/**
* 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.mapreduce.v2.app.launcher;

import static org.mockito.Mockito.mock;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ThreadPoolExecutor;

import junit.framework.Assert;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.MRJobConfig;
import org.apache.hadoop.mapreduce.v2.api.records.JobId;
import org.apache.hadoop.mapreduce.v2.api.records.JobState;
import org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId;
import org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptState;
import org.apache.hadoop.mapreduce.v2.api.records.TaskId;
import org.apache.hadoop.mapreduce.v2.api.records.TaskState;
import org.apache.hadoop.mapreduce.v2.api.records.TaskType;
import org.apache.hadoop.mapreduce.v2.app.AppContext;
import org.apache.hadoop.mapreduce.v2.app.MRApp;
import org.apache.hadoop.mapreduce.v2.app.job.Job;
import org.apache.hadoop.mapreduce.v2.app.job.Task;
import org.apache.hadoop.mapreduce.v2.app.job.TaskAttempt;
import org.apache.hadoop.mapreduce.v2.util.MRBuilderUtils;
import org.apache.hadoop.yarn.api.ContainerManager;
import org.apache.hadoop.yarn.api.records.ApplicationAttemptId;
import org.apache.hadoop.yarn.api.records.ApplicationId;
import org.apache.hadoop.yarn.api.records.ContainerId;
import org.apache.hadoop.yarn.api.records.ContainerToken;
import org.apache.hadoop.yarn.util.BuilderUtils;
import org.junit.Test;

public class TestContainerLauncher {

  static final Log LOG = LogFactory
      .getLog(TestContainerLauncher.class);

  @Test
  public void testPoolSize() throws InterruptedException {

    ApplicationId appId = BuilderUtils.newApplicationId(12345, 67);
    ApplicationAttemptId appAttemptId = BuilderUtils.newApplicationAttemptId(
      appId, 3);
    JobId jobId = MRBuilderUtils.newJobId(appId, 8);
    TaskId taskId = MRBuilderUtils.newTaskId(jobId, 9, TaskType.MAP);
    TaskAttemptId taskAttemptId = MRBuilderUtils.newTaskAttemptId(taskId, 0);
    ContainerId containerId = BuilderUtils.newContainerId(appAttemptId, 10);

    AppContext context = mock(AppContext.class);
    CustomContainerLauncher containerLauncher = new CustomContainerLauncher(
      context);
    containerLauncher.init(new Configuration());
    containerLauncher.start();

    ThreadPoolExecutor threadPool = containerLauncher.getThreadPool();

    // No events yet
    Assert.assertEquals(0, threadPool.getPoolSize());
    Assert.assertEquals(ContainerLauncherImpl.INITIAL_POOL_SIZE,
      threadPool.getCorePoolSize());
    Assert.assertNull(containerLauncher.foundErrors);

    containerLauncher.expectedCorePoolSize = ContainerLauncherImpl.INITIAL_POOL_SIZE;
    for (int i = 0; i < 10; i++) {
      containerLauncher.handle(new ContainerLauncherEvent(taskAttemptId,
        containerId, "host" + i + ":1234", null,
        ContainerLauncher.EventType.CONTAINER_REMOTE_LAUNCH));
    }
    waitForEvents(containerLauncher, 10);
    Assert.assertEquals(10, threadPool.getPoolSize());
    Assert.assertNull(containerLauncher.foundErrors);

    // Same set of hosts, so no change
    containerLauncher.expectedCorePoolSize = ContainerLauncherImpl.INITIAL_POOL_SIZE;
    containerLauncher.finishEventHandling = true;
    for (int i = 0; i < 10; i++) {
      containerLauncher.handle(new ContainerLauncherEvent(taskAttemptId,
        containerId, "host" + i + ":1234", null,
        ContainerLauncher.EventType.CONTAINER_REMOTE_LAUNCH));
    }
    waitForEvents(containerLauncher, 20);
    Assert.assertEquals(10, threadPool.getPoolSize());
    Assert.assertNull(containerLauncher.foundErrors);

    // Different hosts, there should be an increase in core-thread-pool size to
    // 21(11hosts+10buffer)
    // Core pool size should be 21 but the live pool size should be only 11.
    containerLauncher.expectedCorePoolSize = 12 + ContainerLauncherImpl.INITIAL_POOL_SIZE;
    for (int i = 1; i <= 2; i++) {
      containerLauncher.handle(new ContainerLauncherEvent(taskAttemptId,
        containerId, "host1" + i + ":1234", null,
        ContainerLauncher.EventType.CONTAINER_REMOTE_LAUNCH));
    }
    waitForEvents(containerLauncher, 22);
    Assert.assertEquals(12, threadPool.getPoolSize());
    Assert.assertNull(containerLauncher.foundErrors);

    containerLauncher.stop();
  }

  @Test
  public void testPoolLimits() throws InterruptedException {
    ApplicationId appId = BuilderUtils.newApplicationId(12345, 67);
    ApplicationAttemptId appAttemptId = BuilderUtils.newApplicationAttemptId(
      appId, 3);
    JobId jobId = MRBuilderUtils.newJobId(appId, 8);
    TaskId taskId = MRBuilderUtils.newTaskId(jobId, 9, TaskType.MAP);
    TaskAttemptId taskAttemptId = MRBuilderUtils.newTaskAttemptId(taskId, 0);
    ContainerId containerId = BuilderUtils.newContainerId(appAttemptId, 10);

    AppContext context = mock(AppContext.class);
    CustomContainerLauncher containerLauncher = new CustomContainerLauncher(
      context);
    Configuration conf = new Configuration();
    conf.setInt(MRJobConfig.MR_AM_CONTAINERLAUNCHER_THREAD_COUNT_LIMIT, 12);
    containerLauncher.init(conf);
    containerLauncher.start();

    ThreadPoolExecutor threadPool = containerLauncher.getThreadPool();

    // 10 different hosts
    containerLauncher.expectedCorePoolSize = ContainerLauncherImpl.INITIAL_POOL_SIZE;
    for (int i = 0; i < 10; i++) {
      containerLauncher.handle(new ContainerLauncherEvent(taskAttemptId,
        containerId, "host" + i + ":1234", null,
        ContainerLauncher.EventType.CONTAINER_REMOTE_LAUNCH));
    }
    waitForEvents(containerLauncher, 10);
    Assert.assertEquals(10, threadPool.getPoolSize());
    Assert.assertNull(containerLauncher.foundErrors);

    // 4 more different hosts, but thread pool size should be capped at 12
    containerLauncher.expectedCorePoolSize = 12 ;
    for (int i = 1; i <= 4; i++) {
      containerLauncher.handle(new ContainerLauncherEvent(taskAttemptId,
        containerId, "host1" + i + ":1234", null,
        ContainerLauncher.EventType.CONTAINER_REMOTE_LAUNCH));
    }
    waitForEvents(containerLauncher, 12);
    Assert.assertEquals(12, threadPool.getPoolSize());
    Assert.assertNull(containerLauncher.foundErrors);

    // Make some threads ideal so that remaining events are also done.
    containerLauncher.finishEventHandling = true;
    waitForEvents(containerLauncher, 14);
    Assert.assertEquals(12, threadPool.getPoolSize());
    Assert.assertNull(containerLauncher.foundErrors);

    containerLauncher.stop();
  }

  private void waitForEvents(CustomContainerLauncher containerLauncher,
      int expectedNumEvents) throws InterruptedException {
    int timeOut = 20;
    while (expectedNumEvents != containerLauncher.numEventsProcessed
        || timeOut++ < 20) {
      LOG.info("Waiting for number of events to become " + expectedNumEvents
          + ". It is now " + containerLauncher.numEventsProcessed);
      Thread.sleep(1000);
    }
    Assert
      .assertEquals(expectedNumEvents, containerLauncher.numEventsProcessed);
  }

  @Test
  public void testSlowNM() throws Exception {
    test(false);
  }

  @Test
  public void testSlowNMWithInterruptsSwallowed() throws Exception {
    test(true);
  }

  private void test(boolean swallowInterrupts) throws Exception {

    MRApp app = new MRAppWithSlowNM(swallowInterrupts);

    Configuration conf = new Configuration();
    int maxAttempts = 1;
    conf.setInt(MRJobConfig.MAP_MAX_ATTEMPTS, maxAttempts);
    conf.setBoolean(MRJobConfig.JOB_UBERTASK_ENABLE, false);

    // Set low timeout for NM commands
    conf.setInt(ContainerLauncher.MR_AM_NM_COMMAND_TIMEOUT, 3000);

    Job job = app.submit(conf);
    app.waitForState(job, JobState.RUNNING);

    Map<TaskId, Task> tasks = job.getTasks();
    Assert.assertEquals("Num tasks is not correct", 1, tasks.size());

    Task task = tasks.values().iterator().next();
    app.waitForState(task, TaskState.SCHEDULED);

    Map<TaskAttemptId, TaskAttempt> attempts = tasks.values().iterator()
        .next().getAttempts();
    Assert.assertEquals("Num attempts is not correct", maxAttempts, attempts
        .size());

    TaskAttempt attempt = attempts.values().iterator().next();
    app.waitForState(attempt, TaskAttemptState.ASSIGNED);

    app.waitForState(job, JobState.FAILED);

    String diagnostics = attempt.getDiagnostics().toString();
    LOG.info("attempt.getDiagnostics: " + diagnostics);
    if (swallowInterrupts) {
      Assert.assertEquals("[Container launch failed for "
          + "container_0_0000_01_000000 : Start-container for "
          + "container_0_0000_01_000000 got interrupted. Returning.]",
          diagnostics);
    } else {
      Assert.assertTrue(diagnostics.contains("Container launch failed for "
          + "container_0_0000_01_000000 : "));
      Assert.assertTrue(diagnostics
          .contains(": java.lang.InterruptedException"));
    }

    app.stop();
  }

  private final class CustomContainerLauncher extends ContainerLauncherImpl {

    private volatile int expectedCorePoolSize = 0;
    private volatile int numEventsProcessed = 0;
    private volatile String foundErrors = null;
    private volatile boolean finishEventHandling;
    private CustomContainerLauncher(AppContext context) {
      super(context);
    }

    public ThreadPoolExecutor getThreadPool() {
      return super.launcherPool;
    }

    protected ContainerLauncherImpl.EventProcessor createEventProcessor(
        ContainerLauncherEvent event) {
      // At this point of time, the EventProcessor is being created and so no
      // additional threads would have been created.

      // Core-pool-size should have increased by now.
      if (expectedCorePoolSize != launcherPool.getCorePoolSize()) {
        foundErrors = "Expected " + expectedCorePoolSize + " but found "
            + launcherPool.getCorePoolSize();
      }

      return new ContainerLauncherImpl.EventProcessor(event) {
        @Override
        public void run() {
          // do nothing substantial
          numEventsProcessed++;
          // Stall
          synchronized(this) {
            try {
              while(!finishEventHandling) {
                wait(1000);
              }
            } catch (InterruptedException e) {
              ;
            }
          }
        }
      };
    }
  }

  private static class MRAppWithSlowNM extends MRApp {

    final boolean swallowInterrupts;

    public MRAppWithSlowNM(boolean swallowInterrupts) {
      super(1, 0, false, "TestContainerLauncher", true);
      this.swallowInterrupts = swallowInterrupts;
    }

    @Override
    protected ContainerLauncher createContainerLauncher(AppContext context) {
      return new ContainerLauncherImpl(context) {
        @Override
        protected ContainerManager getCMProxy(ContainerId containerID,
            String containerManagerBindAddr, ContainerToken containerToken)
            throws IOException {
          try {
            synchronized (this) {
              wait(); // Just hang the thread simulating a very slow NM.
            }
          } catch (InterruptedException e) {
            LOG.info(e);
            if (!MRAppWithSlowNM.this.swallowInterrupts) {
              throw new IOException(e);
            }
            Thread.currentThread().interrupt();
          }
          return null;
        }
      };
    };
  }
}