[SPARK-2080] Yarn: report HS URL in client mode, correct user in cluster mode.

Yarn client mode was not setting the app's tracking URL to the
History Server's URL when configured by the user. Now client mode
behaves the same as cluster mode.

In SparkContext.scala, the "user.name" system property had precedence
over the SPARK_USER environment variable. This means that SPARK_USER
was never used, since "user.name" is always set by the JVM. In Yarn
cluster mode, this means the application always reported itself as
being run by user "yarn" (or whatever user was running the Yarn NM).
One could argue that the correct fix would be to use UGI.getCurrentUser()
here, but at least for Yarn that will match what SPARK_USER is set
to.

Author: Marcelo Vanzin <[email protected]>

This patch had conflicts when merged, resolved by
Committer: Thomas Graves <[email protected]>

Closes #1002 from vanzin/yarn-client-url and squashes the following commits:

4046e04 [Marcelo Vanzin] Set HS link in yarn-alpha also.
4c692d9 [Marcelo Vanzin] Yarn: report HS URL in client mode, correct user in cluster mode.

Author: Marcelo Vanzin

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

@@ -297,7 +297,7 @@ class SparkContext(config: SparkConf) extends Logging {
 
   // Set SPARK_USER for user who is running SparkContext.
   val sparkUser = Option {
-    Option(System.getProperty("user.name")).getOrElse(System.getenv("SPARK_USER"))
+    Option(System.getenv("SPARK_USER")).getOrElse(System.getProperty("user.name"))
   }.getOrElse {
     SparkContext.SPARK_UNKNOWN_USER
   }

yarn/alpha/src/main/scala/org/apache/spark/deploy/yarn/ExecutorLauncher.scala

@@ -271,6 +271,7 @@ class ExecutorLauncher(args: ApplicationMasterArguments, conf: Configuration, sp
       .asInstanceOf[FinishApplicationMasterRequest]
     finishReq.setAppAttemptId(appAttemptId)
     finishReq.setFinishApplicationStatus(status)
+    finishReq.setTrackingUrl(sparkConf.get("spark.yarn.historyServer.address", ""))
     resourceManager.finishApplicationMaster(finishReq)
   }
 

yarn/stable/src/main/scala/org/apache/spark/deploy/yarn/ExecutorLauncher.scala

@@ -115,7 +115,7 @@ class ExecutorLauncher(args: ApplicationMasterArguments, conf: Configuration, sp
     val interval = math.min(timeoutInterval / 2, schedulerInterval)
 
     reporterThread = launchReporterThread(interval)
-    
+
 
     // Wait for the reporter thread to Finish.
     reporterThread.join()
@@ -134,12 +134,12 @@ class ExecutorLauncher(args: ApplicationMasterArguments, conf: Configuration, sp
     // LOCAL_DIRS => 2.X, YARN_LOCAL_DIRS => 0.23.X
     val localDirs = Option(System.getenv("YARN_LOCAL_DIRS"))
       .orElse(Option(System.getenv("LOCAL_DIRS")))
- 
+
     localDirs match {
       case None => throw new Exception("Yarn Local dirs can't be empty")
       case Some(l) => l
     }
-  } 
+  }
 
   private def registerApplicationMaster(): RegisterApplicationMasterResponse = {
     logInfo("Registering the ApplicationMaster")