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.job.command;
  
  import alluxio.grpc.CancelTaskCommand;
  import alluxio.grpc.JobCommand;
  import alluxio.grpc.RunTaskCommand;
  import alluxio.grpc.SetTaskPoolSizeCommand;
  import alluxio.job.JobConfig;
  import alluxio.job.util.SerializationUtils;
  
  import com.google.common.collect.Lists;
  import com.google.common.collect.Maps;
  import com.google.protobuf.ByteString;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.util.List;
  import java.util.Map;
  import javax.annotation.concurrent.ThreadSafe;
  
  /**
   * A command manager that manages the commands to issue to the workers.
   */
  @ThreadSafe
  public final class CommandManager {
  
    private static final Logger LOG = LoggerFactory.getLogger(CommandManager.class);
  
    // TODO(yupeng) add retry support
    private final Map<Long, List<JobCommand>> mWorkerIdToPendingCommands = Maps.newHashMap();
  
    /**
     * Constructs a new {@link CommandManager}.
     */
    public CommandManager() {}
  
    /**
     * Submits a run-task command to a specified worker.
     *
     * @param jobId the id of the job
     * @param taskId the id of the task
     * @param jobConfig the job configuration
     * @param taskArgs the arguments passed to the executor on the worker
     * @param workerId the id of the worker
     */
    public synchronized void submitRunTaskCommand(long jobId, long taskId, JobConfig jobConfig,
        Object taskArgs, long workerId) {
      RunTaskCommand.Builder runTaskCommand = RunTaskCommand.newBuilder();
      runTaskCommand.setJobId(jobId);
      runTaskCommand.setTaskId(taskId);
      try {
        runTaskCommand.setJobConfig(ByteString.copyFrom(SerializationUtils.serialize(jobConfig)));
        if (taskArgs != null) {
          runTaskCommand.setTaskArgs(ByteString.copyFrom(SerializationUtils.serialize(taskArgs)));
        }
      } catch (IOException e) {
        // TODO(yupeng) better exception handling
        LOG.info("Failed to serialize the run task command:" + e);
        return;
      }
      JobCommand.Builder command = JobCommand.newBuilder();
      command.setRunTaskCommand(runTaskCommand);
      submit(workerId, command);
    }
  
    /**
     * Submits a cancel-task command to a specified worker.
     *
     * @param jobId the job id
     * @param taskId the task id
     * @param workerId the worker id
     */
    public synchronized void submitCancelTaskCommand(long jobId, long taskId, long workerId) {
      CancelTaskCommand.Builder cancelTaskCommand = CancelTaskCommand.newBuilder();
      cancelTaskCommand.setJobId(jobId);
      cancelTaskCommand.setTaskId(taskId);
      JobCommand.Builder command = JobCommand.newBuilder();
      command.setCancelTaskCommand(cancelTaskCommand);
      submit(workerId, command);
    }
  
    /**
     * Submits a set thread pool size command to specific worker.
     *
     * @param workerId the worker id
     * @param taskPoolSize the task pool size
     */
    public synchronized void submitSetTaskPoolSizeCommand(long workerId, int taskPoolSize) {
      SetTaskPoolSizeCommand.Builder setTaskPoolSizeCommand = SetTaskPoolSizeCommand.newBuilder();
      setTaskPoolSizeCommand.setTaskPoolSize(taskPoolSize);
  
      JobCommand.Builder command = JobCommand.newBuilder();
      command.setSetTaskPoolSizeCommand(setTaskPoolSizeCommand);
      submit(workerId, command);
    }
  
    private synchronized void submit(long workerId, JobCommand.Builder command) {
      if (!mWorkerIdToPendingCommands.containsKey(workerId)) {
        mWorkerIdToPendingCommands.put(workerId, Lists.newArrayList());
      }
      mWorkerIdToPendingCommands.get(workerId).add(command.build());
    }
  
    /**
     * Polls all the pending commands to a worker and removes the commands from the queue.
     *
     * @param workerId id of the worker to send the commands to
     * @return the list of the commends polled
     */
    public synchronized List<alluxio.grpc.JobCommand> pollAllPendingCommands(long workerId) {
      if (!mWorkerIdToPendingCommands.containsKey(workerId)) {
        return Lists.newArrayList();
      }
      List<JobCommand> commands =
          Lists.newArrayList(mWorkerIdToPendingCommands.get(workerId));
      mWorkerIdToPendingCommands.get(workerId).clear();
      return commands;
    }
  }
  