public async Task <WorkflowExecutionContext> ResumeWorkflowAsync(Workflow workflow,
BlockingActivity awaitingActivity, IDictionary <string, object> input = null)
{
var workflowType = await _workflowTypeStore.GetAsync(workflow.WorkflowTypeId);
var activityRecord =
workflowType.Activities.SingleOrDefault(x => x.ActivityId == awaitingActivity.ActivityId);
var workflowContext = await CreateWorkflowExecutionContextAsync(workflowType, workflow, input);
workflowContext.Status = WorkflowStatus.Resuming;
// Signal every activity that the workflow is about to be resumed.
var cancellationToken = new CancellationToken();
await InvokeActivitiesAsync(workflowContext, x => x.Activity.OnInputReceivedAsync(workflowContext, input));
await InvokeActivitiesAsync(workflowContext,
x => x.Activity.OnWorkflowResumingAsync(workflowContext, cancellationToken));
if (cancellationToken.IsCancellationRequested)
{
// Workflow is aborted.
workflowContext.Status = WorkflowStatus.Aborted;
}
else
{
// Check if the current activity can execute.
if (activityRecord != null)
{
var activityContext = workflowContext.GetActivity(activityRecord.ActivityId);
if (await activityContext.Activity.CanExecuteAsync(workflowContext, activityContext))
{
// Signal every activity that the workflow is resumed.
await InvokeActivitiesAsync(workflowContext,
x => x.Activity.OnWorkflowResumedAsync(workflowContext));
// Remove the blocking activity.
workflowContext.Workflow.BlockingActivities.Remove(awaitingActivity);
// Resume the workflow at the specified blocking activity.
await ExecuteWorkflowAsync(workflowContext, activityRecord);
}
else
{
workflowContext.Status = WorkflowStatus.Halted;
return(workflowContext);
}
}
}
if (workflowContext.Status == WorkflowStatus.Finished && workflowType.DeleteFinishedWorkflows)
{
await _workflowStore.DeleteAsync(workflowContext.Workflow);
}
else
{
await PersistAsync(workflowContext);
}
return(workflowContext);
}
protected override void Execute(ActivityExecutionContext activityExecutionContext)
{
var activityDefinition = activityExecutionContext.ActivityBlueprint;
var blockingActivity = new BlockingActivity(activityDefinition.Id, activityDefinition.Type);
activityExecutionContext.WorkflowExecutionContext.WorkflowInstance.BlockingActivities.Add(blockingActivity);
activityExecutionContext.WorkflowExecutionContext.Suspend();
}
public override async ValueTask ExecuteAsync(ActivityExecutionContext activityExecutionContext, CancellationToken cancellationToken)
{
var activityDefinition = activityExecutionContext.ActivityBlueprint;
var blockingActivity = new BlockingActivity(activityDefinition.Id, activityDefinition.Type);
activityExecutionContext.WorkflowExecutionContext.WorkflowInstance.BlockingActivities.Add(blockingActivity);
activityExecutionContext.WorkflowExecutionContext.Suspend();
var mediator = activityExecutionContext.ServiceProvider.GetRequiredService <IMediator>();
await mediator.Publish(new BlockingActivityAdded(activityExecutionContext.WorkflowExecutionContext, blockingActivity), cancellationToken);
}
public async Task <IEnumerable <ActivityRecord> > ExecuteWorkflowAsync(WorkflowExecutionContext workflowContext, ActivityRecord activity)
{
var workflowType = workflowContext.WorkflowType;
var scheduled = new Stack <ActivityRecord>();
var blocking = new List <ActivityRecord>();
var isResuming = workflowContext.Status == WorkflowStatus.Resuming;
var isFirstPass = true;
workflowContext.Status = WorkflowStatus.Executing;
scheduled.Push(activity);
while (scheduled.Count > 0)
{
activity = scheduled.Pop();
var activityContext = workflowContext.GetActivity(activity.ActivityId);
// Signal every activity that the activity is about to be executed.
var cancellationToken = new CancellationToken();
await InvokeActivitiesAsync(workflowContext, x => x.Activity.OnActivityExecutingAsync(workflowContext, activityContext, cancellationToken));
if (cancellationToken.IsCancellationRequested)
{
// Activity is aborted.
workflowContext.Status = WorkflowStatus.Aborted;
break;
}
IList <string> outcomes = new List <string>(0);
try
{
ActivityExecutionResult result;
if (!isResuming)
{
// Execute the current activity.
result = await activityContext.Activity.ExecuteAsync(workflowContext, activityContext);
}
else
{
// Resume the current activity.
result = await activityContext.Activity.ResumeAsync(workflowContext, activityContext);
isResuming = false;
}
if (result.IsHalted)
{
if (isFirstPass)
{
// Resume immediately when this is the first pass.
result = await activityContext.Activity.ResumeAsync(workflowContext, activityContext);
isFirstPass = false;
outcomes = result.Outcomes;
if (result.IsHalted)
{
// Block on this activity.
blocking.Add(activity);
}
}
else
{
// Block on this activity.
blocking.Add(activity);
continue;
}
}
else
{
outcomes = result.Outcomes;
}
}
catch (Exception ex)
{
_logger.LogError(ex, "An unhandled error occurred while executing an activity. Workflow ID: '{WorkflowTypeId}'. Activity: '{ActivityId}', '{ActivityName}'. Putting the workflow in the faulted state.", workflowType.Id, activityContext.ActivityRecord.ActivityId, activityContext.ActivityRecord.Name);
workflowContext.Fault(ex, activityContext);
return(blocking.Distinct());
}
// Signal every activity that the activity is executed.
await InvokeActivitiesAsync(workflowContext, x => x.Activity.OnActivityExecutedAsync(workflowContext, activityContext));
foreach (var outcome in outcomes)
{
// Look for next activity in the graph.
var transition = workflowType.Transitions.FirstOrDefault(x => x.SourceActivityId == activity.ActivityId && x.SourceOutcomeName == outcome);
if (transition != null)
{
var destinationActivity = workflowContext.WorkflowType.Activities.SingleOrDefault(x => x.ActivityId == transition.DestinationActivityId);
scheduled.Push(destinationActivity);
}
}
isFirstPass = false;
}
// Apply Distinct() as two paths could block on the same activity.
var blockingActivities = blocking.Distinct().ToList();
workflowContext.Status = blockingActivities.Any() || workflowContext.Workflow.BlockingActivities.Any() ? WorkflowStatus.Halted : WorkflowStatus.Finished;
foreach (var blockingActivity in blockingActivities)
{
// Workflows containing event activities could end up being blocked on the same activity.
if (!workflowContext.Workflow.BlockingActivities.Any(x => x.ActivityId == blockingActivity.ActivityId))
{
workflowContext.Workflow.BlockingActivities.Add(BlockingActivity.FromActivity(blockingActivity));
}
}
return(blockingActivities);
}
public BlockingActivityRemoved(WorkflowExecutionContext workflowExecutionContext, BlockingActivity blockingActivity)
{
WorkflowExecutionContext = workflowExecutionContext;
BlockingActivity = blockingActivity;
}
