/**
    *
    * 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.hbase.master;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.io.PrintStream;
  import java.io.PrintWriter;
  import java.util.Date;
  import java.util.Map;
  import java.util.Set;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.apache.hadoop.hbase.classification.InterfaceAudience;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.hbase.ServerLoad;
  import org.apache.hadoop.hbase.ServerName;
  import org.apache.hadoop.hbase.monitoring.LogMonitoring;
  import org.apache.hadoop.hbase.monitoring.StateDumpServlet;
  import org.apache.hadoop.hbase.monitoring.TaskMonitor;
  import org.apache.hadoop.hbase.regionserver.RSDumpServlet;
  import org.apache.hadoop.hbase.util.Threads;
  
  @InterfaceAudience.Private
  public class MasterDumpServlet extends StateDumpServlet {
    private static final long serialVersionUID = 1L;
    private static final String LINE =
      "===========================================================";
  
    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws IOException {
      HMaster master = (HMaster) getServletContext().getAttribute(HMaster.MASTER);
      assert master != null : "No Master in context!";
  
      response.setContentType("text/plain");
      OutputStream os = response.getOutputStream();
      PrintWriter out = new PrintWriter(os);
  
      out.println("Master status for " + master.getServerName()
          + " as of " + new Date());
  
      out.println("\n\nVersion Info:");
      out.println(LINE);
      dumpVersionInfo(out);
  
      out.println("\n\nTasks:");
      out.println(LINE);
      TaskMonitor.get().dumpAsText(out);
  
      out.println("\n\nServers:");
      out.println(LINE);
      dumpServers(master, out);
  
      out.println("\n\nRegions-in-transition:");
      out.println(LINE);
      dumpRIT(master, out);
  
      out.println("\n\nExecutors:");
      out.println(LINE);
      dumpExecutors(master.getExecutorService(), out);
  
      out.println("\n\nStacks:");
      out.println(LINE);
      out.flush();
      PrintStream ps = new PrintStream(response.getOutputStream(), false, "UTF-8");
      Threads.printThreadInfo(ps, "");
      ps.flush();
  
      out.println("\n\nMaster configuration:");
      out.println(LINE);
      Configuration conf = master.getConfiguration();
      out.flush();
      conf.writeXml(os);
      os.flush();
  
      out.println("\n\nRecent regionserver aborts:");
      out.println(LINE);
      master.getRegionServerFatalLogBuffer().dumpTo(out);
  
      out.println("\n\nLogs");
     out.println(LINE);
     long tailKb = getTailKbParam(request);
     LogMonitoring.dumpTailOfLogs(out, tailKb);
 
     out.println("\n\nRS Queue:");
     out.println(LINE);
     if(isShowQueueDump(conf)) {
       RSDumpServlet.dumpQueue(master, out);
     }
     out.flush();
   }
 
 
   private void dumpRIT(HMaster master, PrintWriter out) {
     AssignmentManager am = master.getAssignmentManager();
     if (am == null) {
       out.println("AssignmentManager is not initialized");
       return;
     }
 
     Set<RegionState> regionsInTransition = am.getRegionStates().getRegionsInTransition();
     for (RegionState rs : regionsInTransition) {
       String rid = rs.getRegion().getRegionNameAsString();
       out.println("Region " + rid + ": " + rs.toDescriptiveString());
     }
   }
 
   private void dumpServers(HMaster master, PrintWriter out) {
     ServerManager sm = master.getServerManager();
     if (sm == null) {
       out.println("ServerManager is not initialized");
       return;
     }
 
     Map<ServerName, ServerLoad> servers = sm.getOnlineServers();
     for (Map.Entry<ServerName, ServerLoad> e : servers.entrySet()) {
       out.println(e.getKey() + ": " + e.getValue());
     }
   }
 }