/**
    *
    * 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.regionserver;
  
  import java.io.IOException;
  import java.io.OutputStream;
  import java.io.PrintStream;
  import java.io.PrintWriter;
  import java.util.Date;
  
  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.monitoring.LogMonitoring;
  import org.apache.hadoop.hbase.monitoring.StateDumpServlet;
  import org.apache.hadoop.hbase.monitoring.TaskMonitor;
  import org.apache.hadoop.hbase.util.Threads;
  
  @InterfaceAudience.Private
  public class RSDumpServlet extends StateDumpServlet {
    private static final long serialVersionUID = 1L;
    private static final String LINE =
      "===========================================================";
  
    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws IOException {
      HRegionServer hrs = (HRegionServer)getServletContext().getAttribute(
          HRegionServer.REGIONSERVER);
      assert hrs != null : "No RS in context!";
  
      response.setContentType("text/plain");
  
      if (!hrs.isOnline()) {
        response.getWriter().write("The RegionServer is initializing!");
        response.getWriter().close();
        return;
      }
  
      OutputStream os = response.getOutputStream();
      PrintWriter out = new PrintWriter(os);
  
      out.println("RegionServer status for " + hrs.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\nExecutors:");
      out.println(LINE);
      dumpExecutors(hrs.getExecutorService(), out);
  
      out.println("\n\nStacks:");
      out.println(LINE);
      PrintStream ps = new PrintStream(response.getOutputStream(), false, "UTF-8");
      Threads.printThreadInfo(ps, "");
      ps.flush();
  
      out.println("\n\nRS Configuration:");
      out.println(LINE);
      Configuration conf = hrs.getConfiguration();
      out.flush();
      conf.writeXml(os);
      os.flush();
  
      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)) {
        dumpQueue(hrs, out);
      }
  
     out.flush();
   }
 
   public static void dumpQueue(HRegionServer hrs, PrintWriter out)
       throws IOException {
     if (hrs.compactSplitThread != null) {
       // 1. Print out Compaction/Split Queue
       out.println("Compaction/Split Queue summary: "
           + hrs.compactSplitThread.toString() );
       out.println(hrs.compactSplitThread.dumpQueue());
     }
 
     if (hrs.cacheFlusher != null) {
       // 2. Print out flush Queue
       out.println("\nFlush Queue summary: "
           + hrs.cacheFlusher.toString());
       out.println(hrs.cacheFlusher.dumpQueue());
     }
   }
 }