/**
 * 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
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p/>
 * 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.datanode.fsdataset.impl;


import java.util.function.Supplier;
import org.apache.hadoop.fs.CreateFlag;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.hdfs.DFSOutputStream;
import org.apache.hadoop.hdfs.DFSTestUtil;
import org.apache.hadoop.hdfs.server.blockmanagement.BlockManagerTestUtil;
import org.apache.hadoop.hdfs.server.datanode.DataNodeTestUtils;
import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsDatasetSpi;
import org.apache.hadoop.test.GenericTestUtils;
import org.junit.Test;

import java.io.IOException;
import java.util.EnumSet;
import java.util.concurrent.TimeoutException;

import static org.apache.hadoop.fs.CreateFlag.CREATE;
import static org.apache.hadoop.fs.CreateFlag.LAZY_PERSIST;
import static org.apache.hadoop.fs.StorageType.DEFAULT;
import static org.apache.hadoop.fs.StorageType.RAM_DISK;
import static org.hamcrest.core.Is.is;
import static org.junit.Assert.assertThat;

/**
 * Verify that locked memory is used correctly when writing to replicas in
 * memory
 */
public class TestLazyPersistLockedMemory extends LazyPersistTestCase {

  /**
   * RAM disk present but locked memory is set to zero. Placement should
   * fall back to disk.
   */
  @Test
  public void testWithNoLockedMemory()
      throws IOException, TimeoutException, InterruptedException {
    getClusterBuilder().setNumDatanodes(1)
                       .setMaxLockedMemory(0).build();

    final String METHOD_NAME = GenericTestUtils.getMethodName();
    Path path = new Path("/" + METHOD_NAME + ".dat");
    makeTestFile(path, BLOCK_SIZE, true);
    ensureFileReplicasOnStorageType(path, DEFAULT);
  }

  @Test
  public void testReservation()
      throws IOException, TimeoutException, InterruptedException {
    getClusterBuilder().setNumDatanodes(1)
                       .setMaxLockedMemory(BLOCK_SIZE).build();
    final String METHOD_NAME = GenericTestUtils.getMethodName();
    final FsDatasetSpi<?> fsd = cluster.getDataNodes().get(0).getFSDataset();

    // Create a file and ensure the replica in RAM_DISK uses locked memory.
    Path path = new Path("/" + METHOD_NAME + ".dat");
    makeTestFile(path, BLOCK_SIZE, true);
    ensureFileReplicasOnStorageType(path, RAM_DISK);
    assertThat(fsd.getCacheUsed(), is((long) BLOCK_SIZE));
  }

  @Test
  public void testReleaseOnFileDeletion()
      throws IOException, TimeoutException, InterruptedException {
    getClusterBuilder().setNumDatanodes(1)
                       .setMaxLockedMemory(BLOCK_SIZE).build();
    final String METHOD_NAME = GenericTestUtils.getMethodName();
    final FsDatasetSpi<?> fsd = cluster.getDataNodes().get(0).getFSDataset();

    Path path = new Path("/" + METHOD_NAME + ".dat");
    makeTestFile(path, BLOCK_SIZE, true);
    ensureFileReplicasOnStorageType(path, RAM_DISK);
    assertThat(fsd.getCacheUsed(), is((long) BLOCK_SIZE));

    // Delete the file and ensure that the locked memory is released.
    fs.delete(path, false);
    DataNodeTestUtils.triggerBlockReport(cluster.getDataNodes().get(0));
    waitForLockedBytesUsed(fsd, 0);
  }

  /**
   * Verify that locked RAM is released when blocks are evicted from RAM disk.
   */
  @Test
  public void testReleaseOnEviction() throws Exception {
    getClusterBuilder().setNumDatanodes(1)
                       .setMaxLockedMemory(BLOCK_SIZE)
                       .setRamDiskReplicaCapacity(BLOCK_SIZE * 2 - 1)
                       .build();
    final String METHOD_NAME = GenericTestUtils.getMethodName();
    final FsDatasetImpl fsd =
        (FsDatasetImpl) cluster.getDataNodes().get(0).getFSDataset();

    Path path1 = new Path("/" + METHOD_NAME + ".01.dat");
    makeTestFile(path1, BLOCK_SIZE, true);
    assertThat(fsd.getCacheUsed(), is((long) BLOCK_SIZE));

    // Wait until the replica is written to persistent storage.
    waitForMetric("RamDiskBlocksLazyPersisted", 1);

    // Trigger eviction and verify locked bytes were released.
    fsd.evictLazyPersistBlocks(Long.MAX_VALUE);
    verifyRamDiskJMXMetric("RamDiskBlocksEvicted", 1);
    waitForLockedBytesUsed(fsd, 0);
  }

  /**
   * Verify that locked bytes are correctly updated when a block is finalized
   * at less than its max length.
   */
  @Test
  public void testShortBlockFinalized()
      throws IOException, TimeoutException, InterruptedException {
    getClusterBuilder().setNumDatanodes(1).build();
    final String METHOD_NAME = GenericTestUtils.getMethodName();
    final FsDatasetSpi<?> fsd = cluster.getDataNodes().get(0).getFSDataset();

    Path path = new Path("/" + METHOD_NAME + ".dat");
    makeTestFile(path, 1, true);
    assertThat(fsd.getCacheUsed(), is(osPageSize));

    // Delete the file and ensure locked RAM usage goes to zero.
    fs.delete(path, false);
    waitForLockedBytesUsed(fsd, 0);
  }

  /**
   * Verify that locked bytes are correctly updated when the client goes
   * away unexpectedly during a write.
   */
  @Test
  public void testWritePipelineFailure()
    throws IOException, TimeoutException, InterruptedException {
    getClusterBuilder().setNumDatanodes(1).build();
    final String METHOD_NAME = GenericTestUtils.getMethodName();
    final FsDatasetSpi<?> fsd = cluster.getDataNodes().get(0).getFSDataset();

    Path path = new Path("/" + METHOD_NAME + ".dat");

    EnumSet<CreateFlag> createFlags = EnumSet.of(CREATE, LAZY_PERSIST);
    // Write 1 byte to the file and kill the writer.
    final FSDataOutputStream fos =
        fs.create(path,
                  FsPermission.getFileDefault(),
                  createFlags,
                  BUFFER_LENGTH,
                  REPL_FACTOR,
                  BLOCK_SIZE,
                  null);

    fos.write(new byte[1]);
    fos.hsync();
    DFSTestUtil.abortStream((DFSOutputStream) fos.getWrappedStream());
    waitForLockedBytesUsed(fsd, osPageSize);

    // Delete the file and ensure locked RAM goes to zero.
    fs.delete(path, false);
    BlockManagerTestUtil.waitForMarkedDeleteQueueIsEmpty(
        cluster.getNamesystem(0).getBlockManager());
    DataNodeTestUtils.triggerBlockReport(cluster.getDataNodes().get(0));
    waitForLockedBytesUsed(fsd, 0);
  }

  /**
   * Wait until used locked byte count goes to the expected value.
   * @throws TimeoutException after 300 seconds.
   */
  private void waitForLockedBytesUsed(final FsDatasetSpi<?> fsd,
                                      final long expectedLockedBytes)
      throws TimeoutException, InterruptedException {
    GenericTestUtils.waitFor(new Supplier<Boolean>() {
      @Override
      public Boolean get() {
        long cacheUsed = fsd.getCacheUsed();
        LOG.info("cacheUsed=" + cacheUsed + ", waiting for it to be " + expectedLockedBytes);
        if (cacheUsed < 0) {
          throw new IllegalStateException("cacheUsed unpexpectedly negative");
        }
        return (cacheUsed == expectedLockedBytes);
      }
    }, 1000, 300000);
  }
}
