Refactoring the UI interface to add flexibility

This commit introduces three (abstract) classes: WebUI, UITab, and UIPage.
The top of the hierarchy is the WebUI, which contains many tabs and pages.
Each tab in turn contains many pages.

When a UITab is attached to a WebUI, the WebUI creates a handler for each
of the tab's pages. Similarly, when a UIPage is attached to a WebUI, its
handler is created. The server in WebUI is then ready to be bound to a host
and a port.

This commit also breaks down a couple of unnecessarily large files by
moving certain classes to their own files.

core/src/main/scala/org/apache/spark/SparkContext.scala

@@ -158,8 +158,8 @@ class SparkContext(
 
   // Initialize the Spark UI, registering all associated listeners
   private[spark] val ui = new SparkUI(this)
-  ui.bind()
   ui.start()
+  ui.bind()
 
   // Optionally log Spark events
   private[spark] val eventLogger: Option[EventLoggingListener] = {

core/src/main/scala/org/apache/spark/deploy/master/Master.scala

@@ -85,6 +85,7 @@ private[spark] class Master(
   val masterSource = new MasterSource(this)
 
   val webUi = new MasterWebUI(this, webUiPort)
+  webUi.start()
 
   val masterPublicAddress = {
     val envVar = System.getenv("SPARK_PUBLIC_DNS")

core/src/main/scala/org/apache/spark/deploy/master/ui/ApplicationPage.scala

@@ -28,15 +28,17 @@ import org.json4s.JValue
 import org.apache.spark.deploy.JsonProtocol
 import org.apache.spark.deploy.DeployMessages.{MasterStateResponse, RequestMasterState}
 import org.apache.spark.deploy.master.ExecutorInfo
-import org.apache.spark.ui.UIUtils
+import org.apache.spark.ui.{UIPage, UIUtils}
 import org.apache.spark.util.Utils
 
-private[spark] class ApplicationPage(parent: MasterWebUI) {
-  val master = parent.masterActorRef
-  val timeout = parent.timeout
+private[spark] class ApplicationPage(parent: MasterWebUI)
+  extends UIPage("app", includeJson = true) {
+
+  private val master = parent.masterActorRef
+  private val timeout = parent.timeout
 
   /** Executor details for a particular application */
-  def renderJson(request: HttpServletRequest): JValue = {
+  override def renderJson(request: HttpServletRequest): JValue = {
     val appId = request.getParameter("appId")
     val stateFuture = (master ? RequestMasterState)(timeout).mapTo[MasterStateResponse]
     val state = Await.result(stateFuture, timeout)
@@ -47,7 +49,7 @@ private[spark] class ApplicationPage(parent: MasterWebUI) {
   }
 
   /** Executor details for a particular application */
-  def render(request: HttpServletRequest): Seq[Node] = {
+  override def render(request: HttpServletRequest): Seq[Node] = {
     val appId = request.getParameter("appId")
     val stateFuture = (master ? RequestMasterState)(timeout).mapTo[MasterStateResponse]
     val state = Await.result(stateFuture, timeout)
@@ -96,7 +98,7 @@ private[spark] class ApplicationPage(parent: MasterWebUI) {
     UIUtils.basicSparkPage(content, "Application: " + app.desc.name)
   }
 
-  def executorRow(executor: ExecutorInfo): Seq[Node] = {
+  private def executorRow(executor: ExecutorInfo): Seq[Node] = {
     <tr>
       <td>{executor.id}</td>
       <td>

core/src/main/scala/org/apache/spark/deploy/master/ui/IndexPage.scala

@@ -25,24 +25,24 @@ import scala.xml.Node
 import akka.pattern.ask
 import org.json4s.JValue
 
-import org.apache.spark.deploy.{JsonProtocol}
+import org.apache.spark.deploy.JsonProtocol
 import org.apache.spark.deploy.DeployMessages.{MasterStateResponse, RequestMasterState}
 import org.apache.spark.deploy.master.{ApplicationInfo, DriverInfo, WorkerInfo}
-import org.apache.spark.ui.{WebUI, UIUtils}
+import org.apache.spark.ui.{UIPage, UIUtils}
 import org.apache.spark.util.Utils
 
-private[spark] class IndexPage(parent: MasterWebUI) {
-  val master = parent.masterActorRef
-  val timeout = parent.timeout
+private[spark] class IndexPage(parent: MasterWebUI) extends UIPage("", includeJson = true) {
+  private val master = parent.masterActorRef
+  private val timeout = parent.timeout
 
-  def renderJson(request: HttpServletRequest): JValue = {
+  override def renderJson(request: HttpServletRequest): JValue = {
     val stateFuture = (master ? RequestMasterState)(timeout).mapTo[MasterStateResponse]
     val state = Await.result(stateFuture, timeout)
     JsonProtocol.writeMasterState(state)
   }
 
   /** Index view listing applications and executors */
-  def render(request: HttpServletRequest): Seq[Node] = {
+  override def render(request: HttpServletRequest): Seq[Node] = {
     val stateFuture = (master ? RequestMasterState)(timeout).mapTo[MasterStateResponse]
     val state = Await.result(stateFuture, timeout)
 
@@ -139,7 +139,7 @@ private[spark] class IndexPage(parent: MasterWebUI) {
     UIUtils.basicSparkPage(content, "Spark Master at " + state.uri)
   }
 
-  def workerRow(worker: WorkerInfo): Seq[Node] = {
+  private def workerRow(worker: WorkerInfo): Seq[Node] = {
     <tr>
       <td>
         <a href={worker.webUiAddress}>{worker.id}</a>
@@ -154,8 +154,7 @@ private[spark] class IndexPage(parent: MasterWebUI) {
     </tr>
   }
 
-
-  def appRow(app: ApplicationInfo): Seq[Node] = {
+  private def appRow(app: ApplicationInfo): Seq[Node] = {
     <tr>
       <td>
         <a href={"app?appId=" + app.id}>{app.id}</a>
@@ -169,14 +168,14 @@ private[spark] class IndexPage(parent: MasterWebUI) {
       <td sorttable_customkey={app.desc.memoryPerSlave.toString}>
         {Utils.megabytesToString(app.desc.memoryPerSlave)}
       </td>
-      <td>{WebUI.formatDate(app.submitDate)}</td>
+      <td>{UIUtils.formatDate(app.submitDate)}</td>
       <td>{app.desc.user}</td>
       <td>{app.state.toString}</td>
-      <td>{WebUI.formatDuration(app.duration)}</td>
+      <td>{UIUtils.formatDuration(app.duration)}</td>
     </tr>
   }
 
-  def driverRow(driver: DriverInfo): Seq[Node] = {
+  private def driverRow(driver: DriverInfo): Seq[Node] = {
     <tr>
       <td>{driver.id} </td>
       <td>{driver.submitDate}</td>

core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala

@@ -17,64 +17,49 @@
 
 package org.apache.spark.deploy.master.ui
 
-import javax.servlet.http.HttpServletRequest
-
-import org.eclipse.jetty.servlet.ServletContextHandler
-
 import org.apache.spark.Logging
 import org.apache.spark.deploy.master.Master
-import org.apache.spark.ui.{ServerInfo, SparkUI}
+import org.apache.spark.ui.{SparkUI, WebUI}
 import org.apache.spark.ui.JettyUtils._
 import org.apache.spark.util.{AkkaUtils, Utils}
 
 /**
  * Web UI server for the standalone master.
  */
 private[spark]
-class MasterWebUI(val master: Master, requestedPort: Int) extends Logging {
-  val masterActorRef = master.self
-  val timeout = AkkaUtils.askTimeout(master.conf)
+class MasterWebUI(val master: Master, requestedPort: Int)
+  extends WebUI(master.securityMgr) with Logging {
 
   private val host = Utils.localHostName()
   private val port = requestedPort
-  private val applicationPage = new ApplicationPage(this)
-  private val indexPage = new IndexPage(this)
-  private var serverInfo: Option[ServerInfo] = None
+  val masterActorRef = master.self
+  val timeout = AkkaUtils.askTimeout(master.conf)
 
-  private val handlers: Seq[ServletContextHandler] = {
-    master.masterMetricsSystem.getServletHandlers ++
-    master.applicationMetricsSystem.getServletHandlers ++
-    Seq[ServletContextHandler](
-      createStaticHandler(MasterWebUI.STATIC_RESOURCE_DIR, "/static"),
-      createServletHandler("/app/json",
-        (request: HttpServletRequest) => applicationPage.renderJson(request), master.securityMgr),
-      createServletHandler("/app",
-        (request: HttpServletRequest) => applicationPage.render(request), master.securityMgr),
-      createServletHandler("/json",
-        (request: HttpServletRequest) => indexPage.renderJson(request), master.securityMgr),
-      createServletHandler("/",
-        (request: HttpServletRequest) => indexPage.render(request), master.securityMgr)
-    )
+  def start() {
+    attachPage(new ApplicationPage(this))
+    attachPage(new IndexPage(this))
+    attachHandler(createStaticHandler(MasterWebUI.STATIC_RESOURCE_DIR, "/static"))
+    master.masterMetricsSystem.getServletHandlers.foreach(attachHandler)
+    master.applicationMetricsSystem.getServletHandlers.foreach(attachHandler)
   }
 
+  /** Bind to the HTTP server behind this web interface. */
   def bind() {
     try {
       serverInfo = Some(startJettyServer(host, port, handlers, master.conf))
       logInfo("Started Master web UI at http://%s:%d".format(host, boundPort))
     } catch {
       case e: Exception =>
-        logError("Failed to create Master JettyUtils", e)
+        logError("Failed to create Master web UI", e)
         System.exit(1)
     }
   }
 
-  def boundPort: Int = serverInfo.map(_.boundPort).getOrElse(-1)
-
   /** Attach a reconstructed UI to this Master UI. Only valid after bind(). */
   def attachUI(ui: SparkUI) {
     assert(serverInfo.isDefined, "Master UI must be bound to a server before attaching SparkUIs")
     val rootHandler = serverInfo.get.rootHandler
-    for (handler <- ui.handlers) {
+    for (handler <- ui.getHandlers) {
       rootHandler.addHandler(handler)
       if (!handler.isStarted) {
         handler.start()
@@ -86,18 +71,13 @@ class MasterWebUI(val master: Master, requestedPort: Int) extends Logging {
   def detachUI(ui: SparkUI) {
     assert(serverInfo.isDefined, "Master UI must be bound to a server before detaching SparkUIs")
     val rootHandler = serverInfo.get.rootHandler
-    for (handler <- ui.handlers) {
+    for (handler <- ui.getHandlers) {
       if (handler.isStarted) {
         handler.stop()
       }
       rootHandler.removeHandler(handler)
     }
   }
-
-  def stop() {
-    assert(serverInfo.isDefined, "Attempted to stop a Master UI that was not bound to a server!")
-    serverInfo.get.server.stop()
-  }
 }
 
 private[spark] object MasterWebUI {

core/src/main/scala/org/apache/spark/deploy/worker/Worker.scala

@@ -123,8 +123,9 @@ private[spark] class Worker(
     logInfo("Spark home: " + sparkHome)
     createWorkDir()
     webUi = new WorkerWebUI(this, workDir, Some(webUiPort))
-    context.system.eventStream.subscribe(self, classOf[RemotingLifecycleEvent])
+    webUi.start()
     webUi.bind()
+    context.system.eventStream.subscribe(self, classOf[RemotingLifecycleEvent])
     registerWithMaster()
 
     metricsSystem.registerSource(workerSource)

core/src/main/scala/org/apache/spark/deploy/worker/ui/IndexPage.scala

@@ -28,21 +28,21 @@ import org.apache.spark.deploy.JsonProtocol
 import org.apache.spark.deploy.DeployMessages.{RequestWorkerState, WorkerStateResponse}
 import org.apache.spark.deploy.master.DriverState
 import org.apache.spark.deploy.worker.{DriverRunner, ExecutorRunner}
-import org.apache.spark.ui.UIUtils
+import org.apache.spark.ui.{UIPage, UIUtils}
 import org.apache.spark.util.Utils
 
-private[spark] class IndexPage(parent: WorkerWebUI) {
+private[spark] class IndexPage(parent: WorkerWebUI) extends UIPage("", includeJson = true) {
   val workerActor = parent.worker.self
   val worker = parent.worker
   val timeout = parent.timeout
 
-  def renderJson(request: HttpServletRequest): JValue = {
+  override def renderJson(request: HttpServletRequest): JValue = {
     val stateFuture = (workerActor ? RequestWorkerState)(timeout).mapTo[WorkerStateResponse]
     val workerState = Await.result(stateFuture, timeout)
     JsonProtocol.writeWorkerState(workerState)
   }
 
-  def render(request: HttpServletRequest): Seq[Node] = {
+  override def render(request: HttpServletRequest): Seq[Node] = {
     val stateFuture = (workerActor ? RequestWorkerState)(timeout).mapTo[WorkerStateResponse]
     val workerState = Await.result(stateFuture, timeout)