UTimer 2.0.0

UTimer

Lightweight, dependency-injection friendly job scheduler for .NET Core applications. Configure processes and run scheduled jobs in the background — one-shot, at a specific time, recurring (fixed period or cron), and continuations.

Install

dotnet add package UTimer

Setup

var builder = Host.CreateApplicationBuilder(args);

builder.Services.AddUTimer(
    maxDegreeOfParallelism: 20,          // queued jobs running concurrently
    maxQueueSize: 1000,                  // bounded queue; enqueue waits when full
    defaultTimeZone: TimeZoneInfo.Local); // cron time zone; null (default) = UTC

var host = builder.Build();
await host.StartAsync();

All jobs are identified by a string job id.

One-shot jobs

// After a delay (runs exactly once)
string id = JobCreator.CreateJob(() => Console.WriteLine("merhaba"), TimeSpan.FromSeconds(5));

// Async — the returned Task is awaited
JobCreator.CreateJob(async () => await File.WriteAllTextAsync("log.txt", "x"));

// Resolve a service from a fresh DI scope
JobCreator.CreateJob<IMailService>(m => m.SendAsync("a@b.c"));

// Control by id
JobCreator.CancelJob(id);              // cancel before it starts (true if cancelled)
await JobCreator.WaitAsync(id);        // wait for completion

At a specific time

JobCreator.CreateJobAt(() => Raporla(), new DateTime(2026, 9, 5, 14, 30, 0)); // local
JobCreator.CreateJobAt<IMailService>(m => m.GonderAsync(), DateTime.UtcNow.AddHours(3));

Past times run immediately. DateTimeKind.Unspecified is treated as local.

Recurring jobs

// Fixed period: first tick immediately, then "period" between the END of one
// run and the START of the next — ticks never overlap.
string id = JobCreator.CreateRecurringJob(() => Temizle(), TimeSpan.FromMinutes(10));

// Cron (uses AddUTimer's defaultTimeZone; pass an explicit TimeZoneInfo to override)
JobCreator.CreateRecurringJob(() => Raporla(), "0 3 * * *");
JobCreator.CreateRecurringJob(() => Raporla(), "30 9 * * 1", TimeZoneInfo.Local);

// Seconds precision (6-field cron)
JobCreator.CreateRecurringJob(() => Tick(), "*/30 * * * * *",
    cronFormat: UTimer.Cronos.CronFormat.IncludeSeconds);

// With a DI service (fresh scope per tick)
var job = JobCreator.CreateRecurringJob<ICacheService>(c => c.Refresh(), TimeSpan.FromHours(1));
JobCreator.CancelJob(job); // stops the repetition

If the expression body returns a Task (e.g. x => x.RefreshAsync()), it is awaited; a slow tick delays the next one instead of overlapping. A throwing iteration is logged and the loop continues.

Continuations

// Enqueue the parent job and capture its Job ID
string parentJobId = JobCreator.CreateJob(() => Console.WriteLine("Parent job running..."));

// Queue a continuation job that runs after the parent job finishes
string childJobId = JobCreator.ContinueWith(
    parentJobId,
    () => Console.WriteLine("Child continuation job running...")
);

Semantics (OnCompletion): the child runs when the parent finishes, whether the parent succeeded or failed. A canceled parent cancels its children. Continuations can be chained (ContinueWith(childJobId, ...)) and work on queued jobs too. Attach them while the parent is pending or within the one-minute completion retention window.

Background queue

var creator = host.Services.GetRequiredService<JobCreator>();
string id = await creator.EnqueueAsync<IOrderService>(s => s.ProcessAsync(order));

Bounded-channel queue drained by a BackgroundService with a concurrency semaphore. CancelJob(id) works until the job starts running.

Shutdown

On host.StopAsync() (or provider disposal): pending jobs are canceled, running jobs are awaited. Jobs that ignore their CancellationToken can delay shutdown indefinitely — use the Func<CancellationToken, Task> overloads for cancellable work.

Limitations

• In-memory only. A process crash loses pending jobs, continuations and recurring registrations. Re-register recurring jobs at startup; if you need durability, retries and persisted continuations, use Hangfire or Quartz.NET.
• The static JobCreator facade requires the host to be started (AddUTimer + StartAsync); with multiple hosts in one process the last registered one wins.

License

MIT — see LICENSE. Includes vendored Cronos sources (MIT).