/**
 * 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.master;

import static org.junit.Assert.assertNotNull;

import java.io.IOException;
import java.util.concurrent.CountDownLatch;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseClassTestRule;
import org.apache.hadoop.hbase.HBaseTestingUtility;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.MiniHBaseCluster;
import org.apache.hadoop.hbase.StartMiniClusterOption;
import org.apache.hadoop.hbase.testclassification.MasterTests;
import org.apache.hadoop.hbase.testclassification.MediumTests;
import org.apache.hadoop.hbase.util.JVMClusterUtil.MasterThread;
import org.apache.zookeeper.KeeperException;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.ClassRule;
import org.junit.Test;
import org.junit.experimental.categories.Category;

/**
 * Test to confirm that we will not hang when stop a backup master which is trying to become the
 * active master. See HBASE-19838
 */
@Category({ MasterTests.class, MediumTests.class })
public class TestShutdownBackupMaster {

  @ClassRule
  public static final HBaseClassTestRule CLASS_RULE =
      HBaseClassTestRule.forClass(TestShutdownBackupMaster.class);

  private static final HBaseTestingUtility UTIL = new HBaseTestingUtility();

  private static volatile CountDownLatch ARRIVE;

  private static volatile CountDownLatch CONTINUE;

  public static final class MockHMaster extends HMaster {

    public MockHMaster(Configuration conf) throws IOException, KeeperException {
      super(conf);
    }

    @Override
    protected void initClusterSchemaService() throws IOException, InterruptedException {
      if (ARRIVE != null) {
        ARRIVE.countDown();
        CONTINUE.await();
      }
      super.initClusterSchemaService();
    }
  }

  @BeforeClass
  public static void setUpBeforeClass() throws Exception {
    UTIL.getConfiguration().setClass(HConstants.MASTER_IMPL, MockHMaster.class, HMaster.class);
    StartMiniClusterOption option = StartMiniClusterOption.builder()
        .numMasters(2).numRegionServers(2).numDataNodes(2).build();
    UTIL.startMiniCluster(option);
    UTIL.waitUntilAllSystemRegionsAssigned();
  }

  @AfterClass
  public static void tearDownAfterClass() throws Exception {
    // make sure that we can stop the cluster cleanly
    UTIL.shutdownMiniCluster();
  }

  @Test
  public void testShutdownWhileBecomingActive() throws InterruptedException {
    MiniHBaseCluster cluster = UTIL.getHBaseCluster();
    HMaster activeMaster = null;
    HMaster backupMaster = null;
    for (MasterThread t : cluster.getMasterThreads()) {
      if (t.getMaster().isActiveMaster()) {
        activeMaster = t.getMaster();
      } else {
        backupMaster = t.getMaster();
      }
    }
    assertNotNull(activeMaster);
    assertNotNull(backupMaster);
    ARRIVE = new CountDownLatch(1);
    CONTINUE = new CountDownLatch(1);
    activeMaster.abort("Aborting active master for test");
    // wait until we arrive the initClusterSchemaService
    ARRIVE.await();
    // killall RSes
    cluster.getRegionServerThreads().stream().map(t -> t.getRegionServer())
        .forEachOrdered(rs -> rs.abort("Aborting RS for test"));
    CONTINUE.countDown();
  }
}
