[SPARK-24506][UI] Add UI filters to tabs added after binding

Currently, `spark.ui.filters` are not applied to the handlers added after binding the server. This means that every page which is added after starting the UI will not have the filters configured on it. This can allow unauthorized access to the pages.

The PR adds the filters also to the handlers added after the UI starts.

manual tests (without the patch, starting the thriftserver with `--conf spark.ui.filters=org.apache.hadoop.security.authentication.server.AuthenticationFilter --conf spark.org.apache.hadoop.security.authentication.server.AuthenticationFilter.params="type=simple"` you can access `http://localhost:4040/sqlserver`; with the patch, 401 is the response as for the other pages).

Author: Marco Gaido <marcogaido91@gmail.com>

Closes #21523 from mgaido91/SPARK-24506.

(cherry picked from commit f53818d)
Signed-off-by: Marcelo Vanzin <vanzin@cloudera.com>

Author: mgaido91

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

@@ -151,7 +151,6 @@ class HistoryServer(
       completed: Boolean) {
     assert(serverInfo.isDefined, "HistoryServer must be bound before attaching SparkUIs")
     ui.getHandlers.foreach(attachHandler)
-    addFilters(ui.getHandlers, conf)
   }
 
   /** Detach a reconstructed UI from this server. Only valid after bind(). */

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

@@ -250,7 +250,7 @@ private[spark] object JettyUtils extends Logging {
     filters.foreach {
       case filter : String =>
         if (!filter.isEmpty) {
-          logInfo("Adding filter: " + filter)
+          logInfo(s"Adding filter $filter to ${handlers.map(_.getContextPath).mkString(", ")}.")
           val holder : FilterHolder = new FilterHolder()
           holder.setClassName(filter)
           // Get any parameters for each filter
@@ -393,7 +393,7 @@ private[spark] object JettyUtils extends Logging {
       }
 
       pool.setMaxThreads(math.max(pool.getMaxThreads, minThreads))
-      ServerInfo(server, httpPort, securePort, collection)
+      ServerInfo(server, httpPort, securePort, conf, collection)
     } catch {
       case e: Exception =>
         server.stop()
@@ -492,10 +492,12 @@ private[spark] case class ServerInfo(
     server: Server,
     boundPort: Int,
     securePort: Option[Int],
+    conf: SparkConf,
     private val rootHandler: ContextHandlerCollection) {
 
-  def addHandler(handler: ContextHandler): Unit = {
+  def addHandler(handler: ServletContextHandler): Unit = {
     handler.setVirtualHosts(JettyUtils.toVirtualHosts(JettyUtils.SPARK_CONNECTOR_NAME))
+    JettyUtils.addFilters(Seq(handler), conf)
     rootHandler.addHandler(handler)
     if (!handler.isStarted()) {
       handler.start()