[SPARK-6846] [WEBUI] [HOTFIX] return to GET for kill link in UI since YARN AM won't proxy POST

Partial undoing of SPARK-6846; YARN AM proxy won't forward POSTs, so go back to GET for kill links in Spark UI. Standalone UIs are not affected.

Author: Sean Owen <sowen@cloudera.com>

Closes #5837 from srowen/SPARK-6846.2 and squashes the following commits:

c17c386 [Sean Owen] Partial undoing of SPARK-6846; YARN AM proxy won't forward POSTs, so go back to GET for kill links in Spark UI. Standalone UIs are not affected.

5 files changed, 23 insertions, 13 deletions

diff --git a/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala b/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala
index aad9c87bdb..dea0a65eee 100644
--- a/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala
+++ b/core/src/main/scala/org/apache/spark/deploy/master/ui/MasterWebUI.scala
@@ -44,9 +44,9 @@ class MasterWebUI(val master: Master, requestedPort: Int)
     attachPage(masterPage)
     attachHandler(createStaticHandler(MasterWebUI.STATIC_RESOURCE_DIR, "/static"))
     attachHandler(createRedirectHandler(
-      "/app/kill", "/", masterPage.handleAppKillRequest, httpMethod = "POST"))
+      "/app/kill", "/", masterPage.handleAppKillRequest, httpMethods = Set("POST")))
     attachHandler(createRedirectHandler(
-      "/driver/kill", "/", masterPage.handleDriverKillRequest, httpMethod = "POST"))
+      "/driver/kill", "/", masterPage.handleDriverKillRequest, httpMethods = Set("POST")))
   }
 
   /** Attach a reconstructed UI to this Master UI. Only valid after bind(). */
diff --git a/core/src/main/scala/org/apache/spark/ui/JettyUtils.scala b/core/src/main/scala/org/apache/spark/ui/JettyUtils.scala
index a091ca650c..dfd6fdb5e9 100644
--- a/core/src/main/scala/org/apache/spark/ui/JettyUtils.scala
+++ b/core/src/main/scala/org/apache/spark/ui/JettyUtils.scala
@@ -115,19 +115,21 @@ private[spark] object JettyUtils extends Logging {
       destPath: String,
       beforeRedirect: HttpServletRequest => Unit = x => (),
       basePath: String = "",
-      httpMethod: String = "GET"): ServletContextHandler = {
+      httpMethods: Set[String] = Set("GET")): ServletContextHandler = {
     val prefixedDestPath = attachPrefix(basePath, destPath)
     val servlet = new HttpServlet {
       override def doGet(request: HttpServletRequest, response: HttpServletResponse): Unit = {
-        httpMethod match {
-          case "GET" => doRequest(request, response)
-          case _ => response.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED)
+        if (httpMethods.contains("GET")) {
+          doRequest(request, response)
+        } else {
+          response.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED)
         }
       }
       override def doPost(request: HttpServletRequest, response: HttpServletResponse): Unit = {
-        httpMethod match {
-          case "POST" => doRequest(request, response)
-          case _ => response.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED)
+        if (httpMethods.contains("POST")) {
+          doRequest(request, response)
+        } else {
+          response.sendError(HttpServletResponse.SC_METHOD_NOT_ALLOWED)
         }
       }
       private def doRequest(request: HttpServletRequest, response: HttpServletResponse): Unit = {
diff --git a/core/src/main/scala/org/apache/spark/ui/SparkUI.scala b/core/src/main/scala/org/apache/spark/ui/SparkUI.scala
index 580ab8b132..06fce86bd3 100644
--- a/core/src/main/scala/org/apache/spark/ui/SparkUI.scala
+++ b/core/src/main/scala/org/apache/spark/ui/SparkUI.scala
@@ -55,8 +55,10 @@ private[spark] class SparkUI private (
     attachTab(new ExecutorsTab(this))
     attachHandler(createStaticHandler(SparkUI.STATIC_RESOURCE_DIR, "/static"))
     attachHandler(createRedirectHandler("/", "/jobs", basePath = basePath))
+    // This should be POST only, but, the YARN AM proxy won't proxy POSTs
     attachHandler(createRedirectHandler(
-      "/stages/stage/kill", "/stages", stagesTab.handleKillRequest, httpMethod = "POST"))
+      "/stages/stage/kill", "/stages", stagesTab.handleKillRequest,
+      httpMethods = Set("GET", "POST")))
   }
   initialize()
 
diff --git a/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala b/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
index 6d8c7e1fda..a33243d425 100644
--- a/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
+++ b/core/src/main/scala/org/apache/spark/ui/jobs/StageTable.scala
@@ -76,15 +76,20 @@ private[ui] class StageTableBase(
     val basePathUri = UIUtils.prependBaseUri(basePath)
 
     val killLink = if (killEnabled) {
-      val killLinkUri = s"$basePathUri/stages/stage/kill/"
       val confirm =
         s"if (window.confirm('Are you sure you want to kill stage ${s.stageId} ?')) " +
         "{ this.parentNode.submit(); return true; } else { return false; }"
+      // SPARK-6846 this should be POST-only but YARN AM won't proxy POST
+      /*
+      val killLinkUri = s"$basePathUri/stages/stage/kill/"
       <form action={killLinkUri} method="POST" style="display:inline">
         <input type="hidden" name="id" value={s.stageId.toString}/>
         <input type="hidden" name="terminate" value="true"/>
         <a href="#" onclick={confirm} class="kill-link">(kill)</a>
       </form>
+       */
+      val killLinkUri = s"$basePathUri/stages/stage/kill/?id=${s.stageId}&terminate=true"
+      <a href={killLinkUri} onclick={confirm} class="kill-link">(kill)</a>
     }
 
     val nameLinkUri = s"$basePathUri/stages/stage?id=${s.stageId}&attempt=${s.attemptId}"
diff --git a/core/src/test/scala/org/apache/spark/ui/UISeleniumSuite.scala b/core/src/test/scala/org/apache/spark/ui/UISeleniumSuite.scala
index eb9db550fd..d53d7f3ba5 100644
--- a/core/src/test/scala/org/apache/spark/ui/UISeleniumSuite.scala
+++ b/core/src/test/scala/org/apache/spark/ui/UISeleniumSuite.scala
@@ -350,7 +350,7 @@ class UISeleniumSuite extends FunSuite with WebBrowser with Matchers with Before
     }
   }
 
-  test("kill stage is POST only") {
+  test("kill stage POST/GET response is correct") {
     def getResponseCode(url: URL, method: String): Int = {
       val connection = url.openConnection().asInstanceOf[HttpURLConnection]
       connection.setRequestMethod(method)
@@ -365,7 +365,8 @@ class UISeleniumSuite extends FunSuite with WebBrowser with Matchers with Before
       eventually(timeout(5 seconds), interval(50 milliseconds)) {
         val url = new URL(
           sc.ui.get.appUIAddress.stripSuffix("/") + "/stages/stage/kill/?id=0&terminate=true")
-        getResponseCode(url, "GET") should be (405)
+        // SPARK-6846: should be POST only but YARN AM doesn't proxy POST
+        getResponseCode(url, "GET") should be (200)
         getResponseCode(url, "POST") should be (200)
       }
     }