/**
 * 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.hdfs;

import static org.mockito.ArgumentMatchers.anyBoolean;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.ArgumentMatchers.anyShort;
import static org.mockito.ArgumentMatchers.anyLong;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.Mockito.doNothing;
import static org.mockito.Mockito.doThrow;
import static org.mockito.Mockito.spy;

import java.io.DataOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.security.PrivilegedExceptionAction;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Options;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.hdfs.client.impl.LeaseRenewer;
import org.apache.hadoop.hdfs.protocol.ClientProtocol;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocols;
import org.apache.hadoop.ipc.RemoteException;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.security.token.SecretManager.InvalidToken;
import org.apache.hadoop.test.GenericTestUtils;
import org.apache.hadoop.util.Time;
import org.junit.Assert;
import org.junit.Test;
import org.mockito.Mockito;

public class TestLease {
  static boolean hasLease(MiniDFSCluster cluster, Path src) {
    return NameNodeAdapter.getLeaseForPath(cluster.getNameNode(),
            src.toString()) != null;
  }

  static int leaseCount(MiniDFSCluster cluster) {
    return NameNodeAdapter.getLeaseManager(cluster.getNamesystem()).countLease();
  }
  
  static final String dirString = "/test/lease";
  final Path dir = new Path(dirString);
  static final Logger LOG = LoggerFactory.getLogger(TestLease.class);
  final Configuration conf = new HdfsConfiguration();

  @Test
  public void testLeaseAbort() throws Exception {
    MiniDFSCluster cluster =
        new MiniDFSCluster.Builder(conf).numDataNodes(2).build();
    try {
      cluster.waitActive();
      NamenodeProtocols preSpyNN = cluster.getNameNodeRpc();
      NamenodeProtocols spyNN = spy(preSpyNN);

      DFSClient dfs = new DFSClient(null, spyNN, conf, null);
      byte[] buf = new byte[1024];

      FSDataOutputStream c_out = createFsOut(dfs, dirString + "c");
      c_out.write(buf, 0, 1024);
      c_out.close();

      DFSInputStream c_in = dfs.open(dirString + "c");
      FSDataOutputStream d_out = createFsOut(dfs, dirString + "d");

      // stub the renew method.
      doThrow(new RemoteException(InvalidToken.class.getName(),
          "Your token is worthless")).when(spyNN).renewLease(
              anyString(), any());

      // We don't need to wait the lease renewer thread to act.
      // call renewLease() manually.
      // make it look like the soft limit has been exceeded.
      LeaseRenewer originalRenewer = dfs.getLeaseRenewer();
      dfs.lastLeaseRenewal = Time.monotonicNow() -
          HdfsConstants.LEASE_SOFTLIMIT_PERIOD - 1000;
      try {
        dfs.renewLease();
      } catch (IOException e) {}

      // Things should continue to work it passes hard limit without
      // renewing.
      try {
        d_out.write(buf, 0, 1024);
        LOG.info("Write worked beyond the soft limit as expected.");
      } catch (IOException e) {
        Assert.fail("Write failed.");
      }

      long hardlimit = conf.getLong(DFSConfigKeys.DFS_LEASE_HARDLIMIT_KEY,
          DFSConfigKeys.DFS_LEASE_HARDLIMIT_DEFAULT) * 1000;
      // make it look like the hard limit has been exceeded.
      dfs.lastLeaseRenewal = Time.monotonicNow() - hardlimit - 1000;
      dfs.renewLease();

      // this should not work.
      try {
        d_out.write(buf, 0, 1024);
        d_out.close();
        Assert.fail("Write did not fail even after the fatal lease renewal failure");
      } catch (IOException e) {
        LOG.info("Write failed as expected. ", e);
      }

      // If aborted, the renewer should be empty. (no reference to clients)
      Thread.sleep(1000);
      Assert.assertTrue(originalRenewer.isEmpty());

      // unstub
      doNothing().when(spyNN).renewLease(anyString(), any());

      // existing input streams should work
      try {
        int num = c_in.read(buf, 0, 1);
        if (num != 1) {
          Assert.fail("Failed to read 1 byte");
        }
        c_in.close();
      } catch (IOException e) {
         LOG.error("Read failed with ", e);
         Assert.fail("Read after lease renewal failure failed");
      }

      // new file writes should work.
      try {
        c_out = createFsOut(dfs, dirString + "c");
        c_out.write(buf, 0, 1024);
        c_out.close();
      } catch (IOException e) {
        LOG.error("Write failed with ", e);
        Assert.fail("Write failed");
      }
    } finally {
      cluster.shutdown();
    }
  }

  @Test
  public void testLeaseAfterRename() throws Exception {
    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).numDataNodes(2).build();
    try {
      Path p = new Path("/test-file");
      Path d = new Path("/test-d");
      Path d2 = new Path("/test-d-other");

      // open a file to get a lease
      FileSystem fs = cluster.getFileSystem();
      FSDataOutputStream out = fs.create(p);
      out.writeBytes("something");
      //out.hsync();
      Assert.assertTrue(hasLease(cluster, p));
      Assert.assertEquals(1, leaseCount(cluster));
      
      // just to ensure first fs doesn't have any logic to twiddle leases
      DistributedFileSystem fs2 = (DistributedFileSystem) FileSystem.newInstance(fs.getUri(), fs.getConf());

      // rename the file into an existing dir
      LOG.info("DMS: rename file into dir");
      Path pRenamed = new Path(d, p.getName());
      fs2.mkdirs(d);
      fs2.rename(p, pRenamed);
      Assert.assertFalse(p+" exists", fs2.exists(p));
      Assert.assertTrue(pRenamed+" not found", fs2.exists(pRenamed));
      Assert.assertFalse("has lease for "+p, hasLease(cluster, p));
      Assert.assertTrue("no lease for "+pRenamed, hasLease(cluster, pRenamed));
      Assert.assertEquals(1, leaseCount(cluster));
    
      // rename the parent dir to a new non-existent dir
      LOG.info("DMS: rename parent dir");
      Path pRenamedAgain = new Path(d2, pRenamed.getName());
      fs2.rename(d, d2);
      // src gone
      Assert.assertFalse(d+" exists", fs2.exists(d));
      Assert.assertFalse("has lease for "+pRenamed, hasLease(cluster, pRenamed));
      // dst checks
      Assert.assertTrue(d2+" not found", fs2.exists(d2));
      Assert.assertTrue(pRenamedAgain+" not found", fs2.exists(pRenamedAgain));
      Assert.assertTrue("no lease for "+pRenamedAgain, hasLease(cluster, pRenamedAgain));
      Assert.assertEquals(1, leaseCount(cluster));

      // rename the parent dir to existing dir
      // NOTE: rename w/o options moves paths into existing dir
      LOG.info("DMS: rename parent again");
      pRenamed = pRenamedAgain;
      pRenamedAgain = new Path(new Path(d, d2.getName()), p.getName());      
      fs2.mkdirs(d);
      fs2.rename(d2, d);
      // src gone
      Assert.assertFalse(d2+" exists", fs2.exists(d2));
      Assert.assertFalse("no lease for "+pRenamed, hasLease(cluster, pRenamed));
      // dst checks
      Assert.assertTrue(d+" not found", fs2.exists(d));
      Assert.assertTrue(pRenamedAgain +" not found", fs2.exists(pRenamedAgain));
      Assert.assertTrue("no lease for "+pRenamedAgain, hasLease(cluster, pRenamedAgain));
      Assert.assertEquals(1, leaseCount(cluster));
      
      // rename with opts to non-existent dir
      pRenamed = pRenamedAgain;
      pRenamedAgain = new Path(d2, p.getName());
      fs2.rename(pRenamed.getParent(), d2, Options.Rename.OVERWRITE);
      // src gone
      Assert.assertFalse(pRenamed.getParent() +" not found", fs2.exists(pRenamed.getParent()));
      Assert.assertFalse("has lease for "+pRenamed, hasLease(cluster, pRenamed));
      // dst checks
      Assert.assertTrue(d2+" not found", fs2.exists(d2));
      Assert.assertTrue(pRenamedAgain+" not found", fs2.exists(pRenamedAgain));
      Assert.assertTrue("no lease for "+pRenamedAgain, hasLease(cluster, pRenamedAgain));
      Assert.assertEquals(1, leaseCount(cluster));

      // rename with opts to existing dir
      // NOTE: rename with options will not move paths into the existing dir
      pRenamed = pRenamedAgain;
      pRenamedAgain = new Path(d, p.getName());
      fs2.rename(pRenamed.getParent(), d, Options.Rename.OVERWRITE);
      // src gone
      Assert.assertFalse(pRenamed.getParent() +" not found", fs2.exists(pRenamed.getParent()));
      Assert.assertFalse("has lease for "+pRenamed, hasLease(cluster, pRenamed));
      // dst checks
      Assert.assertTrue(d+" not found", fs2.exists(d));
      Assert.assertTrue(pRenamedAgain+" not found", fs2.exists(pRenamedAgain));
      Assert.assertTrue("no lease for "+pRenamedAgain, hasLease(cluster, pRenamedAgain));
      Assert.assertEquals(1, leaseCount(cluster));
      out.close();
    } finally {
      cluster.shutdown();
    }
  }

  /**
   * Test that we can open up a file for write, move it to another location,
   * and then create a new file in the previous location, without causing any
   * lease conflicts.  This is possible because we now use unique inode IDs
   * to identify files to the NameNode.
   */
  @Test
  public void testLeaseAfterRenameAndRecreate() throws Exception {
    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).numDataNodes(2).build();
    try {
      final Path path1 = new Path("/test-file");
      final String contents1 = "contents1";
      final Path path2 = new Path("/test-file-new-location");
      final String contents2 = "contents2";

      // open a file to get a lease
      FileSystem fs = cluster.getFileSystem();
      FSDataOutputStream out1 = fs.create(path1);
      out1.writeBytes(contents1);
      Assert.assertTrue(hasLease(cluster, path1));
      Assert.assertEquals(1, leaseCount(cluster));

      DistributedFileSystem fs2 = (DistributedFileSystem)
          FileSystem.newInstance(fs.getUri(), fs.getConf());
      fs2.rename(path1, path2);

      FSDataOutputStream out2 = fs2.create(path1);
      out2.writeBytes(contents2);
      out2.close();

      // The first file should still be open and valid
      Assert.assertTrue(hasLease(cluster, path2));
      out1.close();

      // Contents should be as expected
      DistributedFileSystem fs3 = (DistributedFileSystem)
          FileSystem.newInstance(fs.getUri(), fs.getConf());
      Assert.assertEquals(contents1, DFSTestUtil.readFile(fs3, path2));
      Assert.assertEquals(contents2, DFSTestUtil.readFile(fs3, path1));
    } finally {
      cluster.shutdown();
    }
  }

  @Test
  public void testLease() throws Exception {
    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).numDataNodes(2).build();
    try {
      FileSystem fs = cluster.getFileSystem();
      Assert.assertTrue(fs.mkdirs(dir));
      
      Path a = new Path(dir, "a");
      Path b = new Path(dir, "b");

      DataOutputStream a_out = fs.create(a);
      a_out.writeBytes("something");

      Assert.assertTrue(hasLease(cluster, a));
      Assert.assertTrue(!hasLease(cluster, b));
      
      DataOutputStream b_out = fs.create(b);
      b_out.writeBytes("something");

      Assert.assertTrue(hasLease(cluster, a));
      Assert.assertTrue(hasLease(cluster, b));

      a_out.close();
      b_out.close();

      Assert.assertTrue(!hasLease(cluster, a));
      Assert.assertTrue(!hasLease(cluster, b));

      Path fileA = new Path(dir, "fileA");
      FSDataOutputStream fileA_out = fs.create(fileA);
      fileA_out.writeBytes("something");
      Assert.assertTrue("Failed to get the lease!", hasLease(cluster, fileA));

      fs.delete(dir, true);
      try {
        fileA_out.hflush();
        Assert.fail("Should validate file existence!");
      } catch (FileNotFoundException e) {
        // expected
        GenericTestUtils.assertExceptionContains("File does not exist", e);
      }
    } finally {
      if (cluster != null) {cluster.shutdown();}
    }
  }

  @SuppressWarnings("unchecked")
  @Test
  public void testFactory() throws Exception {
    final String[] groups = new String[]{"supergroup"};
    final UserGroupInformation[] ugi = new UserGroupInformation[3];
    for(int i = 0; i < ugi.length; i++) {
      ugi[i] = UserGroupInformation.createUserForTesting("user" + i, groups);
    }

    Mockito.doReturn(new HdfsFileStatus.Builder()
          .replication(1)
          .blocksize(1024)
          .perm(new FsPermission((short) 777))
          .owner("owner")
          .group("group")
          .symlink(new byte[0])
          .path(new byte[0])
          .fileId(1010)
          .build())
        .when(mcp)
        .getFileInfo(anyString());
    Mockito.doReturn(new HdfsFileStatus.Builder()
          .replication(1)
          .blocksize(1024)
          .perm(new FsPermission((short) 777))
          .owner("owner")
          .group("group")
          .symlink(new byte[0])
          .path(new byte[0])
          .fileId(1010)
          .build())
        .when(mcp)
        .create(anyString(), any(), anyString(),
            any(), anyBoolean(), anyShort(), anyLong(), any(), any(), any());

    final Configuration conf = new Configuration();
    final DFSClient c1 = createDFSClientAs(ugi[0], conf);
    FSDataOutputStream out1 = createFsOut(c1, "/out1");
    final DFSClient c2 = createDFSClientAs(ugi[0], conf);
    FSDataOutputStream out2 = createFsOut(c2, "/out2");
    Assert.assertEquals(c1.getLeaseRenewer(), c2.getLeaseRenewer());
    final DFSClient c3 = createDFSClientAs(ugi[1], conf);
    FSDataOutputStream out3 = createFsOut(c3, "/out3");
    Assert.assertTrue(c1.getLeaseRenewer() != c3.getLeaseRenewer());
    final DFSClient c4 = createDFSClientAs(ugi[1], conf);
    FSDataOutputStream out4 = createFsOut(c4, "/out4");
    Assert.assertEquals(c3.getLeaseRenewer(), c4.getLeaseRenewer());
    final DFSClient c5 = createDFSClientAs(ugi[2], conf);
    FSDataOutputStream out5 = createFsOut(c5, "/out5");
    Assert.assertTrue(c1.getLeaseRenewer() != c5.getLeaseRenewer());
    Assert.assertTrue(c3.getLeaseRenewer() != c5.getLeaseRenewer());
  }
  
  private FSDataOutputStream createFsOut(DFSClient dfs, String path) 
      throws IOException {
    return new FSDataOutputStream(dfs.create(path, true), null);
  }

  static final ClientProtocol mcp = Mockito.mock(ClientProtocol.class);
  static public DFSClient createDFSClientAs(UserGroupInformation ugi, 
      final Configuration conf) throws Exception {
    return ugi.doAs(new PrivilegedExceptionAction<DFSClient>() {
      @Override
      public DFSClient run() throws Exception {
        return new DFSClient(null, mcp, conf, null);
      }
    });
  }
}
