Remove unnecessary case in EventLogDownloadResource.

Author: harishreedharan

core/src/main/scala/org/apache/spark/deploy/history/FsHistoryProvider.scala

@@ -27,7 +27,7 @@ import com.google.common.util.concurrent.{MoreExecutors, ThreadFactoryBuilder}
 import org.apache.hadoop.fs.{FileStatus, FileSystem, Path}
 import org.apache.hadoop.fs.permission.AccessControlException
 
-import org.apache.spark.{SparkException, Logging, SecurityManager, SparkConf}
+import org.apache.spark.{Logging, SecurityManager, SparkConf, SparkException}
 import org.apache.spark.deploy.SparkHadoopUtil
 import org.apache.spark.io.CompressionCodec
 import org.apache.spark.scheduler._

core/src/main/scala/org/apache/spark/status/api/v1/ApiRootResource.scala

@@ -205,10 +205,13 @@ private[spark] object ApiRootResource {
 private[spark] trait UIRoot {
   def getSparkUI(appKey: String): Option[SparkUI]
   def getApplicationInfoList: Iterator[ApplicationInfo]
-  def writeEventLogs(
-      appId: String,
-      attemptId: Option[String],
-      zipStream: ZipOutputStream): Unit = { }
+
+  def writeEventLogs(appId: String, attemptId: Option[String], zipStream: ZipOutputStream): Unit = {
+    Response.serverError()
+      .entity("Event logs are only available through the history server.")
+      .status(Response.Status.SERVICE_UNAVAILABLE)
+      .build()
+  }
 
   /**
    * Get the spark UI with the given appID, and apply a function

core/src/main/scala/org/apache/spark/status/api/v1/EventLogDownloadResource.scala

@@ -25,7 +25,6 @@ import scala.util.control.NonFatal
 
 import org.apache.spark.{Logging, SparkConf}
 import org.apache.spark.deploy.SparkHadoopUtil
-import org.apache.spark.deploy.history.HistoryServer
 
 @Produces(Array(MediaType.APPLICATION_OCTET_STREAM))
 private[v1] class EventLogDownloadResource(
@@ -36,43 +35,34 @@ private[v1] class EventLogDownloadResource(
 
   @GET
   def getEventLogs(): Response = {
-    uIRoot match {
-      case hs: HistoryServer =>
-        try {
-          val fileName = {
-            attemptId match {
-              case Some(id) => s"eventLogs-$appId-$id.zip"
-              case None => s"eventLogs-$appId.zip"
-            }
-          }
-
-          val stream = new StreamingOutput {
-            override def write(output: OutputStream) = {
-              val zipStream = new ZipOutputStream(output)
-              try {
-                hs.writeEventLogs(appId, attemptId, zipStream)
-              } finally {
-                zipStream.close()
-              }
+    try {
+      val fileName = {
+        attemptId match {
+          case Some(id) => s"eventLogs-$appId-$id.zip"
+          case None => s"eventLogs-$appId.zip"
+        }
+      }
 
-            }
+      val stream = new StreamingOutput {
+        override def write(output: OutputStream) = {
+          val zipStream = new ZipOutputStream(output)
+          try {
+            uIRoot.writeEventLogs(appId, attemptId, zipStream)
+          } finally {
+            zipStream.close()
           }
 
-          Response.ok(stream)
-            .header("Content-Disposition", s"attachment; filename=$fileName")
-            .header("Content-Type", MediaType.APPLICATION_OCTET_STREAM)
-            .build()
-
-        } catch {
-          case NonFatal(e) =>
-            Response.serverError()
-              .entity(s"Event logs are not available for app: $appId.")
-              .status(Response.Status.SERVICE_UNAVAILABLE)
-              .build()
         }
-      case _ =>
+      }
+
+      Response.ok(stream)
+        .header("Content-Disposition", s"attachment; filename=$fileName")
+        .header("Content-Type", MediaType.APPLICATION_OCTET_STREAM)
+        .build()
+    } catch {
+      case NonFatal(e) =>
         Response.serverError()
-          .entity("Event logs are only available through the history server.")
+          .entity(s"Event logs are not available for app: $appId.")
           .status(Response.Status.SERVICE_UNAVAILABLE)
           .build()
     }