Prevent information loss on host shutdown

Do not pass global CancellationToken to persistence operations on host
shutdown. This way it is ensured that persistence operations are not
cancelled.

Author: mamidenn

src/WorkflowCore/Services/BackgroundTasks/WorkflowConsumer.cs

@@ -55,7 +55,7 @@ protected override async Task ProcessItem(string itemId, CancellationToken cance
                     finally
                     {
                         WorkflowActivity.Enrich(result);
-                        await _persistenceStore.PersistWorkflow(workflow, result.Subscriptions, cancellationToken);
+                        await _persistenceStore.PersistWorkflow(workflow, result.Subscriptions);
                         await QueueProvider.QueueWork(itemId, QueueType.Index);
                         _greylist.Remove($"wf:{itemId}");
                     }
@@ -68,10 +68,10 @@ protected override async Task ProcessItem(string itemId, CancellationToken cance
                 {
                     foreach (var sub in result.Subscriptions)
                     {
-                        await TryProcessSubscription(sub, _persistenceStore, cancellationToken);
+                        await TryProcessSubscription(sub, _persistenceStore);
                     }
 
-                    await _persistenceStore.PersistErrors(result.Errors, cancellationToken);
+                    await _persistenceStore.PersistErrors(result.Errors);
 
                     if ((workflow.Status == WorkflowStatus.Runnable) && workflow.NextExecution.HasValue)
                     {
@@ -98,24 +98,28 @@ await _persistenceStore.ScheduleCommand(new ScheduledCommand()
 
         }
 
-        private async Task TryProcessSubscription(EventSubscription subscription, IPersistenceProvider persistenceStore, CancellationToken cancellationToken)
+        private async Task TryProcessSubscription(EventSubscription subscription, IPersistenceProvider persistenceStore)
         {
+            //TODO: move to own class
+            Logger.LogDebug("Subscribing to event {0} {1} for workflow {2} step {3}", subscription.EventName, subscription.EventKey, subscription.WorkflowId, subscription.StepId);
+
+            await persistenceStore.CreateEventSubscription(subscription, cancellationToken);
             if (subscription.EventName != Event.EventTypeActivity)
             {
-                var events = await persistenceStore.GetEvents(subscription.EventName, subscription.EventKey, subscription.SubscribeAsOf, cancellationToken);
+                var events = await persistenceStore.GetEvents(subscription.EventName, subscription.EventKey, subscription.SubscribeAsOf);
 
                 foreach (var evt in events)
                 {
                     var eventKey = $"evt:{evt}";
                     bool acquiredLock = false;
                     try
                     {
-                        acquiredLock = await _lockProvider.AcquireLock(eventKey, cancellationToken);
+                        acquiredLock = await _lockProvider.AcquireLock(eventKey, CancellationToken.None);
                         int attempt = 0;
                         while (!acquiredLock && attempt < 10)
                         {
-                            await Task.Delay(Options.IdleTime, cancellationToken);
-                            acquiredLock = await _lockProvider.AcquireLock(eventKey, cancellationToken);
+                            await Task.Delay(Options.IdleTime);
+                            acquiredLock = await _lockProvider.AcquireLock(eventKey, CancellationToken.None);
 
                             attempt++;
                         }
@@ -127,7 +131,7 @@ private async Task TryProcessSubscription(EventSubscription subscription, IPersi
                         else
                         {
                             _greylist.Remove(eventKey);
-                            await persistenceStore.MarkEventUnprocessed(evt, cancellationToken);
+                            await persistenceStore.MarkEventUnprocessed(evt);
                             await QueueProvider.QueueWork(evt, QueueType.Event);
                         }
                     }