Source code

001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *   http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.reef.io.data.output;
020
021import org.apache.reef.driver.context.ServiceConfiguration;
022import org.apache.reef.evaluator.context.events.ContextStop;
023import org.apache.reef.tang.Configuration;
024import org.apache.reef.tang.Tang;
025import org.apache.reef.tang.annotations.Name;
026import org.apache.reef.tang.annotations.NamedParameter;
027import org.apache.reef.tang.annotations.Parameter;
028import org.apache.reef.tang.annotations.Unit;
029import org.apache.reef.task.events.TaskStart;
030import org.apache.reef.wake.EventHandler;
031
032import javax.inject.Inject;
033import java.io.IOException;
034import java.util.logging.Level;
035import java.util.logging.Logger;
036
037/**
038 * A service class of the task output service.
039 * The file output service provides an output stream,
040 * through which tasks write their output to a file
041 * without considering the current runtime
042 * and collision with other tasks.
043 */
044@Unit
045public final class TaskOutputService implements OutputService {
046  private static final Logger LOG = Logger.getLogger(TaskOutputService.class.getName());
047
048  /**
049   * Output stream provider object through which tasks create output streams.
050   */
051  private final TaskOutputStreamProvider taskOutputStreamProvider;
052
053  /**
054   * Path of the directory where output files are created.
055   */
056  private final String outputPath;
057
058  /**
059   * Service constructor - instantiated via TANG.
060   *
061   * @param taskOutputStreamProvider Output stream provider object through which tasks create file output streams.
062   * @param outputPath Path of the directory where output files are created.
063   */
064  @Inject
065  private TaskOutputService(
066      final TaskOutputStreamProvider taskOutputStreamProvider,
067      @Parameter(OutputPath.class) final String outputPath) {
068    this.taskOutputStreamProvider = taskOutputStreamProvider;
069    this.outputPath = outputPath;
070  }
071
072  /**
073   * Provides a service configuration for the output service.
074   *
075   * @return service configuration.
076   */
077  @Override
078  public Configuration getServiceConfiguration() {
079
080    final Configuration partialServiceConf = ServiceConfiguration.CONF
081        .set(ServiceConfiguration.SERVICES, taskOutputStreamProvider.getClass())
082        .set(ServiceConfiguration.ON_CONTEXT_STOP, ContextStopHandler.class)
083        .set(ServiceConfiguration.ON_TASK_STARTED, TaskStartHandler.class)
084        .build();
085
086    return Tang.Factory.getTang()
087        .newConfigurationBuilder(partialServiceConf)
088        .bindImplementation(OutputStreamProvider.class, taskOutputStreamProvider.getClass())
089        .bindImplementation(TaskOutputStreamProvider.class, taskOutputStreamProvider.getClass())
090        .bindNamedParameter(OutputPath.class, outputPath)
091        .build();
092  }
093
094  /**
095   * Handles the ContextStop event: Close the output stream provider.
096   */
097  private final class ContextStopHandler implements EventHandler<ContextStop> {
098    @Override
099    public void onNext(final ContextStop contextStop) {
100      LOG.log(Level.INFO, "Context stopped, close the OutputStreamProvider.");
101      try {
102        taskOutputStreamProvider.close();
103      } catch (final IOException e) {
104        throw new RuntimeException(e);
105      }
106    }
107  }
108
109  /**
110   * Handles the TaskStart event: Set the task id to the output stream provider.
111   */
112  private final class TaskStartHandler implements EventHandler<TaskStart> {
113    @Override
114    public void onNext(final TaskStart taskStart) {
115      LOG.log(Level.INFO, String.format("Task %s started, create the OutputStreamProvider.", taskStart.getId()));
116      taskOutputStreamProvider.setTaskId(taskStart.getId());
117    }
118  }
119
120  /**
121   * Path of the directory where output files are created.
122   */
123  @NamedParameter(doc = "Path of the directory where output files are created")
124  public static final class OutputPath implements Name<String> {
125  }
126}