Job Scheduler

A simple job scheduling library relying on the async/await pattern in C#.

Type of Jobs

One Time Job

By implementing the IJob interface you tell the scheduler that you just want this job to be executed once and directly upon being scheduled.

Recurring Job

By implementing the IRecurringJob the scheduler will run indefinitely your job with the given delay between execution.

Delayed Job

By implementing the IDelayedJob you tell the scheduler to wait a delay before executing your job.

Debounce Job

By implementing the IDebounceJob you tell the scheduler to only run the latest encounter of the job sharing the same key.

Queue Job

You can register your own queue with their defined concurrency and schedule on them IQueueJob.

Usage

I advise you to use a Dependency Injection (DI) engine (like SimpleInjector) to register the JobRunnerBuilderand JobScheduler as singleton.

Example:

public class MyJob : IRecurringJob
{
    //Set the retry rule in case of failure of the job, in this case we want
    //to retry the job 3 times
    //Works for any type of job
    public IRetryAction FailRule { get; } = new RetryNTimes(3);
   
    //Optional MaxRuntime for the job before its canncellationToke get cancelled
    //Keep in mind, this only cancel the token, we have no clean way of stopping a running task
    //then cancelling the token.
    public TimeSpan? MaxRuntime { get; } = TimeSpan.FromSeconds(5);


    public async Task ExecuteAsync(CancellationToken cancellationToken)
    {
        //Your complex recurring code, here pretty simple
        await Console.Out.WriteLineAsync("Hello World");
    }

    public Task<IRetryAction> OnFailure(JobException exception)
    {
//Any exception that occured when executing your job will be wrapped in a JobException, check the InnerException
//for you to be able to handle a failure without breaking your application neither needed a try/catch in ExecuteAsync


        return Task.CompletedTask;
    }
//This job will run every 15 seconds

    public TimeSpan Delay { get; } = TimeSpan.FromSeconds(15);
}

var builder = new JobRunnerBuilder();
var scheduler = new JobScheduler(builder);

//If you have already a cancellation token that you want to be used for stopping your job, you can pass it as second param
scheduler.Start(new MyJob());

//At the end of your application, you can ask the Scheduler to gracefully stop the running jobs and wait for them to stop.
//You can also pass a cancellationToken to force a non graceful cancellation of the jobs.
await scheduler.StopAsync();

Advanced

You can also use your own TaskScheduler. It's useful if you want to control in which thread your task is run.

var builder = new JobRunnerBuilder();
var scheduler = new JobScheduler(builder);
var taskScheduler = new MyTaskScheduler();

// This way, this specific instance of the job will be run in your defined task scheduler
scheduler.Start(new MyJob(), CancellationToken.None, taskScheduler);

Queue usage

public class OneTimeQueueJob : IQueueJob
{

    public bool HasRun { get; set; }

    public IRetryAction FailRule { get; } = new NoRetry();
    public TimeSpan? MaxRuntime { get; }

    public virtual async Task ExecuteAsync(CancellationToken cancellationToken)
    {
        HasRun = true;
    }

    public Task OnFailure(JobException exception)
    {
        return Task.CompletedTask;
    }

    //Unique key for this job. The queue won't accept twice the same job unless it has finished running.
    public string Key { get; set; } = "test";
    //Unique ID of the queue
    public string QueueId { get; set; } = "test";
  
}
var builder = new JobRunnerBuilder();
var scheduler = new JobScheduler(builder);
//queue with a maximum of 1 job running at a time
var settings = new QueueSettings("test", 1);
scheduler.RegisterQueue(settings);

//Schedule the job as normal, it will be schedule in the queue
scheduler.Start(new OneTimeQueueJob());

Disposable

If your job implement IAsyncDisposable the disposing will be called when the job has finished running.

WaleedLab/Job.Scheduler