/**
 * 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.hdfs.qjournal.server;

import com.google.common.base.Supplier;
import com.google.common.collect.Lists;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.DistributedFileSystem;
import org.apache.hadoop.hdfs.HdfsConfiguration;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.protocol.RollingUpgradeInfo;
import org.apache.hadoop.hdfs.qjournal.MiniJournalCluster;
import org.apache.hadoop.hdfs.qjournal.MiniQJMHACluster;
import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory;
import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
import org.apache.hadoop.hdfs.server.namenode.FileJournalManager.EditLogFile;
import static org.apache.hadoop.hdfs.server.namenode.FileJournalManager
    .getLogFile;
import org.apache.hadoop.hdfs.server.protocol.NamespaceInfo;
import org.apache.hadoop.test.GenericTestUtils;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.TestName;

import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.Random;

/**
 * Unit test for Journal Node formatting upon re-installation and syncing.
 */
public class TestJournalNodeSync {
  private Configuration conf;
  private MiniQJMHACluster qjmhaCluster;
  private MiniDFSCluster dfsCluster;
  private MiniJournalCluster jCluster;
  private FSNamesystem namesystem;
  private int editsPerformed = 0;
  private final String jid = "ns1";
  private int activeNNindex=0;
  private static final int DFS_HA_TAILEDITS_PERIOD_SECONDS=1;

  @Rule
  public TestName testName = new TestName();

  @Before
  public void setUpMiniCluster() throws IOException {
    conf = new HdfsConfiguration();
    conf.setBoolean(DFSConfigKeys.DFS_JOURNALNODE_ENABLE_SYNC_KEY, true);
    conf.setLong(DFSConfigKeys.DFS_JOURNALNODE_SYNC_INTERVAL_KEY, 1000L);
    if (testName.getMethodName().equals(
        "testSyncAfterJNdowntimeWithoutQJournalQueue")) {
      conf.setInt(DFSConfigKeys.DFS_QJOURNAL_QUEUE_SIZE_LIMIT_KEY, 0);
    }
    if (testName.getMethodName().equals("testSyncDuringRollingUpgrade")) {
      conf.setInt(DFSConfigKeys.DFS_HA_TAILEDITS_PERIOD_KEY,
          DFS_HA_TAILEDITS_PERIOD_SECONDS);
    }
    qjmhaCluster = new MiniQJMHACluster.Builder(conf).setNumNameNodes(2)
      .build();
    dfsCluster = qjmhaCluster.getDfsCluster();
    jCluster = qjmhaCluster.getJournalCluster();

    dfsCluster.transitionToActive(0);
    namesystem = dfsCluster.getNamesystem(0);
  }

  @After
  public void shutDownMiniCluster() throws IOException {
    if (qjmhaCluster != null) {
      qjmhaCluster.shutdown();
    }
  }

  @Test(timeout=30000)
  public void testJournalNodeSync() throws Exception {

    //As by default 3 journal nodes are started;
    for(int i=0; i<3; i++) {
      Assert.assertEquals(true,
          jCluster.getJournalNode(i).getJournalSyncerStatus("ns1"));
    }

    File firstJournalDir = jCluster.getJournalDir(0, jid);
    File firstJournalCurrentDir = new StorageDirectory(firstJournalDir)
        .getCurrentDir();

    // Generate some edit logs and delete one.
    long firstTxId = generateEditLog();
    generateEditLog();

    File missingLog = deleteEditLog(firstJournalCurrentDir, firstTxId);

    GenericTestUtils.waitFor(editLogExists(Lists.newArrayList(missingLog)),
        500, 10000);
  }

  @Test(timeout=30000)
  public void testSyncForMultipleMissingLogs() throws Exception {
    File firstJournalDir = jCluster.getJournalDir(0, jid);
    File firstJournalCurrentDir = new StorageDirectory(firstJournalDir)
        .getCurrentDir();

    // Generate some edit logs and delete two.
    long firstTxId = generateEditLog();
    long nextTxId = generateEditLog();

    List<File> missingLogs = Lists.newArrayList();
    missingLogs.add(deleteEditLog(firstJournalCurrentDir, firstTxId));
    missingLogs.add(deleteEditLog(firstJournalCurrentDir, nextTxId));

    GenericTestUtils.waitFor(editLogExists(missingLogs), 500, 10000);
  }

  @Test(timeout=30000)
  public void testSyncForDiscontinuousMissingLogs() throws Exception {
    File firstJournalDir = jCluster.getJournalDir(0, jid);
    File firstJournalCurrentDir = new StorageDirectory(firstJournalDir)
        .getCurrentDir();

    // Generate some edit logs and delete two discontinuous logs.
    long firstTxId = generateEditLog();
    generateEditLog();
    long nextTxId = generateEditLog();

    List<File> missingLogs = Lists.newArrayList();
    missingLogs.add(deleteEditLog(firstJournalCurrentDir, firstTxId));
    missingLogs.add(deleteEditLog(firstJournalCurrentDir, nextTxId));

    GenericTestUtils.waitFor(editLogExists(missingLogs), 500, 10000);
  }

  @Test(timeout=30000)
  public void testMultipleJournalsMissingLogs() throws Exception {
    File firstJournalDir = jCluster.getJournalDir(0, jid);
    File firstJournalCurrentDir = new StorageDirectory(firstJournalDir)
        .getCurrentDir();

    File secondJournalDir = jCluster.getJournalDir(1, jid);
    StorageDirectory sd = new StorageDirectory(secondJournalDir);
    File secondJournalCurrentDir = sd.getCurrentDir();

    // Generate some edit logs and delete one log from two journals.
    long firstTxId = generateEditLog();
    generateEditLog();

    List<File> missingLogs = Lists.newArrayList();
    missingLogs.add(deleteEditLog(firstJournalCurrentDir, firstTxId));
    missingLogs.add(deleteEditLog(secondJournalCurrentDir, firstTxId));

    GenericTestUtils.waitFor(editLogExists(missingLogs), 500, 10000);
  }

  @Test(timeout=60000)
  public void testMultipleJournalsMultipleMissingLogs() throws Exception {
    File firstJournalDir = jCluster.getJournalDir(0, jid);
    File firstJournalCurrentDir = new StorageDirectory(firstJournalDir)
        .getCurrentDir();

    File secondJournalDir = jCluster.getJournalDir(1, jid);
    File secondJournalCurrentDir = new StorageDirectory(secondJournalDir)
        .getCurrentDir();

    File thirdJournalDir = jCluster.getJournalDir(2, jid);
    File thirdJournalCurrentDir = new StorageDirectory(thirdJournalDir)
        .getCurrentDir();

    // Generate some edit logs and delete multiple logs in multiple journals.
    long firstTxId = generateEditLog();
    long secondTxId = generateEditLog();
    long thirdTxId = generateEditLog();

    List<File> missingLogs = Lists.newArrayList();
    missingLogs.add(deleteEditLog(firstJournalCurrentDir, firstTxId));
    missingLogs.add(deleteEditLog(secondJournalCurrentDir, firstTxId));
    missingLogs.add(deleteEditLog(secondJournalCurrentDir, secondTxId));
    missingLogs.add(deleteEditLog(thirdJournalCurrentDir, thirdTxId));

    GenericTestUtils.waitFor(editLogExists(missingLogs), 500, 30000);
  }

  // Test JournalNode Sync by randomly deleting edit logs from one or two of
  // the journals.
  @Test(timeout=60000)
  public void testRandomJournalMissingLogs() throws Exception {
    List<File> missingLogs = deleteEditLogsFromRandomJN();

    GenericTestUtils.waitFor(editLogExists(missingLogs), 500, 30000);
  }

  // Test JournalNode Sync when a JN id down while NN is actively writing
  // logs and comes back up after some time.
  @Test (timeout=300_000)
  public void testSyncAfterJNdowntime() throws Exception {
    File firstJournalDir = jCluster.getJournalDir(0, jid);
    File firstJournalCurrentDir = new StorageDirectory(firstJournalDir)
        .getCurrentDir();
    File secondJournalDir = jCluster.getJournalDir(1, jid);
    File secondJournalCurrentDir = new StorageDirectory(secondJournalDir)
        .getCurrentDir();

    long[] startTxIds = new long[10];

    startTxIds[0] = generateEditLog();
    startTxIds[1] = generateEditLog();

    // Stop the first JN
    jCluster.getJournalNode(0).stop(0);

    // Roll some more edits while the first JN is down
    for (int i = 2; i < 10; i++) {
      startTxIds[i] = generateEditLog(5);
    }

    // Re-start the first JN
    jCluster.restartJournalNode(0);

    // Roll an edit to update the committed tx id of the first JN
    generateEditLog();

    // List the edit logs rolled during JN down time.
    List<File> missingLogs = Lists.newArrayList();
    for (int i = 2; i < 10; i++) {
      EditLogFile logFile = getLogFile(secondJournalCurrentDir, startTxIds[i],
          false);
      missingLogs.add(new File(firstJournalCurrentDir,
          logFile.getFile().getName()));
    }

    // Check that JNSync downloaded the edit logs rolled during JN down time.
    GenericTestUtils.waitFor(editLogExists(missingLogs), 500, 30000);
  }

  /**
   * Test JournalNode Sync when a JN id down while NN is actively writing
   * logs and comes back up after some time with no edit log queueing.
   * Queuing disabled during the cluster setup {@link #setUpMiniCluster()}
   * @throws Exception
   */
  @Test (timeout=300_000)
  public void testSyncAfterJNdowntimeWithoutQJournalQueue() throws Exception{
    // QJournal Queuing is disabled during the cluster setup
    // {@link #setUpMiniCluster()}
    File firstJournalDir = jCluster.getJournalDir(0, jid);
    File firstJournalCurrentDir = new StorageDirectory(firstJournalDir)
        .getCurrentDir();
    File secondJournalDir = jCluster.getJournalDir(1, jid);
    File secondJournalCurrentDir = new StorageDirectory(secondJournalDir)
        .getCurrentDir();

    long[] startTxIds = new long[10];

    startTxIds[0] = generateEditLog();
    startTxIds[1] = generateEditLog(2);

    // Stop the first JN
    jCluster.getJournalNode(0).stop(0);

    // Roll some more edits while the first JN is down
    for (int i = 2; i < 10; i++) {
      startTxIds[i] = generateEditLog(5);
    }

    // Re-start the first JN
    jCluster.restartJournalNode(0);

    // After JN restart and before rolling another edit, the missing edit
    // logs will not by synced as the committed tx id of the JN will be
    // less than the start tx id's of the missing edit logs and edit log queuing
    // has been disabled.
    // Roll an edit to update the committed tx id of the first JN
    generateEditLog(2);

    // List the edit logs rolled during JN down time.
    List<File> missingLogs = Lists.newArrayList();
    for (int i = 2; i < 10; i++) {
      EditLogFile logFile = getLogFile(secondJournalCurrentDir, startTxIds[i],
          false);
      missingLogs.add(new File(firstJournalCurrentDir,
          logFile.getFile().getName()));
    }

    // Check that JNSync downloaded the edit logs rolled during JN down time.
    GenericTestUtils.waitFor(editLogExists(missingLogs), 500, 30000);

    // Check that all the missing edit logs have been downloaded via
    // JournalNodeSyncer alone (as the edit log queueing has been disabled)
    long numEditLogsSynced = jCluster.getJournalNode(0).getOrCreateJournal(jid)
        .getMetrics().getNumEditLogsSynced().value();
    Assert.assertTrue("Edit logs downloaded outside syncer. Expected 8 or " +
            "more downloads, got " + numEditLogsSynced + " downloads instead",
        numEditLogsSynced >= 8);
  }

  // Test JournalNode Sync when a JN is formatted while NN is actively writing
  // logs.
  @Test (timeout=300_000)
  public void testSyncAfterJNformat() throws Exception{
    File firstJournalDir = jCluster.getJournalDir(0, jid);
    File firstJournalCurrentDir = new StorageDirectory(firstJournalDir)
        .getCurrentDir();
    File secondJournalDir = jCluster.getJournalDir(1, jid);
    File secondJournalCurrentDir = new StorageDirectory(secondJournalDir)
        .getCurrentDir();

    long[] startTxIds = new long[10];

    startTxIds[0] = generateEditLog(1);
    startTxIds[1] = generateEditLog(2);
    startTxIds[2] = generateEditLog(4);
    startTxIds[3] = generateEditLog(6);

    Journal journal1 = jCluster.getJournalNode(0).getOrCreateJournal(jid);
    NamespaceInfo nsInfo = journal1.getStorage().getNamespaceInfo();

    // Delete contents of current directory of one JN
    for (File file : firstJournalCurrentDir.listFiles()) {
      file.delete();
    }

    // Format the JN
    journal1.format(nsInfo);

    // Roll some more edits
    for (int i = 4; i < 10; i++) {
      startTxIds[i] = generateEditLog(5);
    }

    // List the edit logs rolled during JN down time.
    List<File> missingLogs = Lists.newArrayList();
    for (int i = 0; i < 10; i++) {
      EditLogFile logFile = getLogFile(secondJournalCurrentDir, startTxIds[i],
          false);
      missingLogs.add(new File(firstJournalCurrentDir,
          logFile.getFile().getName()));
    }

    // Check that the formatted JN has all the edit logs.
    GenericTestUtils.waitFor(editLogExists(missingLogs), 500, 30000);
  }

  // Test JournalNode Sync during a Rolling Upgrade of NN.
  @Test (timeout=300_000)
  public void testSyncDuringRollingUpgrade() throws Exception {

    DistributedFileSystem dfsActive;
    int standbyNNindex;

    if (dfsCluster.getNameNode(0).isActiveState()) {
      activeNNindex = 0;
      standbyNNindex = 1;
    } else {
      activeNNindex = 1;
      standbyNNindex = 0;
    }
    dfsActive = dfsCluster.getFileSystem(activeNNindex);

    // Prepare for rolling upgrade
    final RollingUpgradeInfo info = dfsActive.rollingUpgrade(
          HdfsConstants.RollingUpgradeAction.PREPARE);

    //query rolling upgrade
    Assert.assertEquals(info, dfsActive.rollingUpgrade(
        HdfsConstants.RollingUpgradeAction.QUERY));

    // Restart the Standby NN with rollingUpgrade option
    dfsCluster.restartNameNode(standbyNNindex, true,
        "-rollingUpgrade", "started");
    Assert.assertEquals(info, dfsActive.rollingUpgrade(
        HdfsConstants.RollingUpgradeAction.QUERY));

    // Do some edits and delete some edit logs
    List<File> missingLogs = deleteEditLogsFromRandomJN();

    GenericTestUtils.waitFor(editLogExists(missingLogs), 500, 30000);

    // Transition the active NN to standby and standby to active
    dfsCluster.transitionToStandby(activeNNindex);

    // Let Standby NN catch up tailing edit logs before transitioning it to
    // active
    Thread.sleep(30*DFS_HA_TAILEDITS_PERIOD_SECONDS*1000);

    dfsCluster.transitionToActive(standbyNNindex);
    dfsCluster.waitActive();

    activeNNindex=standbyNNindex;
    standbyNNindex=((activeNNindex+1)%2);
    dfsActive = dfsCluster.getFileSystem(activeNNindex);

    Assert.assertTrue(dfsCluster.getNameNode(activeNNindex).isActiveState());
    Assert.assertFalse(dfsCluster.getNameNode(standbyNNindex).isActiveState());

    // Restart the current standby NN (previously active)
    dfsCluster.restartNameNode(standbyNNindex, true,
        "-rollingUpgrade", "started");
    Assert.assertEquals(info, dfsActive.rollingUpgrade(
        HdfsConstants.RollingUpgradeAction.QUERY));
    dfsCluster.waitActive();

    // Do some edits and delete some edit logs
    missingLogs.addAll(deleteEditLogsFromRandomJN());

    // Check that JNSync downloaded the edit logs rolled during rolling upgrade.
    GenericTestUtils.waitFor(editLogExists(missingLogs), 500, 30000);

    //finalize rolling upgrade
    final RollingUpgradeInfo finalize = dfsActive.rollingUpgrade(
        HdfsConstants.RollingUpgradeAction.FINALIZE);
    Assert.assertTrue(finalize.isFinalized());

    // Check the missing edit logs exist after finalizing rolling upgrade
    for (File editLog : missingLogs) {
      Assert.assertTrue("Edit log missing after finalizing rolling upgrade",
          editLog.exists());
    }
  }

  private File deleteEditLog(File currentDir, long startTxId)
      throws IOException {
    EditLogFile logFile = getLogFile(currentDir, startTxId);
    while (logFile.isInProgress()) {
      dfsCluster.getNameNode(activeNNindex).getRpcServer().rollEditLog();
      logFile = getLogFile(currentDir, startTxId);
    }
    File deleteFile = logFile.getFile();
    Assert.assertTrue("Couldn't delete edit log file", deleteFile.delete());

    return deleteFile;
  }

  private List<File> deleteEditLogsFromRandomJN() throws IOException {
    Random random = new Random();

    List<File> journalCurrentDirs = Lists.newArrayList();

    for (int i = 0; i < 3; i++) {
      journalCurrentDirs.add(new StorageDirectory(jCluster.getJournalDir(i,
          jid)).getCurrentDir());
    }

    long[] startTxIds = new long[20];
    for (int i = 0; i < 20; i++) {
      startTxIds[i] = generateEditLog();
    }

    int count = 0, startTxIdIndex;
    long startTxId;
    int journalIndex;
    List<File> missingLogs = Lists.newArrayList();
    List<Integer> deletedStartTxIds = Lists.newArrayList();
    while (count < 5) {
      // Select a random edit log to delete
      startTxIdIndex = random.nextInt(20);
      while (deletedStartTxIds.contains(startTxIdIndex)) {
        startTxIdIndex = random.nextInt(20);
      }
      startTxId = startTxIds[startTxIdIndex];
      deletedStartTxIds.add(startTxIdIndex);

      // Delete the randomly selected edit log segment from randomly selected
      // journal node
      journalIndex = random.nextInt(3);
      missingLogs.add(deleteEditLog(journalCurrentDirs.get(journalIndex),
          startTxId));

      count++;
    }

    return missingLogs;
  }

  /**
   * Do a mutative metadata operation on the file system.
   *
   * @return true if the operation was successful, false otherwise.
   */
  private boolean doAnEdit() throws IOException {
    return dfsCluster.getFileSystem(activeNNindex).mkdirs(
        new Path("/tmp", Integer.toString(editsPerformed++)));
  }

  /**
   * Does an edit and rolls the Edit Log.
   *
   * @return the startTxId of next segment after rolling edits.
   */
  private long generateEditLog() throws IOException {
    return generateEditLog(1);
  }

  /**
   * Does specified number of edits and rolls the Edit Log.
   *
   * @param numEdits number of Edits to perform
   * @return the startTxId of next segment after rolling edits.
   */
  private long generateEditLog(int numEdits) throws IOException {
    long lastWrittenTxId = dfsCluster.getNameNode(activeNNindex).getFSImage()
        .getEditLog().getLastWrittenTxId();
    for (int i = 1; i <= numEdits; i++) {
      Assert.assertTrue("Failed to do an edit", doAnEdit());
    }
    dfsCluster.getNameNode(activeNNindex).getRpcServer().rollEditLog();
    return lastWrittenTxId;
  }

  private Supplier<Boolean> editLogExists(List<File> editLogs) {
    Supplier<Boolean> supplier = new Supplier<Boolean>() {
      @Override
      public Boolean get() {
        for (File editLog : editLogs) {
          if (!editLog.exists()) {
            return false;
          }
        }
        return true;
      }
    };
    return supplier;
  }
}
