package org.apache.helix.filestore;
   
   /*
    * 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.
   */
  
  import java.io.IOException;
  
  public class RsyncInvoker
  {
    private Thread backgroundThread;
    private final String remoteHost;
    private final String remoteLogDir;
    private final String localLogDir;
  
    public RsyncInvoker(String remoteHost, String remoteBaseDir,
        String localBaseDir)
    {
      this.remoteHost = remoteHost;
      this.remoteLogDir = remoteBaseDir;
      this.localLogDir = localBaseDir;
    }
  
    public boolean rsync(String relativePath)
    {
      int exitVal = -1;
      try
      {
        ProcessBuilder pb = new ProcessBuilder( "rsync", 
             remoteLogDir+"/"+ relativePath , localLogDir);
        System.out.println("Rsyncing source:"+ remoteLogDir+"/"+ relativePath  + " dest:"+ localLogDir);
        ExternalCommand ec = new ExternalCommand(pb);
        ec.start();
        exitVal = ec.waitFor();
        if (exitVal != 0)
        {
          System.out.println("Failed to rsync "+ ec.getStringError());
        } else
        {
          return true;
        }
      } catch (IOException e)
      {
        e.printStackTrace();
      } catch (InterruptedException e)
      {
        e.printStackTrace();
      }
  
      return false;
    }
    public boolean stop(){
      if( backgroundThread!=null){
        backgroundThread.interrupt();
      }
      return true;
    }
    public boolean runInBackground()
    {
      backgroundThread = new Thread(new Runnable()
      {
        public void run()
        {
          try
          {
            int sleep = 1000;
            while (true)
            {
              int exitVal = -1;
              try
              {
                Thread.sleep(sleep);
                ProcessBuilder pb = new ProcessBuilder( "rsync", "-rvt",
                     remoteLogDir+"/", localLogDir);
                //System.out.println("Background rsync source:"+remoteLogDir+"/" +" dest:"+ localLogDir);
                ExternalCommand ec;
                ec = new ExternalCommand(pb);
                ec.start();
                exitVal = ec.waitFor();
                String stringError = ec.getStringError();
                if(stringError!=null && stringError.length()>0)
                System.err.println(stringError);
                //System.out.println(ec.getStringOutput());
                
             } catch (IOException e)
             {
               e.printStackTrace();
             }
             if (exitVal != 0)
             {
               
               sleep = Math.min(2 * sleep, 2 * 60 * 1000);
               System.out.println("Failed to rsync retrying in " + sleep / 1000
                   + " seconds");
             } else
             {
               sleep = 1000;
             }
           }
         } catch (InterruptedException e)
         {
           e.printStackTrace();
           Thread.currentThread().interrupt();
         }
       }
     });
     backgroundThread.start();
     return true;
   }
   public static void main(String[] args)
   {
     String remoteHost= "localhost";
     String remoteLogDir="data/localhost_12000/translog";
     String localLogDir="data/localhost_12001/translog";
     RsyncInvoker rsyncInvoker = new RsyncInvoker(remoteHost, remoteLogDir, localLogDir);
     rsyncInvoker.runInBackground();
   }
 }