ZeroAlloc.Scheduling

ZeroAlloc.Scheduling is a source-generated background job scheduler for .NET 8 and .NET 10. Decorate any class with [Job] and the source generator wires up the executor, DI registration, and recurring startup automatically — no reflection, no convention scanning at runtime.

Install

The source generator is bundled into the main package — a single PackageReference is all you need:

dotnet add package ZeroAlloc.Scheduling
dotnet add package ZeroAlloc.Scheduling.InMemory   # or EfCore / Redis

The standalone ZeroAlloc.Scheduling.Generator package is still published for backwards compatibility with existing direct PackageReferences, but new consumers should reference only ZeroAlloc.Scheduling.

Example

// 1. Define a job — the generator picks it up automatically
[Job(Every = Every.Hour)]
public sealed class CleanupExpiredSessionsJob : IJob
{
    private readonly ISessionRepository _repo;
    public CleanupExpiredSessionsJob(ISessionRepository repo) => _repo = repo;

    public async ValueTask ExecuteAsync(JobContext ctx, CancellationToken ct)
        => await _repo.DeleteExpiredAsync(ct);
}

// 2. Register — generated AddCleanupExpiredSessionsJob() wires executor + recurring startup
services.AddScheduling()
        .WithInMemoryStore()
        .AddCleanupExpiredSessionsJob();

// 3. Enqueue a one-off job from application code
public class OrderService(IScheduler scheduler)
{
    public async Task CompleteOrderAsync(Order order, CancellationToken ct)
    {
        await ProcessAsync(order, ct);
        await scheduler.EnqueueAsync(new SendOrderConfirmationJob(order.Id), ct);
    }
}

Performance

Head-to-head vs Coravel 5.0.4 (de-facto in-process scheduler) and a hand-rolled BackgroundService + Timer baseline. .NET 10.0.7, i9-12900HK, BenchmarkDotNet v0.15.4.

Operation	Coravel	Naive Timer	ZA.Scheduling
Job registration	8,211 ns / 696 B per call	— (compile-time)	compile-time, 0 ns runtime
Single dispatch	(registration only)	0.01 ns	0.25 ns (parity, JIT-inlined)

Honest reading: Coravel's Schedule() is a runtime call that allocates a queue entry; ZA.Scheduling's [Job] registration happens at compile time via source generation — no equivalent runtime cost. For dispatch overhead, ZA matches a hand-written Timer (both inlined to near-zero). The value of the abstraction is [Job] itself (declarative retries / cron / store-backed persistence), not raw dispatch speed.

Full methodology + design analysis: docs/performance.md.

Features

• Source generator — [Job] on a class emits a typed executor, DI extension method, and optional recurring startup (IHostedService)
• Recurring jobs — [Job(Cron = "0 * * * *")] or [Job(Every = Every.Hour)] — scheduled via Cronos at startup
• Retry with backoff — exponential retry up to MaxAttempts (per-job or global); dead-letters after exhaustion
• Multiple backends — InMemory (dev/test), EF Core (SQL Server / PostgreSQL / SQLite), Redis
• Dashboard — embedded HTML/JS dashboard via app.MapJobsDashboard("/jobs")
• Blazor component — <JobsDashboard> Razor component for integration into Blazor apps
• Mediator bridge — [Job] + IRequest<Unit> auto-registers MediatorJobTypeExecutor<T>, routing execution through ZeroAlloc.Mediator pipeline behaviors
• Native AOT compatible — no reflection at runtime; all dispatch resolved at compile time

Dashboard

An embedded HTML/JS dashboard — summary cards for each job state, a live-refreshing table with per-row requeue / delete actions, and fully responsive down to mobile widths.

app.MapJobsDashboard("/jobs");

// Optional: protect with auth
app.MapJobsDashboard("/jobs").RequireAuthorization("AdminPolicy");

Tablet (768 × 1024) and mobile (375 × 812) captures live in docs/screenshots/.

See Dashboard for the full endpoint reference and the Blazor component.

Packages

Package	Description
ZeroAlloc.Scheduling	Core interfaces, worker service, scheduler
ZeroAlloc.Scheduling.Generator	Source generator (analyzer reference)
ZeroAlloc.Scheduling.InMemory	In-process store for development and testing
ZeroAlloc.Scheduling.EfCore	EF Core store (SQL Server, PostgreSQL, SQLite)
ZeroAlloc.Scheduling.Redis	Redis store for distributed deployments
ZeroAlloc.Scheduling.Dashboard	Embedded HTML dashboard (MapJobsDashboard)
ZeroAlloc.Scheduling.Dashboard.Blazor	Blazor component library
ZeroAlloc.Scheduling.Mediator	ZeroAlloc.Mediator bridge

Documentation

Page	Description
Getting Started	Install and schedule your first job in five minutes
Source Generator	[Job], Every, Cron, generated extension methods
Backends	InMemory, EF Core, and Redis store configuration
Dashboard	Embedded HTML dashboard and Blazor component
Mediator Bridge	Route job execution through ZeroAlloc.Mediator
Diagnostics	ZASCH001 compiler warning reference
Performance	Throughput, allocation profile, and tuning guide

License

MIT