add license to jar

Author: pjfanning

build.sbt

@@ -130,6 +130,8 @@ pomExtra := {
   )
 }
 
+MetaInfLicenseCopy.settings
+
 ThisBuild / githubWorkflowBuild := Seq(
   WorkflowStep
     .Sbt(List("coverage", "test", "coverageReport"), name = Some("Scala 2.13 build"), cond = Some("startsWith(matrix.scala, '2.13')")),

project/MetaInfLicenseCopy.scala

@@ -0,0 +1,22 @@
+import sbt.Keys._
+import sbt._
+
+/**
+  * Copies LICENSE file into jar META-INF dir
+  */
+object MetaInfLicenseCopy {
+
+  val settings: Seq[Setting[_]] = inConfig(Compile)(
+    Seq(
+      resourceGenerators += copyFileToMetaInf(resourceManaged, "LICENSE")
+    )
+  )
+
+  def copyFileToMetaInf(dir: SettingKey[File], fileName: String) = Def.task[Seq[File]] {
+    val fromFile = (LocalRootProject / baseDirectory).value / fileName
+    val toFile = resourceManaged.value / "META-INF" / fileName
+    IO.copyFile(fromFile, toFile)
+    Seq(toFile)
+  }
+
+}