YARN-10361. Make custom DAO classes configurable into RMWebApp#JAXBContextResolver.

Contributed by Bilwa ST.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java

@@ -2398,7 +2398,13 @@ public static boolean isAclEnabled(Configuration conf) {
       "yarn.http.rmwebapp.external.classes";
 
   public static final String YARN_HTTP_WEBAPP_SCHEDULER_PAGE =
-      "hadoop.http.rmwebapp.scheduler.page.class";
+      "yarn.http.rmwebapp.scheduler.page.class";
+
+  public static final String YARN_HTTP_WEBAPP_CUSTOM_DAO_CLASSES =
+      "yarn.http.rmwebapp.custom.dao.classes";
+
+  public static final String YARN_HTTP_WEBAPP_CUSTOM_UNWRAPPED_DAO_CLASSES =
+      "yarn.http.rmwebapp.custom.unwrapped.dao.classes";
 
   /**
    * Whether or not users are allowed to request that Docker containers honor

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml

@@ -3355,10 +3355,26 @@
     <description>
     Used to specify custom scheduler page
     </description>
-    <name>hadoop.http.rmwebapp.scheduler.page.class</name>
+    <name>yarn.http.rmwebapp.scheduler.page.class</name>
     <value></value>
   </property>
 
+  <property>
+    <description>
+    Used to specify custom DAO classes used by custom web services.
+    </description>
+    <name>yarn.http.rmwebapp.custom.dao.classes</name>
+    <value></value>
+  </property>
+
+  <property>
+    <description>
+    Used to specify custom DAO classes used by custom web services which requires
+    root unwrapping.
+    </description>
+    <name>yarn.http.rmwebapp.custom.unwrapped.dao.classes</name>
+    <value></value>
+  </property>
 
   <property>
     <description>The Node Label script to run. Script output Line starting with

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/JAXBContextResolver.java

@@ -18,6 +18,7 @@
 
 package org.apache.hadoop.yarn.server.resourcemanager.webapp;
 
+import com.google.inject.Inject;
 import com.google.inject.Singleton;
 import com.sun.jersey.api.json.JSONConfiguration;
 import com.sun.jersey.api.json.JSONJAXBContext;
@@ -28,6 +29,10 @@
 import javax.ws.rs.ext.Provider;
 import javax.xml.bind.JAXBContext;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.UserInfo;
 import org.apache.hadoop.yarn.server.resourcemanager.webapp.dao.*;
 import org.apache.hadoop.yarn.webapp.RemoteExceptionData;
@@ -36,9 +41,17 @@
 @Provider
 public class JAXBContextResolver implements ContextResolver<JAXBContext> {
 
+  private static final Log LOG =
+      LogFactory.getLog(JAXBContextResolver.class.getName());
+
   private final Map<Class, JAXBContext> typesContextMap;
 
   public JAXBContextResolver() throws Exception {
+    this(new Configuration());
+  }
+
+  @Inject
+  public JAXBContextResolver(Configuration conf) throws Exception {
 
     JAXBContext context;
     JAXBContext unWrappedRootContext;
@@ -66,17 +79,54 @@ public JAXBContextResolver() throws Exception {
             DelegationToken.class, AppQueue.class, AppPriority.class,
             ResourceOptionInfo.class };
 
+    ArrayList<Class> finalcTypesList = new ArrayList<>();
+    ArrayList<Class> finalRootUnwrappedTypesList = new ArrayList<>();
+
+    Collections.addAll(finalcTypesList, cTypes);
+    Collections.addAll(finalRootUnwrappedTypesList, rootUnwrappedTypes);
+
+    // Add Custom DAO Classes
+    Class[] daoClasses = null;
+    Class[] unwrappedDaoClasses = null;
+    boolean loadCustom = true;
+    try {
+      daoClasses = conf
+          .getClasses(YarnConfiguration.YARN_HTTP_WEBAPP_CUSTOM_DAO_CLASSES);
+      unwrappedDaoClasses = conf.getClasses(
+          YarnConfiguration.YARN_HTTP_WEBAPP_CUSTOM_UNWRAPPED_DAO_CLASSES);
+    } catch (Exception e) {
+      LOG.warn("Failed to load custom dao class: " + e);
+      loadCustom = false;
+    }
+
+    if (loadCustom) {
+      if (daoClasses != null) {
+        Collections.addAll(finalcTypesList, daoClasses);
+        LOG.debug("Added custom dao classes: " + Arrays.toString(daoClasses));
+      }
+      if (unwrappedDaoClasses != null) {
+        Collections.addAll(finalRootUnwrappedTypesList, unwrappedDaoClasses);
+        LOG.debug("Added custom Unwrapped dao classes: "
+            + Arrays.toString(unwrappedDaoClasses));
+      }
+    }
+
+    final Class[] finalcTypes = finalcTypesList
+        .toArray(new Class[finalcTypesList.size()]);
+    final Class[] finalRootUnwrappedTypes = finalRootUnwrappedTypesList
+        .toArray(new Class[finalRootUnwrappedTypesList.size()]);
+
     this.typesContextMap = new HashMap<Class, JAXBContext>();
     context =
         new JSONJAXBContext(JSONConfiguration.natural().rootUnwrapping(false)
-          .build(), cTypes);
+          .build(), finalcTypes);
     unWrappedRootContext =
         new JSONJAXBContext(JSONConfiguration.natural().rootUnwrapping(true)
-          .build(), rootUnwrappedTypes);
+          .build(), finalRootUnwrappedTypes);
-    for (Class type : cTypes) {
+    for (Class type : finalcTypes) {
       typesContextMap.put(type, context);
     }
-    for (Class type : rootUnwrappedTypes) {
+    for (Class type : finalRootUnwrappedTypes) {
       typesContextMap.put(type, unWrappedRootContext);
     }
   }