source: branches/2839_HiveProjectManagement/HeuristicLab.Clients.Hive/3.3/ConcurrentTaskDownloader.cs @ 16057

Last change on this file since 16057 was 16057, checked in by jkarder, 15 months ago

#2839:

File size: 5.2 KB
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1#region License Information
2/* HeuristicLab
3 * Copyright (C) 2002-2018 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
4 *
5 * This file is part of HeuristicLab.
6 *
7 * HeuristicLab is free software: you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation, either version 3 of the License, or
10 * (at your option) any later version.
11 *
12 * HeuristicLab is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
19 */
20#endregion
21
22using System;
23using System.Threading;
24using System.Threading.Tasks;
25using HeuristicLab.Common;
26using HeuristicLab.Hive;
27
28namespace HeuristicLab.Clients.Hive {
29  /// <summary>
30  /// Downloads and deserializes jobs. It avoids too many jobs beeing downloaded or deserialized at the same time to avoid memory problems
31  /// </summary>
32  public class ConcurrentTaskDownloader<T> : IDisposable where T : class, ITask {
33    private bool abort = false;
34    // use semaphore to ensure only few concurrenct connections and few SerializedJob objects in memory
35    private Semaphore downloadSemaphore;
36    private Semaphore deserializeSemaphore;
37
38    public ConcurrentTaskDownloader(int concurrentDownloads, int concurrentDeserializations) {
39      downloadSemaphore = new Semaphore(concurrentDownloads, concurrentDownloads);
40      deserializeSemaphore = new Semaphore(concurrentDeserializations, concurrentDeserializations);
41    }
42
43    public void DownloadTaskData(Task t, Action<Task, T> onFinishedAction) {
44      Task<Tuple<Task, T>> task = Task<Tuple<Task, TaskData>>.Factory.StartNew(DownloadTaskData, t)
45                                     .ContinueWith((y) => DeserializeTask(y.Result));
46
47      task.ContinueWith((x) => OnTaskFinished(x, onFinishedAction), TaskContinuationOptions.ExecuteSynchronously | TaskContinuationOptions.OnlyOnRanToCompletion);
48      task.ContinueWith((x) => OnTaskFailed(x), TaskContinuationOptions.ExecuteSynchronously | TaskContinuationOptions.OnlyOnFaulted);
49    }
50
51    public void DownloadTaskDataAndTask(Guid taskId, Action<Task, T> onFinishedAction) {
52      Task<Tuple<Task, T>> task = Task<Task>.Factory.StartNew(DownloadTask, taskId)
53                                     .ContinueWith((x) => DownloadTaskData(x.Result))
54                                     .ContinueWith((y) => DeserializeTask(y.Result));
55
56      task.ContinueWith((x) => OnTaskFinished(x, onFinishedAction), TaskContinuationOptions.ExecuteSynchronously | TaskContinuationOptions.OnlyOnRanToCompletion);
57      task.ContinueWith((x) => OnTaskFailed(x), TaskContinuationOptions.ExecuteSynchronously | TaskContinuationOptions.OnlyOnFaulted);
58    }
59
60    private void OnTaskFinished(Task<Tuple<Task, T>> task, Action<Task, T> onFinishedAction) {
61      onFinishedAction(task.Result.Item1, task.Result.Item2);
62    }
63    private void OnTaskFailed(Task<Tuple<Task, T>> task) {
64      task.Exception.Flatten().Handle((e) => { return true; });
65      OnExceptionOccured(task.Exception.Flatten());
66    }
67
68    private Task DownloadTask(object taskId) {
69      Task t = null;
70      HiveClient.TryAndRepeat(() => {
71        t = HiveServiceLocator.Instance.CallHiveService(s => s.GetTask((Guid)taskId));
72      }, Settings.Default.MaxRepeatServiceCalls, "Failed to download task.");
73      return t;
74    }
75
76    protected Tuple<Task, TaskData> DownloadTaskData(object taskId) {
77      return DownloadTaskData((Task)taskId);
78    }
79
80    protected Tuple<Task, TaskData> DownloadTaskData(Task task) {
81      downloadSemaphore.WaitOne();
82      TaskData result = null;
83      try {
84        if (abort) return null;
85        HiveClient.TryAndRepeat(() => {
86          result = HiveServiceLocator.Instance.CallHiveService(s => s.GetTaskData(task.Id));
87        }, Settings.Default.MaxRepeatServiceCalls, "Failed to download task data.");
88      }
89      finally {
90        downloadSemaphore.Release();
91      }
92      return new Tuple<Task, TaskData>(task, result);
93    }
94
95    protected Tuple<Task, T> DeserializeTask(Tuple<Task, TaskData> taskData) {
96      deserializeSemaphore.WaitOne();
97      try {
98        if (abort || taskData.Item2 == null || taskData.Item1 == null) return null;
99        var deserializedJob = PersistenceUtil.Deserialize<T>(taskData.Item2.Data);
100        taskData.Item2.Data = null; // reduce memory consumption.
101        return new Tuple<Task, T>(taskData.Item1, deserializedJob);
102      }
103      finally {
104        deserializeSemaphore.Release();
105      }
106    }
107
108    public event EventHandler<EventArgs<Exception>> ExceptionOccured;
109    private void OnExceptionOccured(Exception exception) {
110      var handler = ExceptionOccured;
111      if (handler != null) handler(this, new EventArgs<Exception>(exception));
112    }
113
114    #region IDisposable Members
115    public void Dispose() {
116      deserializeSemaphore.Dispose();
117      downloadSemaphore.Dispose();
118    }
119    #endregion
120  }
121}
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