/**
 * 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.server.namenode.snapshot;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;

import java.util.EnumSet;
import java.util.Map;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.XAttrSetFlag;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.DistributedFileSystem;
import org.apache.hadoop.hdfs.MiniDFSCluster;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.protocol.NSQuotaExceededException;
import org.apache.hadoop.hdfs.protocol.SnapshotAccessControlException;
import org.apache.hadoop.hdfs.server.namenode.NameNode;
import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
import org.apache.hadoop.io.IOUtils;
import org.junit.AfterClass;
import org.junit.Assert;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;

/**
 * Tests interaction of XAttrs with snapshots.
 */
public class TestXAttrWithSnapshot {

  private static MiniDFSCluster cluster;
  private static Configuration conf;
  private static DistributedFileSystem hdfs;
  private static int pathCount = 0;
  private static Path path, snapshotPath;
  private static String snapshotName;
  // XAttrs
  private static final String name1 = "user.a1";
  private static final byte[] value1 = { 0x31, 0x32, 0x33 };
  private static final byte[] newValue1 = { 0x31, 0x31, 0x31 };
  private static final String name2 = "user.a2";
  private static final byte[] value2 = { 0x37, 0x38, 0x39 };

  @Rule
  public ExpectedException exception = ExpectedException.none();

  @BeforeClass
  public static void init() throws Exception {
    conf = new Configuration();
    conf.setBoolean(DFSConfigKeys.DFS_NAMENODE_XATTRS_ENABLED_KEY, true);
    initCluster(true);
  }

  @AfterClass
  public static void shutdown() throws Exception {
    IOUtils.cleanup(null, hdfs);
    if (cluster != null) {
      cluster.shutdown();
    }
  }

  @Before
  public void setUp() {
    ++pathCount;
    path = new Path("/p" + pathCount);
    snapshotName = "snapshot" + pathCount;
    snapshotPath = new Path(path, new Path(".snapshot", snapshotName));
  }

  /**
   * Tests modifying xattrs on a directory that has been snapshotted
   */
  @Test (timeout = 120000)
  public void testModifyReadsCurrentState() throws Exception {
    // Init
    FileSystem.mkdirs(hdfs, path, FsPermission.createImmutable((short) 0700));
    SnapshotTestHelper.createSnapshot(hdfs, path, snapshotName);
    hdfs.setXAttr(path, name1, value1);
    hdfs.setXAttr(path, name2, value2);

    // Verify that current path reflects xattrs, snapshot doesn't
    Map<String, byte[]> xattrs = hdfs.getXAttrs(path);
    assertEquals(xattrs.size(), 2);
    assertArrayEquals(value1, xattrs.get(name1));
    assertArrayEquals(value2, xattrs.get(name2));

    xattrs = hdfs.getXAttrs(snapshotPath);
    assertEquals(xattrs.size(), 0);

    // Modify each xattr and make sure it's reflected
    hdfs.setXAttr(path, name1, value2, EnumSet.of(XAttrSetFlag.REPLACE));
    xattrs = hdfs.getXAttrs(path);
    assertEquals(xattrs.size(), 2);
    assertArrayEquals(value2, xattrs.get(name1));
    assertArrayEquals(value2, xattrs.get(name2));

    hdfs.setXAttr(path, name2, value1, EnumSet.of(XAttrSetFlag.REPLACE));
    xattrs = hdfs.getXAttrs(path);
    assertEquals(xattrs.size(), 2);
    assertArrayEquals(value2, xattrs.get(name1));
    assertArrayEquals(value1, xattrs.get(name2));

    // Paranoia checks
    xattrs = hdfs.getXAttrs(snapshotPath);
    assertEquals(xattrs.size(), 0);

    hdfs.removeXAttr(path, name1);
    hdfs.removeXAttr(path, name2);
    xattrs = hdfs.getXAttrs(path);
    assertEquals(xattrs.size(), 0);
  }

  /**
   * Tests removing xattrs on a directory that has been snapshotted
   */
  @Test (timeout = 120000)
  public void testRemoveReadsCurrentState() throws Exception {
    // Init
    FileSystem.mkdirs(hdfs, path, FsPermission.createImmutable((short) 0700));
    SnapshotTestHelper.createSnapshot(hdfs, path, snapshotName);
    hdfs.setXAttr(path, name1, value1);
    hdfs.setXAttr(path, name2, value2);

    // Verify that current path reflects xattrs, snapshot doesn't
    Map<String, byte[]> xattrs = hdfs.getXAttrs(path);
    assertEquals(xattrs.size(), 2);
    assertArrayEquals(value1, xattrs.get(name1));
    assertArrayEquals(value2, xattrs.get(name2));

    xattrs = hdfs.getXAttrs(snapshotPath);
    assertEquals(xattrs.size(), 0);

    // Remove xattrs and verify one-by-one
    hdfs.removeXAttr(path, name2);
    xattrs = hdfs.getXAttrs(path);
    assertEquals(xattrs.size(), 1);
    assertArrayEquals(value1, xattrs.get(name1));

    hdfs.removeXAttr(path, name1);
    xattrs = hdfs.getXAttrs(path);
    assertEquals(xattrs.size(), 0);
  }

  /**
   * 1) Save xattrs, then create snapshot. Assert that inode of original and
   * snapshot have same xattrs. 2) Change the original xattrs, assert snapshot
   * still has old xattrs.
   */
  @Test
  public void testXAttrForSnapshotRootAfterChange() throws Exception {
    FileSystem.mkdirs(hdfs, path, FsPermission.createImmutable((short) 0700));
    hdfs.setXAttr(path, name1, value1);
    hdfs.setXAttr(path, name2, value2);

    SnapshotTestHelper.createSnapshot(hdfs, path, snapshotName);

    // Both original and snapshot have same XAttrs.
    Map<String, byte[]> xattrs = hdfs.getXAttrs(path);
    Assert.assertEquals(xattrs.size(), 2);
    Assert.assertArrayEquals(value1, xattrs.get(name1));
    Assert.assertArrayEquals(value2, xattrs.get(name2));

    xattrs = hdfs.getXAttrs(snapshotPath);
    Assert.assertEquals(xattrs.size(), 2);
    Assert.assertArrayEquals(value1, xattrs.get(name1));
    Assert.assertArrayEquals(value2, xattrs.get(name2));

    // Original XAttrs have changed, but snapshot still has old XAttrs.
    hdfs.setXAttr(path, name1, newValue1);

    doSnapshotRootChangeAssertions(path, snapshotPath);
    restart(false);
    doSnapshotRootChangeAssertions(path, snapshotPath);
    restart(true);
    doSnapshotRootChangeAssertions(path, snapshotPath);
  }

  private static void doSnapshotRootChangeAssertions(Path path,
      Path snapshotPath) throws Exception {
    Map<String, byte[]> xattrs = hdfs.getXAttrs(path);
    Assert.assertEquals(xattrs.size(), 2);
    Assert.assertArrayEquals(newValue1, xattrs.get(name1));
    Assert.assertArrayEquals(value2, xattrs.get(name2));

    xattrs = hdfs.getXAttrs(snapshotPath);
    Assert.assertEquals(xattrs.size(), 2);
    Assert.assertArrayEquals(value1, xattrs.get(name1));
    Assert.assertArrayEquals(value2, xattrs.get(name2));
  }

  /**
   * 1) Save xattrs, then create snapshot. Assert that inode of original and
   * snapshot have same xattrs. 2) Remove some original xattrs, assert snapshot
   * still has old xattrs.
   */
  @Test
  public void testXAttrForSnapshotRootAfterRemove() throws Exception {
    FileSystem.mkdirs(hdfs, path, FsPermission.createImmutable((short) 0700));
    hdfs.setXAttr(path, name1, value1);
    hdfs.setXAttr(path, name2, value2);

    SnapshotTestHelper.createSnapshot(hdfs, path, snapshotName);

    // Both original and snapshot have same XAttrs.
    Map<String, byte[]> xattrs = hdfs.getXAttrs(path);
    Assert.assertEquals(xattrs.size(), 2);
    Assert.assertArrayEquals(value1, xattrs.get(name1));
    Assert.assertArrayEquals(value2, xattrs.get(name2));

    xattrs = hdfs.getXAttrs(snapshotPath);
    Assert.assertEquals(xattrs.size(), 2);
    Assert.assertArrayEquals(value1, xattrs.get(name1));
    Assert.assertArrayEquals(value2, xattrs.get(name2));

    // Original XAttrs have been removed, but snapshot still has old XAttrs.
    hdfs.removeXAttr(path, name1);
    hdfs.removeXAttr(path, name2);

    doSnapshotRootRemovalAssertions(path, snapshotPath);
    restart(false);
    doSnapshotRootRemovalAssertions(path, snapshotPath);
    restart(true);
    doSnapshotRootRemovalAssertions(path, snapshotPath);
  }

  private static void doSnapshotRootRemovalAssertions(Path path,
      Path snapshotPath) throws Exception {
    Map<String, byte[]> xattrs = hdfs.getXAttrs(path);
    Assert.assertEquals(0, xattrs.size());

    xattrs = hdfs.getXAttrs(snapshotPath);
    Assert.assertEquals(2, xattrs.size());
    Assert.assertArrayEquals(value1, xattrs.get(name1));
    Assert.assertArrayEquals(value2, xattrs.get(name2));
  }

  /**
   * Assert exception of setting xattr on read-only snapshot.
   */
  @Test
  public void testSetXAttrSnapshotPath() throws Exception {
    FileSystem.mkdirs(hdfs, path, FsPermission.createImmutable((short) 0700));
    SnapshotTestHelper.createSnapshot(hdfs, path, snapshotName);
    exception.expect(SnapshotAccessControlException.class);
    hdfs.setXAttr(snapshotPath, name1, value1);
  }

  /**
   * Assert exception of setting xattr when exceeding quota.
   */
  @Test
  public void testSetXAttrExceedsQuota() throws Exception {
    Path filePath = new Path(path, "file1");
    Path fileSnapshotPath = new Path(snapshotPath, "file1");
    FileSystem.mkdirs(hdfs, path, FsPermission.createImmutable((short) 0755));
    hdfs.allowSnapshot(path);
    hdfs.setQuota(path, 3, HdfsConstants.QUOTA_DONT_SET);
    FileSystem.create(hdfs, filePath,
        FsPermission.createImmutable((short) 0600)).close();
    hdfs.setXAttr(filePath, name1, value1);

    hdfs.createSnapshot(path, snapshotName);

    byte[] value = hdfs.getXAttr(filePath, name1);
    Assert.assertArrayEquals(value, value1);

    value = hdfs.getXAttr(fileSnapshotPath, name1);
    Assert.assertArrayEquals(value, value1);

    exception.expect(NSQuotaExceededException.class);
    hdfs.setXAttr(filePath, name2, value2);
  }


  /**
   * Test that an exception is thrown when adding an XAttr Feature to
   * a snapshotted path
   */
  @Test
  public void testSetXAttrAfterSnapshotExceedsQuota() throws Exception {
    Path filePath = new Path(path, "file1");
    FileSystem.mkdirs(hdfs, path, FsPermission.createImmutable((short) 0755));
    hdfs.allowSnapshot(path);
    hdfs.setQuota(path, 3, HdfsConstants.QUOTA_DONT_SET);
    FileSystem.create(hdfs, filePath,
        FsPermission.createImmutable((short) 0600)).close();
    hdfs.createSnapshot(path, snapshotName);
    // This adds an XAttr feature, which can throw an exception
    exception.expect(NSQuotaExceededException.class);
    hdfs.setXAttr(filePath, name1, value1);
  }

  /**
   * Assert exception of removing xattr when exceeding quota.
   */
  @Test
  public void testRemoveXAttrExceedsQuota() throws Exception {
    Path filePath = new Path(path, "file1");
    Path fileSnapshotPath = new Path(snapshotPath, "file1");
    FileSystem.mkdirs(hdfs, path, FsPermission.createImmutable((short) 0755));
    hdfs.allowSnapshot(path);
    hdfs.setQuota(path, 3, HdfsConstants.QUOTA_DONT_SET);
    FileSystem.create(hdfs, filePath,
        FsPermission.createImmutable((short) 0600)).close();
    hdfs.setXAttr(filePath, name1, value1);

    hdfs.createSnapshot(path, snapshotName);

    byte[] value = hdfs.getXAttr(filePath, name1);
    Assert.assertArrayEquals(value, value1);

    value = hdfs.getXAttr(fileSnapshotPath, name1);
    Assert.assertArrayEquals(value, value1);

    exception.expect(NSQuotaExceededException.class);
    hdfs.removeXAttr(filePath, name1);
  }

  /**
   * Initialize the cluster, wait for it to become active, and get FileSystem
   * instances for our test users.
   * 
   * @param format if true, format the NameNode and DataNodes before starting up
   * @throws Exception if any step fails
   */
  private static void initCluster(boolean format) throws Exception {
    cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1).format(format)
        .build();
    cluster.waitActive();
    hdfs = cluster.getFileSystem();
  }

  /**
   * Restart the cluster, optionally saving a new checkpoint.
   * 
   * @param checkpoint boolean true to save a new checkpoint
   * @throws Exception if restart fails
   */
  private static void restart(boolean checkpoint) throws Exception {
    NameNode nameNode = cluster.getNameNode();
    if (checkpoint) {
      NameNodeAdapter.enterSafeMode(nameNode, false);
      NameNodeAdapter.saveNamespace(nameNode);
    }
    shutdown();
    initCluster(false);
  }
}