Ability to kill jobs thru the UI.

This behavior can be turned on be settings the following variable: spark.ui.killEnabled=true (default=false)
Adding DAGScheduler event StageCancelled and corresponding handlers.
Added cancellation reason to handlers.

Author: Sundeep Narravula <[email protected]>

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

@@ -1076,6 +1076,16 @@ class SparkContext(
     dagScheduler.cancelAllJobs()
   }
 
+  /** Cancel a given job if it's scheduled or running */
+  def cancelJob(jobId: Int) {
+    dagScheduler.cancelJob(jobId)
+  }
+
+  /** Cancel a given stage and all jobs associated with it */
+  def cancelStage(stageId: Int) {
+    dagScheduler.cancelStage(stageId)
+  }
+
   /**
    * Clean a closure to make it ready to serialized and send to tasks
    * (removes unreferenced variables in $outer's, updates REPL variables)

core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala

@@ -494,7 +494,7 @@ class DAGScheduler(
   /**
    * Cancel a job that is running or waiting in the queue.
    */
-  def cancelJob(jobId: Int) {
+  private[spark] def cancelJob(jobId: Int) {
     logInfo("Asked to cancel job " + jobId)
     eventProcessActor ! JobCancelled(jobId)
   }
@@ -511,6 +511,13 @@ class DAGScheduler(
     eventProcessActor ! AllJobsCancelled
   }
 
+  /**
+   * Cancel all jobs associated with a running or scheduled stage.
+   */
+  def cancelStage(stageId: Int) {
+    eventProcessActor ! StageCancelled(stageId)
+  }
+
   /**
    * Process one event retrieved from the event processing actor.
    *
@@ -551,6 +558,9 @@ class DAGScheduler(
           submitStage(finalStage)
         }
 
+      case StageCancelled(stageId) =>
+        handleStageCancellation(stageId)
+
       case JobCancelled(jobId) =>
         handleJobCancellation(jobId)
 
@@ -560,11 +570,11 @@ class DAGScheduler(
         val activeInGroup = activeJobs.filter(activeJob =>
           groupId == activeJob.properties.get(SparkContext.SPARK_JOB_GROUP_ID))
         val jobIds = activeInGroup.map(_.jobId)
-        jobIds.foreach(handleJobCancellation)
+        jobIds.foreach(jobId => handleJobCancellation(jobId, "as part of cancelled job group %s".format(groupId)))
 
       case AllJobsCancelled =>
         // Cancel all running jobs.
-        runningStages.map(_.jobId).foreach(handleJobCancellation)
+        runningStages.map(_.jobId).foreach(jobId => handleJobCancellation(jobId, "as part of cancellation of all jobs"))
         activeJobs.clear()      // These should already be empty by this point,
         jobIdToActiveJob.clear()   // but just in case we lost track of some jobs...
 
@@ -991,11 +1001,23 @@ class DAGScheduler(
     }
   }
 
-  private def handleJobCancellation(jobId: Int) {
+  private def handleStageCancellation(stageId: Int) {
+    if (stageIdToJobIds.contains(stageId)) {
+      val jobsThatUseStage: Array[Int] = stageIdToJobIds(stageId).toArray.sorted
+      jobsThatUseStage.foreach(jobId => {
+        handleJobCancellation(jobId, "because Stage %s was cancelled".format(stageId))
+      })
+    } else {
+      logInfo("No active jobs to kill for Stage " + stageId)
+    }
+  }
+
+  private def handleJobCancellation(jobId: Int, reason: String = "") {
     if (!jobIdToStageIds.contains(jobId)) {
       logDebug("Trying to cancel unregistered job " + jobId)
     } else {
-      failJobAndIndependentStages(jobIdToActiveJob(jobId), s"Job $jobId cancelled", None)
+      failJobAndIndependentStages(jobIdToActiveJob(jobId), 
+        "Job %d cancelled %s".format(jobId, reason), None)
     }
   }
 

core/src/main/scala/org/apache/spark/scheduler/DAGSchedulerEvent.scala

@@ -44,6 +44,8 @@ private[scheduler] case class JobSubmitted(
     properties: Properties = null)
   extends DAGSchedulerEvent
 
+private[scheduler] case class StageCancelled(stageId: Int) extends DAGSchedulerEvent
+
 private[scheduler] case class JobCancelled(jobId: Int) extends DAGSchedulerEvent
 
 private[scheduler] case class JobGroupCancelled(groupId: String) extends DAGSchedulerEvent

core/src/main/scala/org/apache/spark/ui/SparkUI.scala

@@ -46,6 +46,7 @@ private[spark] class SparkUI(
   val live = sc != null
 
   val securityManager = if (live) sc.env.securityManager else new SecurityManager(conf)
+  val killEnabled = conf.get("spark.ui.killEnabled", "false").toBoolean
 
   private val bindHost = Utils.localHostName()
   private val publicHost = Option(System.getenv("SPARK_PUBLIC_DNS")).getOrElse(bindHost)

core/src/main/scala/org/apache/spark/ui/jobs/IndexPage.scala

@@ -41,7 +41,8 @@ private[ui] class IndexPage(parent: JobProgressUI) {
       val failedStages = listener.failedStages.reverse.toSeq
       val now = System.currentTimeMillis()
 
-      val activeStagesTable = new StageTable(activeStages.sortBy(_.submissionTime).reverse, parent)
+      val activeStagesTable =
+        new StageTable(activeStages.sortBy(_.submissionTime).reverse, parent, parent.killEnabled)
       val completedStagesTable =
         new StageTable(completedStages.sortBy(_.submissionTime).reverse, parent)
       val failedStagesTable = new StageTable(failedStages.sortBy(_.submissionTime).reverse, parent)

core/src/main/scala/org/apache/spark/ui/jobs/JobProgressListener.scala

@@ -61,6 +61,7 @@ private[ui] class JobProgressListener(conf: SparkConf) extends SparkListener {
   val stageIdToPool = HashMap[Int, String]()
   val stageIdToDescription = HashMap[Int, String]()
   val poolToActiveStages = HashMap[String, HashMap[Int, StageInfo]]()
+  val jobIdToStageIds = HashMap[Int, Seq[Int]]()
 
   val executorIdToBlockManagerId = HashMap[String, BlockManagerId]()
 

core/src/main/scala/org/apache/spark/ui/jobs/JobProgressUI.scala

@@ -33,6 +33,7 @@ private[ui] class JobProgressUI(parent: SparkUI) {
   val basePath = parent.basePath
   val live = parent.live
   val sc = parent.sc
+  val killEnabled = parent.killEnabled
 
   lazy val listener = _listener.get
   lazy val isFairScheduler = listener.schedulingMode.exists(_ == SchedulingMode.FAIR)
@@ -56,5 +57,5 @@ private[ui] class JobProgressUI(parent: SparkUI) {
       (request: HttpServletRequest) => poolPage.render(request), parent.securityManager, basePath),
     createServletHandler("/stages",
       (request: HttpServletRequest) => indexPage.render(request), parent.securityManager, basePath)
-  )
+    )
 }

core/src/main/scala/org/apache/spark/ui/jobs/StagePage.scala

@@ -31,11 +31,21 @@ private[ui] class StagePage(parent: JobProgressUI) {
   private val appName = parent.appName
   private val basePath = parent.basePath
   private lazy val listener = parent.listener
+  private lazy val sc = parent.sc
+  private val killEnabled = parent.killEnabled
 
   def render(request: HttpServletRequest): Seq[Node] = {
     listener.synchronized {
       val stageId = request.getParameter("id").toInt
 
+      if (killEnabled) {
+        val killFlag = Option(request.getParameter("terminate")).getOrElse("false").toBoolean
+
+        if (killFlag && listener.activeStages.contains(stageId)) {
+          sc.cancelStage(stageId)
+        }
+      }
+
       if (!listener.stageIdToTaskData.contains(stageId)) {
         val content =
           <div>

core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala

@@ -27,7 +27,7 @@ import org.apache.spark.ui.{WebUI, UIUtils}
 import org.apache.spark.util.Utils
 
 /** Page showing list of all ongoing and recently finished stages */
-private[ui] class StageTable(stages: Seq[StageInfo], parent: JobProgressUI) {
+private[ui] class StageTable(stages: Seq[StageInfo], parent: JobProgressUI, killEnabled: Boolean = false) {
   private val basePath = parent.basePath
   private lazy val listener = parent.listener
   private lazy val isFairScheduler = parent.isFairScheduler
@@ -71,15 +71,28 @@ private[ui] class StageTable(stages: Seq[StageInfo], parent: JobProgressUI) {
     </div>
   }
 
-  /** Render an HTML row that represents a stage */
-  private def stageRow(s: StageInfo): Seq[Node] = {
-    val poolName = listener.stageIdToPool.get(s.stageId)
+  private def makeDescription(s: StageInfo): Seq[Node] = {
     val nameLink =
       <a href={"%s/stages/stage?id=%s".format(UIUtils.prependBaseUri(basePath), s.stageId)}>
         {s.name}
       </a>
+    val killButton =  if (killEnabled) {
+      <form action={"%s/stages/stage/".format(UIUtils.prependBaseUri(basePath))}>
+        <input type="hidden" value={"true"} name="terminate" />
+        <input type="hidden" value={"" + s.stageId} name="id" />
+        <input type="submit" value="Terminate Job"/>
+      </form>
+    }
     val description = listener.stageIdToDescription.get(s.stageId)
-      .map(d => <div><em>{d}</em></div><div>{nameLink}</div>).getOrElse(nameLink)
+      .map(d => <div><em>{d}</em></div><div>{nameLink} {killButton}</div>)
+      .getOrElse(<div>{nameLink} {killButton}</div>)
+
+    return description
+  }
+
+  /** Render an HTML row that represents a stage */
+  private def stageRow(s: StageInfo): Seq[Node] = {
+    val poolName = listener.stageIdToPool.get(s.stageId)
     val submissionTime = s.submissionTime match {
       case Some(t) => WebUI.formatDate(new Date(t))
       case None => "Unknown"
@@ -118,7 +131,7 @@ private[ui] class StageTable(stages: Seq[StageInfo], parent: JobProgressUI) {
           </a>
         </td>
       }}
-      <td>{description}</td>
+      <td>{makeDescription(s)}</td>
       <td valign="middle">{submissionTime}</td>
       <td sorttable_customkey={duration.getOrElse(-1).toString}>{formattedDuration}</td>
       <td class="progress-cell">