YARN-1658. Modified web-app framework to let standby RMs redirect web-service calls to the active RM. Contributed by Cindy Li.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1577408 13f79535-47bb-0310-9956-ffa450edef68

hadoop-yarn-project/CHANGES.txt

@@ -291,6 +291,9 @@ Release 2.4.0 - UNRELEASED
     YARN-1771. Reduce the number of NameNode operations during localization of
     public resources using a cache. (Sangjin Lee via cdouglas)
 
+    YARN-1658. Modified web-app framework to let standby RMs redirect
+    web-service calls to the active RM. (Cindy Li via vinodkv)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-client/src/test/java/org/apache/hadoop/yarn/client/TestRMFailover.java

@@ -271,6 +271,12 @@ public class TestRMFailover extends ClientBaseWithFixes {
     header = getHeader("Refresh", rm2Url + "/cluster/cluster");
     assertEquals(null, header);
 
+    header = getHeader("Refresh", rm2Url + "/ws/v1/cluster/info");
+    assertEquals(null, header);
+
+    header = getHeader("Refresh", rm2Url + "/ws/v1/cluster/apps");
+    assertTrue(header.contains("; url=" + rm1Url));
+
     // Due to the limitation of MiniYARNCluster and dispatcher is a singleton,
     // we couldn't add the test case after explicitFailover();
   }
@@ -286,4 +292,5 @@ public class TestRMFailover extends ClientBaseWithFixes {
     }
     return fieldHeader;
   }
+
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/Dispatcher.java

@@ -57,11 +57,11 @@ public class Dispatcher extends HttpServlet {
 
   private transient final Injector injector;
   private transient final Router router;
-  protected transient final WebApp webApp;
+  private transient final WebApp webApp;
   private volatile boolean devMode = false;
 
   @Inject
-  protected Dispatcher(WebApp webApp, Injector injector, Router router) {
+  Dispatcher(WebApp webApp, Injector injector, Router router) {
     this.webApp = webApp;
     this.injector = injector;
     this.router = router;

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/Router.java

@@ -44,7 +44,7 @@ import com.google.common.collect.Maps;
  * Manages path info to controller#action routing.
  */
 @InterfaceAudience.LimitedPrivate({"YARN", "MapReduce"})
-public class Router {
+class Router {
   static final Logger LOG = LoggerFactory.getLogger(Router.class);
   static final ImmutableList<String> EMPTY_LIST = ImmutableList.of();
   static final CharMatcher SLASH = CharMatcher.is('/');

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/webapp/WebApp.java

@@ -122,6 +122,10 @@ public abstract class WebApp extends ServletModule {
 
   public String name() { return this.name; }
 
+  public String wsName() {
+    return this.wsName;
+  }
+
   void addServePathSpec(String path) { this.servePathSpecs.add(path); }
 
   public String[] getServePathSpecs() {
@@ -134,7 +138,7 @@ public abstract class WebApp extends ServletModule {
    * more easily differentiate the different webapps.
    * @param path  the path to redirect to
    */
-  protected void setRedirectPath(String path) {
+  void setRedirectPath(String path) {
     this.redirectPath = path;
   }
 
@@ -160,10 +164,10 @@ public abstract class WebApp extends ServletModule {
       serve(path).with(Dispatcher.class);
     }
 
-    configureRSServlets();
+    configureWebAppServlets();
   }
 
-  protected void configureRSServlets() {
+  protected void configureWebAppServlets() {
     // Add in the web services filters/serves if app has them.
     // Using Jersey/guice integration module. If user has web services
     // they must have also bound a default one in their webapp code.
@@ -182,9 +186,12 @@ public abstract class WebApp extends ServletModule {
       params.put(FeaturesAndProperties.FEATURE_XMLROOTELEMENT_PROCESSING, "true");
       params.put(ResourceConfig.PROPERTY_CONTAINER_REQUEST_FILTERS, GZIPContentEncodingFilter.class.getName());
       params.put(ResourceConfig.PROPERTY_CONTAINER_RESPONSE_FILTERS, GZIPContentEncodingFilter.class.getName());
-      filter("/*").through(GuiceContainer.class, params);
+      filter("/*").through(getWebAppFilterClass(), params);
     }
+  }
 
+  protected Class<? extends GuiceContainer> getWebAppFilterClass() {
+    return GuiceContainer.class;
   }
 
   /**
@@ -274,4 +281,5 @@ public abstract class WebApp extends ServletModule {
   }
 
   public abstract void setup();
+
 }

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

@@ -29,11 +29,12 @@ import org.apache.hadoop.yarn.server.resourcemanager.RMHAUtils;
 import org.apache.hadoop.yarn.server.resourcemanager.ResourceManager;
 import org.apache.hadoop.yarn.server.resourcemanager.security.QueueACLsManager;
 import org.apache.hadoop.yarn.server.security.ApplicationACLsManager;
-import org.apache.hadoop.yarn.webapp.Dispatcher;
 import org.apache.hadoop.yarn.webapp.GenericExceptionHandler;
 import org.apache.hadoop.yarn.webapp.WebApp;
 import org.apache.hadoop.yarn.webapp.YarnWebParams;
 
+import com.sun.jersey.guice.spi.container.servlet.GuiceContainer;
+
 /**
  * The RM webapp
  */
@@ -51,6 +52,8 @@ public class RMWebApp extends WebApp implements YarnWebParams {
     bind(JAXBContextResolver.class);
     bind(RMWebServices.class);
     bind(GenericExceptionHandler.class);
+    bind(RMWebApp.class).toInstance(this);
+
     if (rm != null) {
       bind(ResourceManager.class).toInstance(rm);
       bind(RMContext.class).toInstance(rm.getRMContext());
@@ -68,17 +71,8 @@ public class RMWebApp extends WebApp implements YarnWebParams {
   }
 
   @Override
-  public void configureServlets() {
-    setup();
-
-    serve("/").with(RMDispatcher.class);
-    serve("/__stop").with(Dispatcher.class);
-
-    for (String path : super.getServePathSpecs()) {
-      serve(path).with(RMDispatcher.class);
-    }
-
-    configureRSServlets();
+  protected Class<? extends GuiceContainer> getWebAppFilterClass() {
+    return RMWebAppFilter.class;
   }
 
   public void checkIfStandbyRM() {

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

@@ -21,59 +21,63 @@ package org.apache.hadoop.yarn.server.resourcemanager.webapp;
 import java.io.IOException;
 import java.io.PrintWriter;
 
+import javax.inject.Inject;
+import javax.inject.Singleton;
+import javax.servlet.FilterChain;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
-import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.http.HtmlQuoting;
-import org.apache.hadoop.yarn.webapp.Dispatcher;
-import org.apache.hadoop.yarn.webapp.Router;
-import org.apache.hadoop.yarn.webapp.WebApp;
 
-import com.google.inject.Inject;
 import com.google.inject.Injector;
-import com.google.inject.Singleton;
+import com.sun.jersey.guice.spi.container.servlet.GuiceContainer;
 
-@InterfaceAudience.LimitedPrivate({ "YARN", "MapReduce" })
 @Singleton
-public class RMDispatcher extends Dispatcher {
+public class RMWebAppFilter extends GuiceContainer {
 
+  private Injector injector;
   /**
-   *
+   * 
    */
   private static final long serialVersionUID = 1L;
 
   @Inject
-  RMDispatcher(WebApp webApp, Injector injector, Router router) {
-    super(webApp, injector, router);
+  public RMWebAppFilter(Injector injector) {
+    super(injector);
+    this.injector=injector;
   }
 
   @Override
-  public void service(HttpServletRequest req, HttpServletResponse res)
-      throws ServletException, IOException {
-    res.setCharacterEncoding("UTF-8");
-    String uri = HtmlQuoting.quoteHtmlChars(req.getRequestURI());
+  public void doFilter(HttpServletRequest request,
+      HttpServletResponse response, FilterChain chain) throws IOException,
+      ServletException {
+    response.setCharacterEncoding("UTF-8");
+    String uri = HtmlQuoting.quoteHtmlChars(request.getRequestURI());
 
     if (uri == null) {
       uri = "/";
     }
-
-    RMWebApp rmWebApp = (RMWebApp) webApp;
+    RMWebApp rmWebApp = injector.getInstance(RMWebApp.class);
     rmWebApp.checkIfStandbyRM();
     if (rmWebApp.isStandby()
+        && !uri.equals("/" + rmWebApp.wsName() + "/v1/cluster/info")
         && !uri.equals("/" + rmWebApp.name() + "/cluster")) {
       String redirectPath = rmWebApp.getRedirectPath() + uri;
+
       if (redirectPath != null && !redirectPath.isEmpty()) {
         String redirectMsg =
             "This is standby RM. Redirecting to the current active RM: "
                 + redirectPath;
-        res.addHeader("Refresh", "3; url=" + redirectPath);
-        PrintWriter out = res.getWriter();
+        response.addHeader("Refresh", "3; url=" + redirectPath);
+        PrintWriter out = response.getWriter();
         out.println(redirectMsg);
         return;
       }
     }
-    super.service(req, res);
+
+    super.doFilter(request, response, chain);
+
   }
+
 }