foo
+          |
+          |structure Foo {
+          |  a: Integer
+          |}""".stripMargin,
+      createFolders = true
+    )
+
+    os.write.over(
+      bar.millSourcePath / "smithy" / "bar.smithy",
+      s"""|$$version: "2.0"
+          |
+          |namespace bar
+          |
+          |use foo#Foo
+          |
+          |// Checking that Foo can be found by virtue of the bar project depending on the foo project
+          |structure Bar {
+          |  foo: Foo
+          |}""".stripMargin,
+      createFolders = true
+    )
+
+    os.write.over(
+      bar.millSourcePath / "src" / "Test.scala",
+      s"""|package bar
+          |
+          |import foo._
+          |
+          |object BarTest {
+          |
+          |  def main(args: Array[String]): Unit = println(Bar(Some(Foo(Some(1)))))
+          |
+          |}""".stripMargin,
+      createFolders = true
+    )
+
+    compileWorks(foo, fooEv)
+    checkFileExist(
+      fooEv.outPath / "smithy4sOutputDir.dest" / "scala" / "foo" / "Foo.scala",
+      shouldExist = true
+    )
+
+    compileWorks(bar, barEv)
+    checkFileExist(
+      barEv.outPath / "smithy4sOutputDir.dest" / "scala" / "foo" / "Foo.scala",
+      shouldExist = false
+    )
+    checkFileExist(
+      barEv.outPath / "smithy4sOutputDir.dest" / "scala" / "bar" / "Bar.scala",
+      shouldExist = true
+    )
+  }
+
+  private def compileWorks(
+      sm: ScalaModule,
+      testEvaluator: testKit.TestEvaluator
+  )(implicit loc: Location) = {
+    val result = testEvaluator(sm.compile).map(_._1)
+    assertEquals(result.isRight, true)
+  }
+
+  private def checkFileExist(path: os.Path, shouldExist: Boolean) = {
+    if (!os.exists(path) && shouldExist) {
+      sys.error(s"${path} file not found")
+    }
+    if (os.exists(path) && !shouldExist) {
+      sys.error(s"${path} file should not exist")
+    }
+  }
+}

project/Smithy4sPlugin.scala

@@ -31,6 +31,8 @@ object Smithy4sPlugin extends AutoPlugin {
   val Scala213 = "2.13.8"
   val Scala3 = "3.2.0"
 
+  val millVersion = IO.readLines(file(".") / ".mill-version").head.trim()
+
   implicit class ProjectMatrixOps(val pm: ProjectMatrix) extends AnyVal {
     def http4sJvmPlatform(
         scalaVersions: Seq[String],