From 6c2ce3d56b14ce4139cbecc1cfe026e5a838f319 Mon Sep 17 00:00:00 2001
From: Prabhu Joseph <prabhujoseph@apache.org>
Date: Thu, 6 Aug 2020 19:15:16 +0530
Subject: [PATCH] YARN-10389. Option to override RMWebServices with custom
 WebService class

Contributed by Tanu Ajmera. Reviewed by Bilwa ST and Sunil G.
---
 .../hadoop/yarn/conf/YarnConfiguration.java     |  3 +++
 .../src/main/resources/yarn-default.xml         |  9 +++++++++
 .../server/resourcemanager/webapp/RMWebApp.java | 17 ++++++++++-------
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
index 19ce6221b0..6c1be0e34a 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
@@ -2406,6 +2406,9 @@ public static boolean isAclEnabled(Configuration conf) {
   public static final String YARN_HTTP_WEBAPP_CUSTOM_UNWRAPPED_DAO_CLASSES =
       "yarn.http.rmwebapp.custom.unwrapped.dao.classes";
 
+  public static final String YARN_WEBAPP_CUSTOM_WEBSERVICE_CLASS =
+      "yarn.webapp.custom.webservice.class";
+
   /**
    * Whether or not users are allowed to request that Docker containers honor
    * the debug deletion delay. This is useful for troubleshooting Docker
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
index 2208b00d8a..47f123918b 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
@@ -3376,6 +3376,15 @@
     <value></value>
   </property>
 
+  <property>
+    <description>
+    Used to specify custom WebServices class to bind with RMWebApp overriding
+    the default RMWebServices.
+    </description>
+    <name>yarn.webapp.custom.webservice.class</name>
+    <value></value>
+  </property>
+
   <property>
     <description>The Node Label script to run. Script output Line starting with
      "NODE_PARTITION:" will be considered as Node Label Partition. In case of
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/RMWebApp.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/RMWebApp.java
index 5075d25056..3ed53f6dcc 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/RMWebApp.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/RMWebApp.java
@@ -22,6 +22,7 @@
 
 import java.net.InetSocketAddress;
 
+import org.apache.hadoop.conf.Configuration;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.apache.hadoop.ha.HAServiceProtocol.HAServiceState;
@@ -44,6 +45,7 @@ public class RMWebApp extends WebApp implements YarnWebParams {
       LoggerFactory.getLogger(RMWebApp.class.getName());
   private final ResourceManager rm;
   private boolean standby = false;
+  private Configuration conf;
 
   public RMWebApp(ResourceManager rm) {
     this.rm = rm;
@@ -51,15 +53,17 @@ public RMWebApp(ResourceManager rm) {
 
   @Override
   public void setup() {
+    conf = rm.getConfig();
     bind(JAXBContextResolver.class);
-    bind(RMWebServices.class);
+    Class webService = conf.getClass(
+        YarnConfiguration.YARN_WEBAPP_CUSTOM_WEBSERVICE_CLASS,
+        RMWebServices.class);
+    bind(webService);
     bind(GenericExceptionHandler.class);
     bind(RMWebApp.class).toInstance(this);
     bindExternalClasses();
+    bind(ResourceManager.class).toInstance(rm);
 
-    if (rm != null) {
-      bind(ResourceManager.class).toInstance(rm);
-    }
     route("/", RmController.class);
     route(pajoin("/nodes", NODE_STATE), RmController.class, "nodes");
     route(pajoin("/apps", APP_STATE), RmController.class);
@@ -99,8 +103,7 @@ public String getRedirectPath() {
   }
 
   private void bindExternalClasses() {
-    YarnConfiguration yarnConf = new YarnConfiguration(rm.getConfig());
-    Class<?>[] externalClasses = yarnConf
+    Class<?>[] externalClasses = conf
         .getClasses(YarnConfiguration.YARN_HTTP_WEBAPP_EXTERNAL_CLASSES);
     for (Class<?> c : externalClasses) {
       bind(c);
@@ -111,7 +114,7 @@ private void bindExternalClasses() {
   private String buildRedirectPath() {
     // make a copy of the original configuration so not to mutate it. Also use
     // an YarnConfiguration to force loading of yarn-site.xml.
-    YarnConfiguration yarnConf = new YarnConfiguration(rm.getConfig());
+    YarnConfiguration yarnConf = new YarnConfiguration(conf);
     String activeRMHAId = RMHAUtils.findActiveRMHAId(yarnConf);
     String path = "";
     if (activeRMHAId != null) {