/**
 * 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.*;

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

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HBaseConfiguration;
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.MediumTests;
import org.apache.hadoop.hbase.client.Durability;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.regionserver.HRegion;
import org.apache.hadoop.hbase.util.Bytes;
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 HLog 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 final Path DIR = TEST_UTIL.getDataTestDir("TestDurability");

  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();
    CONF.setLong("hbase.regionserver.optionallogflushinterval", 500*1000);
    TEST_UTIL.startMiniDFSCluster(1);

    CLUSTER = TEST_UTIL.getDFSCluster();
    FS = CLUSTER.getFileSystem();
  }

  @AfterClass
  public static void tearDownAfterClass() throws Exception {
    TEST_UTIL.shutdownMiniCluster();
  }

  @Test
  public void testDurability() throws Exception {
    HLog wal = new HLog(FS, new Path(DIR, "hlogdir"),
        new Path(DIR, "hlogdir_archive"), CONF);
    byte[] tableName = Bytes.toBytes("TestDurability");
    HRegion region = createHRegion(tableName, "region", wal, false);
    HRegion deferredRegion = createHRegion(tableName, "deferredRegion", wal, true);

    region.put(newPut(null));

    verifyHLogCount(wal, 1);

    // a put through the deferred table does not write to the wal immdiately
    deferredRegion.put(newPut(null));
    verifyHLogCount(wal, 1);
    // but will after we sync the wal
    wal.sync();
    verifyHLogCount(wal, 2);

    // a put through a deferred table will be sync with the put sync'ed put
    deferredRegion.put(newPut(null));
    verifyHLogCount(wal, 2);
    region.put(newPut(null));
    verifyHLogCount(wal, 4);

    // a put through a deferred table will be sync with the put sync'ed put
    deferredRegion.put(newPut(Durability.USE_DEFAULT));
    verifyHLogCount(wal, 4);
    region.put(newPut(Durability.USE_DEFAULT));
    verifyHLogCount(wal, 6);

    // SKIP_WAL never writes to the wal
    region.put(newPut(Durability.SKIP_WAL));
    deferredRegion.put(newPut(Durability.SKIP_WAL));
    verifyHLogCount(wal, 6);
    wal.sync();
    verifyHLogCount(wal, 6);

    // async overrides sync table default
    region.put(newPut(Durability.ASYNC_WAL));
    deferredRegion.put(newPut(Durability.ASYNC_WAL));
    verifyHLogCount(wal, 6);
    wal.sync();
    verifyHLogCount(wal, 8);

    // sync overrides async table default
    region.put(newPut(Durability.SYNC_WAL));
    deferredRegion.put(newPut(Durability.SYNC_WAL));
    verifyHLogCount(wal, 10);

    // fsync behaves like sync
    region.put(newPut(Durability.FSYNC_WAL));
    deferredRegion.put(newPut(Durability.FSYNC_WAL));
    verifyHLogCount(wal, 12);
  }

  private Put[] newPut(Durability durability) {
    Put p = new Put(ROW);
    p.add(FAMILY, COL, COL);
    if (durability != null) {
      p.setDurability(durability);
    }
    return new Put[]{p};
  }

  private void verifyHLogCount(HLog log, int expected) throws Exception {
    Path walPath = log.computeFilename();
    HLog.Reader reader = HLog.getReader(FS, walPath, CONF);
    int count = 0;
    HLog.Entry entry = new HLog.Entry();
    while (reader.next(entry) != null) count++;
    reader.close();
    assertEquals(expected, count);
  }

  // lifted from TestAtomicOperation
  private HRegion createHRegion (byte [] tableName, String callingMethod, HLog log, boolean isDeferredLogFlush)
    throws IOException {
      HTableDescriptor htd = new HTableDescriptor(tableName);
      htd.setDeferredLogFlush(isDeferredLogFlush);
      HColumnDescriptor hcd = new HColumnDescriptor(FAMILY);
      htd.addFamily(hcd);
      HRegionInfo info = new HRegionInfo(htd.getName(), 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, HBaseConfiguration.create(), htd, log);
    }

}