source: branches/HeuristicLab.Hive-3.4/sources/HeuristicLab.HiveEngine/3.4/HiveEngine.cs @ 6198

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using HeuristicLab.Clients.Hive;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Hive;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.PluginInfrastructure;

namespace HeuristicLab.HiveEngine {
  /// <summary>
  /// Represents an engine that executes operations which can be executed in parallel on the hive
  /// </summary>
  [StorableClass]
  [Item("Hive Engine", "Engine for parallel execution on the hive. You need enable `Parallel` for at least one operator in your operator graph to have all childoperations parallelized. Also those childoperations must not have sideeffects on a higher scope.")]
  public class HiveEngine : Engine {
    private Semaphore maxConcurrentConnections = new Semaphore(4, 4); // avoid too many connections
    private Semaphore maxSerializedJobsInMemory = new Semaphore(4, 4); // avoid memory problems
    private CancellationToken cancellationToken;

    [Storable]
    private IOperator currentOperator;

    [Storable]
    public string ResourceNames { get; set; }

    [Storable]
    private int priority;
    public int Priority {
      get { return priority; }
      set { priority = value; }
    }

    [Storable]
    private TimeSpan executionTimeOnHive;
    public TimeSpan ExecutionTimeOnHive {
      get { return executionTimeOnHive; }
      set {
        if (value != executionTimeOnHive) {
          executionTimeOnHive = value;
          OnExecutionTimeOnHiveChanged();
        }
      }
    }

    [Storable]
    private bool useLocalPlugins;
    public bool UseLocalPlugins {
      get { return useLocalPlugins; }
      set { useLocalPlugins = value; }
    }

    [Storable]
    private ItemCollection<RefreshableHiveExperiment> hiveExperiments;
    public ItemCollection<RefreshableHiveExperiment> HiveExperiments {
      get { return hiveExperiments; }
      set { hiveExperiments = value; }
    }

    private List<Plugin> onlinePlugins;
    public List<Plugin> OnlinePlugins {
      get { return onlinePlugins; }
      set { onlinePlugins = value; }
    }

    private List<Plugin> alreadyUploadedPlugins;
    public List<Plugin> AlreadyUploadedPlugins {
      get { return alreadyUploadedPlugins; }
      set { alreadyUploadedPlugins = value; }
    }

    #region constructors and cloning
    public HiveEngine() {
      ResourceNames = "HEAL";
      HiveExperiments = new ItemCollection<RefreshableHiveExperiment>();
      Priority = 0;
    }

    [StorableConstructor]
    protected HiveEngine(bool deserializing) : base(deserializing) { }
    protected HiveEngine(HiveEngine original, Cloner cloner)
      : base(original, cloner) {
      this.ResourceNames = original.ResourceNames;
      this.currentOperator = cloner.Clone(original.currentOperator);
      this.priority = original.priority;
      this.executionTimeOnHive = original.executionTimeOnHive;
      this.useLocalPlugins = original.useLocalPlugins;
    }
    public override IDeepCloneable Clone(Cloner cloner) {
      return new HiveEngine(this, cloner);
    }
    #endregion

    #region Events
    protected override void OnPrepared() {
      base.OnPrepared();
      this.ExecutionTimeOnHive = TimeSpan.Zero;
    }

    public event EventHandler ExecutionTimeOnHiveChanged;
    protected virtual void OnExecutionTimeOnHiveChanged() {
      var handler = ExecutionTimeOnHiveChanged;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    #endregion

    protected override void Run(CancellationToken cancellationToken) {
      this.cancellationToken = cancellationToken;
      Run(ExecutionStack);
    }

    private void Run(object state) {
      Stack<IOperation> executionStack = (Stack<IOperation>)state;
      IOperation next;
      OperationCollection coll;
      IAtomicOperation operation;
      TaskScheduler.UnobservedTaskException += new EventHandler<UnobservedTaskExceptionEventArgs>(TaskScheduler_UnobservedTaskException);

      this.OnlinePlugins = ServiceLocator.Instance.CallHiveService(s => s.GetPlugins()).Where(x => x.IsLocal == false).ToList();
      this.AlreadyUploadedPlugins = new List<Plugin>();

      while (ExecutionStack.Count > 0) {
        cancellationToken.ThrowIfCancellationRequested();

        next = ExecutionStack.Pop();
        if (next is OperationCollection) {
          coll = (OperationCollection)next;
          if (coll.Parallel) {
            // clone the parent scope here and reuse it for each operation. otherwise for each job the whole scope-tree first needs to be copied and then cleaned, which causes a lot of work for the Garbage Collector
            IScope parentScopeClone = (IScope)((IAtomicOperation)coll.First()).Scope.Parent.Clone();
            parentScopeClone.SubScopes.Clear();
            parentScopeClone.ClearParentScopes();

            EngineJob[] jobs = new EngineJob[coll.Count];
            for (int i = 0; i < coll.Count; i++) {
              jobs[i] = new EngineJob(coll[i], new SequentialEngine.SequentialEngine());
            }

            IScope[] scopes = ExecuteOnHive(jobs, parentScopeClone, cancellationToken);
            //IScope[] scopes = ExecuteLocally(jobs, parentScopeClone, cancellationToken);

            for (int i = 0; i < coll.Count; i++) {
              if (coll[i] is IAtomicOperation) {
                ExchangeScope(scopes[i], ((IAtomicOperation)coll[i]).Scope);
              } else if (coll[i] is OperationCollection) {
                // todo ??
              }
            }
          } else {
            for (int i = coll.Count - 1; i >= 0; i--)
              if (coll[i] != null) executionStack.Push(coll[i]);
          }
        } else if (next is IAtomicOperation) {
          operation = (IAtomicOperation)next;
          try {
            next = operation.Operator.Execute((IExecutionContext)operation, cancellationToken);
          }
          catch (Exception ex) {
            ExecutionStack.Push(operation);
            if (ex is OperationCanceledException) throw ex;
            else throw new OperatorExecutionException(operation.Operator, ex);
          }
          if (next != null) ExecutionStack.Push(next);

          if (operation.Operator.Breakpoint) {
            LogMessage(string.Format("Breakpoint: {0}", operation.Operator.Name != string.Empty ? operation.Operator.Name : operation.Operator.ItemName));
            Pause();
          }
        }
      }
    }

    private void TaskScheduler_UnobservedTaskException(object sender, UnobservedTaskExceptionEventArgs e) {
      e.SetObserved(); // avoid crash of process
    }

    private IRandom FindRandomParameter(IExecutionContext ec) {
      try {
        if (ec == null)
          return null;

        foreach (var p in ec.Parameters) {
          if (p.Name == "Random" && p is IValueParameter)
            return ((IValueParameter)p).Value as IRandom;
        }
        return FindRandomParameter(ec.Parent);
      }
      catch { return null; }
    }

    private static void ReIntegrateScope(IAtomicOperation source, IAtomicOperation target) {
      ExchangeScope(source.Scope, target.Scope);
    }

    private static void ExchangeScope(IScope source, IScope target) {
      target.Variables.Clear();
      target.Variables.AddRange(source.Variables);
      target.SubScopes.Clear();
      target.SubScopes.AddRange(source.SubScopes);
      // TODO: validate if parent scopes match - otherwise source is invalid
    }

    // testfunction:
    private IScope[] ExecuteLocally(EngineJob[] jobs, IScope parentScopeClone, CancellationToken cancellationToken) {
      IScope[] scopes = new Scope[jobs.Length];
      for (int i = 0; i < jobs.Length; i++) {
        var serialized = PersistenceUtil.Serialize(jobs[i]);
        var deserialized = PersistenceUtil.Deserialize<IJob>(serialized);
        deserialized.Start();
        while (deserialized.ExecutionState != ExecutionState.Stopped) {
          Thread.Sleep(100);
        }
        var serialized2 = PersistenceUtil.Serialize(deserialized);
        var deserialized2 = PersistenceUtil.Deserialize<EngineJob>(serialized2);
        var newScope = ((IAtomicOperation)deserialized2.InitialOperation).Scope;
        scopes[i] = newScope;
      }
      return scopes;
    }

    /// <summary>
    /// This method blocks until all jobs are finished
    /// TODO: Cancelation needs to be refined; all tasks currently stay in Semaphore.WaitOne after cancelation
    /// </summary>
    /// <param name="jobs"></param>
    private IScope[] ExecuteOnHive(EngineJob[] jobs, IScope parentScopeClone, CancellationToken cancellationToken) {
      LogMessage(string.Format("Executing {0} operations on the hive.", jobs.Length));
      IScope[] scopes = new Scope[jobs.Length];
      object locker = new object();
      IDictionary<Guid, int> jobIndices = new Dictionary<Guid, int>();
      var hiveExperiment = new HiveExperiment();

      try {
        List<Guid> remainingJobIds = new List<Guid>();

        // create hive experiment
        hiveExperiment.Name = "HiveEngine Run " + hiveExperiments.Count;
        hiveExperiment.DateCreated = DateTime.Now;
        hiveExperiment.UseLocalPlugins = this.UseLocalPlugins;
        hiveExperiment.ResourceNames = this.ResourceNames;
        var refreshableHiveExperiment = new RefreshableHiveExperiment(hiveExperiment);
        refreshableHiveExperiment.IsControllable = false;
        hiveExperiments.Add(refreshableHiveExperiment);

        // create upload-tasks
        var uploadTasks = new List<Task<Job>>();
        for (int i = 0; i < jobs.Length; i++) {
          hiveExperiment.HiveJobs.Add(new EngineHiveJob(jobs[i], parentScopeClone));

          // shuffle random variable to avoid the same random sequence in each operation; todo: does not yet work (it cannot find the random variable)
          IRandom random = FindRandomParameter(jobs[i].InitialOperation as IExecutionContext);
          if (random != null)
            random.Reset(random.Next());
        }
        ExperimentManagerClient.StartExperiment((e) => { throw e; }, refreshableHiveExperiment);
        // do polling until experiment is finished and all jobs are downloaded
        while (!refreshableHiveExperiment.AllJobsFinished()) {
          Thread.Sleep(500);
          this.ExecutionTimeOnHive = TimeSpan.FromMilliseconds(hiveExperiments.Sum(x => x.HiveExperiment.ExecutionTime.TotalMilliseconds));
          cancellationToken.ThrowIfCancellationRequested();
        }
        LogMessage(string.Format("{0} finished (TotalExecutionTime: {1}).", refreshableHiveExperiment.ToString(), refreshableHiveExperiment.HiveExperiment.ExecutionTime));

        // get scopes
        int j = 0;
        foreach (var hiveJob in hiveExperiment.HiveJobs) {
          var scope = ((IAtomicOperation) ((EngineJob)hiveJob.ItemJob).InitialOperation).Scope;
          scopes[j++] = scope;
        }
        refreshableHiveExperiment.RefreshAutomatically = false;
        DeleteHiveExperiment(hiveExperiment.Id);
        return scopes;
      }
      catch (OperationCanceledException e) {
        lock (locker) {
          if (jobIndices != null) DeleteHiveExperiment(hiveExperiment.Id);
        }
        throw e;
      }
      catch (Exception e) {
        lock (locker) {
          if (jobIndices != null) DeleteHiveExperiment(hiveExperiment.Id);
        }
        LogException(e);
        throw e;
      }
    }

    private void DeleteHiveExperiment(Guid hiveExperimentId) {
      TryAndRepeat(() => {
        ServiceLocator.Instance.CallHiveService(s => s.DeleteHiveExperiment(hiveExperimentId));
      }, 5, string.Format("Could not delete jobs"));
    }

    private static object locker = new object();
    private Job UploadJob(object keyValuePairObj, IScope parentScopeClone, CancellationToken cancellationToken, List<Guid> resourceIds, Guid hiveExperimentId) {
      var keyValuePair = (KeyValuePair<int, EngineJob>)keyValuePairObj;
      Job job = new Job();

      try {
        maxSerializedJobsInMemory.WaitOne();
        JobData jobData = new JobData();
        IEnumerable<Type> usedTypes;

        // clone operation and remove unnecessary scopes; don't do this earlier to avoid memory problems
        lock (locker) {
          ((IAtomicOperation)keyValuePair.Value.InitialOperation).Scope.Parent = parentScopeClone;
          keyValuePair.Value.InitialOperation = (IOperation)keyValuePair.Value.InitialOperation.Clone();
          if (keyValuePair.Value.InitialOperation is IAtomicOperation)
            ((IAtomicOperation)keyValuePair.Value.InitialOperation).Scope.ClearParentScopes();
          jobData.Data = PersistenceUtil.Serialize(keyValuePair.Value, out usedTypes);
        }
        var neededPlugins = new List<IPluginDescription>();

        bool useAllLocalPlugins = true;
        if (useAllLocalPlugins) {
          // use all plugins
          neededPlugins.AddRange(ApplicationManager.Manager.Plugins);
        } else {
          // use only 
          PluginUtil.CollectDeclaringPlugins(neededPlugins, usedTypes);
        }

        job.CoresNeeded = 1;
        job.PluginsNeededIds = ServiceLocator.Instance.CallHiveService(s => PluginUtil.GetPluginDependencies(s, this.OnlinePlugins, this.AlreadyUploadedPlugins, neededPlugins, useLocalPlugins));
        job.Priority = priority;
        job.HiveExperimentId = hiveExperimentId;

        try {
          maxConcurrentConnections.WaitOne();
          while (job.Id == Guid.Empty) { // repeat until success
            cancellationToken.ThrowIfCancellationRequested();
            try {
              job.Id = ServiceLocator.Instance.CallHiveService(s => s.AddJob(job, jobData, resourceIds));
            }
            catch (Exception e) {
              LogException(e);
              LogMessage("Repeating upload");
            }
          }
        }
        finally {
          maxConcurrentConnections.Release();
        }
      }
      finally {
        maxSerializedJobsInMemory.Release();
      }
      return job;
    }

    private List<Guid> GetResourceIds() {
      return ServiceLocator.Instance.CallHiveService(service => {
        var resourceNames = ResourceNames.Split(';');
        var resourceIds = new List<Guid>();
        foreach (var resourceName in resourceNames) {
          Guid resourceId = service.GetResourceId(resourceName);
          if (resourceId == Guid.Empty) {
            throw new ResourceNotFoundException(string.Format("Could not find the resource '{0}'", resourceName));
          }
          resourceIds.Add(resourceId);
        }
        return resourceIds;
      });
    }

    private EngineJob DownloadJob(IDictionary<Guid, int> jobIndices, object jobIdObj, CancellationToken cancellationToken) {
      Guid jobId = (Guid)jobIdObj;
      JobData jobData = null;
      EngineJob engineJob = null;
      try {
        maxSerializedJobsInMemory.WaitOne();
        maxConcurrentConnections.WaitOne();
        while (jobData == null) { // repeat until success
          cancellationToken.ThrowIfCancellationRequested();
          try {
            jobData = ServiceLocator.Instance.CallHiveService(s => s.GetJobData(jobId));
          }
          catch (Exception e) {
            LogException(e);
            LogMessage("Repeating download");
          }
        }
        engineJob = PersistenceUtil.Deserialize<EngineJob>(jobData.Data);
        jobData = null;
        LogMessage(string.Format("Downloaded job #{0}", jobIndices[jobId] + 1, jobId));
      }
      finally {
        maxConcurrentConnections.Release();
        maxSerializedJobsInMemory.Release();
      }
      return engineJob;
    }

    /// <summary>
    /// Threadsafe message logging
    /// </summary>
    private void LogMessage(string message) {
      lock (Log) {
        Log.LogMessage(message);
      }
    }

    /// <summary>
    /// Threadsafe exception logging
    /// </summary>
    private void LogException(Exception exception) {
      lock (Log) {
        Log.LogException(exception);
      }
    }

    /// <summary>
    /// Executes the action. If it throws an exception it is repeated until repetition-count is reached.
    /// If repetitions is -1, it is repeated infinitely.
    /// </summary>
    private static void TryAndRepeat(Action action, int repetitions, string errorMessage) {
      try { action(); }
      catch (Exception e) {
        repetitions--;
        if (repetitions <= 0)
          throw new HiveEngineException(errorMessage, e);
        TryAndRepeat(action, repetitions, errorMessage);
      }
    }
  }

  public static class EnumerableExtensions {
    public static TimeSpan Sum(this IEnumerable<TimeSpan> times) {
      return TimeSpan.FromMilliseconds(times.Select(e => e.TotalMilliseconds).Sum());
    }
  }
}