tomscut commented on a change in pull request #2896: URL: https://github.com/apache/hadoop/pull/2896#discussion_r612106334
########## File path: hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NetworkTopologyServlet.java ########## @@ -0,0 +1,115 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.hadoop.hdfs.server.namenode; + +import org.apache.hadoop.classification.InterfaceAudience; +import org.apache.hadoop.hdfs.server.blockmanagement.BlockManager; +import org.apache.hadoop.net.NetUtils; +import org.apache.hadoop.net.Node; +import org.apache.hadoop.net.NodeBase; +import org.apache.hadoop.util.StringUtils; + +import javax.servlet.ServletContext; +import javax.servlet.http.HttpServletRequest; +import javax.servlet.http.HttpServletResponse; +import java.io.IOException; +import java.io.PrintStream; +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.List; +import java.util.TreeSet; + +/** + * A servlet to print out the network topology. + */ [email protected] +public class NetworkTopologyServlet extends DfsServlet { + + public static final String PATH_SPEC = "/topology"; + + @Override + public void doGet(HttpServletRequest request, HttpServletResponse response) + throws IOException { + final ServletContext context = getServletContext(); + NameNode nn = NameNodeHttpServer.getNameNodeFromContext(context); + BlockManager bm = nn.getNamesystem().getBlockManager(); + List<Node> leaves = bm.getDatanodeManager().getNetworkTopology() + .getLeaves(NodeBase.ROOT); + + response.setContentType("text/plain; charset=UTF-8"); + try (PrintStream out = new PrintStream( + response.getOutputStream(), false, "UTF-8")) { + printTopology(out, leaves); + } catch (Throwable t) { + String errMsg = "Print network topology failed. " + + StringUtils.stringifyException(t); + response.sendError(HttpServletResponse.SC_GONE, errMsg); + throw new IOException(errMsg); + } finally { + response.getOutputStream().close(); + } + } + + /** + * Display each rack and the nodes assigned to that rack, as determined + * by the NameNode, in a hierarchical manner. The nodes and racks are + * sorted alphabetically. + * + * @param stream print stream + * @param leaves leaves nodes under base scope + */ + public void printTopology(PrintStream stream, List<Node> leaves) { + if (leaves.size() == 0) { + stream.print("No DataNodes"); + return; + } + + // Build a map of rack -> nodes from the datanode report + HashMap<String, TreeSet<String>> tree = new HashMap<String, TreeSet<String>>(); + for(Node dni : leaves) { + String location = dni.getNetworkLocation(); + String name = dni.getName(); + + if(!tree.containsKey(location)) { Review comment: Thanks @goiri for your careful review, I will fix these problems quickly. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
