YARN-10720. YARN WebAppProxyServlet should support connection timeout…

… to prevent proxy server from hanging. Contributed by Qi Zhu.

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

@@ -2668,6 +2668,20 @@ public static boolean isAclEnabled(Configuration conf) {
 
   public static final String DEFAULT_RM_APPLICATION_HTTPS_POLICY = "NONE";
 
+
+  // If the proxy connection time enabled.
+  public static final String RM_PROXY_TIMEOUT_ENABLED =
+      RM_PREFIX + "proxy.timeout.enabled";
+
+  public static final boolean DEFALUT_RM_PROXY_TIMEOUT_ENABLED =
+      true;
+
+  public static final String RM_PROXY_CONNECTION_TIMEOUT =
+      RM_PREFIX + "proxy.connection.timeout";
+
+  public static final int DEFAULT_RM_PROXY_CONNECTION_TIMEOUT =
+      60000;
+
   /**
    * Interval of time the linux container executor should try cleaning up
    * cgroups entry when cleaning up a container. This is required due to what 

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

@@ -2574,6 +2574,18 @@
     <value/>
   </property>
 
+  <property>
+    <description>Enable the web proxy connection timeout, default is enabled.</description>
+    <name>yarn.resourcemanager.proxy.timeout.enabled</name>
+    <value>true</value>
+  </property>
+
+  <property>
+    <description>The web proxy connection timeout.</description>
+    <name>yarn.resourcemanager.proxy.connection.timeout</name>
+    <value>60000</value>
+  </property>
+
   <!-- Applications' Configuration -->
 
   <property>

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/WebAppProxyServlet.java

@@ -122,6 +122,9 @@ public HTML<WebAppProxyServlet.__> html() {
     }
   }
 
+  protected void setConf(YarnConfiguration conf){
+    this.conf = conf;
+  }
   /**
    * Default constructor
    */
@@ -230,6 +233,14 @@ private void proxyLink(final HttpServletRequest req,
 
     String httpsPolicy = conf.get(YarnConfiguration.RM_APPLICATION_HTTPS_POLICY,
         YarnConfiguration.DEFAULT_RM_APPLICATION_HTTPS_POLICY);
+
+    boolean connectionTimeoutEnabled =
+        conf.getBoolean(YarnConfiguration.RM_PROXY_TIMEOUT_ENABLED,
+        YarnConfiguration.DEFALUT_RM_PROXY_TIMEOUT_ENABLED);
+    int connectionTimeout =
+        conf.getInt(YarnConfiguration.RM_PROXY_CONNECTION_TIMEOUT,
+            YarnConfiguration.DEFAULT_RM_PROXY_CONNECTION_TIMEOUT);
+
     if (httpsPolicy.equals("LENIENT") || httpsPolicy.equals("STRICT")) {
       ProxyCA proxyCA = getProxyCA();
       // ProxyCA could be null when the Proxy is run outside the RM
@@ -250,10 +261,18 @@ private void proxyLink(final HttpServletRequest req,
     InetAddress localAddress = InetAddress.getByName(proxyHost);
     LOG.debug("local InetAddress for proxy host: {}", localAddress);
     httpClientBuilder.setDefaultRequestConfig(
-        RequestConfig.custom()
-        .setCircularRedirectsAllowed(true)
-        .setLocalAddress(localAddress)
-        .build());
+        connectionTimeoutEnabled ?
+            RequestConfig.custom()
+                .setCircularRedirectsAllowed(true)
+                .setLocalAddress(localAddress)
+                .setConnectionRequestTimeout(connectionTimeout)
+                .setSocketTimeout(connectionTimeout)
+                .setConnectTimeout(connectionTimeout)
+                .build() :
+            RequestConfig.custom()
+                .setCircularRedirectsAllowed(true)
+                .setLocalAddress(localAddress)
+                .build());
 
     HttpRequestBase base = null;
     if (method.equals(HTTP.GET)) {
@@ -621,7 +640,6 @@ private FetchedAppReport getFetchedAppReport(ApplicationId id)
    * again... If this method returns true, there was a redirect, and
    * it was handled by redirecting the current request to an error page.
    *
-   * @param path the part of the request path after the app id
    * @param id the app id
    * @param req the request object
    * @param resp the response object

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/test/java/org/apache/hadoop/yarn/server/webproxy/TestWebAppProxyServlet.java

@@ -23,6 +23,8 @@
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
@@ -35,10 +37,14 @@
 import java.net.HttpURLConnection;
 import java.net.URI;
 import java.net.URL;
+import java.net.SocketTimeoutException;
+import java.util.Collections;
 import java.util.Enumeration;
 import java.util.List;
 import java.util.Map;
 
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletContext;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
@@ -98,6 +104,7 @@ public static void start() throws Exception {
     context.setContextPath("/foo");
     server.setHandler(context);
     context.addServlet(new ServletHolder(TestServlet.class), "/bar");
+    context.addServlet(new ServletHolder(TimeOutTestServlet.class), "/timeout");
     ((ServerConnector)server.getConnectors()[0]).setHost("localhost");
     server.start();
     originalPort = ((ServerConnector)server.getConnectors()[0]).getLocalPort();
@@ -145,6 +152,29 @@ protected void doPost(HttpServletRequest req, HttpServletResponse resp)
     }
   }
 
+  @SuppressWarnings("serial")
+  public static class TimeOutTestServlet extends HttpServlet {
+
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
+        throws ServletException, IOException {
+      try {
+        Thread.sleep(10 * 1000);
+      } catch (InterruptedException e) {
+        LOG.warn("doGet() interrupted", e);
+        resp.setStatus(HttpServletResponse.SC_BAD_REQUEST);
+        return;
+      }
+      resp.setStatus(HttpServletResponse.SC_OK);
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
+        throws ServletException, IOException {
+      resp.setStatus(HttpServletResponse.SC_OK);
+    }
+  }
+
   @Test(timeout=5000)
   public void testWebAppProxyServlet() throws Exception {
     configuration.set(YarnConfiguration.PROXY_ADDRESS, "localhost:9090");
@@ -256,6 +286,45 @@ public void testWebAppProxyServlet() throws Exception {
     }
   }
 
+  @Test(expected = SocketTimeoutException.class)
+  public void testWebAppProxyConnectionTimeout()
+      throws IOException, ServletException{
+    HttpServletRequest request = mock(HttpServletRequest.class);
+    when(request.getMethod()).thenReturn("GET");
+    when(request.getRemoteUser()).thenReturn("dr.who");
+    when(request.getPathInfo()).thenReturn("/application_00_0");
+    when(request.getHeaderNames()).thenReturn(Collections.emptyEnumeration());
+
+    HttpServletResponse response = mock(HttpServletResponse.class);
+    when(response.getOutputStream()).thenReturn(null);
+
+    WebAppProxyServlet servlet = new WebAppProxyServlet();
+    YarnConfiguration conf = new YarnConfiguration();
+    conf.setBoolean(YarnConfiguration.RM_PROXY_TIMEOUT_ENABLED,
+        true);
+    conf.setInt(YarnConfiguration.RM_PROXY_CONNECTION_TIMEOUT,
+        1000);
+
+    servlet.setConf(conf);
+
+    ServletConfig config = mock(ServletConfig.class);
+    ServletContext context = mock(ServletContext.class);
+    when(config.getServletContext()).thenReturn(context);
+
+    AppReportFetcherForTest appReportFetcher =
+        new AppReportFetcherForTest(new YarnConfiguration());
+
+    when(config.getServletContext()
+        .getAttribute(WebAppProxy.FETCHER_ATTRIBUTE))
+        .thenReturn(appReportFetcher);
+
+    appReportFetcher.answer = 7;
+
+    servlet.init(config);
+    servlet.doGet(request, response);
+
+  }
+
   @Test(timeout=5000)
   public void testAppReportForEmptyTrackingUrl() throws Exception {
     configuration.set(YarnConfiguration.PROXY_ADDRESS, "localhost:9090");
@@ -391,9 +460,9 @@ public void testWebAppProxyServerMainMethod() throws Exception {
 
   @Test(timeout=5000)
   public void testCheckHttpsStrictAndNotProvided() throws Exception {
-    HttpServletResponse resp = Mockito.mock(HttpServletResponse.class);
+    HttpServletResponse resp = mock(HttpServletResponse.class);
     StringWriter sw = new StringWriter();
-    Mockito.when(resp.getWriter()).thenReturn(new PrintWriter(sw));
+    when(resp.getWriter()).thenReturn(new PrintWriter(sw));
     YarnConfiguration conf = new YarnConfiguration();
     final URI httpLink = new URI("http://foo.com");
     final URI httpsLink = new URI("https://foo.com");
@@ -566,6 +635,12 @@ public FetchedAppReport getApplicationReport(ApplicationId appId)
         return result;
       } else if (answer == 6) {
         return getDefaultApplicationReport(appId, false);
+      } else if (answer == 7) {
+        // test connection timeout
+        FetchedAppReport result = getDefaultApplicationReport(appId);
+        result.getApplicationReport().setOriginalTrackingUrl("localhost:"
+            + originalPort + "/foo/timeout?a=b#main");
+        return result;
       }
       return null;
     }