/**
    * 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.hbase.snapshot;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertTrue;
  
  import java.io.IOException;
  import java.net.URI;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileStatus;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.CategoryBasedTimeout;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HConstants;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.client.Admin;
  import org.apache.hadoop.hbase.client.HTable;
  import org.apache.hadoop.hbase.client.Table;
  import org.apache.hadoop.hbase.master.snapshot.SnapshotManager;
  import org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription;
  import org.apache.hadoop.hbase.protobuf.generated.SnapshotProtos.SnapshotFileInfo;
  import org.apache.hadoop.hbase.protobuf.generated.SnapshotProtos.SnapshotRegionManifest;
  import org.apache.hadoop.hbase.snapshot.SnapshotTestingUtils.SnapshotMock;
  import org.apache.hadoop.hbase.testclassification.MediumTests;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.apache.hadoop.hbase.util.Pair;
  import org.junit.After;
  import org.junit.AfterClass;
  import org.junit.Before;
  import org.junit.BeforeClass;
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  import org.junit.rules.TestRule;
  
  /**
   * Test Export Snapshot Tool
   */
  @Category(MediumTests.class)
  public class TestExportSnapshot {
    @Rule public final TestRule timeout = CategoryBasedTimeout.builder().
        withTimeout(this.getClass()).withLookingForStuckThread(true).build();
    private static final Log LOG = LogFactory.getLog(TestExportSnapshot.class);
  
    protected final static HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
  
    private final static byte[] FAMILY = Bytes.toBytes("cf");
  
    private byte[] emptySnapshotName;
    private byte[] snapshotName;
    private int tableNumFiles;
    private TableName tableName;
    private Admin admin;
  
    public static void setUpBaseConf(Configuration conf) {
      conf.setBoolean(SnapshotManager.HBASE_SNAPSHOT_ENABLED, true);
      conf.setInt("hbase.regionserver.msginterval", 100);
      conf.setInt("hbase.client.pause", 250);
      conf.setInt(HConstants.HBASE_CLIENT_RETRIES_NUMBER, 6);
      conf.setBoolean("hbase.master.enabletable.roundrobin", true);
      conf.setInt("mapreduce.map.maxattempts", 10);
    }
  
    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
      setUpBaseConf(TEST_UTIL.getConfiguration());
      TEST_UTIL.startMiniCluster(3);
      TEST_UTIL.startMiniMapReduceCluster();
    }
  
    @AfterClass
    public static void tearDownAfterClass() throws Exception {
     TEST_UTIL.shutdownMiniMapReduceCluster();
     TEST_UTIL.shutdownMiniCluster();
   }
 
   /**
    * Create a table and take a snapshot of the table used by the export test.
    */
   @Before
   public void setUp() throws Exception {
     this.admin = TEST_UTIL.getHBaseAdmin();
 
     long tid = System.currentTimeMillis();
     tableName = TableName.valueOf("testtb-" + tid);
     snapshotName = Bytes.toBytes("snaptb0-" + tid);
     emptySnapshotName = Bytes.toBytes("emptySnaptb0-" + tid);
 
     // create Table
     SnapshotTestingUtils.createTable(TEST_UTIL, tableName, FAMILY);
 
     // Take an empty snapshot
     admin.snapshot(emptySnapshotName, tableName);
 
     // Add some rows
     SnapshotTestingUtils.loadData(TEST_UTIL, tableName, 50, FAMILY);
     tableNumFiles = admin.getTableRegions(tableName).size();
 
     // take a snapshot
     admin.snapshot(snapshotName, tableName);
   }
 
   @After
   public void tearDown() throws Exception {
     TEST_UTIL.deleteTable(tableName);
     SnapshotTestingUtils.deleteAllSnapshots(TEST_UTIL.getHBaseAdmin());
     SnapshotTestingUtils.deleteArchiveDirectory(TEST_UTIL);
   }
 
 
   /**
    * Verfy the result of getBalanceSplits() method.
    * The result are groups of files, used as input list for the "export" mappers.
    * All the groups should have similar amount of data.
    *
    * The input list is a pair of file path and length.
    * The getBalanceSplits() function sort it by length,
    * and assign to each group a file, going back and forth through the groups.
    */
   @Test
   public void testBalanceSplit() throws Exception {
     // Create a list of files
     List<Pair<SnapshotFileInfo, Long>> files = new ArrayList<Pair<SnapshotFileInfo, Long>>();
     for (long i = 0; i <= 20; i++) {
       SnapshotFileInfo fileInfo = SnapshotFileInfo.newBuilder()
         .setType(SnapshotFileInfo.Type.HFILE)
         .setHfile("file-" + i)
         .build();
       files.add(new Pair<SnapshotFileInfo, Long>(fileInfo, i));
     }
 
     // Create 5 groups (total size 210)
     //    group 0: 20, 11, 10,  1 (total size: 42)
     //    group 1: 19, 12,  9,  2 (total size: 42)
     //    group 2: 18, 13,  8,  3 (total size: 42)
     //    group 3: 17, 12,  7,  4 (total size: 42)
     //    group 4: 16, 11,  6,  5 (total size: 42)
     List<List<Pair<SnapshotFileInfo, Long>>> splits = ExportSnapshot.getBalancedSplits(files, 5);
     assertEquals(5, splits.size());
 
     String[] split0 = new String[] {"file-20", "file-11", "file-10", "file-1", "file-0"};
     verifyBalanceSplit(splits.get(0), split0, 42);
     String[] split1 = new String[] {"file-19", "file-12", "file-9",  "file-2"};
     verifyBalanceSplit(splits.get(1), split1, 42);
     String[] split2 = new String[] {"file-18", "file-13", "file-8",  "file-3"};
     verifyBalanceSplit(splits.get(2), split2, 42);
     String[] split3 = new String[] {"file-17", "file-14", "file-7",  "file-4"};
     verifyBalanceSplit(splits.get(3), split3, 42);
     String[] split4 = new String[] {"file-16", "file-15", "file-6",  "file-5"};
     verifyBalanceSplit(splits.get(4), split4, 42);
   }
 
   private void verifyBalanceSplit(final List<Pair<SnapshotFileInfo, Long>> split,
       final String[] expected, final long expectedSize) {
     assertEquals(expected.length, split.size());
     long totalSize = 0;
     for (int i = 0; i < expected.length; ++i) {
       Pair<SnapshotFileInfo, Long> fileInfo = split.get(i);
       assertEquals(expected[i], fileInfo.getFirst().getHfile());
       totalSize += fileInfo.getSecond();
     }
     assertEquals(expectedSize, totalSize);
   }
 
   /**
    * Verify if exported snapshot and copied files matches the original one.
    */
   @Test
   public void testExportFileSystemState() throws Exception {
     testExportFileSystemState(tableName, snapshotName, snapshotName, tableNumFiles);
   }
 
   @Test
   public void testExportFileSystemStateWithSkipTmp() throws Exception {
     TEST_UTIL.getConfiguration().setBoolean(ExportSnapshot.CONF_SKIP_TMP, true);
     testExportFileSystemState(tableName, snapshotName, snapshotName, tableNumFiles);
   }
 
   @Test
   public void testEmptyExportFileSystemState() throws Exception {
     testExportFileSystemState(tableName, emptySnapshotName, emptySnapshotName, 0);
   }
 
   @Test
   public void testConsecutiveExports() throws Exception {
     Path copyDir = getLocalDestinationDir();
     testExportFileSystemState(tableName, snapshotName, snapshotName, tableNumFiles, copyDir, false);
     testExportFileSystemState(tableName, snapshotName, snapshotName, tableNumFiles, copyDir, true);
     removeExportDir(copyDir);
   }
 
   @Test
   public void testExportWithTargetName() throws Exception {
     final byte[] targetName = Bytes.toBytes("testExportWithTargetName");
     testExportFileSystemState(tableName, snapshotName, targetName, tableNumFiles);
   }
 
   /**
    * Mock a snapshot with files in the archive dir,
    * two regions, and one reference file.
    */
   @Test
   public void testSnapshotWithRefsExportFileSystemState() throws Exception {
     Configuration conf = TEST_UTIL.getConfiguration();
 
     Path rootDir = TEST_UTIL.getHBaseCluster().getMaster().getMasterFileSystem().getRootDir();
     FileSystem fs = TEST_UTIL.getHBaseCluster().getMaster().getMasterFileSystem().getFileSystem();
 
     SnapshotMock snapshotMock = new SnapshotMock(TEST_UTIL.getConfiguration(), fs, rootDir);
     SnapshotMock.SnapshotBuilder builder =
         snapshotMock.createSnapshotV2("tableWithRefsV1", "tableWithRefsV1");
     testSnapshotWithRefsExportFileSystemState(builder);
 
     snapshotMock = new SnapshotMock(TEST_UTIL.getConfiguration(), fs, rootDir);
     builder = snapshotMock.createSnapshotV2("tableWithRefsV2", "tableWithRefsV1");
     testSnapshotWithRefsExportFileSystemState(builder);
   }
 
   /**
    * Generates a couple of regions for the specified SnapshotMock,
    * and then it will run the export and verification.
    */
   private void testSnapshotWithRefsExportFileSystemState(SnapshotMock.SnapshotBuilder builder)
       throws Exception {
     Path[] r1Files = builder.addRegion();
     Path[] r2Files = builder.addRegion();
     builder.commit();
     int snapshotFilesCount = r1Files.length + r2Files.length;
 
     byte[] snapshotName = Bytes.toBytes(builder.getSnapshotDescription().getName());
     TableName tableName = builder.getTableDescriptor().getTableName();
     testExportFileSystemState(tableName, snapshotName, snapshotName, snapshotFilesCount);
   }
 
   private void testExportFileSystemState(final TableName tableName, final byte[] snapshotName,
       final byte[] targetName, int filesExpected) throws Exception {
     Path copyDir = getHdfsDestinationDir();
     testExportFileSystemState(tableName, snapshotName, targetName, filesExpected, copyDir, false);
     removeExportDir(copyDir);
   }
 
   /**
    * Test ExportSnapshot
    */
   private void testExportFileSystemState(final TableName tableName, final byte[] snapshotName,
       final byte[] targetName, int filesExpected, Path copyDir, boolean overwrite)
       throws Exception {
     URI hdfsUri = FileSystem.get(TEST_UTIL.getConfiguration()).getUri();
     FileSystem fs = FileSystem.get(copyDir.toUri(), new Configuration());
     copyDir = copyDir.makeQualified(fs);
 
     List<String> opts = new ArrayList<String>();
     opts.add("-snapshot");
     opts.add(Bytes.toString(snapshotName));
     opts.add("-copy-to");
     opts.add(copyDir.toString());
     if (targetName != snapshotName) {
       opts.add("-target");
       opts.add(Bytes.toString(targetName));
     }
     if (overwrite) opts.add("-overwrite");
 
     // Export Snapshot
     int res = ExportSnapshot.innerMain(TEST_UTIL.getConfiguration(),
         opts.toArray(new String[opts.size()]));
     assertEquals(0, res);
 
     // Verify File-System state
     FileStatus[] rootFiles = fs.listStatus(copyDir);
     assertEquals(filesExpected > 0 ? 2 : 1, rootFiles.length);
     for (FileStatus fileStatus: rootFiles) {
       String name = fileStatus.getPath().getName();
       assertTrue(fileStatus.isDirectory());
       assertTrue(name.equals(HConstants.SNAPSHOT_DIR_NAME) ||
                  name.equals(HConstants.HFILE_ARCHIVE_DIRECTORY));
     }
 
     // compare the snapshot metadata and verify the hfiles
     final FileSystem hdfs = FileSystem.get(hdfsUri, TEST_UTIL.getConfiguration());
     final Path snapshotDir = new Path(HConstants.SNAPSHOT_DIR_NAME, Bytes.toString(snapshotName));
     final Path targetDir = new Path(HConstants.SNAPSHOT_DIR_NAME, Bytes.toString(targetName));
     verifySnapshotDir(hdfs, new Path(TEST_UTIL.getDefaultRootDirPath(), snapshotDir),
         fs, new Path(copyDir, targetDir));
     Set<String> snapshotFiles = verifySnapshot(fs, copyDir, tableName, Bytes.toString(targetName));
     assertEquals(filesExpected, snapshotFiles.size());
   }
 
   /**
    * Check that ExportSnapshot will return a failure if something fails.
    */
   @Test
   public void testExportFailure() throws Exception {
     assertEquals(1, runExportAndInjectFailures(snapshotName, false));
   }
 
   /**
    * Check that ExportSnapshot will succede if something fails but the retry succede.
    */
   @Test
   public void testExportRetry() throws Exception {
     assertEquals(0, runExportAndInjectFailures(snapshotName, true));
   }
 
   /*
    * Execute the ExportSnapshot job injecting failures
    */
   private int runExportAndInjectFailures(final byte[] snapshotName, boolean retry)
       throws Exception {
     Path copyDir = getLocalDestinationDir();
     URI hdfsUri = FileSystem.get(TEST_UTIL.getConfiguration()).getUri();
     FileSystem fs = FileSystem.get(copyDir.toUri(), new Configuration());
     copyDir = copyDir.makeQualified(fs);
 
     Configuration conf = new Configuration(TEST_UTIL.getConfiguration());
     conf.setBoolean(ExportSnapshot.CONF_TEST_FAILURE, true);
     conf.setBoolean(ExportSnapshot.CONF_TEST_RETRY, retry);
 
     // Export Snapshot
     Path sourceDir = TEST_UTIL.getHBaseCluster().getMaster().getMasterFileSystem().getRootDir();
     int res = ExportSnapshot.innerMain(conf, new String[] {
       "-snapshot", Bytes.toString(snapshotName),
       "-copy-from", sourceDir.toString(),
       "-copy-to", copyDir.toString()
     });
     return res;
   }
 
   /*
    * verify if the snapshot folder on file-system 1 match the one on file-system 2
    */
   private void verifySnapshotDir(final FileSystem fs1, final Path root1,
       final FileSystem fs2, final Path root2) throws IOException {
     assertEquals(listFiles(fs1, root1, root1), listFiles(fs2, root2, root2));
   }
 
   /*
    * Verify if the files exists
    */
   private Set<String> verifySnapshot(final FileSystem fs, final Path rootDir,
       final TableName tableName, final String snapshotName) throws IOException {
     final Path exportedSnapshot = new Path(rootDir,
       new Path(HConstants.SNAPSHOT_DIR_NAME, snapshotName));
     final Set<String> snapshotFiles = new HashSet<String>();
     final Path exportedArchive = new Path(rootDir, HConstants.HFILE_ARCHIVE_DIRECTORY);
     SnapshotReferenceUtil.visitReferencedFiles(TEST_UTIL.getConfiguration(), fs, exportedSnapshot,
           new SnapshotReferenceUtil.SnapshotVisitor() {
         @Override
         public void storeFile(final HRegionInfo regionInfo, final String family,
             final SnapshotRegionManifest.StoreFile storeFile) throws IOException {
           String hfile = storeFile.getName();
           snapshotFiles.add(hfile);
           if (storeFile.hasReference()) {
             // Nothing to do here, we have already the reference embedded
           } else {
             verifyNonEmptyFile(new Path(exportedArchive,
               new Path(FSUtils.getTableDir(new Path("./"), tableName),
                   new Path(regionInfo.getEncodedName(), new Path(family, hfile)))));
           }
         }
 
         private void verifyNonEmptyFile(final Path path) throws IOException {
           assertTrue(path + " should exists", fs.exists(path));
           assertTrue(path + " should not be empty", fs.getFileStatus(path).getLen() > 0);
         }
     });
 
     // Verify Snapshot description
     SnapshotDescription desc = SnapshotDescriptionUtils.readSnapshotInfo(fs, exportedSnapshot);
     assertTrue(desc.getName().equals(snapshotName));
     assertTrue(desc.getTable().equals(tableName.getNameAsString()));
     return snapshotFiles;
   }
 
   private Set<String> listFiles(final FileSystem fs, final Path root, final Path dir)
       throws IOException {
     Set<String> files = new HashSet<String>();
     int rootPrefix = root.toString().length();
     FileStatus[] list = FSUtils.listStatus(fs, dir);
     if (list != null) {
       for (FileStatus fstat: list) {
         LOG.debug(fstat.getPath());
         if (fstat.isDirectory()) {
           files.addAll(listFiles(fs, root, fstat.getPath()));
         } else {
           files.add(fstat.getPath().toString().substring(rootPrefix));
         }
       }
     }
     return files;
   }
 
   private Path getHdfsDestinationDir() {
     Path rootDir = TEST_UTIL.getHBaseCluster().getMaster().getMasterFileSystem().getRootDir();
     Path path = new Path(new Path(rootDir, "export-test"), "export-" + System.currentTimeMillis());
     LOG.info("HDFS export destination path: " + path);
     return path;
   }
 
   private Path getLocalDestinationDir() {
     Path path = TEST_UTIL.getDataTestDir("local-export-" + System.currentTimeMillis());
     LOG.info("Local export destination path: " + path);
     return path;
   }
 
   private void removeExportDir(final Path path) throws IOException {
     FileSystem fs = FileSystem.get(path.toUri(), new Configuration());
     fs.delete(path, true);
   }
 }