cvelezpena / cs-schtick

A C# scheduled task runner built on Schyntax.

C# Schtick

A scheduled task runner built on Schyntax (a domain-specific language for defining event schedules in a terse, but readable, format).

Usage

Best practice is to make a singleton instance of the Schtick class.

using Schyntax;

var schtick = new Schtick();

// setup an exception handler so we know when tasks blow up
schtick.OnTaskException += (task, exception) => LogException(ex);

// add a task which will call DoSomeTask every hour at 15 minutes past the hour
schtick.AddTask("unique-task-name", "min(15)", (task, timeIntendedToRun) => DoSomeTask());

For complete documentation of schedule format language itself, see the Schyntax project.

AddTask() has several optional arguments which are documented in Schtick.cs and will show up in intellisense.

Async Task Callbacks

For async callbacks, use Schtick.AddAsyncTask().

schtick.AddAsyncTask("task-name", "hour(*)", async (task, time) => await DoSomethingAsync());

ScheduledTask Objects

AddTask() and AddAsyncTask() return an instance of ScheduledTask. This object has properties like Name, IsScheduleRunning, and IsCallbackExecuting. It can be used to start and stop the schedule via StartSchedule() and StopSchedule(). There is also an UpdateSchedule() method which allows you keep the same task, but run it on a different schedule.

The ScheduledTask object is also the first argument to all task callbacks.

Application Shutdown

To ensure the application doesn't terminate in the middle of an executing callback, you should call the Schtick.Shutdown() method before the app terminates. Shutdown is an async method which completes when all scheduled tasks have been stopped and all running callbacks have completed.

A good way to do this in an ASP.NET app is to use a registered object.

public class RegisteredSchtick : IRegisteredObject
{
	public Schtick Schtick { get; }
	
	public RegisteredSchtick(Schtick schtick)
	{
		Schtick = schtick;
	}

	public void Stop(bool immediate)
	{
		if (!Schtick.IsShuttingDown)
		{
			Schtick.Shutdown().ContinueWith(task => HostingEnvironment.UnregisterObject(this));
		}
	}
}

On app start:

_schtick = new Schtick();
HostingEnvironment.RegisterObject(new RegisteredSchtick(_schtick));