Activity Time Event Action Node

Time Event Action Node

A Time Event Action Node activates when its typed TimeEvent becomes due. It is an event-triggered action: Stateflows schedules the event according to its trigger time, then executes the node and follows its outgoing flows.

Define a time event

Derive an event from TimeEvent and calculate its UTC trigger time from the supplied start instant:

public sealed class ReservationExpired : TimeEvent
{
    protected override DateTime GetTriggerTime(DateTime startedAt)
        => startedAt.AddMinutes(15);
}

Register the corresponding node with AddTimeEventAction<TTimeEvent>:

.AddInitial(node => node.AddControlFlow("ReservationTimeout"))
.AddTimeEventAction<ReservationExpired>(
    "ReservationTimeout",
    async c => await reservations.ExpireAsync(
        reservationId, c.CancellationToken),
    node => node.AddControlFlow<FinalNode>())
.AddFinal()

The time event is associated with an active Activity node, not a periodic scan of arbitrary nodes. Give the node an outgoing flow when the Activity should continue after the timeout. The runtime hosting the behavior is responsible for delivering scheduled time events; Orleans hosting uses Orleans reminders. See Accept Event Action Node, Final Node, and Orleans Runtime.