org.apache.hadoop.mapred.TaskGraphServlet Maven / Gradle / Ivy

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/**
 * 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.mapred;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/** The servlet that outputs svg graphics for map / reduce task
 *  statuses
 */
public class TaskGraphServlet extends HttpServlet {

  private static final long serialVersionUID = -1365683739392460020L;

  /**height of the graph w/o margins*/ 
  public static final int width = 600;
  
  /**height of the graph w/o margins*/ 
  public static final int height = 200;
  
  /**margin space on y axis */
  public static final int ymargin = 20;

  /**margin space on x axis */
  public static final int xmargin = 80;
  
  private static final float oneThird = 1f / 3f;
  
  @Override
  public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {

    response.setContentType("image/svg+xml");

    JobTracker tracker = 
      (JobTracker) getServletContext().getAttribute("job.tracker");
    
    String jobIdStr = request.getParameter("jobid");
    if(jobIdStr == null)
      return;
    JobID jobId = JobID.forName(jobIdStr);

    final boolean isMap = "map".equalsIgnoreCase(request.getParameter("type"));
    final TaskReport[] reports = isMap? tracker.getMapTaskReports(jobId) 
                                      : tracker.getReduceTaskReports(jobId);
    if(reports == null || reports.length == 0) {
      return;
    }

    final int numTasks = reports.length;     
    int tasksPerBar = (int)Math.ceil(numTasks / 600d);
    int numBars = (int) Math.ceil((double)numTasks / tasksPerBar);
    int w = Math.max(600, numBars);
    int barWidth = Math.min(10,  w / numBars); //min 1px, max 10px
    int barsPerNotch = (int)Math.ceil(10d / barWidth);
    w = w + numBars / barsPerNotch;
    int totalWidth = w + 2 * xmargin;
    
    //draw a white rectangle
    final PrintWriter out = response.getWriter();
    out.print("\n" + 
      "\n" +
      "\n\n"+
      "");
  }

  /**Computes average progress per bar*/
  private float getMapAvarageProgress(int tasksPerBar, int index
      , TaskReport[] reports ) {
    float progress = 0f;
    int k=0;
    for(;k < tasksPerBar && index + k < reports.length; k++) { 
      progress += reports[index + k].getProgress();
    }
    progress /= k;
    return progress;
  }

  /**Computes average progresses per bar*/
  private float[] getReduceAvarageProgresses(int tasksPerBar, int index
      , TaskReport[] reports ) {
    float[] progresses = new float[] {0,0,0};
    int k=0;
    for(;k < tasksPerBar && index + k < reports.length; k++) {
      float progress = reports[index+k].getProgress();
      for(int j=0; progress > 0 ; j++, progress -= oneThird) {
        if(progress > oneThird)
          progresses[j] += 1f;
        else 
          progresses[j] += progress * 3 ;
      }
    }
    for(int j=0; j<3; j++) { progresses[j] /= k;}
    
    return progresses;
  }
  
  private void printRect(PrintWriter out, int width, int height
      , int x, int y, String color) throws IOException {
    if(height > 0) {
      out.print("\n");
    }
  }
  private void printLine(PrintWriter out, int x1, int x2
      , int y1, int y2, String color) throws IOException {
    out.print("\n"); 
  }
  private void printText(PrintWriter out, int x, int y, String text
      , String anchor) throws IOException {
    out.print("");
    out.print(text); out.print("\n");
  }
}