add discovery implementation and test

build.sbt

@@ -109,7 +109,7 @@ lazy val discoveryEureka = pekkoModule("discovery-eureka")
   .enablePlugins(AutomateHeaderPlugin, ReproducibleBuildsPlugin)
   .settings(
     name := "pekko-discovery-eureka",
-    libraryDependencies := Dependencies.discoveryMarathonApi,
+    libraryDependencies := Dependencies.discoveryEureka,
     mimaPreviousArtifactsSet)
 
 // gathers all enabled routes and serves them (HTTP or otherwise)

discovery-eureka/src/main/resources/reference.conf

@@ -8,6 +8,8 @@ pekko.discovery {
 
   eureka {
     class = org.apache.pekko.discovery.eureka.EurekaServiceDiscovery
+    # default eureka schema
+    eureka-schema = "http"
     # default eureka host
     eureka-host = "127.0.0.1"
     # default eureka port

discovery-eureka/src/main/scala/org/apache/pekko/discovery/eureka/EurekaResponse.scala

@@ -0,0 +1,32 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 org.apache.pekko.discovery.eureka
+
+object EurekaResponse {
+  case class Application(name: String, instance: Seq[Instance])
+  case class Instance(hostName: String, app: String, vipAddress: String, secureVipAddress: String, ipAddr: String, status: String, port: PortWrapper, securePort: PortWrapper, healthCheckUrl: String, statusPageUrl: String, homePageUrl: String, appGroupName: String, dataCenterInfo: DataCenterInfo, lastDirtyTimestamp: String)
+  case class Status()
+  case class PortWrapper(port: Int, enabled: Boolean)
+  case class DataCenterInfo(name: String = "MyOwn", clz : String = "com.netflix.appinfo.InstanceInfo$DefaultDataCenterInfo")
+}
+
+import EurekaResponse._
+
+case class EurekaResponse(application: Application, errorCode: Option[String])

discovery-eureka/src/main/scala/org/apache/pekko/discovery/eureka/EurekaServiceDiscovery.scala

@@ -20,12 +20,70 @@
 package org.apache.pekko.discovery.eureka
 
 import org.apache.pekko.actor.ActorSystem
-import org.apache.pekko.discovery.{ Lookup, ServiceDiscovery }
+import org.apache.pekko.discovery.ServiceDiscovery.{Resolved, ResolvedTarget}
+import org.apache.pekko.discovery.eureka.JsonFormat._
+import org.apache.pekko.discovery.{Lookup, ServiceDiscovery}
+import org.apache.pekko.event.{LogSource, Logging}
+import org.apache.pekko.http.scaladsl.Http
+import org.apache.pekko.http.scaladsl.model.headers._
+import org.apache.pekko.http.scaladsl.model.{HttpRequest, MediaRange, MediaTypes, Uri}
+import org.apache.pekko.http.scaladsl.unmarshalling.Unmarshal
 
+import java.net.InetAddress
 import scala.concurrent.Future
 import scala.concurrent.duration.FiniteDuration
+import scala.util.Try
 
-class EurekaServiceDiscovery(system: ActorSystem) extends ServiceDiscovery {
+class EurekaServiceDiscovery(implicit system: ActorSystem) extends ServiceDiscovery {
+
+  import system.dispatcher
+
+  private val log = Logging(system, getClass)(LogSource.fromClass)
+  private val settings = EurekaSettings(system)
+  private val (schema, host, port, path, group) = (settings.schema, settings.host, settings.port, settings.path, settings.groupName)
+  private val http = Http()
+
+  override def lookup(lookup: Lookup, resolveTimeout: FiniteDuration): Future[ServiceDiscovery.Resolved] = {
+
+    val uriPath = Uri.Path.Empty / path / "apps" / lookup.serviceName
+    val uri = Uri.from(scheme = schema, host = host, port = port).withPath(uriPath)
+    val request = HttpRequest(uri = uri, headers = Seq(`Accept-Encoding`(HttpEncodings.gzip), Accept(MediaRange(MediaTypes.`application/json`))))
+
+    log.info("Requesting seed nodes by: {}", request.uri)
+
+    for {
+      response <- http.singleRequest(request)
+      entity <- response.entity.toStrict(resolveTimeout)
+      response <- {
+        log.debug("Eureka response: [{}]", entity.data.utf8String)
+        val unmarshalled = Unmarshal(entity).to[EurekaResponse]
+        unmarshalled.failed.foreach { _ =>
+          log.error(
+            "Failed to unmarshal Eureka response status [{}], entity: [{}], uri: [{}]",
+            response.status.value,
+            entity.data.utf8String,
+            uri)
+        }
+        unmarshalled
+      }
+      instances <- pick(response.application.instance)
+    } yield Resolved(lookup.serviceName, targets(instances))
+
+  }
+
+  private[eureka] def pick(instances: Seq[EurekaResponse.Instance]): Future[Seq[EurekaResponse.Instance]] = {
+    Future.successful(instances.collect({
+      case instance if instance.status == "UP" && instance.appGroupName == group => instance
+    }))
+  }
+
+  private[eureka] def targets(instances: Seq[EurekaResponse.Instance]): Seq[ResolvedTarget] = {
+    instances.map { instance =>
+      ResolvedTarget(
+        host = instance.ipAddr,
+        port = Some(instance.port.port),
+        address = Try(InetAddress.getByName(instance.ipAddr)).toOption)
+    }
+  }
 
-  override def lookup(lookup: Lookup, resolveTimeout: FiniteDuration): Future[ServiceDiscovery.Resolved] = ???
 }

discovery-eureka/src/main/scala/org/apache/pekko/discovery/eureka/EurekaSettings.scala

@@ -34,16 +34,16 @@ import pekko.annotation.ApiMayChange
 final class EurekaSettings(system: ExtendedActorSystem) extends Extension {
   private val eurekaConfig = system.settings.config.getConfig("pekko.discovery.eureka")
 
-  val eurekaHost: String = eurekaConfig.getString("eureka-host")
-  val eurekaPort: Int = eurekaConfig.getInt("eureka-port")
-  val eurekaPath: String = eurekaConfig.getString("eureka-path")
+  val schema: String =  eurekaConfig.getString("eureka-schema")
+  val host: String = eurekaConfig.getString("eureka-host")
+  val port: Int = eurekaConfig.getInt("eureka-port")
+  val path: String = eurekaConfig.getString("eureka-path")
   val groupName: String = eurekaConfig.getString("group-name")
   val statusPageUrl: String = eurekaConfig.getString("status-page-url")
   val healthCheckUrl: String = eurekaConfig.getString("health-page-url")
   val homePageUrl: String = eurekaConfig.getString("home-page-url")
   val servicePort: Int = eurekaConfig.getInt("service-port")
   val serviceName: String = system.name
-  val managementPort: Int = system.settings.config.getInt("pekko.management.http.port");
   val renewInterval: Long = eurekaConfig.getLong("renew-interval")
 }
 

discovery-eureka/src/main/scala/org/apache/pekko/discovery/eureka/JsonFormat.scala

@@ -0,0 +1,50 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * license agreements; and to You under the Apache License, version 2.0:
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * This file is part of the Apache Pekko project, which was derived from Akka.
+ */
+
+/*
+ * Copyright (C) 2017-2021 Lightbend Inc. <https://www.lightbend.com>
+ */
+
+package org.apache.pekko.discovery.eureka
+
+import org.apache.pekko.discovery.eureka.EurekaResponse.{Application, DataCenterInfo, Instance, PortWrapper}
+import org.apache.pekko.http.scaladsl.marshallers.sprayjson.SprayJsonSupport
+import spray.json._
+
+object JsonFormat extends SprayJsonSupport with DefaultJsonProtocol {
+  implicit val portFormat: JsonFormat[PortWrapper] = new JsonFormat[PortWrapper] {
+
+    override def read(json: JsValue): PortWrapper = {
+      json.asJsObject.getFields("$", "@enabled") match {
+        case Seq(JsNumber(port), JsString(enabled)) => PortWrapper(port.toInt, enabled.toBoolean)
+        case _ => throw DeserializationException("PortWrapper expected")
+      }
+    }
+
+    override def write(obj: PortWrapper): JsValue = JsObject(
+      "$" -> JsNumber(obj.port),
+      "@enabled" -> JsString(obj.enabled.toString))
+  }
+  implicit val dataCenterInfoFormat: JsonFormat[DataCenterInfo] = new JsonFormat[DataCenterInfo] {
+
+    override def read(json: JsValue): DataCenterInfo = {
+      json.asJsObject.getFields("name","@class") match {
+        case Seq(JsString(name), JsString(clz)) => DataCenterInfo(name, clz)
+        case _ => throw DeserializationException("DataCenterInfo expected")
+      }
+    }
+
+    override def write(obj: DataCenterInfo): JsValue = JsObject(
+      "name" -> JsString(obj.name),
+      "@class" -> JsString(obj.clz))
+  }
+  implicit val instanceFormat: JsonFormat[Instance] = jsonFormat14(Instance.apply)
+  implicit val applicationFormat: JsonFormat[Application] = jsonFormat2(Application.apply)
+  implicit val rootFormat: RootJsonFormat[EurekaResponse] = jsonFormat2(EurekaResponse.apply)
+}

discovery-eureka/src/test/scala/EurekaServiceDiscoverySpec.scala

@@ -0,0 +1,85 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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.
+ */
+
+import org.apache.pekko.actor.ActorSystem
+import org.apache.pekko.discovery.ServiceDiscovery.ResolvedTarget
+import org.apache.pekko.discovery.eureka.EurekaServiceDiscovery
+import org.apache.pekko.testkit.TestKitBase
+import org.scalatest.BeforeAndAfterAll
+import org.scalatest.concurrent.ScalaFutures
+import org.scalatest.matchers.should.Matchers
+import org.scalatest.time.{Millis, Seconds, Span}
+import org.scalatest.wordspec.AnyWordSpecLike
+
+import java.net.InetAddress
+import scala.concurrent.duration.DurationInt
+import scala.io.Source
+import scala.util.Try
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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.
+ */
+
+
+class EurekaServiceDiscoverySpec
+  extends AnyWordSpecLike
+    with Matchers
+    with BeforeAndAfterAll
+    with TestKitBase
+    with ScalaFutures {
+  "Eureka Discovery" should {
+    "work for defaults" in {
+
+      val lookupService = new EurekaServiceDiscovery()
+      val resolved = lookupService.lookup("BANK-ACCOUNT", 10.seconds).futureValue
+      resolved.addresses should contain(
+        ResolvedTarget(
+          host = "127.0.0.1",
+          port = Some(8558),
+          address = Try(InetAddress.getByName("127.0.0.1")).toOption))
+
+    }
+  }
+
+  private def resourceAsString(name: String): String =
+    Source.fromInputStream(getClass.getClassLoader.getResourceAsStream(name)).mkString
+
+  override def afterAll(): Unit = {
+    super.afterAll()
+    print("clean up \n")
+  }
+
+  override implicit lazy val system: ActorSystem = ActorSystem("test")
+
+  implicit override val patienceConfig: PatienceConfig =
+    PatienceConfig(timeout = scaled(Span(30, Seconds)), interval = scaled(Span(50, Millis)))
+}

discovery-marathon-api/src/main/scala/org/apache/pekko/discovery/marathon/AppList.scala

@@ -13,8 +13,6 @@
 
 package org.apache.pekko.discovery.marathon
 
-import scala.collection.immutable.Seq
-
 object AppList {
   case class App(container: Option[Container], portDefinitions: Option[Seq[PortDefinition]], tasks: Option[Seq[Task]])
   case class Container(portMappings: Option[Seq[PortMapping]], docker: Option[Docker])

discovery-marathon-api/src/main/scala/org/apache/pekko/discovery/marathon/MarathonApiServiceDiscovery.scala

@@ -20,7 +20,6 @@ import pekko.http.scaladsl._
 import pekko.http.scaladsl.model._
 import pekko.http.scaladsl.unmarshalling.Unmarshal
 
-import scala.collection.immutable.Seq
 import scala.concurrent.Future
 import scala.concurrent.duration.FiniteDuration
 import scala.util.Try

project/Dependencies.scala

@@ -81,6 +81,8 @@ object Dependencies {
     "org.apache.pekko" %% "pekko-stream" % pekkoVersion,
     "org.apache.pekko" %% "pekko-http" % pekkoHttpVersion,
     "org.apache.pekko" %% "pekko-http-spray-json" % pekkoHttpVersion,
+    "org.apache.pekko" %% "pekko-testkit" % pekkoVersion % Test,
+    "org.apache.pekko" %% "pekko-slf4j" % pekkoVersion % Test,
     "org.scalatest" %% "scalatest" % scalaTestVersion % Test)
 
   val discoveryKubernetesApi = Seq(