/**
 * 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.DataOutputStream;
import java.net.URI;
import java.util.Collection;
import java.util.ArrayList;
import org.apache.commons.logging.LogFactory;
import org.apache.commons.logging.Log;
import org.apache.hadoop.mapreduce.test.system.JTProtocol;
import org.apache.hadoop.mapreduce.test.system.TTClient;
import org.apache.hadoop.mapreduce.test.system.JobInfo;
import org.apache.hadoop.mapreduce.test.system.TaskInfo;
import org.apache.hadoop.mapreduce.test.system.MRCluster;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapred.UtilsForTests;

import org.apache.hadoop.mapreduce.test.system.FinishTaskControlAction;
import org.apache.hadoop.filecache.DistributedCache;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.SleepJob;

import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.AfterClass;
import org.junit.Test;

/**
 * Verify the Distributed Cache functionality. This test scenario is for a
 * distributed cache file behaviour when it is not modified before and after
 * being accessed by maximum two jobs. Once a job uses a distributed cache file
 * that file is stored in the mapred.local.dir. If the next job uses the same
 * file, then that is not stored again. So, if two jobs choose the same
 * tasktracker for their job execution then, the distributed cache file should
 * not be found twice.
 * 
 * This testcase runs a job with a distributed cache file. All the tasks'
 * corresponding tasktracker's handle is got and checked for the presence of
 * distributed cache with proper permissions in the proper directory. Next when
 * job runs again and if any of its tasks hits the same tasktracker, which ran
 * one of the task of the previous job, then that file should not be uploaded
 * again and task use the old file. This is verified.
 */

public class TestDistributedCacheUnModifiedFile {

  private static MRCluster cluster = null;
  private static FileSystem dfs = null;
  private static FileSystem ttFs = null;
  private static JobClient client = null;
  private static FsPermission permission = new FsPermission((short) 00777);

  private static String uriPath = "hdfs:///tmp/test.txt";
  private static final Path URIPATH = new Path(uriPath);
  private String distributedFileName = "test.txt";

  static final Log LOG =
      LogFactory.getLog(TestDistributedCacheUnModifiedFile.class);

  public TestDistributedCacheUnModifiedFile() throws Exception {
  }

  @BeforeClass
  public static void setUp() throws Exception {
    cluster = MRCluster.createCluster(new Configuration());
    cluster.setUp();
    client = cluster.getJTClient().getClient();
    dfs = client.getFs();
    // Deleting the file if it already exists
    dfs.delete(URIPATH, true);

    Collection<TTClient> tts = cluster.getTTClients();
    // Stopping all TTs
    for (TTClient tt : tts) {
      tt.kill();
    }
    // Starting all TTs
    for (TTClient tt : tts) {
      tt.start();
    }

    // Waiting for 5 seconds to make sure tasktrackers are ready
    Thread.sleep(5000);

    String input = "This will be the content of\n" + "distributed cache\n";
    // Creating the path with the file
    DataOutputStream file =
        UtilsForTests.createTmpFileDFS(dfs, URIPATH, permission, input);
  }

  @AfterClass
  public static void tearDown() throws Exception {
    cluster.tearDown();
    dfs.delete(URIPATH, true);

    Collection<TTClient> tts = cluster.getTTClients();
    // Stopping all TTs
    for (TTClient tt : tts) {
      tt.kill();
    }
    // Starting all TTs
    for (TTClient tt : tts) {
      tt.start();
    }
  }

  @Test
  /**
   * This tests Distributed Cache for unmodified file
   * @param none
   * @return void
   */
  public void testDistributedCache() throws Exception {
    Configuration conf = new Configuration(cluster.getConf());
    JTProtocol wovenClient = cluster.getJTClient().getProxy();

    // This counter will check for count of a loop,
    // which might become infinite.
    int count = 0;
    // This boolean will decide whether to run job again
    boolean continueLoop = true;
    // counter for job Loop
    int countLoop = 0;
    // This counter incerases with all the tasktrackers in which tasks ran
    int taskTrackerCounter = 0;
    // This will store all the tasktrackers in which tasks ran
    ArrayList<String> taskTrackerCollection = new ArrayList<String>();

    do {
      SleepJob job = new SleepJob();
      job.setConf(conf);
      Job slpJob = job.createJob(5, 1, 1000, 1000, 100, 100);

      DistributedCache.createSymlink(conf);
      URI uri = URI.create(uriPath);
      DistributedCache.addCacheFile(uri, conf);
      JobConf jconf = new JobConf(conf);

      // Controls the job till all verification is done
      FinishTaskControlAction.configureControlActionForJob(conf);

      // Submitting the job
      slpJob.submit();
      RunningJob rJob =
          cluster.getJTClient().getClient().getJob(
              org.apache.hadoop.mapred.JobID.downgrade(slpJob.getJobID()));

      // counter for job Loop
      countLoop++;

      TTClient tClient = null;
      JobInfo jInfo = wovenClient.getJobInfo(rJob.getID());
      LOG.info("jInfo is :" + jInfo);

      // Assert if jobInfo is null
      Assert.assertNotNull("jobInfo is null", jInfo);

      // Wait for the job to start running.
      count = 0;
      while (jInfo.getStatus().getRunState() != JobStatus.RUNNING) {
        UtilsForTests.waitFor(10000);
        count++;
        jInfo = wovenClient.getJobInfo(rJob.getID());
        // If the count goes beyond a point, then break; This is to avoid
        // infinite loop under unforeseen circumstances. Testcase will anyway
        // fail later.
        if (count > 10) {
          Assert.fail("job has not reached running state for more than"
              + "100 seconds. Failing at this point");
        }
      }

      LOG.info("job id is :" + rJob.getID().toString());

      TaskInfo[] taskInfos =
          cluster.getJTClient().getProxy().getTaskInfo(rJob.getID());

      boolean distCacheFileIsFound;

      for (TaskInfo taskInfo : taskInfos) {
        distCacheFileIsFound = false;
        String[] taskTrackers = taskInfo.getTaskTrackers();
        for (String taskTracker : taskTrackers) {
          // Formatting tasktracker to get just its FQDN
          taskTracker = UtilsForTests.getFQDNofTT(taskTracker);
          LOG.info("taskTracker is :" + taskTracker);

          // This will be entered from the second job onwards
          if (countLoop > 1) {
            if (taskTracker != null) {
              continueLoop = taskTrackerCollection.contains(taskTracker);
            }
            if (!continueLoop) {
              break;
            }
          }

          // Collecting the tasktrackers
          if (taskTracker != null)
            taskTrackerCollection.add(taskTracker);

          // we have loopped through enough number of times to look for task
          // getting submitted on same tasktrackers.The same tasktracker
          // for subsequent jobs was not hit maybe because of many number
          // of tasktrackers. So, testcase has to stop here.
          if (countLoop > 2) {
            continueLoop = false;
          }

          tClient = cluster.getTTClient(taskTracker);

          // tClient maybe null because the task is already dead. Ex: setup
          if (tClient == null) {
            continue;
          }

          String[] localDirs = tClient.getMapredLocalDirs();
          int distributedFileCount = 0;
          // Go to every single path
          for (String localDir : localDirs) {
            // Public Distributed cache will always be stored under
            // mapre.local.dir/tasktracker/archive
            localDir =
                localDir
                    + Path.SEPARATOR
                    + TaskTracker.getPublicDistributedCacheDir();
            LOG.info("localDir is : " + localDir);

            // Get file status of all the directories
            // and files under that path.
            FileStatus[] fileStatuses =
                tClient.listStatus(localDir, true, true);
            for (FileStatus fileStatus : fileStatuses) {
              Path path = fileStatus.getPath();
              LOG.info("path is :" + path.toString());
              // Checking if the received path ends with
              // the distributed filename
              distCacheFileIsFound =
                  (path.toString()).endsWith(distributedFileName);
              // If file is found, check for its permission.
              // Since the file is found break out of loop
              if (distCacheFileIsFound) {
                LOG.info("PATH found is :" + path.toString());
                distributedFileCount++;
                String filename = path.getName();
                FsPermission fsPerm = fileStatus.getPermission();
                Assert.assertTrue("File Permission is not 777", fsPerm
                    .equals(new FsPermission("777")));
              }
            }
          }

          // Since distributed cache is unmodified in dfs
          // between two job runs, it should not be present more than once
          // in any of the task tracker, in which job ran.
          if (distributedFileCount > 1) {
            Assert.fail("The distributed cache file is more than one");
          } else if (distributedFileCount < 1)
            Assert.fail("The distributed cache file is less than one");
          if (!distCacheFileIsFound) {
            Assert.assertEquals(
                "The distributed cache file does not exist",
                distCacheFileIsFound, false);
          }
        }
      }
      // Allow the job to continue through MR control job.
      for (TaskInfo taskInfoRemaining : taskInfos) {
        FinishTaskControlAction action =
            new FinishTaskControlAction(TaskID.downgrade(taskInfoRemaining
                .getTaskID()));
        Collection<TTClient> tts = cluster.getTTClients();
        for (TTClient cli : tts) {
          cli.getProxy().sendAction(action);
        }
      }

      // Killing the job because all the verification needed
      // for this testcase is completed.
      rJob.killJob();
    } while (continueLoop);
  }
}