YARN-10720. YARN WebAppProxyServlet should support connection timeout to prevent proxy server from hanging. Contributed by Qi Zhu. (#4103)

(cherry picked from commit a0deda1a777d8967fb8c08ac976543cda895773d)

 Conflicts:
	hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
	hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
	hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/WebAppProxyServlet.java
	hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/test/java/org/apache/hadoop/yarn/server/webproxy/TestWebAppProxyServlet.java

(cherry picked from commit dbeb41b46a2cef9a48983add9c3b191915bd6de5)

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

Co-authored-by: Peter Bacsko <pbacsko@cloudera.com>

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

@@ -1882,6 +1882,19 @@ public class YarnConfiguration extends Configuration {
   public static final long DEFAULT_RM_APPLICATION_MONITOR_INTERVAL_MS =
       3000;
 
+  // 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

@@ -2024,6 +2024,18 @@
      <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

@@ -64,15 +64,15 @@ import org.apache.hadoop.yarn.webapp.util.WebAppUtils;
 import org.apache.http.Header;
 import org.apache.http.HttpResponse;
 import org.apache.http.NameValuePair;
+import org.apache.http.client.HttpClient;
+import org.apache.http.client.config.RequestConfig;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.client.methods.HttpPut;
 import org.apache.http.client.methods.HttpRequestBase;
-import org.apache.http.client.params.ClientPNames;
-import org.apache.http.client.params.CookiePolicy;
 import org.apache.http.client.utils.URLEncodedUtils;
-import org.apache.http.conn.params.ConnRoutePNames;
 import org.apache.http.entity.StringEntity;
-import org.apache.http.impl.client.DefaultHttpClient;
+import org.apache.http.impl.client.HttpClientBuilder;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -123,6 +123,9 @@ public class WebAppProxyServlet extends HttpServlet {
     }
   }
 
+  protected void setConf(YarnConfiguration conf){
+    this.conf = conf;
+  }
   /**
    * Default constructor
    */
@@ -189,15 +192,18 @@ public class WebAppProxyServlet extends HttpServlet {
    * @param method the http method
    * @throws IOException on any error.
    */
-  private static void proxyLink(final HttpServletRequest req,
+  private void proxyLink(final HttpServletRequest req,
       final HttpServletResponse resp, final URI link, final Cookie c,
       final String proxyHost, final HTTP method) throws IOException {
-    DefaultHttpClient client = new DefaultHttpClient();
-    client
-        .getParams()
-        .setParameter(ClientPNames.COOKIE_POLICY,
-            CookiePolicy.BROWSER_COMPATIBILITY)
-        .setBooleanParameter(ClientPNames.ALLOW_CIRCULAR_REDIRECTS, true);
+    HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();
+
+    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);
+
     // Make sure we send the request from the proxy address in the config
     // since that is what the AM filter checks against. IP aliasing or
     // similar could cause issues otherwise.
@@ -205,8 +211,19 @@ public class WebAppProxyServlet extends HttpServlet {
     if (LOG.isDebugEnabled()) {
       LOG.debug("local InetAddress for proxy host: {}", localAddress);
     }
-    client.getParams()
-        .setParameter(ConnRoutePNames.LOCAL_ADDRESS, localAddress);
+    httpClientBuilder.setDefaultRequestConfig(
+        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)) {
@@ -248,6 +265,7 @@ public class WebAppProxyServlet extends HttpServlet {
           PROXY_USER_COOKIE_NAME + "=" + URLEncoder.encode(user, "ASCII"));
     }
     OutputStream out = resp.getOutputStream();
+    HttpClient client = httpClientBuilder.build();
     try {
       HttpResponse httpResp = client.execute(base);
       resp.setStatus(httpResp.getStatusLine().getStatusCode());
@@ -571,7 +589,6 @@ public class WebAppProxyServlet extends HttpServlet {
    * 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

@@ -22,6 +22,8 @@ import static org.junit.Assert.assertEquals;
 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;
@@ -32,10 +34,14 @@ import java.net.HttpCookie;
 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;
@@ -90,6 +96,7 @@ public class TestWebAppProxyServlet {
     context.setContextPath("/foo");
     server.setHandler(context);
     context.addServlet(new ServletHolder(TestServlet.class), "/bar");
+    context.addServlet(new ServletHolder(TimeOutTestServlet.class), "/timeout");
     server.getConnectors()[0].setHost("localhost");
     server.start();
     originalPort = server.getConnectors()[0].getLocalPort();
@@ -137,6 +144,29 @@ public class TestWebAppProxyServlet {
     }
   }
 
+  @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");
@@ -248,6 +278,45 @@ public class TestWebAppProxyServlet {
     }
   }
 
+  @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");
@@ -330,12 +399,13 @@ public class TestWebAppProxyServlet {
       assertEquals(proxyConn.getRequestProperties().size(), 4);
       proxyConn.connect();
       assertEquals(HttpURLConnection.HTTP_OK, proxyConn.getResponseCode());
-      // Verify if number of headers received by end server is 8.
-      // Eight headers include Accept, Host, Connection, User-Agent, Cookie,
-      // Origin, Access-Control-Request-Method and
+      // Verify if number of headers received by end server is 9.
+      // This should match WebAppProxyServlet#PASS_THROUGH_HEADERS.
+      // Nine headers include Accept, Host, Connection, User-Agent, Cookie,
+      // Origin, Access-Control-Request-Method, Accept-Encoding, and
       // Access-Control-Request-Headers. Pls note that Unknown-Header is dropped
       // by proxy as it is not in the list of allowed headers.
-      assertEquals(numberOfHeaders, 8);
+      assertEquals(numberOfHeaders, 9);
       assertFalse(hasUnknownHeader);
     } finally {
       proxy.close();
@@ -553,6 +623,12 @@ public class TestWebAppProxyServlet {
         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;
     }