private static bool QueueForExecution <T>(this ScheduledProducer producer, Action <ScheduledTask> options, object instance)
{
var task = NewTask <T>(producer.Settings, instance);
options?.Invoke(task); // <-- at this stage, task should have a RunAt set by the user or it will be default
// Validate the CRON expression:
if (!string.IsNullOrWhiteSpace(task.Expression) && !task.HasValidExpression)
{
throw new ArgumentException("The provided CRON expression is invalid. Have you tried the CronTemplates?");
}
// Handle when no start time is provided up front
if (task.RunAt == default(DateTimeOffset))
{
task.RunAt = DateTimeOffset.UtcNow;
if (task.NextOccurrence.HasValue)
{
task.RunAt = task.NextOccurrence.Value;
}
}
// Set the "Start" property only once, equal to the very first RunAt
task.Start = task.RunAt;
if (!producer.Settings.DelayTasks)
{
return(producer.AttemptTask(task, false));
}
producer.Settings.Store?.Save(task);
return(true);
}
/// <summary>
/// Schedules a new task for delayed execution for the given producer.
///
/// If the user does NOT provide a RunAt during options, but an expression IS provided, the next occurrence of the expression, relative to now, will be selected as the start time.
/// Otherwise, the task will be scheduled for now.
///
/// </summary>
/// <typeparam name="T">The type of the task. The task is created at trigger time. The trigger type must have a parameterless constructor.</typeparam>
/// <param name="options">Allows configuring task-specific features. Note that this is NOT invoked at invocation time lazily, but at scheduling time (i.e. immediately). </param>
/// <param name="configure">Allows setting parameters on the scheduled task. Note that this is NOT invoked at invocation time lazily, but at scheduling time (i.e. immediately).</param>
/// <returns>Whether the scheduled operation was successfull; if `true`, it was either scheduled or ran successfully, depending on configuration. If `false`, it either failed to schedule or failed during execution, depending on configuration.</returns>
public static bool ScheduleAsync <T>(this ScheduledProducer producer, Action <ScheduledTask> options = null, Action <T> configure = null) where T : class, new()
{
T instance = null;
if (configure != null)
{
instance = (T)Activator.CreateInstance(typeof(T));
configure(instance);
}
return(QueueForExecution <T>(producer, options, instance));
}
