| | | 1 | | using Elsa.Mediator.Services; |
| | | 2 | | using Microsoft.Extensions.Logging; |
| | | 3 | | |
| | | 4 | | namespace Elsa.Common.ShellHandlers; |
| | | 5 | | |
| | 2 | 6 | | public sealed class MediatorBackgroundProcessingCoordinator( |
| | 2 | 7 | | BackgroundCommandProcessor commandProcessor, |
| | 2 | 8 | | BackgroundNotificationProcessor notificationProcessor, |
| | 2 | 9 | | BackgroundJobProcessor jobProcessor, |
| | 2 | 10 | | ILogger<MediatorBackgroundProcessingCoordinator> logger) : IAsyncDisposable |
| | | 11 | | { |
| | 2 | 12 | | private readonly SemaphoreSlim _lock = new(1, 1); |
| | | 13 | | private CancellationTokenSource? _cancellationTokenSource; |
| | | 14 | | private Task? _processingTask; |
| | | 15 | | private int _referenceCount; |
| | | 16 | | |
| | | 17 | | public async Task StartAsync(CancellationToken cancellationToken = default) |
| | | 18 | | { |
| | 3 | 19 | | await _lock.WaitAsync(cancellationToken); |
| | | 20 | | try |
| | | 21 | | { |
| | 3 | 22 | | if (_referenceCount++ > 0) |
| | 1 | 23 | | return; |
| | | 24 | | |
| | 2 | 25 | | _cancellationTokenSource = new(); |
| | 2 | 26 | | _processingTask = Task.WhenAll( |
| | 2 | 27 | | commandProcessor.ExecuteAsync(_cancellationTokenSource.Token), |
| | 2 | 28 | | notificationProcessor.ExecuteAsync(_cancellationTokenSource.Token), |
| | 2 | 29 | | jobProcessor.ExecuteAsync(_cancellationTokenSource.Token)); |
| | 2 | 30 | | } |
| | | 31 | | finally |
| | | 32 | | { |
| | 3 | 33 | | _lock.Release(); |
| | | 34 | | } |
| | 3 | 35 | | } |
| | | 36 | | |
| | | 37 | | public async Task StopAsync(CancellationToken cancellationToken = default) |
| | | 38 | | { |
| | | 39 | | Task? processingTask; |
| | | 40 | | CancellationTokenSource? cancellationTokenSource; |
| | | 41 | | |
| | 5 | 42 | | await _lock.WaitAsync(cancellationToken); |
| | | 43 | | try |
| | | 44 | | { |
| | 5 | 45 | | if (_referenceCount == 0) |
| | 0 | 46 | | return; |
| | | 47 | | |
| | 5 | 48 | | if (--_referenceCount > 0) |
| | 1 | 49 | | return; |
| | | 50 | | |
| | 4 | 51 | | processingTask = _processingTask; |
| | 4 | 52 | | cancellationTokenSource = _cancellationTokenSource; |
| | 4 | 53 | | _processingTask = null; |
| | 4 | 54 | | _cancellationTokenSource = null; |
| | 4 | 55 | | } |
| | | 56 | | finally |
| | | 57 | | { |
| | 5 | 58 | | _lock.Release(); |
| | | 59 | | } |
| | | 60 | | |
| | 4 | 61 | | if (cancellationTokenSource is null) |
| | 2 | 62 | | return; |
| | | 63 | | |
| | 2 | 64 | | await cancellationTokenSource.CancelAsync(); |
| | | 65 | | |
| | 2 | 66 | | if (processingTask is not null) |
| | | 67 | | { |
| | | 68 | | try |
| | | 69 | | { |
| | 2 | 70 | | await processingTask.WaitAsync(cancellationToken); |
| | 2 | 71 | | } |
| | 0 | 72 | | catch (OperationCanceledException) when (cancellationTokenSource.IsCancellationRequested) |
| | | 73 | | { |
| | 0 | 74 | | } |
| | 0 | 75 | | catch (Exception e) |
| | | 76 | | { |
| | 0 | 77 | | logger.LogError(e, "An error occurred while stopping mediator background processing"); |
| | 0 | 78 | | throw; |
| | | 79 | | } |
| | | 80 | | } |
| | | 81 | | |
| | 2 | 82 | | cancellationTokenSource.Dispose(); |
| | 5 | 83 | | } |
| | | 84 | | |
| | | 85 | | public async ValueTask DisposeAsync() |
| | | 86 | | { |
| | 2 | 87 | | _referenceCount = 1; |
| | 2 | 88 | | await StopAsync(CancellationToken.None); |
| | 2 | 89 | | _lock.Dispose(); |
| | 2 | 90 | | } |
| | | 91 | | } |