Align Scala sample with the rest of our samples (#3020)

* Correct differences between scala and the rest

* Update dependencies and scala version

* Some cleanups

docs/serving/samples/hello-world/helloworld-scala/Dockerfile

@@ -1,5 +1,5 @@
 # Use an SBT image matching the Scala and JDK version.
-FROM hseeberger/scala-sbt:8u265_1.4.2_2.12.12 as builder
+FROM hseeberger/scala-sbt:8u265_1.4.2_2.13.3 as builder
 
 # Copy local code to the container image.
 WORKDIR /app
@@ -16,7 +16,7 @@ RUN sbt assembly
 FROM openjdk:8-jre-alpine
 
 # Copy the jar to the production image from the builder stage.
-COPY --from=builder /app/target/scala-2.12/helloworld-*.jar /helloworld.jar
+COPY --from=builder /app/target/scala-2.13/helloworld-*.jar /helloworld.jar
 
 # Run the web service on container startup.
 CMD ["java", "-Djava.security.egd=file:/dev/./urandom", "-jar", "/helloworld.jar"]

docs/serving/samples/hello-world/helloworld-scala/README.md

@@ -27,7 +27,7 @@ cd knative-docs/docs/serving/samples/hello-world/helloworld-scala
 
 ## Configuring the Service descriptor
 
-Importantly, in [helloworld-scala.yaml](./helloworld-scala.yaml) **change the
+Importantly, in [service.yaml](./service.yaml) **change the
 image reference to match up with your designated repository**, i.e. replace
 `{username}` with your Dockerhub username in the example below.
 

docs/serving/samples/hello-world/helloworld-scala/build.sbt

@@ -4,14 +4,14 @@ name := "helloworld-scala"
 
 version := "0.0.1"
 
-scalaVersion := "2.12.8"
+scalaVersion := "2.13.3"
 
-mainClass in Compile := Some("klang.HelloWorldScala")
+mainClass in Compile := Some("example.HelloWorldScala")
 
 scalacOptions ++= Seq("-encoding", "UTF-8")
 
-lazy val akkaVersion = "2.5.16"
+lazy val akkaVersion = "2.6.10"
-lazy val akkaHttpVersion = "10.1.5"
+lazy val akkaHttpVersion = "10.2.1"
 
 libraryDependencies ++= Seq(
     "com.typesafe.akka" %% "akka-actor" % akkaVersion,

docs/serving/samples/hello-world/helloworld-scala/service.yaml

@@ -9,7 +9,5 @@ spec:
       containers:
       - image: docker.io/{username}/helloworld-scala
         env:
-          - name: MESSAGE
+        - name: TARGET
-            value: "Scala & Akka on Knative says hello!"
+          value: "Scala Sample v1"
-          - name: HOST
-            value: "localhost"

docs/serving/samples/hello-world/helloworld-scala/src/main/resources/application.conf

@@ -3,6 +3,6 @@ helloworld {
   host = ${?HOST}
   port = 8080
   port = ${?PORT}
-  message = "Hello World!"
+  target = "World"
-  message = ${?MESSAGE}
+  target = ${?TARGET}
 }

docs/serving/samples/hello-world/helloworld-scala/src/main/scala/example/HelloWorldScala.scala

@@ -1,4 +1,4 @@
-package klang
+package example
 
 import akka.actor.ActorSystem
 import akka.event.LoggingAdapter
@@ -15,8 +15,6 @@ object HelloWorldScala {
   def main(args: Array[String]): Unit = {
     // Creates and initializes an Akka Actor System
     implicit val system: ActorSystem = ActorSystem("HelloWorldScala")
-    // Creates and initializes a Materializer to be used for the Akka HTTP Server
-    implicit val mat: Materializer = ActorMaterializer()
     // Specifies where any Futures in this code will execute
     implicit val ec: ExecutionContext = system.dispatcher
     // Obtains a logger to be used for the sample
@@ -25,7 +23,7 @@ object HelloWorldScala {
     val config = system.settings.config
 
     // These are read from the application.conf file under `resources`
-    val message = config.getString("helloworld.message")
+    val target = config.getString("helloworld.target")
     val host = config.getString("helloworld.host")
     val port = config.getInt("helloworld.port")
 
@@ -34,13 +32,13 @@ object HelloWorldScala {
       path("") {
         get {
           log.info("Received request to HelloWorldScala")
-          complete(HttpEntity(`text/html(UTF-8)`, message))
+          complete(HttpEntity(`text/html(UTF-8)`, s"Hello $target!"))
         }
       }
 
     // Here we create the Http server, and bind it to the host and the port,
     // so we can serve requests using the route(s) we defined previously.
-    val binding = Http().bindAndHandle(serviceRoute, host, port) andThen {
+    val binding = Http().newServerAt(host, port).bind(serviceRoute) andThen {
       case Success(sb) =>
         log.info("Bound: {}", sb)
       case Failure(t) =>