Use UIRoot directly in ApiRootResource. Also, use Response class to set headers.

Author: harishreedharan

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

@@ -173,8 +173,9 @@ class HistoryServer(
     getApplicationList().iterator.map(ApplicationsListResource.appHistoryInfoToPublicAppInfo)
   }
 
-  def copyEventLogsToDirectory(appId: String, destDir: File): Unit = {
+  def copyEventLogsToDirectory(appId: String, destDir: File): Boolean = {
     provider.copyApplicationEventLogs(appId, destDir)
+    true
   }
 
 

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

@@ -16,6 +16,7 @@
  */
 package org.apache.spark.status.api.v1
 
+import java.io.File
 import javax.servlet.ServletContext
 import javax.ws.rs._
 import javax.ws.rs.core.{Context, Response}
@@ -168,11 +169,8 @@ private[v1] class ApiRootResource extends UIRootFromServletContext {
   def getEventLogs(
       @PathParam("appId") appId: String,
       @PathParam("attemptId") attemptId: String): EventLogDownloadResource = {
-    uiRoot.withSparkUI(appId, Some(attemptId)) { ui =>
-      new EventLogDownloadResource(ui, appId)
-    }
+    new EventLogDownloadResource(uiRoot, appId)
   }
-
 }
 
 private[spark] object ApiRootResource {

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

@@ -16,54 +16,59 @@
  */
 package org.apache.spark.status.api.v1
 
-import java.io.{BufferedInputStream, FileInputStream, OutputStream, File, InputStream}
-import javax.ws.rs.ext.Provider
+import java.io.{BufferedInputStream, FileInputStream, OutputStream}
 import javax.ws.rs.{GET, Produces}
-import javax.ws.rs.core.{StreamingOutput, MultivaluedMap, MediaType}
+import javax.ws.rs.core.{Response, StreamingOutput, MediaType}
 
 import org.apache.spark.deploy.history.HistoryServer
 import org.apache.spark.util.Utils
 
-
+@Produces(Array(MediaType.APPLICATION_OCTET_STREAM))
 private[v1] class EventLogDownloadResource(val uIRoot: UIRoot, val appId: String) {
 
-  private def getErrorOutput(err: String): StreamingOutput = {
-    new StreamingOutput {
-      override def write(outputStream: OutputStream): Unit = {
-        outputStream.write(
-          s"File download not available for application : $appId due to $err".getBytes("utf-8"))
-      }
-    }
-  }
-
   @GET
-  @Produces(Array(MediaType.APPLICATION_OCTET_STREAM))
-  def getEventLogs(): StreamingOutput = {
+  def getEventLogs(): Response = {
     uIRoot match {
       case hs: HistoryServer =>
         val dir = Utils.createTempDir()
         Utils.chmod700(dir)
         hs.copyEventLogsToDirectory(appId, dir)
         dir.listFiles().headOption.foreach { file =>
-          return new StreamingOutput {
+          val stream  = new StreamingOutput {
             override def write(output: OutputStream): Unit = {
-              val inStream = new BufferedInputStream(new FileInputStream(file))
-              val buffer = new Array[Byte](1024 * 1024)
-              var dataRemains = true
-              while (dataRemains) {
-                val read = inStream.read(buffer)
-                if (read > 0) {
-                  output.write(buffer, 0, read)
-                } else {
-                  dataRemains = false
+              try {
+                val inStream = new BufferedInputStream(new FileInputStream(file))
+                val buffer = new Array[Byte](1024 * 1024)
+                var dataRemains = true
+                while (dataRemains) {
+                  val read = inStream.read(buffer)
+                  if (read > 0) {
+                    output.write(buffer, 0, read)
+                  } else {
+                    dataRemains = false
+                  }
                 }
+                output.flush()
+              } finally {
+                Utils.deleteRecursively(dir)
               }
-              output.flush()
             }
           }
+          return Response.ok(stream)
+            .header("Content-Length", file.length().toString)
+            .header("Content-Disposition", s"attachment; filename=${file.getName}")
+            .header("Content-Type", MediaType.APPLICATION_OCTET_STREAM)
+            .build()
         }
-        getErrorOutput("No files in dir.")
-      case _ => getErrorOutput("hs not history server")
+        Response.serverError()
+          .entity(s"Event logs for $appId not found.")
+          .status(Response.Status.NOT_FOUND)
+          .build()
+      case _ =>
+        Response.serverError()
+          .entity("History Server is not running - cannot return event logs.")
+          .status(Response.Status.SERVICE_UNAVAILABLE)
+          .build()
     }
   }
 }