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

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.hdfs.MiniDFSCluster.DataNodeProperties;
import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
import org.apache.hadoop.hdfs.server.blockmanagement.BlockManagerTestUtil;
import org.apache.hadoop.hdfs.server.namenode.FSNamesystem;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.StartupOption;
import org.apache.hadoop.hdfs.server.namenode.NameNode;
import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
import org.apache.hadoop.test.GenericTestUtils;

import static org.junit.Assert.*;
import org.junit.Before;
import org.junit.After;
import org.junit.Test;

import com.google.common.base.Supplier;
import com.google.common.collect.Lists;

/**
 * Tests to verify safe mode correctness.
 */
public class TestSafeMode {
  private static final Path TEST_PATH = new Path("/test");
  private static final int BLOCK_SIZE = 1024;
  Configuration conf; 
  MiniDFSCluster cluster;
  FileSystem fs;
  DistributedFileSystem dfs;

  @Before
  public void startUp() throws IOException {
    conf = new HdfsConfiguration();
    conf.setInt(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, BLOCK_SIZE);
    cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1).build();
    cluster.waitActive();      
    fs = cluster.getFileSystem();
    dfs = (DistributedFileSystem)fs;
  }

  @After
  public void tearDown() throws IOException {
    if (fs != null) {
      fs.close();
    }
    if (cluster != null) {
      cluster.shutdown();
    }
  }

  /**
   * This test verifies that if SafeMode is manually entered, name-node does not
   * come out of safe mode even after the startup safe mode conditions are met.
   * <ol>
   * <li>Start cluster with 1 data-node.</li>
   * <li>Create 2 files with replication 1.</li>
   * <li>Re-start cluster with 0 data-nodes. 
   * Name-node should stay in automatic safe-mode.</li>
   * <li>Enter safe mode manually.</li>
   * <li>Start the data-node.</li>
   * <li>Wait longer than <tt>dfs.namenode.safemode.extension</tt> and 
   * verify that the name-node is still in safe mode.</li>
   * </ol>
   *  
   * @throws IOException
   */
  @Test
  public void testManualSafeMode() throws IOException {      
    fs = (DistributedFileSystem)cluster.getFileSystem();
    Path file1 = new Path("/tmp/testManualSafeMode/file1");
    Path file2 = new Path("/tmp/testManualSafeMode/file2");
    
    // create two files with one block each.
    DFSTestUtil.createFile(fs, file1, 1000, (short)1, 0);
    DFSTestUtil.createFile(fs, file2, 1000, (short)1, 0);
    fs.close();
    cluster.shutdown();
    
    // now bring up just the NameNode.
    cluster = new MiniDFSCluster.Builder(conf).numDataNodes(0).format(false).build();
    cluster.waitActive();
    dfs = (DistributedFileSystem)cluster.getFileSystem();
    
    assertTrue("No datanode is started. Should be in SafeMode", 
               dfs.setSafeMode(SafeModeAction.SAFEMODE_GET));
    
    // manually set safemode.
    dfs.setSafeMode(SafeModeAction.SAFEMODE_ENTER);
    
    // now bring up the datanode and wait for it to be active.
    cluster.startDataNodes(conf, 1, true, null, null);
    cluster.waitActive();
    
    // wait longer than dfs.namenode.safemode.extension
    try {
      Thread.sleep(2000);
    } catch (InterruptedException ignored) {}

    assertTrue("should still be in SafeMode",
        dfs.setSafeMode(SafeModeAction.SAFEMODE_GET));
    assertFalse("should not be in SafeMode", 
        dfs.setSafeMode(SafeModeAction.SAFEMODE_LEAVE));
  }

  /**
   * Test that, if there are no blocks in the filesystem,
   * the NameNode doesn't enter the "safemode extension" period.
   */
  @Test(timeout=45000)
  public void testNoExtensionIfNoBlocks() throws IOException {
    cluster.getConfiguration(0).setInt(
        DFSConfigKeys.DFS_NAMENODE_SAFEMODE_EXTENSION_KEY, 60000);
    cluster.restartNameNode();
    // Even though we have safemode extension set high, we should immediately
    // exit safemode on startup because there are no blocks in the namespace.
    String status = cluster.getNameNode().getNamesystem().getSafemode();
    assertEquals("", status);
  }
  
  /**
   * Test that the NN initializes its under-replicated blocks queue
   * before it is ready to exit safemode (HDFS-1476)
   */
  @Test(timeout=45000)
  public void testInitializeReplQueuesEarly() throws Exception {
    // Spray the blocks around the cluster when we add DNs instead of
    // concentrating all blocks on the first node.
    BlockManagerTestUtil.setWritingPrefersLocalNode(
        cluster.getNamesystem().getBlockManager(), false);
    
    cluster.startDataNodes(conf, 2, true, StartupOption.REGULAR, null);
    cluster.waitActive();
    DFSTestUtil.createFile(fs, TEST_PATH, 15*BLOCK_SIZE, (short)1, 1L);
    
    
    List<DataNodeProperties> dnprops = Lists.newLinkedList();
    dnprops.add(cluster.stopDataNode(0));
    dnprops.add(cluster.stopDataNode(0));
    dnprops.add(cluster.stopDataNode(0));
    
    cluster.getConfiguration(0).setFloat(
        DFSConfigKeys.DFS_NAMENODE_REPL_QUEUE_THRESHOLD_PCT_KEY, 1f/15f);
    
    cluster.restartNameNode();
    final NameNode nn = cluster.getNameNode();
    
    String status = nn.getNamesystem().getSafemode();
    assertEquals("Safe mode is ON.The reported blocks 0 needs additional " +
        "15 blocks to reach the threshold 0.9990 of total blocks 15. " +
        "Safe mode will be turned off automatically.", status);
    assertFalse("Mis-replicated block queues should not be initialized " +
        "until threshold is crossed",
        NameNodeAdapter.safeModeInitializedReplQueues(nn));
    
    cluster.restartDataNode(dnprops.remove(0));

    // Wait for the block report from the restarted DN to come in.
    GenericTestUtils.waitFor(new Supplier<Boolean>() {
      @Override
      public Boolean get() {
        return NameNodeAdapter.getSafeModeSafeBlocks(nn) > 0;
      }
    }, 10, 10000);
    // SafeMode is fine-grain synchronized, so the processMisReplicatedBlocks
    // call is still going on at this point - wait until it's done by grabbing
    // the lock.
    nn.getNamesystem().writeLock();
    nn.getNamesystem().writeUnlock();
    int safe = NameNodeAdapter.getSafeModeSafeBlocks(nn);
    assertTrue("Expected first block report to make some but not all blocks " +
        "safe. Got: " + safe, safe >= 1 && safe < 15);
    BlockManagerTestUtil.updateState(nn.getNamesystem().getBlockManager());
    
    assertTrue(NameNodeAdapter.safeModeInitializedReplQueues(nn));
    assertEquals(15 - safe, nn.getNamesystem().getUnderReplicatedBlocks());
    
    cluster.restartDataNodes();
  }

  /**
   * Test that, when under-replicated blocks are processed at the end of
   * safe-mode, blocks currently under construction are not considered
   * under-construction or missing. Regression test for HDFS-2822.
   */
  @Test
  public void testRbwBlocksNotConsideredUnderReplicated() throws IOException {
    List<FSDataOutputStream> stms = Lists.newArrayList();
    try {
      // Create some junk blocks so that the NN doesn't just immediately
      // exit safemode on restart.
      DFSTestUtil.createFile(fs, new Path("/junk-blocks"),
          BLOCK_SIZE*4, (short)1, 1L);
      // Create several files which are left open. It's important to
      // create several here, because otherwise the first iteration of the
      // replication monitor will pull them off the replication queue and
      // hide this bug from the test!
      for (int i = 0; i < 10; i++) {
        FSDataOutputStream stm = fs.create(
            new Path("/append-" + i), true, BLOCK_SIZE, (short) 1, BLOCK_SIZE);
        stms.add(stm);
        stm.write(1);
        stm.hflush();
      }

      cluster.restartNameNode();
      FSNamesystem ns = cluster.getNameNode(0).getNamesystem();
      BlockManagerTestUtil.updateState(ns.getBlockManager());
      assertEquals(0, ns.getPendingReplicationBlocks());
      assertEquals(0, ns.getCorruptReplicaBlocks());
      assertEquals(0, ns.getMissingBlocksCount());

    } finally {
      for (FSDataOutputStream stm : stms) {
        IOUtils.closeStream(stm);
      }
      cluster.shutdown();
    }
  }

  public interface FSRun {
    public abstract void run(FileSystem fs) throws IOException;
  }

  /**
   * Assert that the given function fails to run due to a safe 
   * mode exception.
   */
  public void runFsFun(String msg, FSRun f) {
    try {
      f.run(fs);
      fail(msg);
     } catch (IOException ioe) {
       assertTrue(ioe.getMessage().contains("safe mode"));
     }
  }

  /**
   * Run various fs operations while the NN is in safe mode,
   * assert that they are either allowed or fail as expected.
   */
  @Test
  public void testOperationsWhileInSafeMode() throws IOException {
    final Path file1 = new Path("/file1");

    assertFalse(dfs.setSafeMode(SafeModeAction.SAFEMODE_GET));
    DFSTestUtil.createFile(fs, file1, 1024, (short)1, 0);
    assertTrue("Could not enter SM", 
        dfs.setSafeMode(SafeModeAction.SAFEMODE_ENTER));

    runFsFun("Set quota while in SM", new FSRun() { 
      public void run(FileSystem fs) throws IOException {
        ((DistributedFileSystem)fs).setQuota(file1, 1, 1); 
      }});

    runFsFun("Set perm while in SM", new FSRun() {
      public void run(FileSystem fs) throws IOException {
        fs.setPermission(file1, FsPermission.getDefault());
      }});

    runFsFun("Set owner while in SM", new FSRun() {
      public void run(FileSystem fs) throws IOException {
        fs.setOwner(file1, "user", "group");
      }});

    runFsFun("Set repl while in SM", new FSRun() {
      public void run(FileSystem fs) throws IOException {
        fs.setReplication(file1, (short)1);
      }});

    runFsFun("Append file while in SM", new FSRun() {
      public void run(FileSystem fs) throws IOException {
        DFSTestUtil.appendFile(fs, file1, "new bytes");
      }});

    runFsFun("Delete file while in SM", new FSRun() {
      public void run(FileSystem fs) throws IOException {
        fs.delete(file1, false);
      }});

    runFsFun("Rename file while in SM", new FSRun() {
      public void run(FileSystem fs) throws IOException {
        fs.rename(file1, new Path("file2"));
      }});

    try {
      fs.setTimes(file1, 0, 0);
    } catch (IOException ioe) {
      fail("Set times failed while in SM");
    }

    try {
      DFSTestUtil.readFile(fs, file1);
    } catch (IOException ioe) {
      fail("Set times failed while in SM");
    }

    assertFalse("Could not leave SM",
        dfs.setSafeMode(SafeModeAction.SAFEMODE_LEAVE));
  }

  /**
   * Verify that the NameNode stays in safemode when dfs.safemode.datanode.min
   * is set to a number greater than the number of live datanodes.
   */
  @Test
  public void testDatanodeThreshold() throws IOException {
    cluster.shutdown();
    Configuration conf = cluster.getConfiguration(0);
    conf.setInt(DFSConfigKeys.DFS_NAMENODE_SAFEMODE_EXTENSION_KEY, 0);
    conf.setInt(DFSConfigKeys.DFS_NAMENODE_SAFEMODE_MIN_DATANODES_KEY, 1);

    cluster.restartNameNode();
    fs = (DistributedFileSystem)cluster.getFileSystem();

    String tipMsg = cluster.getNamesystem().getSafemode();
    assertTrue("Safemode tip message looks right: " + tipMsg,
               tipMsg.contains("The number of live datanodes 0 needs an additional " +
                               "1 live datanodes to reach the minimum number 1. " +
                               "Safe mode will be turned off automatically."));

    // Start a datanode
    cluster.startDataNodes(conf, 1, true, null, null);

    // Wait long enough for safemode check to refire
    try {
      Thread.sleep(1000);
    } catch (InterruptedException ignored) {}

    // We now should be out of safe mode.
    assertEquals("", cluster.getNamesystem().getSafemode());
  }

  /*
   * Tests some utility methods that surround the SafeMode's state.
   * @throws IOException when there's an issue connecting to the test DFS.
   */
  public void testSafeModeUtils() throws IOException {
    dfs = (DistributedFileSystem)cluster.getFileSystem();

    // Enter safemode.
    dfs.setSafeMode(SafeModeAction.SAFEMODE_ENTER);
    assertTrue("State was expected to be in safemode.", dfs.isInSafeMode());

    // Exit safemode.
    dfs.setSafeMode(SafeModeAction.SAFEMODE_LEAVE);
    assertFalse("State was expected to be out of safemode.", dfs.isInSafeMode());
  }
}