private async ValueTask <IActivityExecutionResult?> TryExecuteActivityAsync(
            ActivityOperation activityOperation,
            ActivityExecutionContext activityExecutionContext,
            IActivity activity,
            CancellationToken cancellationToken)
        {
            try
            {
                return(await activityOperation(activityExecutionContext, activity));
            }
            catch (Exception e)
            {
                _logger.LogWarning(e, "Failed to run activity {ActivityId} of workflow {WorkflowInstanceId}", activity.Id, activityExecutionContext.WorkflowInstance.Id);
                activityExecutionContext.Fault(e);
                await _mediator.Publish(new ActivityFaulted(e, activityExecutionContext, activity), cancellationToken);
            }

            return(null);
        }
        private async ValueTask RunCoreAsync(WorkflowExecutionContext workflowExecutionContext, ActivityOperation activityOperation, CancellationToken cancellationToken = default)
        {
            var scope             = workflowExecutionContext.ServiceProvider;
            var workflowBlueprint = workflowExecutionContext.WorkflowBlueprint;
            var workflowInstance  = workflowExecutionContext.WorkflowInstance;
            var burstStarted      = false;

            while (workflowExecutionContext.HasScheduledActivities)
            {
                var scheduledActivity = workflowInstance.CurrentActivity = workflowExecutionContext.PopScheduledActivity();
                var currentActivityId = scheduledActivity.ActivityId;
                var activityBlueprint = workflowBlueprint.GetActivity(currentActivityId) !;
                var resuming          = activityOperation == Resume;
                var outputReference   = workflowInstance.Output;
                var output            = outputReference != null ? await _workflowStorageService.LoadAsync(outputReference.ProviderName, new WorkflowStorageContext(workflowInstance, outputReference.ActivityId), "Output", cancellationToken) : null;

                var input = !burstStarted ? workflowExecutionContext.Input : scheduledActivity.Input ?? output;
                var activityExecutionContext = new ActivityExecutionContext(scope, workflowExecutionContext, activityBlueprint, input, resuming, cancellationToken);
                var runtimeActivityInstance  = await activityExecutionContext.ActivateActivityAsync(cancellationToken);

                var activityType = runtimeActivityInstance.ActivityType;
                using var executionScope = AmbientActivityExecutionContext.EnterScope(activityExecutionContext);
                var activity = await activityType.ActivateAsync(activityExecutionContext);

                if (!burstStarted)
                {
                    await _mediator.Publish(new WorkflowExecutionBurstStarting(workflowExecutionContext, activityExecutionContext), cancellationToken);

                    burstStarted = true;
                }

                if (resuming)
                {
                    await _mediator.Publish(new ActivityResuming(activityExecutionContext, activity), cancellationToken);
                }

                await _mediator.Publish(new ActivityExecuting(activityExecutionContext, activity), cancellationToken);

                var result = await TryExecuteActivityAsync(activityOperation, activityExecutionContext, activity, cancellationToken);

                if (result == null)
                {
                    return;
                }

                await _mediator.Publish(new ActivityExecuted(activityExecutionContext, activity), cancellationToken);

                await _mediator.Publish(new ActivityExecutionResultExecuting(result, activityExecutionContext), cancellationToken);

                await result.ExecuteAsync(activityExecutionContext, cancellationToken);

                workflowExecutionContext.CompletePass();
                workflowInstance.LastExecutedActivityId = currentActivityId;
                await _mediator.Publish(new ActivityExecutionResultExecuted(result, activityExecutionContext), cancellationToken);

                await _mediator.Publish(new WorkflowExecutionPassCompleted(workflowExecutionContext, activityExecutionContext), cancellationToken);

                if (!workflowExecutionContext.HasScheduledActivities)
                {
                    await _mediator.Publish(new WorkflowExecutionBurstCompleted(workflowExecutionContext, activityExecutionContext), cancellationToken);
                }

                activityOperation = Execute;
            }

            workflowInstance.CurrentActivity = null;

            if (workflowExecutionContext.HasBlockingActivities)
            {
                workflowExecutionContext.Suspend();
            }

            if (workflowExecutionContext.Status == WorkflowStatus.Running)
            {
                await workflowExecutionContext.CompleteAsync();
            }
        }
 private async ValueTask RunAsync(WorkflowExecutionContext workflowExecutionContext, ActivityOperation activityOperation, CancellationToken cancellationToken = default)
 {
     try
     {
         await RunCoreAsync(workflowExecutionContext, activityOperation, cancellationToken);
     }
     catch (Exception e)
     {
         _logger.LogWarning(e, "Failed to run workflow {WorkflowInstanceId}", workflowExecutionContext.WorkflowInstance.Id);
         workflowExecutionContext.Fault(e, null, null, activityOperation == Resume);
     }
 }