Add akka service discovery example app

[#157854651]

Signed-off-by: Christian Ang <[email protected]>

.gitignore

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+.idea

akka-sample-cluster-on-cloudfoundry/.gitignore

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+*.class
+*.log
+
+# sbt specific
+.cache
+.history
+.lib/
+.idea/
+dist/*
+target/
+lib_managed/
+src_managed/
+project/boot/
+project/plugins/project/
+
+# Scala-IDE specific
+.scala_dependencies
+.worksheet
+*.sc
+*.tgz
+*.zip
+bosh-lite
+diego-release
+garden-runc-release
+cf-release
+netman-release
+bin

akka-sample-cluster-on-cloudfoundry/README.md

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+This repo contains sample Akka Cluster app integrated with Service Discovery.
+
+# How to run Akka Cluster on Cloud Foundry (CF)
+
+Thanks to [this git repo](https://github.com/gtantachuco-pivotal/akka-sample-cluster-on-cloudfoundry) for the original version of this example, which uses Amalgam8.
+
+This is a short guide to walk you through how to deploy and run Akka Cluster-based application on [Cloud Foundry (CF)](https://cloudfoundry.org)
+
+**Note:** Akka with no Remoting / Cluster can run on CF with no additional requirement. This article deals with cases when Remoting / Cluster features are used.
+
+**Background:** [Akka Cluster](http://doc.akka.io/docs/akka/snapshot/scala/cluster-usage.html) is based on TCP communication or optionally can use UDP instead in Akka version >= 2.4.11.
+CF's standard container-to-container (C2C) mechanism allows apps talking to other apps via TCP or UDP; however, the ingress traffic to the entry point application supports only HTTP(S) and TCP.
+
+In this guide we will use this CF C2C feature to show how to run Akka Cluster that uses TCP.
+
+## Prerequisites
+
+The following instructions for this example assume the following:
+- [This git repo](https://github.com/cloudfoundry/cf-networking-examples) cloned to ~/workspace
+- [The CF Networking Release git repo](https://github.com/cloudfoundry/cf-networking-release) cloned to ~/workspace
+- A Cloud Foundry with Service Discovery enabled; service discovery is part of the cf-networking-release
+
+## Get ready to deploy apps to CF
+
+- Login to CF:
+```
+cf login...
+```
+- Target the org and space where you want to deploy your apps:
+```
+cf target -o...
+```
+
+## Build the Akka application
+
+You can deploy Akka application by using your foundation's [java-buildpack](https://github.com/cloudfoundry/java-buildpack.git). Our sample application is inspired by [akka-sample-cluster](https://github.com/akka/akka/tree/master/akka-samples/akka-sample-cluster-scala)).
+It has backend nodes that calculate factorial upon receiving messages from frontend nodes. Frontend nodes also expose HTTP interface `GET <frontend-hostname>/info` that shows number of jobs completed.
+
+- Go to your local repo's folder
+```
+cd ~/workspace/cf-networking-examples/akka-sample-cluster-on-cloudfoundry/akka-sample-cluster/
+```
+- Compile and package both Akka backend and frontend components:
+```
+sbt backend:assembly # backend
+sbt frontend:assembly # frontend
+```
+
+## Deploying Akka backend application
+
+- Deploy, but do not start yet, sample Akka backend: with `--no-route` and `--health-check-type none` options since backend doesn't expose any HTTP ports:
+```
+cf push --no-start --no-route --health-check-type none akka-backend -p target/scala-2.11/akka-sample-backend.jar -b java_buildpack_offline
+```
+- Map an internal route to the backend application. Assuming your internal tld is `apps.internal`:
+```
+cf map-route akka-backend apps.internal --hostname akka-backend
+```
+- Add this network policy, to allow the backend nodes to communicate:
+```
+cf add-network-policy akka-backend --destination-app akka-backend --port 2551 --protocol tcp
+```
+- Start the backend app:
+```
+cf start akka-backend
+```
+- Check the log to see that first node joined itself:
+```
+cf logs akka-backend
+```
+- **IMPORTANT:** To prevent cluster split, verify that the first node is running before scaling it.
+- Scale backend to 2 instances:
+```
+cf scale akka-backend -i 2
+```
+
+## Deploying Akka frontend application
+
+- Deploy, but don't start yet, the sample Akka frontend:
+```
+cf push akka-frontend --no-start -p target/scala-2.11/akka-sample-frontend.jar -b  java_buildpack_offline
+```
+- Add this network policy to allow frontend app to communicate with backend app cannot via backend's TCP:2551 port:
+```
+cf add-network-policy akka-frontend --destination-app akka-backend --port 2551 --protocol tcp
+```
+- Start the fronted app:
+```
+cf start akka-frontend
+```
+- In separate windows or terminal sessions, check logs from both frontend and backend to ensure all client/server and server-to-server communications are working fine:
+```
+cf logs akka-backend
+cf logs akka-frontend
+```
+- Verify that it works:
+```
+curl akka-frontend.<YOUR_CF_DOMAIN>/info
+```
+- If all is working, it should show the number of completed jobs
+
+## Summary
+
+This guide shows the implementation of a successful PoC; hence, it requires more than that to have a production Akka Cluster on CF.

akka-sample-cluster-on-cloudfoundry/akka-sample-cluster/COPYING

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akka-sample-cluster-on-cloudfoundry/akka-sample-cluster/LICENSE

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+Activator Template by Typesafe
+
+Licensed under Public Domain (CC0)
+
+To the extent possible under law, the person who associated CC0 with
+this Activator Tempate has waived all copyright and related or neighboring
+rights to this Activator Template.
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+You should have received a copy of the CC0 legalcode along with this
+work.  If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.

akka-sample-cluster-on-cloudfoundry/akka-sample-cluster/build.sbt

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+val akkaV = "2.4.3"
+
+resolvers ++= Seq("Typesafe Repo" at "http://repo.typesafe.com/typesafe/releases/")
+
+val Frontend = config("frontend") extend(Compile)
+val Backend = config("backend") extend(Compile)
+def customAssemblySettings =
+  inConfig(Frontend)(baseAssemblySettings ++
+    inTask(assembly)(mainClass := Some("sample.cluster.factorial.FactorialFrontend")) ++
+    inTask(assembly)(assemblyJarName := "akka-sample-frontend.jar")) ++
+    inConfig(Backend)(baseAssemblySettings ++
+      inTask(assembly)(mainClass := Some("sample.cluster.factorial.FactorialBackend")) ++
+      inTask(assembly)(assemblyJarName := "akka-sample-backend.jar"))
+
+val project = Project(
+  id = "akka-sample-cluster-scala",
+  base = file("."),
+  settings = customAssemblySettings ++ Defaults.coreDefaultSettings ++ Seq(
+    name := """akka-sample-cluster""",
+    scalaVersion := "2.11.8",
+    // scalaVersion := provided by Typesafe Reactive Platform
+    scalacOptions in Compile ++= Seq("-encoding", "UTF-8", "-target:jvm-1.6", "-deprecation", "-feature", "-unchecked", "-Xlog-reflective-calls", "-Xlint"),
+    javacOptions in Compile ++= Seq("-source", "1.6", "-target", "1.6", "-Xlint:unchecked", "-Xlint:deprecation"),
+    libraryDependencies ++= Seq(
+      "com.typesafe.akka" %% "akka-cluster" % akkaV,
+      "com.typesafe.akka" %% "akka-multi-node-testkit" % akkaV,
+      "com.typesafe.akka" %% "akka-http-experimental" % akkaV,
+      "com.typesafe.akka" %% "akka-http-spray-json-experimental" % akkaV,
+      "com.typesafe.akka" %% "akka-contrib" % akkaV,
+      "org.scalaj" %% "scalaj-http" % "2.3.0",
+      "com.typesafe.play" %% "play-json" % "2.3.4",
+      "org.scalatest" %% "scalatest" % "2.2.1" % "test"//,
+      /*"org.fusesource" % "sigar" % "1.6.4"*/),
+    javaOptions in run ++= Seq(
+      //"-Djava.library.path=./sigar",
+      "-Xms128m", "-Xmx1024m"),
+    Keys.fork in run := true,  
+    mainClass in (Compile, run) := Some("sample.cluster.simple.SimpleClusterApp"),
+    parallelExecution in Test := false,
+    mainClass in assembly := Some("sample.cluster.factorial.FactorialApp")
+  )
+)

akka-sample-cluster-on-cloudfoundry/akka-sample-cluster/project/assembly.sbt

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+addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.14.3")

akka-sample-cluster-on-cloudfoundry/akka-sample-cluster/project/build.properties

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+#Activator-generated Properties
+#Fri Aug 26 13:05:39 EDT 2016
+template.uuid=472c6099-8b2b-4aee-a669-dbaab0c53138
+sbt.version=0.13.7

akka-sample-cluster-on-cloudfoundry/akka-sample-cluster/project/plugins.sbt

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+
+resolvers += Classpaths.typesafeReleases
+
+addSbtPlugin("com.typesafe.sbt" % "sbt-multi-jvm" % "0.3.8")
+

akka-sample-cluster-on-cloudfoundry/akka-sample-cluster/src/main/resources/application.conf

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+clustering {
+
+  ip = "127.0.0.1"
+  ip = ${?THIS_IP}
+
+  port = 0
+  port = ${?AKKA_SAMPLE_THIS_PORT}
+
+  seed-host = "akka-backend.apps.internal"
+  seed-host = ${?AKKA_SAMPLE_SEED_IP_1}
+
+  seed-port = 2551
+  seed-port = ${?AKKA_SAMPLE_SEED_PORT_1}
+
+  name = AkkaSampleCluster
+}
+
+akka {
+  actor {
+    provider = "akka.cluster.ClusterActorRefProvider"
+  }
+  remote {
+    log-remote-lifecycle-events = off
+    netty.tcp {
+      hostname = ${clustering.ip}
+      port = ${clustering.port}
+    }
+  }
+
+  cluster {
+    seed-nodes = [
+      "akka.tcp://"${clustering.name}"@"${clustering.seed-host}":"${clustering.seed-port}]
+    auto-down-unreachable-after = 10s
+  }
+}

akka-sample-cluster-on-cloudfoundry/akka-sample-cluster/src/main/resources/factorial.conf

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+include "application"
+
+# //#min-nr-of-members
+akka.cluster.min-nr-of-members = 2
+# //#min-nr-of-members
+
+# //#role-min-nr-of-members
+akka.cluster.role {
+  frontend.min-nr-of-members = 1
+  backend.min-nr-of-members = 1
+}
+# //#role-min-nr-of-members
+
+# //#adaptive-router
+akka.actor.deployment {
+  /factorialFrontend/factorialBackendRouter = {
+    router = round-robin-group # adaptive-group
+    # metrics-selector = heap
+    # metrics-selector = load
+    # metrics-selector = cpu
+    # metrics-selector = mix
+    nr-of-instances = 4
+    routees.paths = ["/user/factorialBackend"]
+    cluster {
+      enabled = on
+      use-role = backend
+      allow-local-routees = off
+    }
+  }
+}
+# //#adaptive-router