content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.master.journal.raft;
  
  import static alluxio.master.journal.raft.RaftSnapshotManagerTest.createSampleSnapshot;
  import static alluxio.master.journal.raft.RaftSnapshotManagerTest.createStateMachineStorage;
  
  import net.bytebuddy.utility.RandomString;
  import org.apache.ratis.server.protocol.TermIndex;
  import org.apache.ratis.statemachine.SnapshotInfo;
  import org.apache.ratis.statemachine.SnapshotRetentionPolicy;
  import org.apache.ratis.statemachine.impl.FileListSnapshotInfo;
  import org.apache.ratis.statemachine.impl.SimpleStateMachineStorage;
  import org.apache.ratis.statemachine.impl.SingleFileSnapshotInfo;
  import org.junit.Assert;
  import org.junit.Before;
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.rules.TemporaryFolder;
  
  import java.io.File;
  import java.io.FileOutputStream;
  import java.io.IOException;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.util.stream.Stream;
  
  public class SnapshotDirStateMachineStorageTest {
    @Rule
    public TemporaryFolder mFolder = new TemporaryFolder();
  
    final SnapshotRetentionPolicy mRetentionPolicy = new SnapshotRetentionPolicy() {
      @Override
      public int getNumSnapshotsRetained() {
        return 1; // keep only 1 snapshot
      }
    };
    SnapshotDirStateMachineStorage mStateMachineStorage;
  
    @Before
    public void before() throws IOException {
      mStateMachineStorage = createStateMachineStorage(mFolder);
    }
  
    @Test
    public void noSnapshot() {
      Assert.assertNull(mStateMachineStorage.getLatestSnapshot());
    }
  
    @Test
    public void onlyUpdateOnLoad() throws IOException {
      Assert.assertNull(mStateMachineStorage.getLatestSnapshot());
      createSampleSnapshot(mStateMachineStorage, 1, 10);
      // still null until new information is loaded
      Assert.assertNull(mStateMachineStorage.getLatestSnapshot());
    }
  
    @Test
    public void singleSnapshot() throws IOException {
      createSampleSnapshot(mStateMachineStorage, 1, 10);
      mStateMachineStorage.loadLatestSnapshot();
      SnapshotInfo latestSnapshot = mStateMachineStorage.getLatestSnapshot();
      Assert.assertTrue(latestSnapshot instanceof FileListSnapshotInfo);
      Assert.assertEquals(TermIndex.valueOf(1, 10), latestSnapshot.getTermIndex());
    }
  
    @Test
    public void newerIndex() throws IOException {
      createSampleSnapshot(mStateMachineStorage, 1, 10);
      mStateMachineStorage.loadLatestSnapshot();
      Assert.assertEquals(TermIndex.valueOf(1, 10),
          mStateMachineStorage.getLatestSnapshot().getTermIndex());
      createSampleSnapshot(mStateMachineStorage, 1, 15);
      mStateMachineStorage.loadLatestSnapshot();
      Assert.assertEquals(TermIndex.valueOf(1, 15),
          mStateMachineStorage.getLatestSnapshot().getTermIndex());
    }
  
    @Test
    public void newerTerm() throws IOException {
      createSampleSnapshot(mStateMachineStorage, 1, 10);
      mStateMachineStorage.loadLatestSnapshot();
      Assert.assertEquals(TermIndex.valueOf(1, 10),
          mStateMachineStorage.getLatestSnapshot().getTermIndex());
      createSampleSnapshot(mStateMachineStorage, 2, 5);
      mStateMachineStorage.loadLatestSnapshot();
      Assert.assertEquals(TermIndex.valueOf(2, 5),
          mStateMachineStorage.getLatestSnapshot().getTermIndex());
    }
  
    @Test
    public void noDeletionUnlessSignaled() throws IOException {
      createSampleSnapshot(mStateMachineStorage, 1, 1);
      createSampleSnapshot(mStateMachineStorage, 2, 10);
      createSampleSnapshot(mStateMachineStorage, 3, 100);
  
      mStateMachineStorage.loadLatestSnapshot();
      mStateMachineStorage.cleanupOldSnapshots(mRetentionPolicy);
      // no deletion unless signaled
      try (Stream<Path> s = Files.list(mStateMachineStorage.getSnapshotDir().toPath())) {
        Assert.assertEquals(3, s.count());
      }
    }
  
    @Test
    public void noopDeleteIfEmpty() throws IOException {
      mStateMachineStorage.loadLatestSnapshot();
      mStateMachineStorage.signalNewSnapshot();
      mStateMachineStorage.cleanupOldSnapshots(mRetentionPolicy);
      try (Stream<Path> s = Files.list(mStateMachineStorage.getSnapshotDir().toPath())) {
        Assert.assertEquals(0, s.count());
      }
    }
  
    @Test
    public void noopDeleteIfOneOnly() throws IOException {
      createSampleSnapshot(mStateMachineStorage, 1, 10);
  
      mStateMachineStorage.loadLatestSnapshot();
      mStateMachineStorage.signalNewSnapshot();
      mStateMachineStorage.cleanupOldSnapshots(mRetentionPolicy);
      // no deletion unless signaled
      try (Stream<Path> s = Files.list(mStateMachineStorage.getSnapshotDir().toPath())) {
        Assert.assertEquals(1, s.count());
      }
    }
  
    @Test
    public void deleteMultiple() throws IOException {
      createSampleSnapshot(mStateMachineStorage, 1, 1);
      createSampleSnapshot(mStateMachineStorage, 2, 10);
      createSampleSnapshot(mStateMachineStorage, 3, 100);
  
      mStateMachineStorage.signalNewSnapshot();
      mStateMachineStorage.cleanupOldSnapshots(mRetentionPolicy);
      // no deletion unless signaled
      try (Stream<Path> s = Files.list(mStateMachineStorage.getSnapshotDir().toPath())) {
        Assert.assertEquals(1, s.count());
      }
      mStateMachineStorage.loadLatestSnapshot();
      Assert.assertEquals(TermIndex.valueOf(3, 100),
          mStateMachineStorage.getLatestSnapshot().getTermIndex());
    }
  
    @Test
    public void backwardsCompatible() throws IOException {
      createSampleSnapshot(mStateMachineStorage, 1, 1);
      String snapshotFile = SimpleStateMachineStorage.getSnapshotFileName(2, 10);
      try (FileOutputStream outputStream =
               new FileOutputStream(new File(mStateMachineStorage.getSnapshotDir(), snapshotFile))) {
        outputStream.write(RandomString.make().getBytes());
      }
      mStateMachineStorage.loadLatestSnapshot();
      SnapshotInfo latestSnapshot = mStateMachineStorage.getLatestSnapshot();
      Assert.assertTrue(latestSnapshot instanceof SingleFileSnapshotInfo);
      Assert.assertEquals(TermIndex.valueOf(2, 10), latestSnapshot.getTermIndex());
    }
  }
  