/**
    * 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.regionserver.wal;
  
  import static org.junit.Assert.assertEquals;
  import static org.junit.Assert.assertNull;
  
  import java.io.IOException;
  
  import org.apache.hadoop.conf.Configuration;
  import org.apache.hadoop.fs.FileSystem;
  import org.apache.hadoop.fs.Path;
  import org.apache.hadoop.hbase.HBaseTestingUtility;
  import org.apache.hadoop.hbase.HColumnDescriptor;
  import org.apache.hadoop.hbase.HRegionInfo;
  import org.apache.hadoop.hbase.HTableDescriptor;
  import org.apache.hadoop.hbase.testclassification.MediumTests;
  import org.apache.hadoop.hbase.TableName;
  import org.apache.hadoop.hbase.client.Durability;
  import org.apache.hadoop.hbase.client.Increment;
  import org.apache.hadoop.hbase.client.Put;
  import org.apache.hadoop.hbase.client.Result;
  import org.apache.hadoop.hbase.regionserver.HRegion;
  import org.apache.hadoop.hbase.util.Bytes;
  import org.apache.hadoop.hbase.util.FSUtils;
  import org.apache.hadoop.hbase.wal.DefaultWALProvider;
  import org.apache.hadoop.hbase.wal.WAL;
  import org.apache.hadoop.hbase.wal.WALFactory;
  import org.apache.hadoop.hdfs.MiniDFSCluster;
  import org.junit.AfterClass;
  import org.junit.BeforeClass;
  import org.junit.Test;
  import org.junit.experimental.categories.Category;
  
  /**
   * Tests for WAL write durability
   */
  @Category(MediumTests.class)
  public class TestDurability {
    private static final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
    private static FileSystem FS;
    private static MiniDFSCluster CLUSTER;
    private static Configuration CONF;
    private static Path DIR;
  
    private static byte[] FAMILY = Bytes.toBytes("family");
    private static byte[] ROW = Bytes.toBytes("row");
    private static byte[] COL = Bytes.toBytes("col");
  
  
    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
      CONF = TEST_UTIL.getConfiguration();
      TEST_UTIL.startMiniDFSCluster(1);
  
      CLUSTER = TEST_UTIL.getDFSCluster();
      FS = CLUSTER.getFileSystem();
      DIR = TEST_UTIL.getDataTestDirOnTestFS("TestDurability");
      FSUtils.setRootDir(CONF, DIR);
    }
  
    @AfterClass
    public static void tearDownAfterClass() throws Exception {
      TEST_UTIL.shutdownMiniCluster();
    }
  
    @Test
    public void testDurability() throws Exception {
      final WALFactory wals = new WALFactory(CONF, null, "TestDurability");
      byte[] tableName = Bytes.toBytes("TestDurability");
      final WAL wal = wals.getWAL(tableName, null);
      HRegion region = createHRegion(tableName, "region", wal, Durability.USE_DEFAULT);
      HRegion deferredRegion = createHRegion(tableName, "deferredRegion", wal, Durability.ASYNC_WAL);
  
      region.put(newPut(null));
      verifyWALCount(wals, wal, 1);
  
      // a put through the deferred table does not write to the wal immediately,
      // but maybe has been successfully sync-ed by the underlying AsyncWriter +
      // AsyncFlusher thread
      deferredRegion.put(newPut(null));
      // but will after we sync the wal
      wal.sync();
     verifyWALCount(wals, wal, 2);
 
     // a put through a deferred table will be sync with the put sync'ed put
     deferredRegion.put(newPut(null));
     wal.sync();
     verifyWALCount(wals, wal, 3);
     region.put(newPut(null));
     verifyWALCount(wals, wal, 4);
 
     // a put through a deferred table will be sync with the put sync'ed put
     deferredRegion.put(newPut(Durability.USE_DEFAULT));
     wal.sync();
     verifyWALCount(wals, wal, 5);
     region.put(newPut(Durability.USE_DEFAULT));
     verifyWALCount(wals, wal, 6);
 
     // SKIP_WAL never writes to the wal
     region.put(newPut(Durability.SKIP_WAL));
     deferredRegion.put(newPut(Durability.SKIP_WAL));
     verifyWALCount(wals, wal, 6);
     wal.sync();
     verifyWALCount(wals, wal, 6);
 
     // Async overrides sync table default
     region.put(newPut(Durability.ASYNC_WAL));
     deferredRegion.put(newPut(Durability.ASYNC_WAL));
     wal.sync();
     verifyWALCount(wals, wal, 8);
 
     // sync overrides async table default
     region.put(newPut(Durability.SYNC_WAL));
     deferredRegion.put(newPut(Durability.SYNC_WAL));
     verifyWALCount(wals, wal, 10);
 
     // fsync behaves like sync
     region.put(newPut(Durability.FSYNC_WAL));
     deferredRegion.put(newPut(Durability.FSYNC_WAL));
     verifyWALCount(wals, wal, 12);
   }
 
   @Test
   public void testIncrement() throws Exception {
     byte[] row1 = Bytes.toBytes("row1");
     byte[] col1 = Bytes.toBytes("col1");
     byte[] col2 = Bytes.toBytes("col2");
     byte[] col3 = Bytes.toBytes("col3");
 
     // Setting up region
     final WALFactory wals = new WALFactory(CONF, null, "TestIncrement");
     byte[] tableName = Bytes.toBytes("TestIncrement");
     final WAL wal = wals.getWAL(tableName, null);
     HRegion region = createHRegion(tableName, "increment", wal, Durability.USE_DEFAULT);
 
     // col1: amount = 0, 1 write back to WAL
     Increment inc1 = new Increment(row1);
     inc1.addColumn(FAMILY, col1, 0);
     Result res = region.increment(inc1);
     assertEquals(1, res.size());
     assertEquals(0, Bytes.toLong(res.getValue(FAMILY, col1)));
     verifyWALCount(wals, wal, 1);
 
     // col1: amount = 1, 1 write back to WAL
     inc1 = new Increment(row1);
     inc1.addColumn(FAMILY, col1, 1);
     res = region.increment(inc1);
     assertEquals(1, res.size());
     assertEquals(1, Bytes.toLong(res.getValue(FAMILY, col1)));
     verifyWALCount(wals, wal, 2);
 
     // col1: amount = 0, 0 write back to WAL
     inc1 = new Increment(row1);
     inc1.addColumn(FAMILY, col1, 0);
     res = region.increment(inc1);
     assertEquals(1, res.size());
     assertEquals(1, Bytes.toLong(res.getValue(FAMILY, col1)));
     verifyWALCount(wals, wal, 2);
 
     // col1: amount = 0, col2: amount = 0, col3: amount = 0
     // 1 write back to WAL
     inc1 = new Increment(row1);
     inc1.addColumn(FAMILY, col1, 0);
     inc1.addColumn(FAMILY, col2, 0);
     inc1.addColumn(FAMILY, col3, 0);
     res = region.increment(inc1);
     assertEquals(3, res.size());
     assertEquals(1, Bytes.toLong(res.getValue(FAMILY, col1)));
     assertEquals(0, Bytes.toLong(res.getValue(FAMILY, col2)));
     assertEquals(0, Bytes.toLong(res.getValue(FAMILY, col3)));
     verifyWALCount(wals, wal, 3);
 
     // col1: amount = 5, col2: amount = 4, col3: amount = 3
     // 1 write back to WAL
     inc1 = new Increment(row1);
     inc1.addColumn(FAMILY, col1, 5);
     inc1.addColumn(FAMILY, col2, 4);
     inc1.addColumn(FAMILY, col3, 3);
     res = region.increment(inc1);
     assertEquals(3, res.size());
     assertEquals(6, Bytes.toLong(res.getValue(FAMILY, col1)));
     assertEquals(4, Bytes.toLong(res.getValue(FAMILY, col2)));
     assertEquals(3, Bytes.toLong(res.getValue(FAMILY, col3)));
     verifyWALCount(wals, wal, 4);
   }
   
   /*
    * Test when returnResults set to false in increment it should not return the result instead it
    * resturn null.
    */
   @Test
   public void testIncrementWithReturnResultsSetToFalse() throws Exception {
     byte[] row1 = Bytes.toBytes("row1");
     byte[] col1 = Bytes.toBytes("col1");
 
     // Setting up region
     final WALFactory wals = new WALFactory(CONF, null, "testIncrementWithReturnResultsSetToFalse");
     byte[] tableName = Bytes.toBytes("testIncrementWithReturnResultsSetToFalse");
     final WAL wal = wals.getWAL(tableName, null);
     HRegion region = createHRegion(tableName, "increment", wal, Durability.USE_DEFAULT);
 
     Increment inc1 = new Increment(row1);
     inc1.setReturnResults(false);
     inc1.addColumn(FAMILY, col1, 1);
     Result res = region.increment(inc1);
     assertNull(res);
   }
 
   private Put newPut(Durability durability) {
     Put p = new Put(ROW);
     p.add(FAMILY, COL, COL);
     if (durability != null) {
       p.setDurability(durability);
     }
     return p;
   }
 
   private void verifyWALCount(WALFactory wals, WAL log, int expected) throws Exception {
     Path walPath = DefaultWALProvider.getCurrentFileName(log);
     WAL.Reader reader = wals.createReader(FS, walPath);
     int count = 0;
     WAL.Entry entry = new WAL.Entry();
     while (reader.next(entry) != null) count++;
     reader.close();
     assertEquals(expected, count);
   }
 
   // lifted from TestAtomicOperation
   private HRegion createHRegion (byte [] tableName, String callingMethod,
       WAL log, Durability durability)
     throws IOException {
       HTableDescriptor htd = new HTableDescriptor(TableName.valueOf(tableName));
       htd.setDurability(durability);
       HColumnDescriptor hcd = new HColumnDescriptor(FAMILY);
       htd.addFamily(hcd);
       HRegionInfo info = new HRegionInfo(htd.getTableName(), null, null, false);
       Path path = new Path(DIR + callingMethod);
       if (FS.exists(path)) {
         if (!FS.delete(path, true)) {
           throw new IOException("Failed delete of " + path);
         }
       }
       return HRegion.createHRegion(info, path, CONF, htd, log);
     }
 
 }