Restart Flow/Source/Sink #19950

akka-docs/src/test/scala/docs/stream/RestartDocSpec.scala

@@ -0,0 +1,67 @@
+/**
+ * Copyright (C) 2015-2017 Lightbend Inc. <http://www.lightbend.com>
+ */
+package docs.stream
+
+import akka.NotUsed
+import akka.stream.{ ActorMaterializer, KillSwitches }
+import akka.stream.scaladsl._
+import akka.testkit.AkkaSpec
+import docs.CompileOnlySpec
+
+import scala.concurrent.duration._
+import scala.concurrent._
+
+class RestartDocSpec extends AkkaSpec with CompileOnlySpec {
+  implicit val materializer = ActorMaterializer()
+  import system.dispatcher
+
+  // Mock akka-http interfaces
+  object Http {
+    def apply() = this
+    def singleRequest(req: HttpRequest) = Future.successful(())
+  }
+  case class HttpRequest(uri: String)
+  case class Unmarshal(b: Any) {
+    def to[T]: Future[T] = Promise[T]().future
+  }
+  case class ServerSentEvent()
+
+  def doSomethingElse(): Unit = ()
+
+  "Restart stages" should {
+
+    "demonstrate a restart with backoff source" in compileOnlySpec {
+
+      //#restart-with-backoff-source
+      val restartSource = RestartSource.withBackoff(
+        minBackoff = 3.seconds,
+        maxBackoff = 30.seconds,
+        randomFactor = 0.2 // adds 20% "noise" to vary the intervals slightly
+      ) { () =>
+        // Create a source from a future of a source
+        Source.fromFutureSource {
+          // Make a single request with akka-http
+          Http().singleRequest(HttpRequest(
+            uri = "http://example.com/eventstream"
+          ))
+            // Unmarshall it as a source of server sent events
+            .flatMap(Unmarshal(_).to[Source[ServerSentEvent, NotUsed]])
+        }
+      }
+      //#restart-with-backoff-source
+
+      //#with-kill-switch
+      val killSwitch = restartSource
+        .viaMat(KillSwitches.single)(Keep.right)
+        .toMat(Sink.foreach(event => println(s"Got event: $event")))(Keep.left)
+        .run()
+
+      doSomethingElse()
+
+      killSwitch.shutdown()
+      //#with-kill-switch
+    }
+
+  }
+}