Expose attemptId in Stage.

Author: rxin

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

@@ -75,9 +75,11 @@ case class SparkListenerBlockManagerRemoved(blockManagerId: BlockManagerId)
 @DeveloperApi
 case class SparkListenerUnpersistRDD(rddId: Int) extends SparkListenerEvent
 
+@DeveloperApi
 case class SparkListenerApplicationStart(appName: String, time: Long, sparkUser: String)
   extends SparkListenerEvent
 
+@DeveloperApi
 case class SparkListenerApplicationEnd(time: Long) extends SparkListenerEvent
 
 /** An event used in the listener to shutdown the listener daemon thread. */

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

@@ -106,6 +106,8 @@ private[spark] class Stage(
     id
   }
 
+  def attemptId: Int = nextAttemptId
+
   val name = callSite.short
   val details = callSite.long